This book contains essays on the most important crops of State of India like , coconut, arecanut, pepper, cardamom, vanilla, coffee, tea, rubber and teak which have formulated the destinies of the people of Kerala from time to time, an essay on grain amaranths which are often referred to as the newly emerging food crops and another essay on dasamula group of medicinal plants which are familiar to any ker- alite as the source materials of the ayurvedic medicinal combination dasamula. CROPS OF KERALA AN OVERVIEW (Prof. K.V. Mohanan commemoration volume)

Editors V.V. Radhakrishnan T.K. Hrideek A.V. Raghu K.T. Chandramohanan

Gregor Mendel Foundation Department of Botany Calicut University, Kerala- 673635, India Crops of Kerala- An overview

Editors V.V. Radhakrishnan T.K. Hrideek A.V. Raghu K.T. Chandramohanan

ISBN 978-81-935133-0-9

© Gregor Mendel Foundation, Department of Botany, Calicut University, Kerala- 673635, India

Published May 2018

Book design Ashok Kumar P.K.

Cover Sandeep Prabhakara

Printing Priya oŠset Thrissur, Ph : 9526265101

Publisher Gregor Mendel Foundation, Department of Botany, Calicut University, Kerala- 673635, India. Prof. K.V. Mohanan

Born to Smt. K.V. Meenakshi and Sri. N.V. Sankunni of Mookkuthala village of the present Malappuram District of Kerala State of India in 1958, Prof. K.V. Mohanan had his lower primary education at Government Lower Primary School, Mookkuthala and upper primary and secondary education at Government High School, Mookkuthala. He completed his pre degree education at M.E.S. Ponnani College, Ponnani and undergraduate education at Sreekrishna College, Guruvayur. His post graduate education was at Zamorin’s Guruvayurappan College, Calicut and his pre-doctoral and doctoral education was at Department of Botany, University of Calicut. He secured his M.Sc. (Botany), M.Phil. (Genetics & Plant Breeding) and Ph.D. (Genetics & Plant Breeding) degrees from University of Calicut and worked under University of Calicut in various academic capacities from 1982 to 2018 which includes 17 years as Lecturer, Senior Lecturer and Selection Grade Lecturer in the PG Department of Botany of Zamorin’s Guruvayurappan College, Calicut affiliated to University of Calicut and 8 years as Reader and more than 11 years as Professor at Department of Botany, University of Calicut. During his career at University of Calicut, he has held di—erent academic positions, memberships in various academic associations and memberships in the editorial boards of some important international journals. During his academic career he officiated as member/chairman of UG and PG Boards of Studies of Botany, Plant Science and Plantation Development of di—erent Universities. He was instrumental in starting a Centre for PG Studies in Plantation Development at University of Calicut and he officiated as its Coordinator from 1999 to 2009. He established the Interuniversity Centre for Plant Biotechnology at University of Calicut with funding from Government of Kerala and officiated as its Director from 2009 to 2018. He officiated as Head of the Department of Botany, University of Calicut from 2010 to 2012 and as Director, School of Biosciences, University of Calicut from 2015 to 2018. He has worked as a member of the official bodies of the University of Calicut like Planning Board, Faculty of Science, Academic Council and Senate during his academic career. He officiated as secretary of Gregor Mendel Foundation from 2006 to 2018 and during his tenure he reoriented its activities and organized several national seminars. He completed his tenure as secretary of Gregor Mendel Foundation in 2018 and has been inducted as Patron of the foundation from 2018. As on 01-05-2018 he has 175 research publications, 9 books, 3 book chapters, 30 popular science papers, 13 doctoral programmes guided, 5 M.Phil. projects guided and more than 50 PG projects guided. His major areas of interest include genetics, breeding and biotechnology of rice, spices, plantation crops and medicinal plants. His students are placed at academic positions in the universities and colleges of Kerala, scientižc positions under Government of India, Government of Kerala and Non-Governmental Research Institutes, extension positions in various commodity boards of Government of India and scientižc and technical positions abroad. His major research contributions include studies on tillering behavior, clonal propagation and ratoon cropping in rice, conservation of native rice cultivars, indigenous rice farming systems, salt tolerance in rice and conservation, genetics and breeding of cardamom, vanilla, co—ee, tea, medicinal plants and underutilized zingiberaceous tuber crops. He has carried out studies on the agroeconomic situations of the small and marginal farmers of Wayanad District of Kerala and come out with information on the fragility of the agricultural livelihoods of Wayanad. Contents Preface Foreword

Biology and cultivation of rice Surekha Y. Pawar 1 Saline rice habitats- an overview with special reference to Kaippad system of rice cultivation K.T. Chandramohanan 15 Recent advances in rice biotechnology T.S. Jishinprakash and A. Yusuf 26 Biology and cultivation of coconut K. Samsudeen 38 Biology and cultivation of arecanut N.R. Nagaraja, K.S. Ananda and M.K. Rajesh 46 Biology and cultivation of black pepper, the king of spices B. Sasikumar 51 Biology and cultivation of cardamom, the queen of spices V.V. Radhakrishnan 64 Biology and cultivation of vanilla, the prince of spices V.V. Radhakrishnan 73 Biology and cultivation of grain amaranths V. Prajitha and J.E. Thoppil 78 Biology and cultivation of co‚ee V.B. Sureshkumar 86 Biology and cultivation of tea V.V. Radhakrishnan 111 Biology and cultivation of natural rubber P. M. Priyadarshan 118 Biology and cultivation of teak T.K. Hrideek, Suby and M. Amruth 132 Conservation and propagation of dasamula group of medicinal plants A.V. Raghu 142 List of contributors

Preface Professor K.V. Mohanan (Professor, Department of Botany; Director, School of Biosciences and Director, Interuniversity Centre for Plant Biotechnology, University of Calicut, Kerala) is retiring from active service of the University on 14th May 2018 after his academic and research career that spread over a period of more than thirty six years. As he used to say, it was hard work that helped him to grow to the position of a university professor from very humble beginnings. For the very same reason, throughout his life and career Prof. K.V. Mohanan has ardently tried to inculcate the culture of hard work, discipline and scientižc temper not only in his students, but in his family members, colleagues and friends also. As a true humanist with a deep rooted working class identity he has always been insistent in delivering his duties and responsibilities and whatever administrative authority he held, upholding the principles of equity and natural justice. He is a good teacher with strong commitment to the academic improvement of his students and a researcher with uncompromised conviction to scientižc temper and methodology providing no chance to any unhealthy practice debilitating the true pursuit of knowledge. Majority of his students both at the post graduate and doctoral levels have got placed at academic positions in the universities and colleges of Kerala, scientižc positions under Government of India, Government of Kerala and Non-Governmental Research Institutes, extension positions in various commodity boards of Government of India and scientižc and technical positions abroad. This book contains essays on the most important crops of Kerala State of India like rice, coconut, arecanut, pepper, cardamom, vanilla, co—ee, tea, rubber and teak which have formulated the destinies of the people of Kerala from time to time, an essay on grain amaranths which are often referred to as the food crop of future and another essay on dasamula group of medicinal plants which is familiar to any keralite as the source materials of the ayurvedic medicinal combination dasamula. The book is a compilation of review papers contributed by di—erent authors and the authors have invariably depended on available literature to prepare the manuscripts. All such sources of information are hereby acknowledged with gratitude. We the students of Prof. K.V. Mohanan are proud to dedicate this commemorative volume to the farmers across the world and the students of natural science as a token of our affection to our beloved teacher and as the reaffirmation of our commitment to society.

Crops of Kerala – An overview 1 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Biology and cultivation of rice Surekha Y. Pawar Genetics and Plant Breeding Division, Department of Botany, University of Calicut, Kerala- 673635, India.

Rice is the staple cereal food of about Oryzoideae, Tribe Oryzeae and Genus Oryza 50% of the world’s human population. Rice L. The genus Oryza consists of 23 wild and is considered the second most important grain weedy and two cultivated species. The two crop in the world after wheat and it is widely cultivated species are the Asian rice known cultivated throughout the world. About 90% of as L. and the African rice known the world’s rice is produced and consumed in as Steud. Asian rice is cul- Asia, remaining 5% in America, 3% in Africa tivated in almost all the rice growing areas and 1% each in Europe and Oceania. Rice of the world and African rice is cultivated in has played an important role in ensuring food western tropical Africa. security of Asia. Rice is now largely cultivated in most of the tropical, subtropical and med- Species complex iterranean regions having characteristically The species of the genus Oryza are broadly warm and humid climatic conditions. classižed into four complexes. They are the following: 1. Sativa; 2. Officinalis; 3. Taxonomy of rice Ridleyi; 4. Meyeriana. The Sativa complex Rice belongs to Kingdom Plantae, comprises the cultivated species O. sativa and Subkingdom Tracheobionta, Superdivision O. glaberrima and their wild ancestors that Spematophyta, Division Magnoliophyta, are perennial and rhizomatous: O. longis- Class Lilliopsida, Subclass Commelinidae, taminata, O. barthii, O. rupogon, etc. The Order Cyperales, Family Poaceae, Subfamily basic chromosome number of the genus is

Species complexes of the genus Oryza and their geographical distribution Chromosome Geographical Species complex Genome number (2n) distribution I. Sativa complex 1. O. sativa L. 24 AA Cosmopolitan 2. O. nivara Sharma et Shastry 24 AA South & Southeast Asia South &Southeast 3. O. rupogon Gri—. 24 AA Asia, South China 4. O. meridionalis Ng. 24 AA Tropical Australia 2 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Chromosome Geographical Species complex Genome number (2n) distribution 5. O. glumaepetula Steud. 24 AA Tropical America 6. O. glaberrima Steud. 24 AA Tropical West Africa

7. O. barthii A. Chev. et Roehr 24 AA West Africa

8. O. longistaminata A. Chev. et 24 AA Tropical Africa Roehr. II. O”cinalis complex/Latifolia complex

9. O. punctata Kotschy ex Steud. 24 BB East Africa 10. O. rhizomatis Vaughan 24 CC Sri Lanka 11. O. minuta J.S.Pesl. Ex C.B. Presl. 48 BBCC Philippines, New Guinea 12. O. malamphuzaensis Krishn. et Kerala, 48 BBCC Chandr. Tamil Nadu 13. O. ocinalis Wall. ex Watt 24 CC South & Southeast Asia 14. O. eichingeri A. Peter 24 CC East Africa, Sri Lanka 15. O. latifolia Desv. 48 CCDD Central &South America 16. O. alta Swallen 48 CCDD Central &South America

17. O. grandiglumis (Doell) Prod. 48 CCDD South America 18. O. australiensis Domin. 24 EE Northern Australia 19. O. schweinfurthiana Prod. 48 BBCC Tropical Africa

III. Meyeriana complex 20. O. granulata Nees et Arn. ex Watt 24 GG South & Southeast Asia 21. O. meyeriana (Zoll.et Mor. Ex 24 GG Southeast Asia Steud.) Baill. IV. Ridleyi complex

22. O. longiglumis Jansen 48 HHJJ Indonesia, New Guinea

23. O. ridleyi Hook. f. 48 HHJJ Southeast Asia V. Unclassi˜ed (belonging to no complex) 24. O. brachyantha A. Chev. et Roehr. 24 FF West &Central Africa 25. O. schlechteri Pilger 48 HHKK Indonesia, New Guinea Crops of Kerala – An overview 3 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

12. The species are either diploid with 2n=24 According to archeological and historical chromosomes or tetraploid with 2n=48 chro- evidence, the primary centers of origin of mosomes. On the basis of crossability and Oryza sativa are the foothills of Himalayas in ease of gene transfer, the species of Sativa the North and hills in the northeast of India complex is the primary gene pool of rice. The to the mountain ranges of south east Asia species belonging to Officinalis complex con- and south west China. The primary centre of stitute the secondary pool. Crosses between O. origin of O. glaberrima is considered to be the sativa and the species of Officinalis complex inner delta of River Niger in Africa. Another can be accomplished through embryo rescue school of thought believes that rice might have technique. The species belonging to Ridleyi got domesticated in the 5th millennium BC and Meyeriana complexes and O. schlecteri and it is generally agreed that river valleys (unclassižed) constitute the tertiary genepool. of Yangtze and Mekong rivers could be the Based on genome analysis and degree of primary centre of origin of O. sativa. The foot- sexual compatibility, the species have been hills of the eastern Himalayas, Chattisgarh, grouped under nine distinct genomes and Jaypore tract of Orissa, northeastern India, they are A, B, C, D, E, F, G, H and J. northern parts of Myanmar and Thailand, Yunnan province of China etc. are some of the Origin and distribution centres of diversity of Asian cultivated rice. The origin and domestication of rice is not Currently, O. sativa is cultivated worldwide specižcally known. Most probably rice orig- and it is also grown from sea level to 3000 inated around 3000 BC in South and South m in both temperate and tropical climates. East Asia. The progenitor of rice originated Many scientists believe that common wild in tropical swamps and was shade-loving. rice, O. rupogon is the wild ancestor of O. Schematic representation of the evolutionary pathways of Asian and African

COMMON ANCESTOR (O. PERENNIS)

Asian rice African rice (South and South-west Asia) (Tropical Africa)

Wile perennial O. rutipogon (AA) O. longistaminata (AA) Weedy Wile annual races annual O. nivara (AA) O. barthii (AA) O. spontanea O. stapfii

Cultivated O. glaberrima (AA) annual O. sativa (AA) Tdmporate japonica

Indica Japonica Tropical japonica (Javanica) 4 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Characteristic features of the three varietal groups (subspecies) of O. sativa Subspecies Characteristics Indica Japonica Javanica Tillering High Low Low Height Tall Medium Tall Lodging Easily Not easily Not easily Photoperiod Sensitive Non-sensitive Non-sensitive Cold temperature Sensitive Tolerant Tolerant Grain shattering Easily Not easily Not easily Grain type Long to medium Short and round Large and bold Grain texture Non-sticky Sticky Intermediate sativa and O. longistaminata is the wild plant morphological characters adapting to ancestor of O. glaberrima. Oryza perennis di—erent ecological conditions. Hence, in the is considered the common ancestor of both past 20 years plant breeders have changed these species. It is believed that O. sativa the entire plant structure based on ‘plant evolved from O. rupogon through O. nivara ideotype concept’. and O. glaberrima from O. longistaminata through O. barthii. Ecology of rice Rice is grown in a diverse range of agro- Varietal groups of Oryza sativa ecological and climatic conditions from the Cultivated forms arose out of some wild wettest areas in the world to the driest des- species resembling the wild species O. peren- erts. Following are the di—erent types of rice nis. Many scientists believe that rice (2n=24) agroecological zones seen in India as well as is a balanced secondary polyploid with a basic in di—erent parts of the world: 1) Irrigated chromosome number 5. This number got agroecological zone; 2) Rainfed lowland agro- duplicated and two additional chromosomes ecological zone; 3) Rainfed upland agroeco- were added (10+2). This plant on duplication logical zone; 4) Flood prone agroecological gave rise to the progenitor of rice with 2n=24. zone; 5) Coastal saline agroecological zone; From India, rice moved to China where prob- 6) Cold/hill agroecological zone. ably for the žrst time it was domesticated. It Irrigated rice is grown in puddled soil moved northward to Japan via Korea. From in bunded rice želds with one or more crops India, rice also moved to Africa and America planted each year. Irrigation is the main with the help of Arabian countries. As a result source of water in the dry season and rainfall of centuries of selection by man and nature for in the wet season. Irrigated rice accounts for desired quality with adaptation to new niches, 55% of the global rice area and contributes during the process of domestication O. sativa 75% of global rice production. The countries di—erentiated into three varietal groups: with the largest areas of irrigated rice are Indica, Japonica and Javanica. Japonica is China, India, Indonesia and Vietnam. With cultivated in north China, Korea and Japan. adequate irrigation water, two or even three Indica is cultivated worldwide and Javanica crops of rice can be produced in a year. In in Indonesia. Di—erentiation of O. sativa into India, rice is grown under irrigated con- three forms has been the result of changes ditions in the states of Punjab, Haryana, in leaf shape and size, grain shape and other Uttar Pradesh, Jammu & Kashmir, Andhra Crops of Kerala – An overview 5 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Pradesh, Tamil Nadu, Sikkim, Karnataka, Flood prone agroecological rice zones are Himachal Pradesh and Gujarat. The total characterized by periods of extreme ¬ooding area under irrigated rice is about 22 million and drought. Yields are low and variable in hectares, which amounts for about nearly 46 the ¬ood prone agroecological zones. Flood percent of the total area under rice crop in prone ecosystems are prevalent in south the country. and southeast Asia and ¬ooding usually Rainfed lowland rice production is vari- occurs during the wet season from June to able because of the lack of technology used. November. Farmers using rainfed lowland agroecolog- Coastal saline agroecological rice zones ical zone are typically challenged by poor of India are seen in the coastal zones of soil quality, drought or ¬ood conditions and Andhra Pradesh, Kerala, Tamil Nadu and erratic yields. It is grown in areas such as West Bengal on the South and East coast and east India, Bangladesh, Indonesia, Phillipines Gujarat and Maharashtra on the West coast. and Thailand. Nearly 25 percent of total rice Total coastal saline rice area is estimated to is grown in rainfed lowland agroecological be about 1 million hectares which accounts zone. In India, lowland area accounts for 32.4 for 2.3% of area under rice cultivation. More percent of the total area under the crop in often the coastal saline soils show dežciency the country and the area is about 14 million of iron and zinc resulting in reduced tillering hectares. Depending upon the water regimes, as well as in chlorosis. the lowland rice agroecological zone can be In cold /hill agroecological rice zones the further divided into three subagroecologi- crop is invariably a—ected by low temperature cal zones as follows: 1) Shallow lowland rice: in the early stage and sometimes at the ¬ow- water depth below 50 cm; 2) Semi deep water ering stage resulting in sterility. Hence, the rice: water depth between 50 and 100 cm; 3) yield in cold /hill region is reduced. In India, Deep water rice: water depth more than 100 such areas lie in the hill regions comprising cm in the želd. The soil is poor in nutrients Jammu and Kashmir, Uttaranchal and the such as nitrogen, phosphorous and organic northeastern hill states. Total cold/ hill area matter. But the soil is very rich in potassium. is estimated to be about 1 million hectares, Deep water rice areas are prone to seasonal which accounts for approximately 20% of the ¬oods and duration of which varies from year area under rice cultivation. to year. Rainfed upland rice želds are generally Major rice producing countries of the dry, unbunded and cultivation is directly world seeded. Land utilized in upland rice produc- The top ten paddy rice producing coun- tion can be low lying, drought prone, rolling tries in the world are China, India, Indonesia, or steep sloping. Upland zones are found in Bangladesh, Vietnam, Thailand, Burma, Asia, Africa and Latin America. In India, Phillipines, Brazil and Japan, where China approximately 13.5% of the total area under and India alone contribute rice to nearly rice crops in the country accounts for upland half of the world’s human population. China rices. Upland rice areas lie in eastern zone is the topmost rice producer in the world. comprising of Assam, Bihar, Chattisgarh, Approximately 90% of the rice cultivation Orissa, eastern Uttar Pradesh, West Bengal in this country is in the irrigated agroeco- and north eastern hill region. In the rainfed logical zone and the country produces nearly upland rice, there is no standing water in the 35% of the total rice of the world. Globally, želd after a few hours of desistance of rain India stands žrst in rice area and second because of the uneven topography. The upland in rice production, after China. It contrib- rice accounts for about 60 million hectares utes 21.5% of global rice production. After and productivity of upland rice is very low. India, Indonesia leads in rice production. 6 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Seasons of rice cultivation in India Percentage Sowing Harvesting of rice crop Duration of the Season period period grown in the rice varieties season Short duration Pre Kharif rice May to September to varieties ranging 7% (Autumn rice) August October from 90 to 110 days Kharif rice June to November to Medium to long 84% (Winter rice) July December duration varieties

Rabi rice November to March to Short duration 9% (Summer rice) February June varieties

Bangladesh is a major rice producer tak- rice is a staple food and they are one of the ing the fourth position in the world. The largest rice producers across the globe. It wealth of Vietnam is largely dependent on has a share of 2.8% in the total production rice production. Nearly 82% of the nation’s of rice in the world. Luzon and the western land is used for rice cultivation. Red river and Vasayas are major sites in the country where Mekong are the two main deltas that mark rice is produced. This rice production helps the main rice growing areas in the country. the country in growing their economy. Brazil Thailand is considered as one of the biggest is the largest producer and consumer of rice rice exporters in the world. , an in South America. Irrigated rice is the most is a variety native to Thailand important system of production. Increase in and is grown throughout the country. It is rice production is the result of a combination long grained with a subtle ¬oral aroma and of adequate technology investments, yield a soft sticky texture when cooked and it is improvement and climate. Brazil contributes the most popular rice in Thailand as well nearly 1.7% of the world’s rice production and as in southeast Asian countries. Burma is the nation is an importer as well as exporter considered as one of the leading rice producers of rice. for over a century. In early 1900s, Burma was the largest rice producer in the world but this Rice growing regions of India was reversed after World War II. Farming in Rice growing regions of India may be Japan is highly mechanized and the country broadly grouped into žve. The southern region stands as one of the most industrialized coun- is spread in Andhra Pradesh, Karnataka, tries with deep attachment to rice farming. Kerala, Tamil Nadu and Pondicherry. Here But due to the shortage of farmlands, this rice is mainly grown as irrigated crop in the country is unable to produce enough quantity deltas of the rivers Godavari, Krishna and of rice as other nations. Improved varieties Cauvery. Rice is grown as a rainfed crop of are cultivated in most of the in the non-deltaic areas of Tamil Nadu. regions of the country. Rice ecosystems in The western region is spread in the states Japan cover an extensive range of latitudes, of Gujarat, Maharashtra and Rajasthan. including subtropical and temperate regions. Here rice is largely grown under rainfed Most of the rice želds are on the plains of conditions during June/August-October/ the major river basins and many are also December. The northern region is spread located in terraces and valleys. In Philipines, in Haryana, Himachal Pradesh, Jammu & Crops of Kerala – An overview 7 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Kashmir, Punjab, western Uttar Pradesh Shahjahanpur and Agra. Andhra Pradesh is and Uttaranchal. Rice is grown from May/ another leading rice producer of the country July to September/ December mainly as an holding a share of more than 12% in total irrigated crop. The eastern region is spread rice production. Rice is an important crop in Bihar, Chattisgarh, Madhya Pradesh, in Punjab. Punjab accounts for about 10% Orissa, eastern Uttar Pradesh and West of the total rice production of the country. Bengal. This area has the highest intensity , the best quality rice known for of rice cultivation in the country. Here, rice is its great aroma and taste is grown widely grown mainly under rainfed conditions due in Punjab. Tamil Nadu is the žfth largest to heavy rainfall. The Northeastern region producer of rice in the country and the state is spread in Assam and north-eastern states. holds a share of about 7% of total rice produc- In Assam, rice is grown in the basin of river tion of the country. Bihar is also one among Brahmaputra. Rice is grown mainly under the largest rice producing states in India rainfed conditions as this region receives and the state has got fertile land and stable very heavy rainfall. Largest rice produc - climatic conditions. Chattisgarh contributes ing states of India are West Bengal, Uttar more than 5% of the total rice production in Pradesh, Andhra Pradesh, Punjab, Tamil India. Odisha also accounts for about 5% of Nadu, Bihar, Chattisgarh, Odisha, Assam the total rice production in India. Almost 65% and Karnataka. But rice is grown widely of the cultivated land of Odisha is dedicated across the nation in more than 15 states in to rice cultivation, which makes rice a very an area of over 400 lakh hectares and top 10 important crop for the state. rice producing states account for more than 80% of total rice production in India. West Rice growing seasons of India Bengal is the topmost among all rice produc- Rice growing seasons vary in di—erent ing states with more than 13% contribution parts of India, depending upon tempera- in India’s rice production. Some of the major ture, rainfall and other climatic conditions. rice producing districts of West Bengal are Therefore, two or three crops of rice are grown Burdwan, Hooghly, Murshidabad, Howrah, in a year in di—erent regions of the country and Nadia. Uttar Pradesh is the second according to the climatic conditions. There leading rice producing state of India. Some are three major seasons for growing rice in of the major rice growing areas of the state India. They are 1) Pre Kharif rice (Autumn are Sharanpur, Budaun, Bareilly, Aligarh, rice), Kharif rice (Winter rice) and Rabi rice

Vernacular names of rice seasons of India Autumn rice Summer Winter rice Region/ State (Pre-kharif rice (Kharif rice) rice) (Rabi rice) West Bengal Aus Aman Boro Assam Ahu Sale Boro Odisha Beali Sarad Dalua Bihar Bhadai Agahani Garma Kerala Virippu Mundakan Punja /Thaladi/ Kuruvai/Ker/ Tamil Nadu Pishanam/ Navrai Sornavari Karthingal Andhra Pradesh Sarava Dalwa Uttarakhand Chetaki/ Jethi 8 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

(Summer rice). eastern and southern regions, two crops of However, the time of sowing as well as rice are taken in a year. But in the north and harvesting slightly di—ers from state to western regions where winter temperatures state according to climatic conditions and are fairly low only one crop of rice is taken rainfall pattern. Autumn rice, winter rice during the Kharif season. and summer rice have di—erent names in Growth and development of rice di—erent parts of the country. Some of them are list below: Depending upon the variety and the environment under which rice is grown, it In the north-eastern and southern region, usually takes 3 to 6 months from germination rice is grown in all the three seasons. In some to maturity. The growth of the rice plant can Rice cropping seasons of diŠerent states/regions of India

Region Autumn/ Pre Kharif Winter/ Kharif Summer/Rabi

Sowing Harvesting Sowing Harvesting Sowing Harvesting A. Northern Region Jun- Haryana Nov-Dec July Jun- Punjab Nov-Dec July Jun- West UP Nov-Dec July Jun- H P Nov-Dec July Jun- J & K Nov-Dec July B. Western Region Jun- Gujarat Nov-Dec July Jun- Maharashtra Nov-Dec July Jun- Rajasthan Nov-Dec July C. North Eastern Region Apr- Jun- Nov- Assam Aug-Sept Nov-Dec Mar-June May July Feb Jun- East M.P. Nov-Dec July May- Jun- Dec- Orissa Sep-Dec Dec-Jan Apr-May Aug Aug Jan May- Jun- Jan- East U.P Sep-Dec Nov-Dec Apr-June Aug July Feb Apr- Jun- West Bengal Sep-Dec Nov-Dec Oct-Feb Mar-May Aug July Crops of Kerala – An overview 9 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

D. Southern Region Andhra May- Jun- Nov- Sep-Oct Nov-Dec Mar-May Pradesh June July Jan May- Dec- Karnataka Sep-Dec June Nov-Feb Mar-June Aug Feb Apri- Sept- Dec- Kerala Aug-Oct Jan-Feb Mar-Apr Jun Oct Jan Apr- Jun- Oct- Tamil Nadu July-Aug Nov-Dec Mar-May May July Jan Apr- Sept- Sornavari July-Aug Dec-Jan May Oct May- Kar Aug-Sept Oct March Jun Jun- July- Kuruvai Sep-Oct Dec-Jan July Aug be divided into three stages or phases: 1) elongation but no appreciable senescence of Vegetative phase: the period from germina- leaves will be noticeable. tion to the initiation of panicle primordia. 2) The reproductive growth stage is charac- Reproductive phase: the period from panicle terised by culm elongation (increase in plant primordial initiation to heading (¬owering). height), decline in tiller production, emergence 3) Ripening phase: the period from heading of the ¬ag leaf (the last leaf that develop about to mature grain. The vegetative phase of 18 days before heading), booting, heading the rice plant begins with germination of and ¬owering. The initiation of the panicle grain which is signižed by the emergence primordium at the tip of the growing shoot of the radicle or coleoptile and plumule from marks the start of the reproductive phase. the germinating embryo. The seedling stage Initiation of panicle primordia usually takes starts right after emergence and lasts until place about 30 days before heading, which just before the žrst tiller appears. The stage can be recognized only under a microscope. is characterised by active tillering, gradual Panicle development continues and the young increase in plant height and leaf emergence panicle primordium becomes visible to the at regular intervals. Tillers emerge from naked eye in a few days as a transparent auxiliary buds of the nodes and displace the structure 1 mm to 2 mm long with a spongy leaf as they grow and develop. The vegetative tip. The developing spikelets then become stage may be divided into two phases: (a) distinguishable. The increase in the size of active vegetative phase (from germination the young panicle and its upward extension to maximum tiller number) and (b) lag veg- inside the upper leaf sheaths is detectable etative phase (from maximum tiller number as a bulge in the rapidly elongating culms. to stem elongation and then later to panicle This is called the booting stage and is fol- initiation stage). Active tillering refers to a lowed by panicle emergence from the ¬ag leaf stage when the increase in tiller number per sheath, commonly called heading. Heading unit of time is high. Primary tillers emerge means panicle exertion. Spikelet anthesis (or žrst and then they give rise to secondary opening) begins on the following day. It takes tillers. In some varieties, tertiary tillers 10 to 14 days for a crop to complete heading are also produced and they arise from the because of variation in panicle exertion within secondary tillers as the plant grows longer tillers of the same plant and between plants and larger. Active tillering results in stem in the same želd. Anthesis or blooming refers 10 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). to a series of events between the opening and generally remains in the top 20 cm of soil closing of the spikelet lasting about 1 to 2.5 in the case of transplanted rice. In direct hours. It begins with the protrusion of the seeded rice, the roots go deeper depending žrst dehiscing anthers in the terminal spike- on the availability of water and soil physi- lets on the panicle branches. Pollination and cal properties. The root system consists of fertilization follow. Anthesis normally occurs crown roots and the nodal roots. Crown roots between 8 and 13 hours in tropical environ- (the adventitious roots, including mat roots) ment. Fertilization is completed within 5 to develop from nodes below the soil surface and 6 hours later. Only a very few spikelets have the nodal roots develop from nodes above anthesis in the afternoon. the soil surface. The main rooting system The ripening stage starts with fertiliza- of the plant develops at later stages of plant tion. Based on the texture and colour of the growth, when roots develop horizontally from growing grains, the stage can be subdivided the nodes of the stem below the ground level. into milky, dough, yellow-ripe and maturity The rice stem, also called as culm is hol- stages. Ripening is characterised by leaf low and is made up of nodes and internodes. senescence, grain growth, increase in grain The culm is more or less erect, cylindrical size and weight and change of grain colour. and hollow except at the nodes. Culms are In the milk grain stage, the grains begin shorter in direct seeded upland rice varieties to get žlled with a milky material which than in transplanted low land rice varieties. can be squeezed out by pressing the grain Primary tillers emerge from the main culm between the žngers. The panicle looks green in alternate order. Emergence of the second- and starts to bend. Senescence at the base of ary tillers from the žrst node of the primary the tillers is progressing. During the dough tiller also follows the same pattern. Tillering grain stage, the milky grain portion of the potential of di—erent varieties of rice di—ers grain žrst turns into soft dough and later considerably. Tillers emerge continuously into hard dough. The grains in the panicle during the vegetative stage (up to 60 days begin to change from green to yellow. In the after transplanting). mature grain stage, the individual grains become matured, fully developed and turn The number of leaves borne on an axis is yellow and hard. The upper leaves dry rapidly equal to the number of nodes. The žrst leaf of although the leaves of some varieties remain the plant is the sheathing leaf or coleoptile. green. The time duration of the vegetative, In most rice varieties the leaf sheath may reproductive and ripening phases change almost completely cover the upper internode. based on varietal di—erences. The leaves are born at an angle on every node and they possess two parts viz., the leaf blade Botany of rice and the leaf sheath which wraps the culm. Rice is a monocotyledonous plant normally Rice leaf can be distinguished from other grown as an annual crop in tropical regions rice like grasses by the presence of ligule of the world. It can survive as perennial and a pair of auricles. The white band at the and can perennate through the production junction of the blade and the sheath is called of ratoon tillers. The plant has jointed stem collar. The ligule is the papery scale located known as culm, with ¬at leaves and terminal inside the blade and it looks like continuation paniculate in¬orescences. Soon after plant- of the sheath. The auricles are hairy, sickle ing, rice seeds give out seminal roots from the shaped appendages located at the junction of radicle. These are of temporary nature. The the collar and the sheath. The shape of the real functional roots are secondary adventi- leaf lamina is linear-lanceolate, in which the tious that are produced from the lower nodes length of the leaf is much greater than the of the culm. The root system is žbrous and width that they appear ribbon like. Crops of Kerala – An overview 11 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

The in¬orescence of rice is borne on ter- at the ventral side of the spikelet next to the minal shoots known as panicles (compound lemma. The rest of the caryopsis is occupied raceme) with single ¬owered spikelets. At by the starchy endosperm. The endosperm maturity, it is droopy in nature. The number consists of aleurone layer that encloses the of panicles present depends upon the variet- embryo and it is the storehouse of food for ies. Direct seeded upland low-yielding vari- the embryo. The white starchy endosperm eties have generally 3-4 panicles per plant, consists of starch granules embedded is a while the low land high-yielding varieities proteinaceous matrix containing sugar, fats, have 6-10 panicles per plant. crude žber and inorganic matter. The individual spikelet consists of two Adjacent to the embryo is a dot called short outer glumes (sterile lemma) and a hilum. This makes the point of attachment normal fertile lemma and palea. The ¬ower of the caryopsis to the palea. Another scar has got two small, oval, thick and ¬eshing at the tip of the caryopsis marks the base of bodies called the lodicules situated at the the style. The embryo contains the embryonic base of the axis. The spikelet is born on the leaf (plumule) and embryonic root (radicle). pedicel which connects with the panicle The plumule is enclosed by a sheath (cole- branch. All the parts found above the outer optile) and the radicle is ensheathed by the glumes collectively form the ¬oret. When coleorhiza. the ¬oral parts mature the lodicules swell and open so as to expose the mature ¬oral Rice farming parts. The fertile lemma and palea enclose In India, rice can be cultivated in di—er- the sexual organs consisting of six stamens ent ways based on the type of region. But arranged in whorls and a pistil at the cen- the traditional methods are still in use for tre. The stamens are composed of 2-celled rice cultivation. Methods of rice cultivation anthers (bilobed anthers) borne on slender followed in India are broad casting method, žlaments, while the pistil consists of ovary, drilling method, transplantation method and style and feathery bižd stigma. The stigma Japanese method. In broadcasting method, is a plumose structure borne on the style seeds are sown by hands. It is practiced in which, in turn, is an extension of the ovary. those areas which are comparatively dry and The anther present in the stamen includes 4 less fertile and do not have much labourers to elongated sacs where pollen grains are stored. work on the želds. Yields are the minimum The rice grain, called caryopsis develops but it requires minimum inputs. In drilling after pollination and fertilization are com- method, the žrst step is ploughing of land pleted. The outer protective covering of grain and then sowing the seeds in the burrows. is called the hull which consists of a lemma, This method is mostly conžned to peninsular a palea, an awn (tail), a rachilla (grain stem) India. In transplantation method, the seeds and two sterile lemmas. The hull is the hard are sown in nursery beds and seedlings are cover of seed, which accounts for 20% of total prepared. After 4-5 weeks the seedlings are seed weight. Other parts of the grain are uprooted and planted in the želd which has the pericarp, seed coat, nucellus, embryo already been prepared for the purpose. It is a and endosperm. The embryo is fused with very difficult method and requires heavy inputs. the endosperm. The dehulled rice grain is But it gives higher yields and this method is known as as brownish pericarp practiced in areas of fertile soil, abundant covers it. The pericarp is the outermost rainfall and higher labour availability. layer which envelopes the caryopsis and is Rice is grown on a variety of soils and yield removed when rice is fully milled or polished. is obtained according to the varying climatic Beneath the pericarp are two layers of cells conditions. The climatic factors a—ecting representing the seed coat. The embryo lies cultivation of rice are temperature, rainfall 12 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). and day length. Rice is a tropical as well as are separated. It is the vegetative part of sub-tropical crop and temperature in¬uences the rice plant and may be burned or left on the development, growth and yield of rice. It the želd as a natural manure for the next requires a fairly high temperature, ranging crop. It is used for several other purposes from 20oC to 37oC. The optimum temperature such as thatching houses, as cattle feed and favourable for the development and growth of also in handicraft industry for making fancy the rice crop is 30oC during day time and 20oC products like baskets, wall hangings, etc. It is during night time. Rainfall is a very import- also used as domestic fuel. Rice straw along ant climatic factor as paddy requires more with other žbrous materials can be used to water than any other crop. Rice cultivation prepare pulp for making boards and paper. is done only in those areas where minimum It is also used for making beds for growing rainfall is 115 cm. But, regions having aver- mushrooms. age annual rainfall between 175cm to 300cm are the most suitable. Photoperiodically, rice Rice husk is a short day plant. But there are varieties Rice husks (or rice hulls) are the hard which are non-sensitive to photoperiodic ¬uc- protective coverings of rice grains. The husk tuations. Direct light from the sun is needed protects the seed during the growing season. for the development and growth of rice plants. It is made of hard materials such as silica The yield of rice is in¬uenced by the solar and lignin which is non-edible to man. Rice radiation particularly during the last 35 to husk is used as fuel in the rice mills to gen- 45 days of its ripening period. erate steam for the parboiling process. It is Rice soils should have good water holding also used as a fuel for power generation and capacity. Silt clay, silt clay loam and clay are also as a domestic fuel. Rice husk is used some of the soil textures that are best for rice as a fuel in brick production and to make farming. Rice is also grown in saline areas building materials, fertilizers, insulation of deltaic regions. Fertile riverine alluvial materials, etc. soil is good for rice cultivation. The growing areas of rice should be kept weed free and Rice bran it should be applied with fertilizers with a Rice bran is the hard outer layer of the source of nitrogen. grain. It is especially obtained while polish- ing brown rice. It consists of the combined Processing and products aleurone layer and pericarp. It can be con- Mature rice plants are harvested and sumed by humans and cattle. Rice bran is the grains are detached from the panicles rich in various antioxidants and it is also a manually or with the help of machines. The good source of Vitamin B. Rice bran is used major products of rice harvest include straw for enriching breads and breakfast cereals and paddy. The straw is dried and kept for to increase the intake of dietary žbre. It is future use. The rice is dried and stored. especially used for oil production, which is Afterwards the rice is milled and the products used for cooking purposes. It has other health include milled rice, husk and bran. Each of benežts also. Gamma Oryzanol is a powerful the above products has got their own uses antioxidant only found in rice bran oil. It is and all of them are important in the life and e—ective in lowering cholesterol levels in the culture of the farmers. Usually, milled rice blood, reducing liver cholesterol synthesis and is considered as the product and the others to an extent treating menopausal disorders. as byproducts. Gamma Oryzanol can impede the progress Rice straw of melanin pigmentation by restraining the Rice straw is a by-product obtained erythematic activity of tyrosinase. The oil when paddy is harvested and the grains is also rich in phytosterols and vitamin E Crops of Kerala – An overview 13 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

(Tocopherol and Tocotrienol). Phytosterol nutritive value, changes the texture of cooked reduces cholesterol level, provides anti-in- rice and reduces the breakage in milling. It ¬ammatory e—ects, inhibits the growth is a better source of žber, calcium, potassium of cancer cells and improves the immune and Vitamin B6 than . Parboiled system. Tocopherol and Tocotrienol help in rice is consumed as a staple food in many preventing oxidation and in žghting free rad- regions of India. Pu—ed rice, beaten rice icals. Vitamin E extracted from rice bran is etc. are value added products made from used in cosmetics and hair products. Rice . bran wax obtained from rice bran oil is used instead of carnauba wax in cosmetics, confec- tionary products, shoe creams and polishing Broken rice is a grade of rice consisting of compounds. grains broken in the milling process. Broken rice can be sold as poultry feed as well as Milled rice it can be converted into products like rice Milled rice is the primary source of car- noodles, vermicelli, rice alcohol, rice ¬our, etc. bohydrates and milling of paddy rice gives Broken rice is used to make starch and this a yield of 50% of milled rice (endosperm) as starch has applications as a food ingredient, its major product and 20% of rice husk, 8% as laundry starch and also in cosmetics and of rice bran and 2% of rice germ. Based on textile industry. the milling process, di—erent types of milled Rice ’our rice are obtained. Rice ¬our is the powdered form produced Brown rice from white or brown rice. It is widely used as gluten free ¬our. When the outermost layer (husk) of rice is removed, the resultant product is the brown Rice starch rice. It retains its bran and germ layers that Rice starch is produced from the endo- give it a characteristic tan brown colour. It sperm of the grain and is used as a thickener is rich in vitamin B B , B , B , iron etc. as 1, 2 3 6 in sauces and desserts and in the manufac- compared to polished rice. It generally needs ture of rice syrup. longer cooking time and has a shelf life of about 6 months. Brewer’s rice Very small broken rice is called brewer’s White rice rice and is a mixture of broken rice, rice bran White rice is polished rice and it is called and rice germ. It is an ingredient used in white rice since the outer brown layer of bran brewing and also for the processing of other is removed. Polished white rice is mainly fermented products. consumed as a staple food after cooking. Crop improvement in rice Parboiled rice Crop improvement is the development of Parboiled rice is rice that has been par- new varieties which will perform better than tially boiled in the husk. The three basic the existing ones. Crop improvement pro- steps of parboiling are soaking, steaming grammes of any crop are designed based on and drying. This process hardens the starch certain objectives that are formulated based in the grains so that they remain žrmer, less on the needs and requirements of the farm- sticky and separate when cooked. The process ers and the community at large. The major forces the vitamins and minerals from the goals of crop improvement generally include outer layer of the grains into the endosperm, increasing the yield of crops, improving the which is the part we eat. It increases its crop quality to meet consumer demands, 14 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). developing crops that will adapt to climatic has estimated to contribute in the areas of and environmental changes, developing diversity analysis, transcriptomics, functional varieties that mature early and developing genomics, marker development, quantitative varieties that are resistant to diseases and trait loci mapping and molecular breeding pests. Conventional methods like selection for the purpose. Several new varieties have and hybridization and advanced methods like been developed by scientists across the world mutation breeding, polyploidy breeding and using the above tools and techniques. Rice biotechnological breeding are adopted for the is the žrst food crop the genome sequence above purpose based on various factors. of which was completely sequenced. This It is estimated that by the year 2025 it will will make it possible to identify the genes be necessary to produce about 60% more rice in rice that are responsible for productivity, to meet food needs. Great e—orts are being environmental adaptation and resistance to made to breed new rice varieties with greater stress so as to transfer them to new variet- yield potential and to improve crop manage- ies and to augment their functioning under ment levels to enhance average yields. India stressed environmental conditions. Crops of Kerala – An overview 15 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Saline rice habitats- an overview with special reference to Kaippad system of rice cultivation K.T. Chandramohanan PG Department of Botany, Government Brennen College, Dharmadam, Thalassery, Kerala- 670106, India.

Hunger is a cause of poverty, and land. World’s rice production was 745 million thus of hunger. The large size of world popu- metric tonnes in 2013. The demand for rice lation does make it hard to provide a decent is predicted to increase by 50% by 2050. FAO standard of living to everyone. Low agricul- has predicted that rice production will need tural productivity, post-harvest loss, and lack to increase from 600 million tonnes annually of nutritious food are important factors con- to 800 million tonnes by 2025. However, aver- tributing to it. Climate change is increas- age growths in rice yields per hectare have ingly viewed as a current and future ground not kept up with population increases and of hunger and poverty. Escalating drought, demand, and have in fact decreased substan- ¬ooding and changing climatic patterns make tially over years. Furthermore, rapid urban- shift in crops and farming practices essential ization and industrialization has created a that may not be easily accomplished. One of situation where this increasing food demand the major problems faced by agriculture is the is to be met on decreasing agricultural lands. loss of agricultural land and as more land is The world’s annual rice production will lost, it will become more difficult to produce have to increase markedly over the next 30 the quantity of food needed to feed the grow- years to keep up with population growth and ing human population. Worldwide, around income induced demand for food. Among low three million hectares of agricultural land and middle income countries, rice is by far are lost each year because the soil degrades the most important crop worldwide. With and becomes unusable due to erosion by the accelerating loss of productive rice land wind or water leading to the movement of due to rising sea levels, salinization, erosion, soil components from one location to another. and human settlements, the problem becomes An additional four million hectares are lost one of increasing yields under ever more try- each year when agricultural land is converted ing circumstances. From 1965-67 through and used for highways, housing, factories, 1989-91, the improvements in productivity and other urban needs. spawned by the Green Revolution spread rap- Rice is one of the major cereal food crops idly. During those years, total rice production of the world. Being grown worldwide, it is the almost doubled. Most of this increase came staple food of more than half of the world’s from increased yields and increased cropping population. Rice is being planted now on intensity, although some resulted from new about 159 million hectares annually and it land brought under cultivation or shift to rice comes to about 11% of the world’s cultivated from other crops. Further yield increases have 16 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). been constrained by diminishing returns and cultivated under a diversity of conditions. But have been increasingly di¯culttoachieve. Kerala is a dežcient state in rice production. In India, area under rice cultivation was The dežcit in rice production is increasing 34.255 million hectares in 1961, 44.712 mil- year after year due to reduction in rice area lion hectares in 2000 and 43.771 million hect- arising out of the large scale conversion of ares in 2007 and rice production was 51.386 paddy lands for raising other crops or for million metric tonnes in 1961, 127.465 million residential purposes. metric tonnes in 2000 and 144. 647 million As far as Kerala is concerned rice is metric tonnes in 2007. Rice yield in India was a socially and politically important crop. gradually raised from 1.50 tonnes ha-1 in 1961 The wet and humid tropical climate of the to 3.30 tonnes ha-1 in 2007. In 2012-13, area region is favourable for the cultivation of rice. under cultivation is 42.75 million hectares Traditionally rice occupied a key position in and production 105.24 million metric tonnes. Kerala’s agriculture. But the area under rice India is one of the largest rice growing coun- has been declining over the years, with a tries accounting for about one-third of the possibility of extinction of rice farming in world acreage under the crop. It is grown in the state. The livelihood safety of the rural almost all the states of India, covering more agrarian population spinning around rice than 30 per cent of the total cultivated area. farming is at risk. The employment opportu- Its cultivation is mostly concentrated in river nities in this sector, especially for women are valleys, deltas and low lying coastal areas of declining at a hasty rate. Rice being a labour northeastern and southern India. intensive crop, the rising cost of production In Kerala, the area under rice cultiva- is taking away rice farmers from cultivation. tion has been getting reduced through the Environmental and ecological implications of years. In 1961 the rice area in Kerala was large scale area conversion from rice farms 0.753 million hectares and it increased to are disturbing. In 1975, Kerala’s rice produc- 0.928 million hectares in 1968. From there tion was over 50 percent of its consumption it got consistently reduced to 0.348 million requirement. By 2010 the consumption pro- hectares in 2000 and 0.229 million hectares duction gap has increased to 84 percent. As in 2007. Rice production in Kerala was 1.481 rice remains the staple food, food security million metric tonnes in 1961 and 1.630 mil- of the state is at stake and dependency on lion metric tonnes in 1990. It got reduced to other States for our staple food is increasing 1.127 million metric tonnes in 2000 and 0.819 dangerously. million metric tonnes in 2007. In 2012-13 it Abiotic stresses are serious in magnitude has been reported to be 0.508299 million and widespread in occurrence and thus cre- metric tonnes. However, rice yield in Kerala ate major hurdles to attaining higher crop has shown a gradual increase over the years productivity. Tapping the potential of large and it reached a value of 3.58 t ha-1 in 2007 salt a—ected areas to increase rice produc- against the national yield of 3.30 t ha-1. In tion would contribute to food security and 2012-13 it has been reported as 2.58 t ha-1. alleviate poverty in unfavorable rice grow- Rice forms the staple food of the people of ing environments where the resource poor Kerala and contributes a major share towards farmers live. However, this would require its economy. It is grown in a vast range of the development of salt tolerant varieties ecological niches, ranging from regions situ- and their widespread adoption by farmers. ated 3 meters below MSL as in Kuttanad to Because of urbanization and water scarcity, an altitude of 1400 m as in the high ranges. the expansion of land use for food production It is cultivated under 3 to 4 meters of depth has almost stagnated and has shown a down- of water as well as in purely rainfed uplands ward trend in the case of many important with no standing water. In Kerala rice crop is crops with high input requirements, including Crops of Kerala – An overview 17 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). rice. The possibilities for rice area expan- the wettest areas in the world to the driest sion in most Asian countries are almost deserts. Rice adapts readily to production exhausted. The options obtainable to produce under these varied conditions. more rice include mounting irrigated areas A substantial part of the rice farms are or favourable environments with high pro- located in ecologically fragile and critical ductivity, increasing the productivity of rice environmental systems extended across in unfavorable ecosystems and harnessing Asia and Africa and to some extent in other unfavourable areas with potential for food continents also. Rice farming in these agro production. ecosystems is highly specižc and specialized. Population explosion and declining of Additional land for food crop production the availability of arable land and quality will be required to produce food for the ever irrigation water are forcing crop production increasing world population. The tidal lands into more and more marginal environments are an important land resource and they are facing abiotic stresses, thus limiting the adap- marginal in the sense that reclamation costs tation and productivity of staple food crops. In are high, crop yields are low and soil and future, one cannot wait for a major increase water management is difficult. The rice vari- in land area accessible for cropping. At the eties grown in the tidal swamps are for the same time, cultivated area is declining fast most part traditional photoperiod sensitive in most of the developing countries due to a varieties requiring more than 200 days from variety of reasons. It is estimated that half of seeding to maturity. The high yielding, wet- the world’s farms have been damaged by salt. land irrigated varieties are not adapted to To tackle these problems, the ability of the soils and hydrology of the tidal swamps. crops to tolerate such conditions has become However, no other crops can be grown in such a key research issue in the world. Rice is a areas. more amenable crop to marshy soils near sea Rice has vast variability for tolerance to coast, the unexploited areas where we have most abiotic stresses and it is the only eco- to pay more attention to extend the area of nomic crop that can grow well in waterlogged rice cultivation in future. This soil is saline environments tolerating salinity up to a cer- due to saline sea water inundation. At this tain extent. The crop can be grown in coastal situation, salinity tolerant genetic resources belts that are always prone to inundation and varieties of rice can play a major role to by sea water during high tides, resulting in achieve the goal of food security. Further, salinization. Under these conditions, only some degree of cultivar tolerance for salinity salt and submergence tolerant crops are the stresses available with certain traditional economically viable farming options. land races not exploited so far has great The nearly 30 million hectares of coastal signižcance in crop improvement. saline soils in South and Southeast Asia o—er promise as potential rice lands. Varietal Marginalized saline lands and rice tolerance for salinity and accessory growth cultivation limiting factors should be exploited in bring- Rice production occurs mainly in four ing marginal land under rice. The use of agroecological environments: irrigated improved, salt tolerant, disease and insect (mostly lowland), rainfed upland, rainfed resistant rice varieties, coupled with the cor- lowland and deep water. Deep water areas rection of nutrient dežciencies will enable are spread along riversides and deltas where farmers to double or triple their present yields production is based on annual ¬ooding. Rice on saline soils and also to expand rice growing is produced in a wide range of locations and into surrounding uncultivated lands. under a variety of climatic conditions, from Saline soils vary widely in their chemical, 18 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). physical, and hydrological properties.The salt whereas coastal saline soils of the humid source may be seawater, surface or under- tropics and subtropics are characterized by ground saline water or wind. In arid and the presence of mangrove species. Most plants semiarid areas salts brought by capillary su—er salt injury at EC values exceeding 4 action, surface runo—, or inter¬ow accu- mmho cm-1 at 25°C. Many crops can stand mulate in the soil prožle. In coastal areas much higher concentrations than generally salinity is due to direct inundation by salt supposed if the solution consists of physio- water or upward or lateral movement of saline graphically balanced salts as in seawater. groundwater. The salt content of a soil varies Crop yield decreases markedly with increase vertically, horizontally, and with season. The in salt concentration, but the threshold con- pH ranges from 2.5 for saline acid sulphate centration and the rate of yield decrease vary soils to 8.5 for saline alkali soils. Soil salinity with the species. in the humid tropics ranges from 1 to 50%, Sri Lanka’s low lying western coastal and the nutrient status varies from very low ¬oodplain lands still remain unproductive to moderately high. Inland saline soils have because of impeded drainage and submer- a pH >7. They are low in Nitrogen and in gence which has created unfavorable soil available Phosphorus, but are well supplied conditions and as a result rice cultivation with Potassium. Hydrology and relief are is unprožtable and most of the paddies are important in determining the suitability of either not regularly cultivated or cultivated saline lands for rice production. The vast only one season a year. Special characteristics coastal saline tracts of South and Southeast such as seed viability, resistance to storage Asia are in the deltas of big rivers. Most of pests and good cooking quality after a long them have an elevation of 0-10 m above mean period of storage have made the traditional sea level. The tracts are subject to ¬ooding varieties popular. Traditional varieties have by fresh water during the wet season and growth vigour at the seedling stage and their submergence by salt water during the dry early height helps them withstand ¬ooding season when the discharge from the river and compete well with weeds. The saline soils system is low and seawater comes up the of the humid region of South and Southeast creeks and canals. The groundwater of the Asia are economically important because tracts is 1 to 2 m below the surface and is they are located in deltas, estuaries, coastal -1 saline with an EC of 2 mmho cm in the fringes or river basins that are climatically, -1 wet season and 20 mmho cm in the dry physiographically and hydrologically suited season. Coastal saline soils are subjected to to rice; rainfall is adequate for leaching the tidal ¬ooding. The amplitude of tides in India soil and growing at least one rice crop a year; varies from 0 to 6 m. the lands are close to densely populated areas Coastal saline soils subjected to tides fall where labour for and knowhow of rice cul- into four main zones: 1. The strip nearest to tivation are available. Tidal swamp lands the sea subjected to daily tides. 2. A strip in Indonesia include swampy areas directly several kilometers wide subjected to only and indirectly in¬uenced by sea tide, low-ly- exceptionally high tides; 3. An area where ing freshwater swamps and highland rain tides exercise their e—ect through rivers and fed swamps una—ected by sea tides. Pozas creeks; 4. A wide zone not in¬uenced by tides veraneras, the tidal swamp rice areas of but by the upward thrust of saline water. Ecuador, are shallow depressions that žll Zones 3 and 4 are suited for rice production with fresh water during the January-May on reclamation without high inputs. Strongly rainy season and are transplanted to rice as saline soils are barren. Less strongly saline the water level recedes during the long May- soils in arid areas are characterized by patchy December dry season and it provides about growth of halophytic grasses and shrubs, 25% of Ecuador’s annual rice production. The Crops of Kerala – An overview 19 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). tidal swamp rice production of Thailand is ¬oodplains. Bangladesh is ideally suited for mainly in the central plain and along the east integrating aquaculture with rice farming. coast of the southern peninsula. Salinity of About 4.1 million hectares of land are the tidal swamp areas gradually decreases covered by wetlands of di—erent categories in inward from the seashore caused by ¬ood- India. They are predominantly located in the ing with seawater during the high tides Himalayan Terai, Gangetic and Brahmaputra and ingress of seawater along the estuar- ¬oodplains, deltaic regions of east coast, for- ies, creeks, drains and rivers, especially in ested valley swamps of north eastern India, the dry season and it ¬uctuates depending saline expanses of hot arid regions of Gujarat on the amount of rainfall in the area, tidal and Rajasthan, deltaic regions of east and movements and discharge of fresh water west coast, wet humid zones of the penin- from the inland area. Salinity ranges from sula and the fringing mangrove swamps -1 2 to 6 mmho cm in the rainy season, which of Andaman and Nicobar. In the coastal starts in June or July, and increases sharply regions of India, a complex and ecologically -1 to 15-30 mmho cm during the dry season. responsive farming system has evolved over Farmers in tidal swamp areas provide land centuries. In this system, rice and žsh cul- with high bunds and sluice gates to control tivation alternates through a mechanism of the water level in the rice želds and usually water control. About 0.8 million hectares of grow only one crop per year. Rice varieties coastal land in West Bengal, India is highly grown are tall or intermediate depending saline and therefore relatively uncultivable, on the water level in the rice želds. Rice especially during winter and summer and production in ¬ooded rice želds in the coastal here submergence also is a problem. One lowlands of Vietnam including the Mekong third of this area has been brought under Delta and the Red River Delta occupy about cultivation by putting earthen bunds along 12% of the total rice cultivated areas and the margins of tidal rivers and estuaries many farmers have adopted extensive and to prevent tidal inundation, but the total semi intensive culture methods including production per unit area remains low. The integrated rice-shrimp and shrimp mono- low yields may be due to excessive rainfall culture systems. The practice of integrated during the monsoon, poor drainage, lack of rice-shrimp farming, which involves a wet good quality water for irrigation or high soil season rice crop and a dry season shrimp salinity during rabi cultivation. The coastal crop on the same land, has enabled farmers area is always subjected to salinity problem. to make signižcantly higher income than the In the coastal land, rice is grown in about 10 traditional rice monoculture practice. The lakh hectares during di—erent seasons, which Sundarban forest area spans one-third of accounts for nearly 17% of the total area under the southern portion of Bangladesh and is rice in the state. Coastal saline rice is com- known to be highly saline. In the moderate to monly a—ected by various levels of soil and highly saline southwest coastal areas, farm- water salinity and su—ers from salinity in ers can only grow a single rice crop during di—erent stages of crop growth. The salinity the monsoon season when the salinity levels of irrigation water varies between 1.0- 4.0 are relatively low. Fish-rice culture is consid- dS m-1 or more depending on the source of ered as an ideal method of land use since the irrigation water and the time period within land is used to produce both rice and žsh. the year. A farm household survey carried Fish-rice culture is now developing rapidly out in coastal lands of four districts revealed in many countries in Asia. In Bangladesh, that about 30% of surveyed lands are non-sa- rice-žsh culture has been gaining popular- line, 55% are moderately saline and 15% are ity at Kuliarchar, Brahambaria, Narail, and severely saline. Severe salinity during dry Muktagacha sites attached to various river season is predominant in deeply ¬ooded lands 20 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). and moderate salinity is more prominent in viz. bello, korgut, khochro and kalo novan shallow lowlands. Due to salinity, yield loss of are with good grain quality characteristics. up to 37% was observed in boro rice. With the Popular rice varieties grown in this area are increase of irrigation facilities, rainfed low- korgut, khochro and assgo. land and ¬ood prone situation has gradually Costal saline ecosystems of Kerala been converted into irrigated boro ecosystem. With a long coastal line of about 580 km, The area and contribution of boro rice to the Kerala has several lagoons or backwaters total rice production of the coastal districts covering a very large area linked to the sea. has steadily increased over the years. While In most of the coastal land, deltaic areas at its contribution to total rice production in these areas in 1980 was only 14%, it has river mouths and reclaimed backwaters are increased to nearly 24% in 2007-08. The yield either at sea level or 1.0 to 1.5 m below MSL. of paddy in coastal saline soil is poor and This leads to incursion of sea water up to a the average yield during kharif is about 3.0 distance of 10 to 20 km upstream during tonns ha-1 and during rabi about 4.0 ton ns high tides. These periodically saline water ha-1. The coastal saline soils are often a—ected inundated lands constitute the major saline with dežciency of iron and zinc which causes soil areas of the state covering an area of chlorosis and reduced tillering. The želds 30,000 ha. with sufficient water retaining capacity The coastal saline soils of South India for a long period, those are free from heavy are highly underutilized because the use of ¬ooding are suitable for rice-žsh farming ground waters for normal crop production system. This system is being followed by the is not possible due to the poor water qual- small and marginal farmers in rain fed low ity. At present, the entire coastal area is lying areas especially in coastal belt and is mostly monocropped with rice being the only proved to be a prožtable cropping system. crop during the monsoon period. The land Currently, rice-boro rice and rice-aquacul- remains fallow during the rest of the year ture are the two major farming systems that due to lack of good quality irrigation water are being adopted in the coastal region over and high soil salinity. Hydromorphic saline the last decade. The coastal saline soils in soils are common in Kerala and are found Maharashtra are all along the west coast in near the coastal tracts of the state in the the districts of Sindhudurg, Ratnagiri, Thane districts of Alappuzha, Ernakulam, Thrissur, and Raigad. In spite of the high rainfall to Malappuram and Kannur. The network of the extent of about 2000 mm and above in backwaters and estuaries serve as inlet for these areas, they are suitable only for growing tidal waters to ¬ow inland into these areas saline resistant rice varieties which is the causing salinity. Only one crop of rice is raised common crop of the region. These soils are in these areas during August to December locally known as khar or khajan (khazan) using salt resistant varieties. EC of these soils lands. Rice is the predominant food crop of during the growing season ranges from 0.1 Goa and it occupies an area of 39% of the total to 2 dS m-1. Maximum accumulation of toxic cultivated land in the state and the khazan salts is observed during summer (March- lands occupy an area of 17,200 ha. The khazan April) when the EC may rise to as high as lands have the potential for growing tradi- -1 tional rice cultivars which are salt tolerant 15.0 dS m . Kole soils are a particular soil during rainy season without supplemental type in Thrissur and Malapuram covering irrigation. In khazan land the rice cultivars an area of 11,000 ha and are waterlogged grown are limited, but specižc traditional like Kuttanad soils. These are shallow and rice cultivars are grown predominantly. acid saline due to intrusion of sea water. The The traditionally cultivated rice cultivars soils are hard, brittle and poor in fertility. Crops of Kerala – An overview 21 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

The network of backwaters and estuaries values throughout the prožle. In general, in serves as an inlet of sea water and causes the coastal saline soils of the state, the EC salinity in the area. There are two kinds of of the soil, in summer months, varied from saline soils in the state, (i) normal saline soils 12.0 to 24.0 dS m-1. However, during rainy and (ii) acid sulphate saline soils. The normal season the EC ranged from 6.0 to 8.0 dS m-1. saline soils are generally found in narrow Kerala State on the south western coast strips along the sea coast and are generally of India in the tropical humid zone has a pre- sandy and brownish in colour, but in places dominantly agricultural economy, very high they may have heavier texture also. Most of population density and therefore high pres- the soils have impeded drainage. The acid sure on cultivable land. The close association soils, called kari soils, are mostly present of agricultural crops, tree crops and animals in the mouth of streams and rivers in the in the homesteads represents an excellent low lying areas. They are silty clay in tex- example of sustainable and productive agro- ture and subjected to sea water inundation, forestry. Rice farming in the conventional black in colour, resembling peat soils. Soils farming areas of the state is intensive to a show very low pH due to transformation of considerable extent and improved varieties 2- 2- SO4 to S by Sulphur reducing bacteria and are generally used. However, speciality rice are rich in Sulphur compounds. Due to high farming systems which are habitat specižc water table and impeded drainage, soil pro- and cultivar specižc are popular throughout žles show a large number of mottlings. The the costal belt of Kerala. soil pH decreases to about 3.0 after drying. The pokkali system of rice cultivation in The mineral layer is 25- 50 cm thick or even the acid saline soils of south central Kerala thicker generally located in marshy places is a unique method of rice production. In below the sea level and has poor permeability. this method, a single crop of rice is taken in Soil salinity is very high in summer season the low saline phase of the production cycle but low in monsoon season. Organic layer (June to mid-October) on mounds, followed in the soil consists of partially decomposed by prawn farming during the high saline upper layer and un-decomposed lower layer. phase (November to April). A noteworthy The soils are generally low in N and P but rich feature of this traditional rice cultivation in K. The acid sulphate soils show toxicity method is that neither chemical fertilizers of Fe, Al, Mn and dežciency of Cu and Zn at nor plant protection chemicals are applied times. Rice is usually the only crop grown. In to the crop. The pokkali želds are also sub- Kerala, the pokkali saline soils manifested jected to periodic submergence. The daily acidic properties and it was the main cause tidal in¬ows and out¬ows, besides the tre- of infertility. mendous microbial activity owing to the When the soil salinity gets washed o— presence of large quantities of organic matter due to heavy rains, the inherent acidity of (decomposed aquatic weed mass and paddy the soil gets regenerated and it exhibits very stubbles), make the pokkali želds particularly strong pH values in the range of 3.5 to 5.5. fertile. In spite of this, the average rice yield The soil pH of the area has been reported to realized by pokkali farmers is only ~2000 kg be slightly acidic (6.3 to 6.5), strongly acidic ha-1, making rice cultivation in this region (3.4 to 4.8) and slightly alkaline (7.0 to 7.5) somewhat unprožtable. VTL5 is a promis - throughout the depth of the soil prožles taken ing ‘Mashuri’ mutant for cultivation in the in Kannur, Calicut and Ernakulam districts, coastal saline ecosystems of Kerala, with high respectively. In general, the coastal saline yield potential and ability to perform well soils in Kerala have strongly acidic (3.5 to under the acid saline situations and with the 5.5) soil pH. The saline acid sulphate soils essentiality of little or no external inputs to of the Malabar coast of Kerala have high EC sustain rice cultivation in the pokkali areas of 22 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Kerala. Kerala Agricultural University has locally available materials and laterite soil to developed žve saline tolerant, high yielding a height of 1 to 1.5 m. Crop is directly sown rice cultivars suited to the pokkali ecosys- or transplanted when water is around 10 to tem of Kerala. The cultivars are Vyttila-1, 15 cm deep. A few decades back a number of Vyttila-2, Vyttila-3, Vyttila-4, and Vyttila-5. local cultivars of rice were cultivated in the Pokkali rice being cultivated in the Districts kole želds but nowadays improved varieties of Alappuzha, Ernakulam and Thrissur has like Jyothi, Uma and Jaya are cultivated. been granted geographical indication registry Fish farming is usually carried out during by GI Registry o¯ce, Chennai March to September. The kole lands which form one of the rice Kaippad rice farming system granaries of Kerala are part of the unique vembanad-kole wetland ecosystem, the A complex and ecologically responsive largest brackish, humid tropical wetland rice-žsh farming system has evolved in the ecosystem in the southwest coast of India coastal wetland regions of India over past comprising of 151250 ha, fed by 10 rivers centuries and it is about 0.7 million hectares. and exposed to diurnal tidal cycles. Within Rice cultivation in these lands takes place the vembanad-kole wetland ecosystem, the either under deep or ¬oating water conditions. kole lands cover an area of about 13,632 ha The rice varieties cultivated are traditional spread over Thrissur and Malappuram dis- types with an average yield of about 1.5 to tricts of Central Kerala. The name kole refers 2 tonnes per hectare. An important char- to the peculiar type of cultivation practice acteristic of this farming system is that to carried out on these lands and in the regional facilitate the cultivation of rice during the dry language kole indicates bumper part of the year, the land has to be dewatered yield or high returns in case ¬oods did not for sowing and subsequently protected from damage the crop. Kole lands extend from the saline water intrusion for crop growth; rest northern bank of Chalakudy River in the of the year it remains under fresh or saline south to the southern bank of Bharatapuzha water depending on the ecological setting. River in the north. The kole lands remain For the practicing of this farming, di—erent submerged under ¬ood water for about six types of water control, not only for the rice months in a year and this seasonal alteration cultivation but also for the culture of žsh as gives it both terrestrial and water related well, are required. Variations exist in these properties which determine the ecosystem farming systems across areas depending on structure and process which in turn give the ecological, technological, institutional rise to various provisioning services. Rice and organizational set ups conditioning the is the most important crop cultivated in the wetland resources base. kole land. Virippu (autumn crop) is usually Kaippad, the indigenous rice-žsh farm- cultivated in higher rice želds around the ing system of coastal North Kerala in India kole land where the duration of ¬ood lasts is a natural system utilizing indigenous only for a few days. Mundakan (winter crop) is knowledge and ensuring efficient utilization cultivated in medium elevation želds around of local resources. The proximity to sea and the kole lands where the ¬ood water recedes subsequent periodic seawater inundation by August. When the ¬ood water in the kole ensure the uniqueness of the rice varieties želds starts subsiding by the end of south west cultivated and contribute to the high degree monsoon season, pumping out of water by of specialization in the cultural practices fol- using petti and para which is an indigenous lowed in the region. The less remunerative pumping device will be carried out in 10 to rice cultivation compliments a prožtable 15 days. After this bunds around the želds žsh culture, making it a unique agro-eco- are raised and strengthened by means of logical continuum. The farming system is Crops of Kerala – An overview 23 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). traditionally organic, as farmers desist from this tidal in¬ow. For this purpose bunds the use of agrochemicals since it hampers are constructed at the narrow ridges of the the productivity of the succeeding žsh crop. kaippad želds near the river using the sticky This system is similar to the pokkali sys- mud and wild grasses which are available tem of rice cultivation practiced in Central in the river banks. Bunds are about 2-3 m Kerala. Kaippad and pokkali can be seen in breadth and 2.5-3 m height, a little over as e¯cientalternativesforthe in situ con- the water level at the time of high tide. The servation of indigenous rice varieties and bunds are locally called chira or kandi. The cultivation practices. Kaippad farms are also ¬ow of water is regulated by wooden sluice decreasing in area. In the nineteen seventies gates locally known as mancha. about 2500 ha of kaippad rice želds existed Normally only one crop of rice is raised in the Kannur District of Kerala, but now annually in the area. Cultivation starts in it has been restricted to about 600 ha. The April and ends by October. Agricultural oper- major traditional rice cultivars cultivated in ations are started in mid-April by draining the area are Kuthiru, Orkayama, Mundon, out the saline water completely and allowing Kandorkutty, Orpandy and Odiyan. the želds to dry for about one month. After The average rice yield of these local cul- drying, small soil mounds are primed by tivars is about 2000 kg ha–1, making rice workers who are experts in the task. Using cultivation in this region unprožtable. Lack spade like implements, they start the work of realization of the potential of high yielding early in the morning and žnish it before rice varieties to this rain fed, shallow lowland the sun starts mighty down. The mounds, is the major reason for the low productivity locally called potta or kuthiru are of two and shrinkage of kaippad želds. The tradi- kinds: hemispherical mounds with 30-45 tional cultivars are susceptible to lodging cm height and 50-60 cm diameter and long because of the poor culm strength and exces- strips with 30 cm width. The mound making sive culm length and they are with poor grain operations are completed by the middle of qualities like awn, long bold nature and heavy May. The sluices are opened by the begin- shattering. Panicles of these cultivars are ning of monsoon showers. The salinity of the long but less in number of grains. However, soil of mounds is washed away in the heavy these cultivars are resistant to all pests and south west monsoon of early June. The fresh diseases in the natural želd conditions of river water tides also help to leach away the kaippad and the cooked rice is delicious. The salinity. Germinated seeds are sown on the high yielding saline resistant pokkali vari- mounds at this time. eties do not perform well in kaippad saline Before sowing, the farmers soak the tracts. This may be due to the di—erence in the rice seeds in water for one day and the wet physicochemical properties of the soils. The seeds are kept for three days in jute bags soil pH throughout the depth of soil prožles to germinate. Germinated seeds are sown of kaippad is slightly acidic, whereas that of on the mounds in the low to medium saline pokkali is slightly alkaline. phase of the ecosystem. After 30-45 days Kaippad agriculture is related to vari- of vegetative growth, the seedlings on the ous traditional customs and local indigenous mounds are dug out along with the root soil knowledge which are echoed in the beliefs with the help of spades and are spread out and practices of local people due largely and planted uniformly. This process usually to their proximity to the natural resource extends till the end of July. Other than the bases. The kaippad želds are low lying and manual removal of weeds by the middle of submerged in water as they are subjected to August, there are no other cultural operations tidal invasion. For starting the agricultural carried out till harvest. Neither fertilizers operations the land is made dry by controlling nor pesticides are applied. Harvesting is 24 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). done during September–October months. Crop cultivars/ varieties used While harvesting, only the panicles are Kaippad system of rice cultivation is an cut and collected and the rest of the plant integrated organic farming system in which parts is left to decay in water, which in turn rice cultivation and aquaculture go together becomes feed of the prawns and žshes that in coastal brackish water marshes which is grow subsequently. rich in organic matter. Local salinity toler- Traditional žsh rearing is carried out ant rice cultivars like Chovverian, Kuthiru, in kaippad farms during the high saline Kuttusan, Orkazhama, and Orthadian phase i.e., from November to April. Prawn have been found to be cultivated in this or žsh inžltration in the želds begins after area. However, the cultivar Kuthiru is used the monsoon. After the retreat of north east more commonly followed by Orkazhama and monsoon, strengthening of the bunds around Kuttusan. The remaining two cultivars are the želds is carried out using sticky mud and only very rarely cultivated. wild grasses taken from the river side and A study by the present author revealed the wooden sluices are kept open to allow that all the above žve rice cultivars are the entry of tidal water from the rivers. The tall and plant height is relatively higher in forceful tidal water brings with it the seeds Chovverian with an average of 150.4 cm. of prawns and žshes in to the želds. Water Number of tillers at harvest was 10 in Kuthiru is kept in the želds for two to three months and 7 in Orthadian. Ear bearing tillers were by closing the sluice gates using žlters and it relatively higher in number in Orkazhama allows the prawns and other small žshes to with an average of 8.4. Panicles of these grow. The growing žshes feed on the leftovers cultivars were long but less in number of of the harvested crop. Decomposed rice stub- grains and the grains were bold with red bles support the abundant growth of algae kernel. Hundred grain weight was higher in which in turn become feed for žsh. The rice Orthadian and the lowest in Kuttusan. Yield crop draws nutrients from the excrement per plant was higher in Kuthiru and the low- and other remnants of these sea creatures. est in Orthadian. The varieties di—er in their Additionally, diversity of ¬ora and fauna in morphological and physicochemical charac- this area is rich when compared to modern teristics and cooking qualities. Seed to seed rice farming systems. Fertility of the želd duration of Kuthiru and Orthadian was 110 is increased due to left over rice stubbles -120 days, that of Orkazhama and Kuttusan 135 -140 days and that of Chovverian 125-130 and post-harvest growth of vegetation. days. These saline tolerant traditional land Fish is caught during low tide when water races are low yielders and are susceptible to is released through the sluices. A net is žxed lodging because of the poor culm strength to the sluices to catch žsh and the event of and excessive culm length, with poor grain žshing is locally known as kandi koodal. Fish qualities like awn on grains and heavy shat- catching event is locally known as aachu. The tering of grains. However, these cultivars are daily tidal in¬ows and out¬ows, besides the resistant to pests and diseases in natural želd tremendous microbial activity owing to the conditions of kaippad and the cooked rice is presence of large quantities of organic matter delicious. The above traditional cultivars are (decomposed aquatic weed mass and paddy locally known to be resistant to the adverse stubbles) make the kaippad želds fertile. conditions of salinity prevailing in the area. Even when new farming practices become Kuthiru is the most popular cultivar in the widespread, the peculiar farming practices area followed by Orkazhama and Kuttusan. of such agroecosystems are to be protected The remaining two varieties are only very and perfected so as to maintain and enrich rarely cultivated now. Improved varieties the link between man and nature. of the Ezhome series like Ezhome 1 and Crops of Kerala – An overview 25 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Ezhome 2 developed by Kerala Agricultural the presence of non-biodegradable materials University are being used for cultivation in resulting in the decline of water and soil qual- this area recently but there is the threat that ity of the želd, lack of proper drainage system, the native cultivars are abandoned by the occurrence of relatively high salinity in water farmers resulting in erosion of their unique and soil, high labour cost, non-availability genes. However, Ezhome 1 and Ezhome 2 are of agricultural labourers, change of kaippad high yielding and non-lodging vari- land to mangrove areas due to non-cultivation eties meant for the salinity prone rice želds for one or more cultivating seasons and lack of of kaippad and are awn less, non-shattering proper modernization in cultivation practices and with favourable cooking qualities. The This system exists as a world acclaimed average yields of Ezhome-1 and Ezhome-2 farming model complementing the natural -1 -1 are 3500 kg ha and 3200 kgha respectively system, utilizing indigenous knowledge and which is 70 % and 60% more than that of ensuring efficient utilization of local resources. local cultivars. These varieties show lesser The proximity to sea and subsequent peri- duration and are having distinct morpho- odical seawater inundation ensure the logical qualitative traits and di—erent mode uniqueness of the rice varieties cultivated of salinity tolerance mechanism imparting here and contribute to the high degree of varietal diversity to the unique ecosystem specialization in the cultural practices fol- of kaippad. lowed in the region. The less remunerative rice cultivation complements a highly prof- Major challenges to Kaippad rice itable prawn culture, making it a unique cultivation agro-ecological continuum. The farming Major challenges confronted by this system is traditionally organic, as farmers special habitat in general and indigenous desist from the use of agrochemicals in rice rice cultivation in particular include threat farming which hampers the productivity of of uncertainty in rainfall upsetting land the succeeding crop, i.e., the žsh culture. But preparation and cultivation, ambiguous tem- lately, monoculture of žsh/ prawn has caught perature changes a—ecting yield, decline in up, which though provides higher net return the quality of the soil and humus brought to in short run, it is unsustainable both from the želd by the ¬ow of rainwater, especially ecological and social contexts. 26 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Recent advances in rice biotechnology T.S. Jishinprakash and A. Yusuf Plant Biotechnology Division, Department of Botany, University of Calicut, Kerala- 673635, India.

Rice is considered as the ‘model mono- important agronomic traits of rice through cot’ in molecular genomics research with biotechnological techniques. Since the žrst increased output from biotechnology during haploid plants were regenerated from rice the mid-1980s and eventually the žrst food anthers the technology has been a routine crop whose complete genome has been exercise in laboratories involved in agricul- sequenced. Among the key advantages that tural biotechnology and rapid development. rice possesses as a model system are its Seed, immature embryo, the anther and the small genome (~430 Mb), the development protoplasm were used for successful plant and availability of its genome sequences, the regeneration, with success in anther culture rice chromosome 10 sequencing consortium, for haploid plant generation methods. Many its diverse germplasm (84,000 accessions at factors such as genotype, physiological age of IRRI) and the development of a number of donor plant and culture medium a—ect the key resources for genomic mapping research. development of androgenic callus and plant The progress achieved in biotechnology regeneration. applications for rice improvement is in two Though di—erent protocols have been pro- major areas- the use of molecular markers posed to improve the efficiency of another for identifying introgressive genes and gene culture, the plant regeneration frequencies combinations within the rice species and the remained low, especially for indica rice use of transgenic technologies to incorporate cultivars (O. sativa ssp. indica). Rice seeds traits for herbicide tolerance, biotic stress have more potential for callogenesis as com- resistance, abiotic stress resistance and pared to node or shoot tip. Tissue culture of nutritional value into rice. dehusked rice embryo is a novel technique to exploit somaclonal variation and for the Tissue culture improvement of grain quality. The mature Plant tissue culture plays an important embryo in rice is arguably one of the best role in the production of agricultural and explants for genetic transformation because ornamental plants and in the manipulation of of its availability and ease to handle as an plants for improved agronomic performance. explant compared to other tissues, but it Regenerated plants are expected to have the has a low frequency of plant regeneration same genotype as the donor plant; however, from callus through somatic embryogenesis. in some cases, somaclonal variants have Moreover, using mature embryos, little infor- been observed among regenerated plants. In mation is available on the improvement of in recent years, considerable e—orts have been vitro regeneration particularly in indica rice directed towards the improvement of the than japonica type. In addition, a number of Crops of Kerala – An overview 27 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). economically valuable indica varieties are of 91.3%, 76.3% and 72.3% respectively. recalcitrant to in vitro manipulation due to Scutellum of MR 123 and MR 127 varieties their poor callus production and regeneration of rice cultured on MS medium with 2.5 mg/l ability. Callus induction and regeneration 2,4-D showed induction frequency of 70 and is still a challenging task in most indica 76% respectively. Coleoptiles of Neda and rice varieties and therefore, there is a basic Nemat varieties of rice treated with 2 mg/l need to use mature embryos of indica rice kin, 0.5 mg/l NAA and 2 mg/l BAP, 0.5 mg/l to develop an e¯cient in vitro protocol for kin showed regeneration frequency of 32.30% establishing a highly reproducible regener- and 20.95%. ation system for molecular transformation The media constituents and their concen- and breaking seed dormancy. Even with a trations of macronutrients, sucrose and phy- sound methodology on rice tissue culture, tohormones a—ect the regeneration potential. in vitro regeneration of indica rice is still a Miller’s medium was widely used in the late challenge and is genotype dependent. 1960’s and early 1970’s. Other nutrient media Carbohydrate, type of explants used, in common use for rice tissue culture include plant growth regulators, basal salts of the MS, modižed MS, LS , modižed LS, N6, B5 culturing medium, culture conditions and and modižed White’s medium. SK medium most importantly genotype of the explants and Universal medium are recommended as play an important role in successful tissue suitable for indica genotypes. Providing most culture. Mature embryo, immature embryo of the inorganic nitrogen as ammonium rather and immature in¬orescence in eight indica than nitrate appears generally favorable for rice varieties on MS and N6 media with 2, rice tissue culture. 4-D showed highest regeneration frequency. Mature caryopses of Asian indica rice cul- Breeding tured on MS medium with proper nutrients Plant breeding, the science of crop and IAA, NAA, kinetin (kin) and BAP improvement, has traditionally developed and ethylene yielded high frequency callus new varieties through selective breeding. induction. Sucrose (4%W/V) is essential for Plant breeders hybridize plants that have callus induction and using 0.5 mg/l 2,4-D, been selected for some desired trait. The time sucrose and sorbitol combination is the best tested strategy for selecting crop varieties for enhancing regeneration. Three month old with higher yield potential comprises of two mature embryos of two japonica and two phases. The žrst phase involves the creation indica (IR 2153 and Nano Bolera) varieties of variability through hybridization between of rice grown in di—erent concentrations of diverse parents. In the second phase, desir- ABA, PEG, IAA, proline, tryptophan and also able individuals are selected on the basis of various doses of NaCl, revealed that ABA and želd observations and yield trials. Rice breed- PEG showed decrease in regeneration fre- ing has made signižcant progress towards quency, proline has no e—ect on regeneration higher yield, improved quality, greater dis- frequency; IAA showed decrease in shoot and ease resistance and other important charac- increase in root regeneration. Mature seeds ters of agricultural importance in the past of Kusan, Lamsan, Selasi and Siam varieties and even in future. It has been estimated of rice when grown on MS medium along that on the average about 1% increase has with 2, 4-D, NAA, kin, BAP showed high occurred per year in the yield potential of rice regeneration frequency in Lasman and poor over a 35 year period since the development in Siam and Kusan. Immature/mature seeds of the žrst improved variety of rice, IR8. The of Pusa Basmati 1, HRR 46 and IR 72 variet- potential to increase the yield of crops has ies of rice grown in MS basal medium along continuously increased and there is no reason with NAA showed regeneration frequency why further increases cannot be attained. 28 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

The phenomenon termed heterosis or hybrid components essential for the NPT are: low vigor in the žrst generation (F1) seeds, by tillering capacity, few unproductive tillers, crossing genetically distant breeding lines 200 to 250 grains per panicle, plant height is well known in crop breeding. Rice being a of 90 to 100 cm, thick and strong stems, strictly self-pollinating crop, the identižcation vigorous root system and 100 to 130 days of of cytoplasmic male-sterile (CMS) wild rice growth cycle. These traits would allow the germplasm in the 1970s and their subsequent rice plant to transform more energy into grain use made signižcant progress in developing production, increasing the yield potential by technology based on heterosis. about 20% but with more input and cost. In 1981, Japan launched a project aiming at The rice green revolution combining varieties from indica and japonica In the 1960s, scientists realized that most groups to develop a super high-yielding rice tall traditional rice varieties lodged during cultivar. The development of NPT was based nitrogen fertilizer application, which is the on tropical japonica germplasm derived from main constraint to grain yield. IR8, the žrst Indonesia, as the source of low tillering, large high-yielding modern rice cultivar, released panicles, thick stems, vigorous root system by IRRI in 1966 marked the start of ‘green and short stature. The process of developing revolution’ in Asia. IR8 is a semi-dwarf the NPT was more complicated than origi- nally thought. The žrst generation of breeding variety having profuse tillering, sti— culms, lines with the above mentioned traits did not erect leaves, photoperiod insensitivity, high perform as expected. New crosses were made N responsiveness and high harvest index by combining the tropical japonicas with elite (HI) compared to traditional cultivars. The indica breeding lines. The expectation was semi-dwarf (sd1) IR8 was developed from that lines coming out of these crosses would a combination of the Indonesian variety increase the yield of irrigated lowland rice ‘Peta’ and ‘Dee Geo Woo Gen’ from Taiwan. by about 10%. The development of super The key factor responsible for the increase high-yielding rice varieties following the in yield potential was the improvement of concepts has encountered various technical the harvest index. In the following decades, difficulties; however, the basic principles IRRI developed IR36, which became the most remained the same. widely planted variety in the 1980s and IR64 was the most used in the 1990s. However, Hybrid rice these newer varieties were characterized by The hybrid rice concept dates back to disease and insect resistance, they did not 1964 in China. However, only in 1970, when contribute signižcantly to genetic gains for a wild abortive pollen plant was identižed grain yield. Scientists then believed that a in Southern China, the idea began to mate- new breakthrough in yield potential had to rialize and the žrst article indicating the come through a new plant type. potential of hybrid rice was published. The The new plant type (NPT) proposed strategy relied on the male sterility In order to develop super high-yielding produced by the abortive pollen identižed rice varieties it is essential to increase the in the wild species O. sativa L. f. spontanea. biological yield. Searching for a second green Hybrid rice was produced through a three-line revolution, IRRI had been working on a new system, where the žrst line was the genetic rice ideotype or new plant type (NPT) with cytoplasmic male sterility; the second line a HI of 0.6 (60% grain: 40% straw weight) responsible for maintaining the sterility, and and with an increased ability for photosyn- a third line used as the matching parent for thesis to increase total biological yield. The the hybrid with the responsibility of restoring Crops of Kerala – An overview 29 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). the fertility. The žrst set of genetic cytoplas- and maturity period of around 30 days ear- mic male sterile lines was produced in 1970, lier than other conventional cultivars, they while the žrst hybrid rice was released in have greater resistance to the most common 1974, with the hybrids out classing conven- biotic and abiotic stresses, as well as improved tional rice varieties by 20% in yield. In 1999, adaptability to the poor African rice growing the area planted with the hybrids was about soils. 15.5 million ha, representing 50% of the total rice area and 60% of the total Chinese rice Super rice production. India has released a number Super rice is the rice bred for super-high of hybrids since 1989; however, the pace of yield. In 1981, the Ministry of Agriculture, adoption by farmers has been slower than Forestry and Fisheries of Japan launched expected with a cultivation of only 200,000 large scale collaborative research projects to ha. To simplify the hybrid rice production develop super-high-yield rice, along with the system, the concept of environmental genetic improvement of cultivation techniques. This male sterility (EGMS) was introduced. The plan focused on breeding high yielding vari- two environmental factors considered were eties and establishing a system of cultivation to maximize the potential of super-high-yield the photoperiod (PGMS) and the temperature varieties. Over 15 years, implementation of (TGMS) sensitivities, which are controlled the plan led to release of some super-high- by recessive nuclear genes. This technology yield varieties that produced 10 t of brown allows, the use of any genotype with good rice per hectare, an increase of 50% compared traits as male parent, to obtain japonica to the control varieties. Super rice breeding hybrids (e.g., it is difficult to identify restor- in China has been very successful. After the ers for this group), and to develop inter-group establishment of the breeding theory and hybrids such as indica/japonica (e.g., there is strategy of generating an ideotype with strong no restriction regarding the restorer–main- heterosis through inter-subspecies hybridiza- tainer relationship). tion, by using gene pyramiding to combine elite traits through composite crossing to NERICA rice breed super rice varieties, a series of major Upland and low dryland environments are breakthroughs have been achieved in both the two most important rice production eco- conventional and super hybrid rice breeding. systems in Africa, where it is a staple food for A number of new genetic materials with this the sub-Saharan population. WARDA began ideotype have been created successfully and a program to combine the two cultivated rice approved. During the induction of the Super species O. sativa and O. glaberrima in 1991. Rice Varieties Program, great attention has Embryo rescue technique was employed to also been paid to the integration and demon- obtain viable segregating populations due stration of the rice production technology. Collaboration between industry and uni- to their genetic dissimilarity. The newly versity researchers has led to technological developed materials were called ‘new rice innovations and initiation of a demonstration for Africa’ and were popularized as NERICA system for super hybrid rice. varieties. The main features of these new varieties, when compared to the traditional The Green Super Rice (GSR) project was O. glaberrima cultivated by farmers, are their launched in 2008 at the International Rice improved ability to compete with weeds, their Research Institute (IRRI) headquarters, larger panicles with around 400 grains and a with the aim of developing rice varieties higher yield potential. In addition to reduced that retain their stable and sustainable shattering, stronger stems to prevent lodging yield potential even when grown with fewer 30 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). inputs or under unfavorable environmental from this, the use of popular varieties as conditions. Under experimental conditions, recipient parents in the target environment new high-yielding GSR cultivars with the also provides a chance to develop lines with tolerance to multiple abiotic stresses have desired traits related to grain quality, plant already been developed. The GSR project type, tolerance for other stresses in a partic- also released drought tolerant, salinity tol- ular region and farmers’ preferences, thereby erant and submergence tolerant, and high increasing the probability of adoption of the yielding varieties suitable for irrigated con- new varieties. It is also advantageous to ditions. Overall, the most important žnding choose landraces that may have tolerance for is the positive and signižcant e—ect of GSR other stresses along with drought tolerance varieties on yield and net farm income even to increase the possibility of coming up with with substantial ¬ooding (i.e., the rice being lines that can tolerate multiple stresses. It is submerged). In fact, non-GSR varieties are also important that the parents are selected the most a—ected when maximum monthly on the basis of the target ecosystem; the plant rainfall exceeds 1000 mm, while the yield of types required for upland and lowland con- GSR rice varieties is still increasing. ditions are very distinct. The plant types suitable for ¬ooded lowland conditions are high tillering medium to long duration dwarf The principal basis for developing peren- plant types with drought tolerance. This kind nial rice is based on a strategy of intercrossing of plants ensure high yield under normal F1 lines, backcrossing to the cultivated rice conditions with a minimum threat to lodging. parent, and rigorous selection for survival and The long maturity duration also allows the seed set in the želd. Development of peren- plant to attain high biomass and high tiller- nial rice is consequently at the forefront of ing which in turn leads to an increase in yield perennial grain development, and will hope- under normal conditions. The added tolerance fully act as an incentive to succeed in other to drought in such lines also ensures yield species. Despite some success in developing under drought conditions. The traditional a perennial rice phenotype which may be rice varieties have evolved suitable mecha- suitable for more favourable lowland condi- nism(s) to survive under stress. Systematic tions in which abiotic stresses are minimal, screening of rice germplasm has shown that signižcant challenges exist in developing a there are excellent ¬ood tolerant rice types robust perennial rice for the harsher rainfed locally available. Breeding e—orts at IRRI led lowland and especially upland ecosystems, to the evolution of tolerant lines with good where perennial rice is really needed. There agronomic traits. The line “IR 49830-7-2-2” are žve perennial rice (PR) lines, namely combines high tolerance levels with higher PR23, PR57, PR129, PR137 and PR139 that yield potential and resistance to diseases and have been bred. insect pests and it has been extensively used as a donor parent in the breeding programme. Stress tolerant rice “Sudhir” is another variety which has been During the past 30 years, rice breeding developed from the “FR13A” × “Biraj” crosses. e—orts have been directed towards incorpo- This variety has been released by the “Central ration of disease and insect resistance, ear- Variety Release Committee, Indian Council of lier maturity and improving grain quality. Agricultural Research, Government of India” Development of large breeding populations in 1999. In spite of the above developments, using crosses between drought tolerant land- till date, no variety has been developed races and high yielding drought susceptible which combines desirable levels of ¬ooding varieties proved e—ective in combining high tolerance with grain yield. Flooding toler- yield potential with drought tolerance. Apart ant rice “Goda Heenati” apparently does Crops of Kerala – An overview 31 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). not have the same submergence tolerance strategy. The rice genome database called gene. It has been suggested that there are at INE (integrated rice genome explorer) has least three submergence tolerance genes in been developed in order to integrate all the “FR13A”, “Kurkaruppan” and “Goda Heenati”. genomic information (http:// www. dna.a—rc. Further, though “FR13A” is considered to go.jp:82/giot/INE.html). be an excellent source of submergence toler- With the advent of functional genomics, ance especially at young seedling stage (10 after the completion of entire rice genome days), “CN 540 (Suresh)” is found to be more sequencing and large gene sets prediction, resistant than “FR13A” and “FR43B” and approx. 10000 expressed sequence tags (ESTs) this might result in genotypes with better and over 15000 full length cDNAs were ana- submergence tolerance. lysed. Approximately 66700 unique ESTs Major attempts have also been made in have been mapped recently that cover almost breeding for improved submergence toler- 80% of the genome but most were mapped ance through the use of doubled haploid lines to distal parts of chromosomes. Typical of (DHLs), developed using crosses between sub- the redundant sequence families are 18S- mergence tolerant and sensitive rice cultivars. 25S and 5S ribosomal RNA genes, which are Two DHL populations for submergence toler- repeated hundreds of times and clustered in ance have been developed at IRRI using the certain regions of particular chromosomes. cross combination of 1) “IR 49830 × CT 6241” Several gene families, such as ribosomal and 2) “FR13A × IR 42”. Use of DHLs has protein genes and histone genes are scat- recently been reported for identižcation of two tered over the 12 chromosomes. Numerous restriction fragment length polymorphism protein kinase genes were identižed in the (RFLP) markers for submergence tolerance whole genome and many disease resistance of rice which are mapped to a segment of genes belonging to protein kinase families chromosome 9. This chromosome segment are clustered on several chromosomes. About [Sub 1(t)] accounted for 70% of the pheno- 50% of the rice genome, including some parts typic variance in submergence tolerance of of open reading frames (ORFs), is made up this population. It would be rewarding if the Sub 1(t) locus is cloned through map-based of repetitive sequences. Precise identižcation cloning technique. A high resolution map has of many kinds of repetitive sequences has been constructed around the Sub 1(t) locus been carried out using the full genome draft through the use of RFLP and AFLP (ampližed sequences, revealing that the rice genome is fragment length polymorphism) markers. composed of approx. 38 Mb of long and 150 Mb of short repetitive DNA. This showed more Molecular biology than 48000 repetitions of di-, tri- and tetra- The whole rice genome and annotations nucleotide simple sequence repeats (SSRs). Rice is a well studied model plant whose The shortest repetitions are categorized into genome has been decoded, and its transforma- microsatellites of SSRs (less than 10 bp units), tion technology has been very well developed. minisatellites (less than 40 bp units) and The availability of the rice genome, together satellite DNAs (several hundred bp units). with the community annotation and other One member of the TOS type of retrotrans- resources added functionality, transformed poson, Tos17, revealed to transpose to various genetic research and rice breeding. Besides genome positions when cells were subjected its economic importance, rice has a small to stress condition. Tos17 also proved to be genome (430 Mb). RGP has developed whole very useful in enabling thousands of inser- genome physical maps using YACs, BACs, tion mutant lines to be generated. Several and PACs, which is the groundwork for the genes isolated from the tagged mutants by whole genome sequencing using map based PCR screening for pooled DNAs of Tos17 32 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). transposed lines have been reported. This essential knowledge for generating novel is a powerful means to construct a functional plants by the use of artižcial chromosomes. genomics system to search for many genes by both phenotypic screening and DNA sequence Stress response and functional genes for analysis. Distribution and transposition of drought resistance endogenous retrotransposon sequences may Responses at the molecular level during contribute to the organization of genome adaptation to drought stress regulated by structure and evolution, but this remains several genes forming response systems to purely speculative. drought were identižed. Drought genes were divided into two classes according to their Characterization of rice CEN5 mode of action. The žrst class is a functional The characterization of centromere com- gene which protects against drought and the position and a large centromere isolated clone second a regulatory gene that could regulate made it possible to unravel centromere struc- functional genes in signal transduction and ture in chromosome 5. Contig formation with gene expression. YAC and BAC clones and analysis of the dis- There were several signižcant di—erences tribution of major repetitive sequences on the between transgenic rice with the gene for contigs coupled with genetic analysis showed GST and CAT1 and normal rice in growth, that the centromere of chromosome 5 (CEN5) photosynthesis, reduction extent of RWC occupies more than 2 Mb. Several functional (relative water content), accumulation of genes were also scattered between repetitive H2O2 and MDA (malondialdehyde), etc. sequences and were not found to recombine These results implied the GST and CAT1 with each other in meiosis. These genetic transgene mitigated oxidative damage from and physical characters of CEN5 in rice are water stress. Excessive expression of the coli similar to those of centromeres of A. thaliana trehalose synthesis A (otsA) and coli trehalose and other organisms. The maize centromere synthesis B (otsB) transgenic rice, accumu- was also shown to have a similar constitution, lation of trehalose increased and oxidative centered on a high copy number block of short damage caused by photo oxidation decreased. tandem repeats being adjacent to moderately The bi-functional fusion of the TPS and TPP repeated transposon like sequences. (TPSP) transgene enhanced resistance to The rice CEN5 has been partly analysed, drought, salt and cold. By activating gene and several YAC clones possessing repeat GH3.13 of rice and adapting the content of blocks and multiple copies of retrotransposons IAA in leaf, stem and tuber, adaptability to in its 380 kb DNA should be promising can- drought was enhanced. didates for examining centromere function. A gene named osSKIPa, which has an YAC arms with rice telomeres and plant selec- upstream gene for regulating the other tion markers have been constructed and used genes of drought resistance, promotes the for retrožtting the candidate YAC clone. The cell vitality, increased viability in water retrožtted YAC clone, which possesses both stress. A rice mutant named drought and centromere and telomere sequences, should salt tolerant (DST) was developed through function as an artižcial chromosome in rice screening from a mutant library. Further, the cells. If the introduced artižcial chromosome gene DST with stress resistance was cloned could be transmitted to the next generation, and DST down regulated the expression of the it would provide a valuable opportunity to gene related to the metabolism of H2O2, and study genomic organization and interactions the ability of H2O2 elimination was reduced. between original chromosomes and artiž- This resulted in the accumulation of H2O2, cial chromosomes. These might also provide and closing of stomata in the guard cells and Crops of Kerala – An overview 33 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). improved the ability of drought resistance by edu/rice). Rice geneticists have developed a decreasing evaporation of water. classical genetic map of rice for more than 200 phenotypic traits using morphological Gene mapping and isozyme markers. The Rice Genome Nearly 450 genes have been identižed in Research Program (RGP) generated the žrst rice which a—ect biotic and abiotic stresses, high density genetic map by placing 1500 colouration of plant parts and morphological, RFLP markers on rice chromosomes and physiological and biochemical traits. Rice later, a high density rice genetic linkage map researchers have studied the inheritance of was developed with 2275 markers covering morphological traits of 19 genes controlling 1521 cM using the same 186 F2 individuals anthocyanin pigmentation, 12 for hull and derived from the cross between Nipponbare pericarp colour, 28 for spikelet traits, 10 for (japonica) and Kasalath (indica). grain size and shape, 20 for endosperm traits, 22 for panicle traits, 9 for culm traits, 27 for Genetic engineering leaf traits, 11 for duration to heading, 30 Though the contribution of conventional for reproductive traits, 22 for panicle traits breeding methods in enhancing rice produc- and 9 for chlorophyll dežciency viz., albino, tion by means of providing better yielding chlorina, žne striped virescent and zebras. verities with high yield even under stress Many resistance genes to various diseases conditions is remarkable and cannot be have been identižed in rice including 18 for denied, the time has come to incorporate bacterial blight, 20 for blast, 2 for Cercospora, the traditional breeding methods with the 2 for stripe viruses and one each for grassy recent advancements in genetic engineering. stunt, hojablanca and yellow dwarf viruses. It has been almost two decades since the žrst More than 30 genes conferring resistance transgenic rice came into existence. Since to various insect pests such as plant hop- then tremendous progress has been achieved per, green leafhopper, white backed plant by genetic engineers in developing more fre- hopper, zigzag leaf hopper and gall midge quent and routine genetic transformation have been identižed. Most of the mutant protocols by means of direct DNA transfer genes responsible for altered traits have been or Agrobacterium mediated genetic transfor- assigned to linkage groups through genetic mation. Recombinant DNA technology has and cytological analysis. Rice classical genetic resulted in the creation of transgenic rice with map has been developed using more than 170 novel genetic traits and genes for resistance morphological markers. Many quantitative to biotic and abiotic stresses. High throughput trait loci (QTLs) for the various components transformation protocols for rice, activation of drought resistance, submergence tolerance, tagging and insertional mutagenesis have blast and blight disease resistance, nitrogen bearing for enhancing transformation effi- use efficiency, heterosis and heading date ciency. This advancement in technologies has have been tagged using molecular markers. facilitated researchers in introducing several Excellent genetic maps were developed in rice agronomically and economically important using various diverse crosses which include traits including nutritional improvements, BS125/WL02, IR64/Azucena, Nipponbare/ which may not have been possible through Kasalath, AijiaoNante/P16, Milyang23/ conventional breeding. Gihobyeo, ZhaiYeQing8/JinXi17 and BS125/2/ BS125 /WLO2. About 4,897 markers were Agrobacterium mediated gene transfer reported in the Oryza database including Remarkable progress has been made in 2,600 RFLP, 134 RAPD, 235 AFLP, 300 the development of efficient systems for SSR, 75 STS, 116 isozyme and 450 morpho- Agrobacterium tumefaciens mediated trans- logical markers (http://ars-genome.cornell. formation in rice. Attempts were made to 34 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). raise and regenerate transgenic calli after based method. Rice transformed with žve Agrobacterium mediated transformation. di—erent minimal cassettes showed simple Regeneration of Agrobacterium transformed integration pattern coupled with high and calli from root explants and immature stable transgene co-expression over gener- embryos was achieved. Already about 40 ations. Using a biolistic approach, several di—erent genotypes of indica, japonica and transgenes have been introduced into rice javanica rice have been transformed using calli where they express transiently or get sta- this approach. Several factors were found to bly integrated and inherited. This approach have an impact on the e¯ciency of A. tume- has been used for investigation on promoters, faciens mediated transformation, including stress tolerance, nutritional enhancement, Ti plasmid type, bacterial strains with broad gene expression, plant development and grain host range, culture conditions prior to and yield. during inoculation and activation of T-DNA transfer process by exogenously added ace- Other methods tosyringone. Among various explants used, Rice protoplasts can be transformed scutellum derived calli are the material with naked DNA by treatment with PEG of choice for efficient transformation in in the presence of divalent cations such as rice. The successful regeneration of trans- calcium. Transgenic rices are recovered genic plants within a month using scutellum using PEG technology and thus it is the žrst from one day precultured seeds as explants, technique used in transgenic rice production. oould avert the risk of somaclonal variations. Subsequently, this was followed by other The strong in¬uence on the transformation workers and they recovered fertile transgenic frequency is exerted by the plant’s genetic plants from indica rice using PEG. Similarly, background in indica rice although the same fertile transgenic plants were developed using is not apparent for three di—erent japonica electroporation in japonica rice. However, cultivars. protoplasts are not easy to work with and regeneration of fertile plants is problematic. Particle gun bombardment To improve transformation efficiency, a sin- Microprojectile bombardment or biolistics gle cell manipulation supporting robot for high is also an equally successful method as it is throughput microinjection of rice protoplasts considered genotype independent and less has been developed. Besides the standard and labour intensive. It has been associated with widely used techniques as mentioned above, some risk due to the arrangement of multi- certain claims of genetic transformation have ple copies of transgenes, particularly in the been made using novel methods, based on form of inverted repeats and the problem of pollen tube pathway, LASER, imbibition of high copy number of the transgene, unlike embryo or seeds in the presence of DNA and Agrobacterium-mediated transformation. WHISKERSTM. To avoid tissue culture and Despite all these constraints, successful inte- sterile conditions, in planta transformation gration, expression and segregation of multi- method has been developed depending on ple genes were shown in rice using biolistic a needle dipped in Agrobacterium culture method. The problem of rearrangement also to prick the seed’s embryonic portion that has been overcome up to a large extent using subsequently grows into a plant and sets minimal linear cassette (including promoter, transgenic seeds. open reading frame and terminator only) to coat microcarriers. Such ‘clean gene’ technol- Enhancement of stress tolerance ogy would be of great importance in avoiding The response of a plant to environmental undesirable e—ects of vector backbone and it stress is determined by many factors like also provides an alternative to Agrobacterium genotype, developmental stage, duration, Crops of Kerala – An overview 35 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). severity, periodicity as well as additive/syn- Cnaphalocrocis medainalis and brown plant ergistic e—ects of multiple stresses. Stresses hopper Nilaparvata lugens. trigger a wide range of plant responses, from altered gene expression and cellular metab- Bacterial disease resistance olism to changes in growth rates and crop Bacterial blight, caused by Xanthomonas yields. Failure to compensate for a severe oryzae pv. oryzae (Xoo), along with blast and stress can result in plant death. The trans- sheath blight are the most important diseases genic approach can help to generate tolerance of rice and have a worldwide distribution. to several stresses in¬uencing rice production. A total of 30 endogenous genes, conferring host resistance against di—erent Xoo strains Biotic stress tolerance have been identižed and named as Xa1 to Insects attack all parts of the rice plant Xa29. The transgenic approach using these and not only exert physiological damage to or other genes provides a reasonable alter- the plant, but also act as vectors for viral native for genetic enhancement towards diseases. The most important and widely bacterial resistance. The most promising distributed pest species are stem borers, endogenous rice gene for bacterial blight leaf folders, plant hoppers and gall midges. resistance identižed so far is Xa21 , which Chemical insecticides provide a simple way conferred complete protection against bacte- to control insect infestation, but the use of rial blight. Targeting of peptidase sensitive agrochemicals without e—ective biosafety peptides like cecropin to the intracellular rules may lead to both environmental and spaces by means of signal peptides protects health problems. Thus, genetic engineering the peptide from degradation. Overexpression would provide an e—ective and safe way to of OSWRKY71 transcription factor in rice develop insect resistance in rice. Baculoviral also resulted in enhanced resistance to the insecticides are an e—ective means of con- virulent bacterial pathogen Xanthomonas trolling predating insect populations. oryzae pv. oryzae (Xoo) 13751 suggesting its Increasing the insect’s virus susceptibility role in rice defense signaling pathways. reduces the amount of virus needed for suc- cessful application. By introducing the gene Fungal resistance for virus enhancing factor in rice, the e—ec- Fungal resistance genes have been iden- tiveness of baculoviral insecticides against tižed from rice. Most promising endogenous feeding armyworm larvae was enhanced. resistance (R) gene, Pi-ta (cytoplasmic NBS Transgenic rice resistant to insect storage receptor), is responsible for resistance to pests using hydrolase inhibitors was gener- fungal diseases. Substitution of alanine ated. Transgenic rice showed higher tolerance for serine at position 918 was responsible against the rice weevil. Using an alternative for susceptibility to Magnoporthe grisea, approach, rice plants were transformed with causal organism of rice blast disease. spider gene, SPI. Lectins, like GNA, pro- Overexpression of dominant Pi-ta allele in vide an alternative way to control the small a susceptible variety could confer complete brown plant hopper. The expression of GNA in resistance against blast disease. A cluster rice also conferred resistance against green of six tandemly repeated disease resistance leaf hopper and white backed plant hopper. like genes from rice, of which one Nbs2-Pi9( ) Overexpression of cry and GNA imparted encodes a transcription factor and showed resistance against yellow stem borer, brown broad spectrum resistance against di—erent plant hopper, green leaf hopper and the white Magnoporthe grisea isolates in transgenic backed plant hopper and GNA with SBTI rice. Another gene, OSDR8, is involved in in transgenic rice showed varying degrees thiamine biosynthesis and acts upstream of resistance against the rice leaf folder in defense signal transduction pathway. 36 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Pathogenesis related (PR) genes have been and salinity), high light intensity, ¬ooding used widely to address fungal tolerance in and exposure to ozone and heavy metals. plants and transgenic rice expressing ChI11, Most abiotic stresses directly or indirectly which showed only partial protection against lead to the production of free radicals and sheath blight disease. However, signižcant reactive oxygen species, creating oxidative resistance against Rhizoctonia solani has stress. Thus, it is imperative to develop been reported using the same gene. Another stress tolerant varieties. Furthermore, with chitinase gene (RC7) could confer tolerance the extension of crop cultivation to environ- against R. solani (the causal organism of ments which are not optimal for the growth rice sheath blight disease) in transgenic rice. of crop plants, development of stress tolerant Several other genes encoding antifungal pro- plants is becoming increasingly important. teins have been introduced in rice for fungal Transgenic approaches o—er new opportuni- resistance, with variable degrees of success ties to improve tolerance to abiotic stresses. and some are e—ective against bacterial as Overproduction of various compatible solutes well as fungal disease, e.g., cecropins. has been tested in rice, e.g.: glycine betaine, trehalose, proline and polyamines, to achieve Viral resistance signižcant drought, cold and salt tolerance. Insect vector mediated viral diseases Late embryogenesis proteins (LEA) are hydro- cause considerable damage to the rice plant philic proteins žrst reported from barely and and drastically reduce the yield of the plant. the overexpression of LEA encoding genes Transgenic rice plants were produced against from barley or wheat in rice could enhance rice stripe virus to demonstrate for the žrst drought tolerance. Transgenic plants also time that coat protein mediated resistance performed better than wild type plants under to virus infection can be extended to cereals and to the viruses transmitted by an insect prolonged water dežcit conditions. Like com- (plant hopper) vector. To generate virus patible solutes, use of membrane transporters resistant transgenic rice, japonica rice was holds good promise. Water channel proteins, transformed with a hammerhead ribozyme, a aquaporins, are members of the major intrin- catalytic molecule with sequence specižc RNA sic protein family which regulate the pas- cleavage activity. The expression of ribozyme sive movement of water across membranes. confers resistance to infection by rice dwarf Another promising strategy against salinity virus. However, silencing of the gene had stress is the use of Na+ transporters, which an e—ect on the degree of viral resistance transport cytosolic Na+ to the vacuole and, in some lines. Resistance against RRSV has thus protect cellular machinery. Na+/H+ anti- been introduced in rice by expressing 39 kDa porters from Artiplex or E.coli confer high salt spike protein of RRSV and transformation of tolerance in transgenic rice. Overexpression susceptible rice cultivar with RHBV nucleo- of rice Na+/H+ antiporter gene could trans- capsid protein gene and moderate to complete port the sodium to the vacuole and provide resistance was seen in transgenic lines. increased salt tolerance. Genetic engineer- ing for oxidative stress tolerance provides an Abiotic stress tolerance attractive strategy to achieve tolerance for In agricultural systems, abiotic stresses multiple stresses. Enhanced production of are responsible for most of the reduction that glutathione synthase, an enzyme involved in di—erentiates yield potential from harvestable ROS metabolism, could enhance the salt tol- yield. There is a range of external factors that erance in transgenic rice. Similarly, drought adversely a—ect the growth and development tolerance of transgenic rice was improved of crop plants. These include high tempera- by overexpressing superoxide dismutase ture, chilling, freezing, water dežcit (drought from pea. Transgenic plants expressing Crops of Kerala – An overview 37 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). protoporphyrinogen oxidase also experienced of recombinant compounds for human use as lesser oxidative stress than control plants the risk of contamination is very low. Rice calli and cell suspension cultures were trans- Production of novel compounds formed using a codon-optimized synthetic Genetic transformation of rice has been gene for human lysozyme. The expression of used for producing novel compounds. The Helicobacter pylori urease subunit B gene in plant system provides several advantages over rice has provided a basis for further studies the animal or the prokaryotic system, e.g., on the potential of transgenic rice for delivery more safety for human use, post-translational of edible vaccines against H. pylori. modižcation of the expressed protein and less expensive extraction and purižcation. Endosperm targeted production of recombi- Technological innovations nant compounds in rice further provides the Several technological innovations have benežt of storage in the form of seed. Single been helpful to improve the potential and chain Fv antibody (ScFvT84.66) against a ease of utilization of transgenic rice. A high well characterized tumor associated marker level of targeted expression of the transgene(s) antigen, carcino-embryonic antigen, had been within the transgenic plant is highly desirable produced in rice and was stable in transgenic depending on the requirement. The appli- dry seeds for at least žve months at room tem- cation of the bacteriophage T7 RNA poly- perature. Transgenic rice system has been merase - directed gene expression system in successfully used for the production of indus- transgenic rice was three-to-žve-fold better trial valuable enzyme transglutaminase, than CaMV35S gene promoter. In another N(hydroxycinnamoyl) transferase, lupin acid approach, MAR from tobacco, TM2, enhanced phosphatase, human lysozyme, glycogen-like reporter gene expression in transgenic rice peptide for type II diabetes treatment, aller- when used with tissue specižc or constitutive gen specižc T-cell epitope, human granulocyte promoter. Quantižcation of transgene copy colony stimulating factor, hG-CSF and linoleic number is an important exercise and a simple isomers for reducing fat and hypertension real-time quantitative PCR based method to in animals. Foods rich in antihypertensive estimate transgene copy number in trans- activity might hold the promise of reducing genic rice was developed, which has similar hypertension. Antihypertensive peptide results to Southern hybridisation. Real-time RPLKPW fused with rice glutelin stor- PCR for determination of copy number in age protein was expressed in the seeds of transgenic rice has also been used. siRNA transgenic rice plants. Recombinant protein mediated post-transcriptional gene silencing accounted for about 10% of total seed protein (PTGS) has been established as the method in transgenic seeds. Rice cell suspension cul- of choice for functional analysis to silence the ture systems also provide an alternative to function of the targeted gene in transgenic animal/bacterial cell lines for the production rice cells. 38 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Biology and cultivation of coconut K. Samsudeen ICAR-Central Plantation Crops Research Institute, Kasaragod, Kerala- 671124, India.

Coconut served man through ages. Cocos nucifera, a monoecious perennial Originated even before continental drift, monocotyledon, is placed in Arecaceae fam- coconut survived many vagaries of nature ily (formerly Palmaceae) and the sub family outliving all its relatives to develop in to the Cocoideae which includes a total of 27 genera monotypic genus Cocos with the sole species and 600 species. Before 1910 many South nucifera. Place of origin of Cocos nucifera American palm genera were classižed as L. is an enigma even today. One school of Cocos but now Cocos nucifera is considered thought is that coconut originated in Central monospecižc, despite the pantropical distri- American region while another says it is from bution of this palm. The coconut palm, Cocos South East Asia. Fossil records from New nucifera, the most important of all cultivated Zealand indicate that small, coconut like palms, is essentially an oil crop but is also plants grew there as long as 15 million years ranked as an important food crop. The palm ago. Even older fossils have been uncovered not only supplies food, drink and shelter, but in India. An origin for the whole Cocoeae also provides raw materials for a number of tribe in western Gondwanaland seems most important industries. The palm is referred compatible with the present day distribution. to as ‘The Tree of Wealth’ and ‘The Tree of It has been hypothesized that the tribe prob- Life, as it provides all the necessities of life. ably di—erentiated shortly before the break up of that super continent. With its ability Coconut is cultivated in 11.93 million hect- to ¬oat the coconut became independent of ares in 94 countries producing 60.5 million plate tectonics for its dispersal. The wild tons of nuts equivalent of 10 million tons in type evolved by ¬oating between the volca- copra or six million tons in oil. In India, coco- nic islands and atolls where these fringed nut is cultivated in 18 states and three Union the continental plates and not on the lands Territories under 2.16 million ha for the pro- masses at all. It is further postulated that duction of 15.08 million tons. The four south- the coasts and islands of the Tethys Sea could ern states, Kerala, Karnataka, Tamil Nadu have been the ancestral home of the coconut, and Andhra Pradesh account for 90% of area from where it dispersed by ¬oating to other under coconut and 93% of production. Rest islands in the Indian Ocean and from there of the production comes from Maharashtra, into Pacižc Ocean. Wherever originated, coco- Orissa, Pondicherry, Andaman & Nicobar, nut is well adapted to coastal ecosystems of Lakshadweep, Gujarat, Goa, West Bengal tropical world. Today, coconut is found from and non-traditional states like Bihar, Assam, tropic of cancer to tropic of capricorn in the Tripura, Nagaland, Manipur, Meghalaya, cultivated form without any wild relatives. Arunachal Pradesh and Chhattisgarh. Crops of Kerala – An overview 39 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Botany Dwarf varieties have shorter trunks than The coconut palm is a tree sans branches, tall varieties. Palms under excessive shade with a single stem topped by a cluster of long and very close planting exhibit rapid stem pinnate leaves. The palm with indeterminate elongation. In rare instances, branching of growth has only one apical meristem that coconut palms is observed, due to damage gives rise to leaf and in¬orescence primordia. to the terminal bud, and up to žve branches The in¬orescences emerge from leaf axils. have been reported. The stem of the coconut palm, being more Root žbrous in nature, combines sti—ness with ¬ex- The palm being a monocot has an adven- ibility and hence is capable of withstanding titious root system. Roots emerge from the a good amount of lateral strain, even when base of the stem (bole). Number of roots in a exposed to severe winds/cyclones. palm varies with the variety, age of the palm, bole size, and management and ranges from Leaf 1500-7000. The main roots form a number The top of the coconut palm bears a crown of secondary roots that branch into many of leaves, comprising of opened leaves as well rootlets, which help the plant absorb nutrients as unopened leaves in various stages of devel- from the soil. The growing root is initially opment surrounding the growing terminal yellowish white in colour and gradually turns bud. The number of leaves in the crown varies light brown and subsequently becomes red- with the variety, growing environment and dish-brown with age. The tender growing management. An adult palm normally has tip of the root is protected from injury by a about 25-35 opened leaves on the crown. Once root cap. The rootlets, however, are short the leaf emerges, it has an average life span lived and are frequently replaced. From the of about 2-3 years. main roots and rootlets, numerous pneumato- The leaves are long, measuring about 3-6 phores develop, facilitating gaseous exchange m in length depending on the variety, age of between the roots and the atmosphere. the palm, vigour of the tree and environmen- Stem tal and management conditions. In general, The coconut palm has a single, straight tall varieties have longer leaves, while dwarfs stem, greyish in colour, culminating in have relatively shorter leaves. The individual a crown of leaves. The palm has a single leaf consists of a strong petiole, extending terminal bud that produces a succession of to form a rachis with numerous lea¬ets leaves and is well protected by the young inserted on either sides of the rachis. The unopened leaves. The stem is marked by leaf petiole accounts for about one-fourth of the scars. The thickness of the stem is determined total length of the leaf, but varies with the by the environment, in addition to varietal variety. A short and stout petiole is able to di—erences. In certain varieties, the base of better withstand vertical pressure exerted by the stem is swollen and is referred to as the the developing bunch in its axil. The number bole. The stem of the coconut palm becomes of lea¬ets in a mature leaf ranges from 150 to visible once the bole reaches the full stage 250. The žrst lea¬ets at the base are short, of its development. In the initial years, the followed by a gradual increase in length of stem gradually becomes thick and once the the subsequent lea¬ets with the maximum maximum size is reached, there is no fur- length being achieved at about one-third of ther appreciable change in the girth of the the midrib followed by a gradual decline in stem. The length of the stem is determined length towards the top of the leaf. by the age of the palm, variety, environ- The midrib of the lea¬et is a very strong mental conditions and cultural practices. structure. The stomata are žrst formed about 40 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). a year prior to the emergence of the leaf. the 6th and so on. The spirality in a palm Stomata are conžned to the lower surface of can either be right-handed (bunches hang the lea¬ets, are elliptic with two guard cells towards the right of the petiole), or left but containing large starch grains and a small remains the same throughout the life of a opening. Normally, a lea¬et contains about particular tree. The two types of spirals are 170-220 stomata/mm2. Stomatal density is distributed almost equally in a population. a varietal character and higher density has been reported in dwarfs than in tall varieties. Flowers The young leaves have stipules at their The coconut palm is monoecious, with bases, which tend to form a žbrous sheath male and female ¬owers borne on the same that more or less encompasses the trunk. in¬orescence. The in¬orescence emerges from As the leaf becomes older, the stipules dry the leaf axils, with one in¬orescence produced and fall away. In some of the young palms, every month from successive leaf axils, in the stipules tend to persist till the leaf dry adult palms under favourable conditions of and fall. growth. The age at initial ¬owering varies with the variety and environmental condi- The progression of leaf development from tions. The in¬orescence is at žrst visible as bud to leaf takes several years, and the an oblong ¬at structure and is referred to as average time taken from initiation to žnal a ‘spadix’. Subsequently, when the spadix is abscission is almost žve years. Various work- fully mature, the spathe ruptures and exposes ers have studied the stages in development the in¬orescence. of the leaf and sequence of events in di—er- entiation of leaf primordia into adult leaf. The length of the in¬orescence ranges The time taken from di—erentiation of the from 60 cm to 200 cm, depending on the leaf primordium to emergence from the leaf variety, age, nutrient status of the palm and sheath is almost 28-32 months. Once the leaf the cultural conditions. The central axis is emerges, it has an average life span of about referred to as peduncle and bears about 30-35 2-3 years. The season and also soil conditions spikelets. The spikelets carry numerous male in¬uence the process of leaf maturing and ¬owers and a few female ¬owers (generally shedding. The rate of leaf opening appears 1-2, and occasionally more). The female ¬ow- to be more dependent on the temperature ers are borne near the base of the spikelets, rather than the rainfall. Under favourable while the male ¬owers are closely set, and growth conditions the leaves remain on the borne above the female ¬owers. crown for longer period, up to three and a All the ¬owers are sessile/subsessile. A half years after emergence. A higher rate of single in¬orescence has about 8,000-10,000 leaf production, coupled with higher number male ¬owers, while the number of female of leaves on the crown has been observed in ¬owers in an in¬orescence varies consid - heavy bearers. Normally, one year old seed- erably (0-400) depending on the variety, lings have about 7-11 leaves depending on the age of bearing, growing environment and varieties, with majority of them having eight management. However, in the spikeless/spi- leaves. Generally, the number of leaves on cata type of in¬orescence, the central axis the crown increases up to 28-38 and an adult is unbranched and male and female ¬owers tree on an average has got about 30 leaves. (with a preponderance of female ¬owers) are The leaves on the coconut crown are directly borne on the peduncle. arranged in spirals, running either in the The male ¬owers are about 8 mm in length clockwise or anticlockwise direction, or in and contain six perianth lobes arranged in such a way as to ensure maximum light avail- two whorls and six stamens arranged in a ability to each leaf. Hence, the 6th leaf is single whorl. In the centre is a rudimen- located over the 1st leaf, the 11th leaf over tary/abortive pistil. Anthers are normally Crops of Kerala – An overview 41 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). yellowish in colour and attain a bluish green thereby resulting in self-pollination. Even in tinge on maturity. Flowering commences from the absence of overlapping of the male and the distal end of the spikelets and extends female phases in an in¬orescence, self-fer- downwards. The ¬owers open throughout the tilization can occur through overlapping of day, but maximum blooming occurs from 8-10 the male and female phases of successive AM. The interval between the opening of in¬orescences in a palm. In India, chances the žrst male ¬ower and the shedding of the of inter spadix pollination is reported to be last male ¬ower is termed as the male phase about 22% of the total spadices opened during and lasts for 18-22 days, varying with the the year, with maximum possibility in the variety, age of the palm, season and cultural summer months of March, April and May. conditions. Such inter spadix overlapping during the wet The female ¬owers are larger, globular in season has been reported in Philippines as structure and bracteolate with a diameter well as Sri Lanka. of about 13-25 mm. It contains six rounded, concave, imbricate perianth lobes with a Fruit staminodal ring at the base and a short style The fruit of the coconut palm is a drupe, with three stigmas at the centre. Ovary is commonly referred to as the ‘nut’. It contains tricarpellary, syncarpous with a single ana- an internal endosperm referred as kernel tropous ovule in each carpel. However, only with embryo embedded in it and protected one ovule is fertile. Generally, two small, fer- externally by a thick pericarp. The pericarp tile male ¬owers called accessory or axillary has three distinct regions, the outer exocarp/ male ¬owers accompany each female ¬ower. epicarp, middle ¬eshy mesocarp and hard The female ¬owers remain receptive for 1-3 endocarp. days after opening. Generally, the female ¬owers become receptive two to three weeks The fruit starts developing upon fertil- after the opening of the spathe. ization of the female ¬owers. During the Since the male and female ¬owers are sep- course of development, a large number of arate, transmission of pollen from the male female ¬owers shed, leaving only a few on ¬ower to the female ¬ower for fertilization the bunch. The young fruits are initially has to take place. In an in¬orescence, the yellowish in colour, but turn green, yellow male ¬owers mature earlier than the female or red (depending on the variety) on expo- ¬owers and shed the pollen. Pollination in sure to light. On reaching complete maturity, coconut palms is e—ected either through wind the fruits turn brown. The developing fruit or insects. The possibility of cross as well as attains its maximum size and weight about self-fertilization exists in coconut. If there six months after pollination and remains so is time interval between the opening of the for another two months. Subsequently, there last male ¬ower and the opening of the žrst is a drastic reduction in fruit weight along female ¬ower, there is greater possibility of with a slight decrease in the size of the fruit, cross pollination. When there is no gap there due to loss of water. is greater possibility of self-pollination. In majority of the tall coconut varieties, the time The solid endosperm (kernel) begins to interval between the end of the male phase develop when the nuts are about six months and commencement of the female phase is old, and appears as a thin watery lining on 2-3 days and hence pollination is e—ected the shell at the basal end, away from the eyes. through pollen from neighbouring trees (cross As the endosperm formation increases, the pollination). However in some trees, especially meat at this end thickens and subsequently in Dwarf varieties, there is overlapping of the hardens. The solid endosperm reaches its female and male phases in an in¬orescence, maximum thickness when the nuts are 42 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). around nine months old. The fruits are ready Variability for harvest 10-12 months after pollination, The coconut palm, in spite of being a depending on the variety. monotypic species with no known wild rel- atives, exhibits considerable variability in The fruit of the coconut palm contains an forms with several distinct populations and internal endosperm with embryo embedded ecotypes, widely di—ering from each other in in it and protected externally by a thick peri- morphological characters, particularly with carp. The pericarp has three distinct regions, respect to plant habit and fruit characters. the exocarp/epicarp, mesocarp and endocarp. The exocarp/epicarp is the outermost layer Plant habit of the fruit and is a tough žbrous skin, the Coconut palms are broadly classižed into colour of which varies from green to red to two groups based on plant habit viz., the yellow to brown, depending on the variety. talls and the dwarfs. Tall palms are the most The mesocarp is the ¬eshy portion imme- commonly cultivated in all coconut growing diately beneath the epicarp (husk). In the regions of the world. Tall palms grow to a tender fruit, this has an astringent taste height of 20-30 m, have a sturdy stem, com- but in rare instances, it is sweet and edible. mence ¬owering 6-10 years after planting As the fruit matures, this region becomes and continue bearing up to the age of 80-100 more žbrous. The thickness of the mesocarp years. Tall palms are normally cross-polli- varies from 2 cm to 15 cm, depending on the nated and hence highly heterozygous. The variety. Immediately below the mesocarp is fruits are generally medium to large in size the endocarp, which develops into a hard shell and produce good quantity and quality of as the fruit matures. The shell, on its basal copra with fairly high oil content. Among side has three pores (eyes) representing the the indigenous tall cultivars, West Coast three carpels of the ovary. One of the eyes Tall, East Coast Tall, Benaulim Tall, Tiptur is soft while the other two are quite hard. Tall, Andaman Ordinary Tall and Laccadive The žbre over the soft eye is generally softer Ordinary Tall are popular. Some popular and less compact than elsewhere in the fruit. exotic tall cultivars are Fiji Tall, Philippines The seed/kernel is present beneath the hard Ordinary Tall, Sri Lankan Tall, West African shell and is therefore well protected. The Tall, Panama Tall, Malayan Tall, Jamaican thickness of the endosperm (meat) generally Tall and San Ramon Tall. is around 1.3 cm. However, depending on the Dwarf palms have gained importance in variety this may vary from 0.8 to 2.0 mm. recent times due to tender nut qualities and The embryo is situated below the soft eye. In resistance to certain diseases. They are of between the endocarp and the albuminous shorter stature, 8-10 m high when 20 years endosperm is a thin layer of testa/seed coat. old and start bearing about 3-4 years after The testa is brown in colour and adheres to planting and have a short productive life of the endosperm. In the middle of the endo- about 40-50 years. The dwarf palms are more sperm is a cavity žlled with sweet water and homozygous than talls, due to a high degree referred to as the liquid endosperm. In the of self pollination. They produce fruits, which unripe fruit, this central cavity is completely are generally small to medium in size. The žlled with water. However, as the fruit ripens, dwarfs are presumed to have originated from the quantity of water reduces gradually and talls either through mutation or by inbreed- gets completely absorbed by the nut on storage ing or by both. The popular dwarf cultivars for a few months, after harvest. Once the nut grown in India are Chowghat Green Dwarf, water is exhausted, the ability of the fruit to Chowghat Orange Dwarf, Kenthali Orange germinate is lost. Dwarf and Gangabondam Green Dwarf. Crops of Kerala – An overview 43 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Among the exotic dwarf cultivars, Malayan has allowed the development of intermediate Yellow Dwarf, Malayan Orange Dwarf and forms through introgression. Malayan Green Dwarf have become popular Harries (1978) put forth a method for in all coconut growing countries of the world. classižcation of coconut varieties as NiuKafa The tall and dwarf types have been uti- and NiuVai, on the basis of fruit characters lized for development of hybrid varieties, com- and seed-germination traits. NiuKafa and bining the early ¬owering trait of dwarfs with NiuVai types of coconuts were suggested the hardiness and high yielding character of to denote wild and domesticated coconuts, tall parents and also exploiting hybrid vigour. respectively wherein NiuKafa fruits are thick husked, angular and lengthy with smaller Fruit characters inner cavity and late seed germination while Considerable diversity is observed in the NiuVai fruits are round or oblong having large size, shape and colour of fruits of coconut inner cavity and early seed germination. palm. The colour of the fruits varies from Harries did not include the dwarf varieties yellow, shades of green and brown to red under NiuVai and NiuKafa types as these (orange). The variations in shapes of the evolved much later and can survive only coconut fruit are broadly classižed as round, under cultivation. oblong or elliptic. Further, based on the equa- torial view, the shape of coconut fruits can In addition to the variation described be classižed as angled, round or ¬at based above, variation in coconut endosperm tex- on the curvature of the fruit and the pres- ture and quality has been reported in nat- ence of ridges on the fruit. Variations are ural coconut populations. One such is the recorded in shape of the nut inside the fruit Makapuno type from the Philippines where and these are broadly categorized as round, the endosperm is buttery soft and almost oval and oblong. žlls the nut cavity and is used in delicious preparations. Similar soft endosperm types Grouping of varieties are reported from other coconut growing Plant habit, fruit colour and other fruit areas also. In India these types are called characteristics are presently the most con- ThayirThengai and have been reported from venient for grouping of the varieties. In most Andaman Islands. Besides, sweet kernel cases, the size of the fruit is genetically deter- type called Mohacho Narel and sweet ten- mined and not solely the e—ect of environ- der husked type called Kaithathali have also ment. However, further režnements of this been reported from India and are conserved technique can be undertaken for a more fool in želd gene banks. Another variant is the aromatic coconut, wherein the tender nut proof classižcation system. Molecular marker water and solid endosperm have a pleasant studies have classižed the present day coconut aroma, similar to the scented rice aroma, as populations into two major groups: the Pacižc seen in the Klapawangi of Malaysia, Aromatic group with žve sub-groups (Southeast Asia, Dwarf of Philippines, Nam-hom of Thailand, Melanesia, Micronesia, Polynesia and the Aromatic Green Dwarf of Philippines, etc. A Pacižc coast of Central and South America) few other exceptional types are: palms produc- and the Indo-Atlantic group. The Pacižc ing thick shelled nuts (Poropol of Sri Lanka, group includes the domesticated coconut while Tutapaen of Philippines, thick shelled types the Indo-Atlantic group, includes NiuKafa observed in India, China, Indonesia etc.), (wild) coconut types. However, human inter- thin husked fruits (Kelapa Bawang/Onion vention through migration and cultivation Coconut of Indonesia, Lupison of Philippines) has brought the di—erent forms together and and pink husked fruits (Ran Thembili of Sri the resulting opportunity for cross pollination Lanka, Guelle Rose of Mauritius, pinkish 44 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). mesocarp types observed in India, China, make decorative crafts and to make brooms. Fijiand Indonesia, etc.). Another oddity in Toothpicks are made out of the midribs of coconut is the persistence of leaf bases and the lea¬ets. Coconut leaves are also used to in¬orescences, as seen in certain other palm produce good quality paper pulp, hats and species like Palmyra palm. These types are mats, fruit trays, fans, lamp shades, bag,and known to occur in many di—erent coconut utility roof materials. populations. Coconut spathe is traditionally used to Besides these, a number of abnormalities make caps and handbags. The whole in¬ores- have been reported from di—erent coconut cence is used to prepare decoction that has growing regions. These abnormalities, listed medicinal properties. Coconut in¬orescence below, are freaks of nature and not distinct is also used to produce neera by incising and varieties, from the botanical point of view. tapping. The fermented neera is known as The abnormalities include variations in toddy or tuba (Philippines) or tuak (Indonesia stem (polyembrony, branching, suckering), and Malaysia). Fermented neera or toddy is vegetative parts (albinism, rosette seedling, distilled to produce arrack. In the Philippines, chimera, fused lea¬ets/plicata, forked leaves, this alcoholic drink is called lambanog or twin leaves, fused leaves, multi-leaf type), ‘coconut vodka’. The in¬orescence sap can be in¬orescence (double spadix, multispathe, reduced by boiling to create a sweet syrup partial suppression of spikes, secondary or candy. It can be reduced further to yield branching of spikes, unbranched spikes, fas- coconut sugar also referred to as palm sugar ciated spikes, foliation of the spadix, terminal or palm jaggery. in¬orescence, vivipary), ¬ower (hermaphro- Coconut fruit has di—erent layers like dite ¬ower, variation in number of pistillodes, outer husk, middle shell and inner endo- stamens and perianth) and fruits (horned sperm that is both liquid and solid. Each nuts, double ovary, mono, bi and tetracarpic one of these layers has various uses to man- fruits). kind. Coconut liquid endosperm or coconut water can be used as tender coconut water Uses of coconut when it is from 6-8 month old coconut fruit. Coconut serves humanity by providing Tender coconut water is a health drink used each and every part for one or the other uses. by man from prehistoric times. It is a good It is used as source of food, medicine, nutri- source of sugar, žbre, antioxidants, proteins, tion, toiletries and cosmetics. In addition, it vitamins and minerals making it a popular provides construction materials, innumerable sports drink providing energy, hydration and products from coir and activated carbon from endurance. It helps restore any electrolyte shell. The parts and their contribution to imbalances caused by diarrhea, vomiting and various uses are discussed below. after exercising. It is the only natural liquid The root has medicinal properties and that can be directly administered intrave- can be used to treat gall bladder and urinary nously due to its ability to mix with blood. It infections as well as kidney related diseases. is attributed to have antiseptic, antibacterial, It is useful for treating eczema and žbrosis. anti-fungal, and anti-viral properties. It is It helps melt clotted blood. The roots can also used to replace lost ¬uids in cases of in¬u- be used to treat heartburns. Coconut trunk enza, typhoid, malaria, and is said to dissolve is a time tested building material used as kidney stones. Mature coconut water is used timber to make houses, boats, bridges and to produce vinegar. It is also used to make canoes. The treated coconut wood is used nata de coco, a jellylike food. for making furniture. Coconut leaves are Mature endosperm is the source of coco- used as a thatching material, used to wrap nut oil, desiccated coconut, coconut milk and rice for storage, used to make toys, used to coconut chips. In addition to the common use Crops of Kerala – An overview 45 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). in cooking, coconut oil is used in medicine and ingredient for many curries and savory dishes cosmetics and as lubricant. Cosmetic uses of throughout the world. coconut oil are as natural skin softener and Other delicacies from coconut include moisturizer. It reduces fine lines, puffiness palm cabbage and haustorium. Apical buds and dark circles under the eyes, it prevents of adult plants known as ‘palm cabbage’ or skin infections, it has anti-wrinkle properties, heart of palm are edible. They are considered it soothes sunburn and treats blisters and a rare delicacy, as harvesting the buds kills burns. It improves skin tone, elasticity and the palms. Hearts of palm are eaten in salads, age spots. It conditions hair, prevents split- sometimes called ‘millionaire’s salad’. Coconut ends and treats dry ¬aky scalp including haustorium, a spongy absorbent tissue formed dandru—. from the distal portion of the embryo during coconut germination, is also edible. Coconut oil is attributed to have many Coconut shell is the strongest part in coco- medicinal uses. It eases acid re¬ux and nut fruit and it covers endosperm. The shell is gives relief in gall bladder disease, stabilizes used to produce various handicrafts. Coconut blood sugar levels and insulin production, shells are also used to make charcoal which kills viruses causing ¬u and other infec- is used as fuel and is far better than other tious diseases, protects against cancers in charcoals. Coconut shell charcoal is widely the colon, breast and digestive tract, pro- used to produce activated carbon. Coconut tects against intestinal disorders, reduces shell charcoal is widely used in purižcation pain and in¬ammatory conditions such as industry and other industries. arthritis, strengthens liver, protects against Coconut husk is the source of coir which Alzheimer’s disease, improves calcium and is the most industrially used part. Coir is magnesium absorption promoting strong the žbre on the husk and is used to make bones, helps stabilize female hormones and ropes, door mats, potting compost, mattress prevents hot ¬ushes and vaginal dryness stuffing, brushes, mats, rugs and sacks during menopause. Coconut milk is another and as joint sealer for boats (caulking). product from endosperm that has many uses. The coconut palm is grown throughout It is used in a variety of ways in seafood the tropics and dežnes the landscape of many dishes and in baking instead of animal fat. regions in the world adding value to the envi- Coconut milk is used regularly, nearly as a ronment. It is known all over the world for staple ingredient in Southeast Asia and forms its many culinary and other uses; virtually the base of curries. It is used to make a home every part of the coconut palm can be used brew in Rendell Island (Solomon Islands) in some manner or the other and has signif- where it is fermented with sugar and yeast icant economic value. Coconuts’ versatility is and left for a week. The milk can be used sometimes noted in its naming. In Sanskrit, to produce virgin coconut oil by controlled it is ‘kalpavriksha’ (the tree which provides heating and collection of the oil fraction. The all the necessities of life). In the Malay lan- coconut meat or the fresh endosperm is eaten guage, it is ‘pokokseribuguna’ (the tree of and used fresh. The meat is used in deserts a thousand uses). In the Philippines, the and confectioneries. It is also an essential coconut is commonly called the ‘tree of life’. 46 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Biology and cultivation of arecanut N.R. Nagaraja1, K.S. Ananda1 and M.K. Rajesh2 1ICAR-Central Plantation Crops Research Institute, Regional Station, Vittal - 574243, Karnataka, India. 2ICAR-Central Plantation Crops Research Institute, Kasaragod - 671124, Kerala, India.

Arecanut (Areca catechu L.) is one of cultural and economic life of people in the important commercial crops of South India. India, Konkan, Andaman & Nicobar group of Arecanut, along with several other Islands and North Eastern Region of India. In ingredients, is being chewed by many in the world arecanut is mainly grown in India, several countries as it is believed to have China, Myanmar, Bangladesh, Indonesia, numerous medicinal values. It has an Sri Lanka and Thailand. Other countries important place in the alternate system where arecanut is grown are Bhutan, Nepal, of medicine such as Ayurveda, Unani and Malaysia, Kenya, Maldives etc. India ranks Homeopathy and in clinical practices in žrst in the world both in area and produc- certain other countries such as Philippines, tion of arecanut. India is not only the largest China and other South and South East producer but also the largest consumer of Asian countries. The World Health arecanut and it continues to dominate. India Organization has listed out as many as 25 has nearly 50 percent of world arecanut area benežcial e—ects of A. catechu. It has also and contributes more than 56 percent of world been reported that all the alkaloids present production. As per the statistics available, in arecanut possess drug like properties. In India arecanut is grown in an area of Most of the folk medicinal properties of about 4.72 lakh hectares with production and arecanut are now validated and authen- productivity of 7.35 lakh tonnes and 1558 ticated with proper scientižc data. It has kg/ha in 2015-16. antioxidant, anti-in¬ammatory, analgesic, In our country arecanut is mainly anti-diabetic, hypolipidemic, antibacterial, grown in Karnataka, Kerala, Assam, anti-fungal, anti-malerial, anti-viral, Meghalaya, West Bengal and Mizoram anti-HIV and AIDS, anti-aging, memory for its masticatory nuts popularly known improvement, wound healing, anti-ulcer, as ‘betlenuts’ or ‘supari’. Arecanut is also anti-migraine, antihypertensive, anti- grown in other states like Andra Pradesh, depressant, anti-allergic, anthelmintic, Goa, Maharashtra, Tamil Nadu, Nagaland, aphrodisiac, hepatoprotective and cyto- Tripura, Pondicherry etc. Three Indian protective e—ects. Arecanut plant parts states namely, Karnataka, Kerala and are used for the preparation of household Assam produce more than 85 percent of and other articles such as cups, plates, ply our countries’ production. Arecanut plays boards, hard boards, hats, etc. Arecanut a prominent role in the religious, social, extracts are used for preparation of areca Crops of Kerala – An overview 47 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). tea, soap, wine, etc. Arecanut leaf sheath is Planting material production also used as alternate fodder for livestock. Arecanut is propagated by seeds. Being Arecanut (Areca catechu L.) is a a perennial and cross pollinated crop, ade- monocot belonging to the tribe Arecae quate care should be taken in selecting and subtribe Arecinae in the Arecaceae the planting material. family. The palm is an unbranched, erect, Selection of mother palms medium-sized, monoecious tree growing in hot and humid tropical regions of the world Mother palms should be of more than and its center of origin is considered to be 12 years age, regular bearers with early South East Asia. The Areca palm, which bearing nature (36-40 months after plant- is highly cross-pollinated, is an allotetra- ing), with partially drooping or drooping ploid with chromosome number 2n=32. The crown with higher number of leaves (>10) genus Areca includes 76 species, A. catechu and shorter internodes, with high fruit set being the only cultivated species. It has (>55% set) with around 350-400 fresh nuts/ been observed that there is a wide range palm/year, with consistent yield of about of variation existing in plant morphology, 3 kg or more dry kernel (chali)/palm/year, size, shape and colour of fruits between with high recovery of chali from fresh fruit the di—erent areca growing regions and (>25%) and free from pest and diseases between di—erent palms/ accessions of the incidences. Mother palms are selected same region. based on the requirements for processing, chali or tender nut. Arecanut cultivation is mostly conžned to 28º North and South of the equator. It Selection of seed nut grows well within the temperature range Seed nuts of three di—erent types are of 14ºC to 36ºC and is adversely a—ected preferred for seedling production viz., inter by temperatures below 10ºC and above se, hybrid and open pollinated. 40ºC. It can be cultivated up to an altitude of 1000 m above MSL in deep and well Inter se: Seed nuts produced after emas- drained soils with low water table. Due culation and pollination by using the pol- to its susceptibility to low temperature, len of selected palms of the same cultivar/ the palms do not come up at an altitude of variety. more than 1000 m above MSL. Arecanut Hybrid: Seed nuts produced after emas- requires abundant and well distributed culation and pollination between two dif- rainfall. Heavy rainfall and high rela- ferent desired parents. tive humidity are the major constraints Open pollinated: Seed nuts harvested for arecanut cultivation in humid tropics. from selected mother palms of the desired Heavy rainfall leads to leaching of potas- cultivar/variety without any artižcial sium and calcium, while high relative emasculation (removal of male ¬owers) humidity is congenial for development of and pollination. pests and diseases. Arecanut is predom- Fully ripened heavy nuts weighing inantly grown in gravelly laterite soil of more than 35 g will give better germination red clay type and it can also be grown in than lighter nuts and give more number of fertile clay loam soils with special care quality seedlings. The mature nuts should of microsite improvement. Laterite, red be harvested when at least a few nuts in loam and alluvial soils are more suitable the oldest bunch start falling. Normally for arecanut cultivation. Sticky clay and it takes 11-12 months to become a mature sandy, brackish and calcareous soils are seed nut after pollination. Rope harvest not suitable for areca cultivation. of seed nuts is recommended from trees 48 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). which are very tall and in places where Selection of seedlings the ground is hard. The nuts, which ¬oat Seedlings of 1-1.5 years of age having vertically with calyx end pointing upwards six or more leaves (early leaf splitting), 90 in water will produce more vigorous seed- cm height and 26 cm collar girth should lings. Harvested seed nuts can be stored be selected. Seedlings having more than 5 only for about 3 to 6 days since the nuts are nodes after two years are the best seedlings recalcitrant, i.e., viability will be lost soon. to get better yield. The seedling should Nursery techniques in arecanut have well established root system with 5-8 main žbrous roots intact and active while Primary nursery transplanting. The seedlings have to be Sowing the nuts immediately after har- uprooted with a ball of earth adhering to vest in soil/sand and watering will result roots if they are raised in nursery bed. in early and good germination. Selected Seedlings should be free from pests and seed nuts are sown with their stalk end diseases. Polybag seedlings are preferred pointing upwards, 5 cm apart in sand beds for long distance transport. Care should of 1.5 m width and convenient length. be taken to prevent damage/breakage Thick mulching is to be done with straw/ of seedlings at the collar region during areca leaves. Beds are to be watered daily transportation. either by using hose or microsprinklers. Germination of nuts usually commences An area of 4,000 square meters is by 43 days and gets completed by 94 days. required to maintain 50,000 seedlings. Areca sprouts and seedlings are very Secondary nursery delicate and do not withstand exposure For raising the seedlings in secondary to direct sunlight. Hence, proper shade nursery, beds of about 1.5 m width and should be provided to the nursery. The 15cm height are suggested. A spacing of shade may be either of coconut or are- 30-45 cm is considered optimum for plant- canut leaves spread over a pandal or by ing three months old sprouts in secondary covering with 50-75% shade net (green or nursery and repotting in poly bags is also black) or by planting some fast growing preferred. The secondary nursery should green manures or banana around the be given a basal dose of decomposed farm- nursery. The nursery should be watered yard manure or vermicompost @ 5 tonnes regularly during summer and proper per ha. The nursery should be partially drainage should be provided during rainy shaded to get good seedlings. season. Periodical weeding and mulching is required. Nursery can be raised in the Polybag nursery interspaces of coconut plantation and Seed nuts may be sown directly in poly also in widely spaced arecanut gardens. bags of 6”x9” size and 250 gauge thickness, Sprinkler/micro-jet/hose irrigation sys- with holes for drainage. Potting mixture tems are well suited to arecanut nursery should be of Soil: FYM: Sand in the ratio beds/polybag seedlings. 7: 3: 2. Well decomposed farm yard manure or vermicompost and sieved sand should Crop Improvement be used for potting mixture preparation. In India, systematic germplasm collec- Solarization of soil by covering with black tion of arecanut from within and outside polythene sheet and sun drying of potting- the country began in 1957 and screening mixture for one week may be practiced to them under uniform conditions was initi- avoid any soil borne diseases. Daily water- ated at the ICAR-Central Plantation Crops ing during rainless period is needed to Research Institute (CPCRI) Regional ensure desired growth. Station, Vittal. The present germplasm Crops of Kerala – An overview 49 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). holding at ICAR-CPCRI Regional Station, Two dwarf hybrids namely VTLAH-1 Vittal is 176 accessions. Out of these 153 (Vittal Arecanut Hybrid-1) and VTLAH-2 are indigenous eco-types of arecanut (Vittal Arecanut Hybrid-2) were also collected from di—erent parts of India released. Most of these varieties/hybrids and 23 are exotic accessions introduced viz., Mangala, Sumangala, Sreemangala, from Fiji, Mauritius, China, Sri Lanka, Swarnamangala, Mohitnagar, Indonesia, Saigon, Singapore, British Kahikuchi, Madhuramangala, Nalbari, Solomon Islands and Australia and the Shatamangala, VTLAH-1 and VTLAH-2 germplasm represents four species viz., were developed and released by ICAR- Areca catechu L. Areca triandra Roxb., Central Plantation Crops Research Normanbya normanbyii and Actinorhytis Institute (CPCRI). Samrudhi was devel- calapparia. The indigenous collections are oped and released by ICAR-Central from Gujarat, Maharashtra, Karnataka, Island Agricultural Research Institute, Assam, Kerala, West Bengal, Tamil Nadu, Port Blair and ICAR-Central Plantation Meghalaya and Andaman & Nicobar. Crops Research Institute. University of Agricultural Sciences, Dharwad was Identiœcation and release of varieties responsible for release of Sirsi Arecanut Increase in arecanut production over Selection-1. decades was not only due to increased area under cultivation but also increased pro¬- Hybridization in arecanut ductivity contributed by superior varieties, In arecanut, hybridization starts with supply of quality planting materials, bet- removing the portion of rachillae having ter agro-techniques and plant protection male ¬owers (emasculation) soon after measures. Evaluation of available arecanut emergence of the in¬orescence and cov- cultivars for their performance under dif- ering the spadix bearing female ¬owers ferent ecological conditions is a promising with a cloth bag. When the female ¬owers method of obtaining genotypes suited for open, anthers from the desired male par- the di—erent regions of India. But arecanut ent is rubbed against the stigma or the palm is more sensitive to moisture stress pollen is dusted on the stigmatic surface, than coconut and therefore its cultivation by removing the bag. The bag is replaced is restricted to areas with well-distributed over the in¬orescence immediately after rainfall or assured irrigation facilities. pollination. The process is repeated daily Based on the comparative yield trials of for about a week till all the female ¬owers indigenous and exotic accessions, promis- in the spadix open and fruit set can be seen ing cultivars were selected and released after 20 days. In artižcial pollination, fully as varieties for commercial cultivation. opened male ¬owers are collected from the The evaluation of exotic accessions and selected palms and are transferred to a selection for high yield and its attributes, reagent bottle containing 0.5 per cent solu- resulted in release of Mangala (introduced tion of sucrose and the bottle is shaken from China), Sumangala (introduced from gently. The pollen grains thereupon get Indonesia), Sreemangala (introduced from released in the aqueous solution. The Singapore) and Swarnamangala (intro- solution with the pollen grain in suspen- duced from Vietnam). Evaluation of indig- sion is transferred to an ordinary hand enous accessions resulted in the release of atomizer and sprayed onto newly opened high yielding varieties like, Mohitnagar, female ¬owers. The spraying may have Samrudhi, Sirsi Arecanut Selection-1, to be done three to four times, as all the Kahikuchi, Madhuramangala, Nalbari and female ¬owers do not open at the same Shatamangala with high yield potential. time. About 14 per cent increase in fruit set 50 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). was obtained by this method and the same yield potential will directly benežt the could be successfully used in commercial growers by way of enhanced returns and hybridization. reduced cost of various cultural operations like harvesting and spraying. Damages Dwarf hybrids of arecanut to palms due to sun-scorching and heavy Though tall varieties possess high yield wind will be the minimum. Therefore, the potential, they are frequently prone to sun exploitation of dwaržng genes in breeding scorching, wind damage and also become dwarf varieties with high yield potential difficult to manage. The tall nature of was initiated. Hybrids involving Hirehalli the palm hinders various operations like spraying and harvesting which are Dwarf (HD) and released tall varieties as quite labour intensive and cumbersome. parents were developed and evaluated for Arecanut breeding programmes are aimed yield performance and dwarfness. Among at development of dwarf arecanut varieties/ the hybrids, HD x Sumangala and HD x hybrids in addition to yield improvement. Mohitnagar were identižed as superior for Hirehalli Dwarf (HD) a natural mutant yield with dwarfness and recommended identižed in 1963, for its short stature for commercial cultivation as VTLAH-1 is a good genetic source for arecanut (Vittal Arecanut Hybrid-1) and VTLAH-2 improvement. Dwarf hybrids with high (Vittal Arecanut Hybrid-2), respectively. Crops of Kerala – An overview 51 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Biology and cultivation of black pepper, the king of spices B. Sasikumar

Former Principal Scientist & Head, Crop Improvement & Biotechnology Division, ICAR- Indian Institute of Spices Research, Kozhikode, Kerala- 673012, India.

Black pepper (Piper nigrum L.) (Family: 55,000 MT (2015-16). Kerala, Karnataka Piperaceae) is a perennial climbing vine and Tamil Nadu and to a limited extent grown for its berries, extensively used as Maharashtra, Assam, Tripura, Arunachal spice and in medicine, often referred to as Pradesh, Meghalaya and Andaman Nicobar ‘King of Spices’ or ‘Black Gold’. Black pepper are the black pepper growing states/regions has immensely in¬uenced the geopolitical in India. Kerala and Karnataka account for history of the world as it was a much sought a major portion (97.7%) of production of black after commodity since very ancient days. An pepper in the country. essential condiment in the western and east- ern cuisines as food additive and preservative, Climate and soil black pepper was highly priced and frequently Black pepper prefers humid tropics with used to pay rent, tax and even dowry. Black high rainfall and humidity. The hot and pepper has been an integral part of the tra- humid climate of sub mountainous tracts of ditional medicines of the orient also. Western Ghats is ideal for its cultivation. It grows successfully between 20° North and Origin and distribution South latitudes, and from sea level up to 1500 Black pepper is native to the Western m above sea level with temperatures between Ghats of India, where it still occurs wild in 10oand 40° C and a well distributed annual the forests. This area is considered to be the rainfall of 1250-2000 mm. Black pepper can centre of origin of the crop. Center of diversity be grown in a wide range of soils with a pH of the crop is also in this tract as cultivated of 4.5 to 6.5. In its natural habitat it thrives forms are very high in number here and it well in red laterite soils. is believed that black pepper spread out to In India, black pepper is being grown other tropical countries from India. The major either as a homestead crop in the plains or black pepper growing countries at present are as a plantation crop in the midlands and hills India, Indonesia, Tropical Africa, Malaysia, (800-1500 m) besides in valleys in the north Thailand, Brazil, Sri Lanka, Vietnam and eastern states of the country. China. Vietnam is the leading producer currently. Varieties and crop improvement In India black pepper is grown in about Over 75 cultivars of black pepper are 129,000 ha with an annual production of being cultivated in India. The most important 52 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). cultivars are Karimunda (all over Kerala), varieties are monoecious while in the wild Kottanadan (South Kerala), Narayakodi they are dioecious. Cultivated black pepper (Central Kerala), Aimpiriyan (Wayanad), is predominantly self-pollinated (geitonog- Neelamundi (Idukki), Kuthiravally amy). Even though protogyny occurs in black (Kozhikode and Idukki), Balancotta, pepper, it is ine—ective in preventing selžng. Kalluvally (North Kerala), Malligesara and Selections (germplasm, clonal and open Uddagare (Karnataka). Self grown seedlings pollinated) and hybridisation are the import- also contribute to cultivar diversity in black ant breeding strategies adopted in improv- pepper. A few important cultivars and their ing black pepper. Viable sexual reproduction salient features are given below. coupled with excellent mode of vegetative Most of the cultivated black pepper multiplication is a boon in the improvement

Important cultivars of black pepper Fresh Quality attributes mean Cultivar Features yield Oleoresin Piperine Essential Dry (kg/vine) (%) (%) oil (%) recovery (%) Good for higher elevations, good Aimpirian 4-5 15.7 4.7 2.6 34 in quality, late maturing A r a k u l a n Moderate and 2 9.8 4.4 4.7 33 munda regular bearer Moderate Balankotta 1-2 9.3 4.2 5.1 35 and irregular bearing Suitable for all pepper growing Karimunda 2-3 11.0 4.4 4.0 35 areas, high yielder, shade tolerant. Good yielder with high Kalluvally 1-2 8.4-11.8 2.5-5.4 3.0 35-38 dry recovery, drought tolerant High yielding, Kottanadan 5 17.8 6.6 2.5 34-35 drought tolerant High yield, good Kuthiravally 3 15.0 6.0 4.5 35 quality Moderate yielder Narayakodi 1-2 11.0 5.4 4.0 36 with medium quality Good yielder, tolerant to Neelamundi 2 13.9 4.6 3.3 33-34 Phytophthora infection Medium quality Vadakkan 3 10.8 4.2 3.2 - and yield Crops of Kerala – An overview 53 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Improved varieties of black pepper ha) yield (dry)Mean (kg/ (%) recovery Dry contentPiperine (%) contentOleoresin (%) (%) content oil Essential

Variety/ Pedigree Features Hybrid

Hybrid between Not suited Panniyur -1 Uthirankotta x 1242 35.3 5.3 11.8 3.5 to heavily Cheriyakaniakadan shaded areas

Selection (Col. 141) Shade Panniyur -2 2570 35.7 6.6 10.9 - from cv. Balancotta tolerant (KAU) Hybrid (Cul. Late Panniyur -3 331) Uthirankotta x 1953 27.8 5.2 12.7 - maturing Cheriyakaniakadan Selection from Panniyur -4 1277 34.7 - 9.2 - Stable yielder Kuthiravally Open pollinated Tolerant to Panniyur -5 progeny selection 1098 - 5.5 12.3 3.8 shade from Perumkodi Suited to all Clonal selection Panniyur -6 2127 32.9 4.9 8.3 1.3 black pepper from Karimunda tracts Open pollinated Suited to all Panniyur -7 progeny selection 1410 33.6 5.6 10.6 1.5 black pepper from Kuthiravally tracts High Hybrid (HB20052), 1.2 yielding, and Panniyur -8 Panniyur 6 x 1365 39.0 5.7 12.2 tolerant to Panniyur 7 diseases Suited to Kerala, Open Pollinated Panniyur-9 3150 40.0 6.11 12.71 5.0 Karnataka Progeny Selection and Andhra Pradesh Field tolerant Panniyur 2 x Vijay ----- to foot rot Neelamundi disease Suited to all Selection from Subhakara 2352 35.5 3.4 12.4 6.0 black pepper Karimunda (KS-27) tracts 54 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). ha) yield (dry)Mean (kg/ (%) recovery Dry contentPiperine (%) contentOleoresin (%) (%) content oil Essential

Variety/ Pedigree Features Hybrid

Suited to all Selection from Sreekara 2677 35.0 5.3 13.0 7.0 black pepper Karimunda (KS-14) tracts Selection from Late Panchami Aimpiriyan (Coll. 2828 34.0 4.7 12.5 3.4 maturing 856) Selection from Tolerant to Pournami Ottaplackal (Coll. 2333 31.0 4.1 13.8 3.4 root knot 812) nematode Suited to Thiruvana- Clonal selection nthapuram PLD -2 2475 - 3.3 15.5 3.5 from Kottanadan and Kollam districts of Kerala Open pollinated Tolerant to IISR progeny of 2253 43.0 3.3 10.2 3.7 Phytophthora Shakthi Perambramundi foot rot. Tolerant to Phytophthora IISR Clonal selection of foot rot; 2481 32.0 1.65 8.15 3.1 Thevam Thevamundi Suited to high altitudes and plains Hybrid between IISR Suited to Narayakodi x 2880 32.0 2.2 9.65 3.4 Girimunda high altitudes Neelamundi Suited IISR Hybrid between 1440 32.0 4.95 14.6 4.1 to high Malabar Cholamundi x altitudes; rich Excel Panniyur-1 in oleoresin High yielding Arka Coorg OP seedling 3267 37.8 2.1 6.9 1.6 with long Excel selection spike. Crops of Kerala – An overview 55 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). of black pepper. Barring Vadakkan which with septa or split halves of PVC pipes of is a triploid, almost all other black pepper 1.25-1.50 m length and 8-10 cm diameter cultivars are diploid (2n=52). provided with plastic septa at 30 cm intervals Twenty improved varieties of black pepper are žxed at 45° angle on a strong support. have been released for cultivation (Table 2) Rooted cuttings are planted in the trench in India. Panniyur-1 and Panniyur-3 are made earlier at the rate of one cutting for hybrids evolved at the Pepper Research each bamboo split. The lower portions of the Station, Panniyur (Kerala) and have bamboo splits are žlled with rooting medium Uthirankotta and Cheriyakaniakadan as (preferably weathered coir dust-farm yard their female and male parents, respectively. manure mixture in 1:1 ratio) and the growing Vijay is another hybrid developed by the vine is tied to the bamboo split in such a way College of Horticulture, Thrissur, India. IISR as to keep the nodes pressed to the rooting Girimunda and IISR Malabar Excel are the medium. Dried banana leaf sheath žbers or two hybrids released from the ICAR-Indian coir žbres are used for tying. The cuttings Institute of Spices Research, Kozhikode. In are irrigated regularly using a rose can. As the case of Girimunda the female and male the cuttings grow on the bamboo splits, the parents are Narayakodi and Neelamundi splits are žlled with rooting medium and each while Cholamundi and Panniyur I are the node is pressed down to the rooting medium female and male parents of Malabar Excel. and tied. For rapid growth of vines on the bamboo splits, a foliar spray of urea (1 kg), Propagation super phosphate (0.75 kg), muriate of potash Though seeds are viable, black pepper (0.5 kg) and magnesium sulphate (0.25 kg) is mainly propagated using rooted cuttings. in 250 litres of water is to be given @ 0.25 Runners and orthotrops (top shots) are used litre per vine at monthly intervals. for generating rooted cuttings. Rooted pla- When the vine reaches the top of the bam- giotrops or fruiting branches are bush pep- boo splits, (3-4 months after planting of the pers. Di—erent propagation methods are cutting) the terminal bud is nipped o— and employed in black pepper. the vine is crushed at about three nodes above the base, in order to activate the axillary Traditional method buds. After about 10 days, the vine is cut The runner shoots are separated from at the crushed point and removed from the the vine during February-March, and after rooting medium and cut at each node which trimming the leaves, cuttings of 2-3 nodes are has striked roots. Each single nodde cutting planted either in nursery beds or in polythene with the bunch of roots intact is planted in bags žlled with potting mixture (Soil, Sand polythene bags žlled with fumigated pot- and Cow dung in 1:1:1 ratio).Adequate shade ting mixture. Trichoderma @ 1g and VAM has to be provided and the polythene bags @ 100 cc/kg of soil can be added to the potting are to be irrigated frequently. The cuttings mixture. Care should be taken to keep the become ready for planting during May-June. leaf axil above the soil. The polythene bags During good rains, direct planting of runner should be kept in a cool and humid place shoots is also done. and should be covered with thin polythene (200 gauges) sheet to retain humidity. The Rapid multiplication method buds start developing in about three weeks In this method, a trench of 45 cm depth, and then the polybags can be removed and 30 cm width and convenient length is made. kept in shade till main želd planting. The The trench is žlled with rooting medium com- advantages of this method of propagation are prising of forest soil, sand and farm yard rapid multiplication rate (1:40), well developed manure in 1:1:1 ratio. Split halves of bamboo root system, higher želd establishment and 56 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). vigorous growth as a result of better root Serpentine method system. Serpentine layering technique can be used Trench method for the production of rooted cuttings of black A simple, cheap and efficient technique pepper in a cheap and e—ective manner. In a for propagating black pepper from single nursery shed with roožng sheet or shade net, nodes of runner shoots taken from želd grown rooted black pepper cuttings are planted in vines has been developed at IISR. A pit of polythene bags holding about 500 g potting 2.0 m x 1.0 m x 0.5 m size is dug under a mixture, which will serve as mother plants. As the plant grows and produces a few nodes, cool and shaded area. Single nodes of 8-10 small polythene bags (20x10 cm2) žlled with cm length with intact leaves are, taken from potting mixture may be kept horizontally runner shoots of želd grown vines. They are under each node. The node may be kept then planted in polythene bags (25 cm x 15 gently pressed in to the mixture in the bag cm, 200 gauge) žlled at the lower half with a assuring contact with the potting mixture mixture of sand, soil, coir dust and cow dung with the help of a ¬exible twig such as mid in equal proportions. The single nodes are rib of a coconut lea¬et. Roots start grow- to be planted in the bags in such a way that ing from the nodes and the cuttings keep their leaf axil is exposed above the potting on growing further. The process of keeping mixture. The polythene bags with the planted potting mixture žlled polythene bags at every single nodes are arranged in the pit in rows. node junction to induce rooting at each node After keeping the bags in the pit, the pit is repeated. In three months the žrst 10 to should be covered with a polythene sheet. This 12 nodes (from the mother plants) would sheet may be secured in position by placing have rooted profusely and will be ready for weights on the corners. The cuttings should harvest. Each node with the ploythene bag be irrigated at least žve times a day with a is cut just below the rooted node. The cut rose can. Care should be taken to cover the pit end is then also buried into the mixture to with the polythene sheet immediately after induce more roots. Polythene bags used are each irrigation. The poly bag soil is drenched žlled with solarized potting mixture fortižed 2-3 times with copper oxychloride (2g/L). with biocontrol agent. The potting mixture After 2-3 weeks of planting, the cuttings is prepared by mixing two parts of fertile will start producing roots which are visible topsoil, one part of river sand/granite powder through the polythene bags. After the initi- and one part of FYM(2:1:1).The rooted nodes will produce new sprouts in a week time and ation of roots the frequency of irrigation may will be ready for želd planting in 2-3 months be reduced to 3-4 times a day. After about of time. The growing vines are to be irrigated 1 month, new shoots start emerging from every day with a rose can. By this method, the leaf axil. At this stage it is advisable to on an average, 60 cuttings can be harvested keep the pit open for about one hour per day per mother plant in a year. so that the cuttings would harden and will not dry when they are taken out of the pit. Nursery diseases The cuttings can be taken out of the pit after Many pests a—ect the cuttings while in two months of planting and kept in a shaded the nursery. Some of the most serious ones place and watered twice a day. These cuttings are given below. will be ready for želd planting after about 2½ months. By this method 80-85% success Phytophthora infection rate can be obtained. Foliar application of Phytophthora infection is noticed on nutrient solution will also enhance the growth leaves, stems and roots of cuttings in the of the cuttings. nursery. Dark spots with žmbriate margins Crops of Kerala – An overview 57 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). appear on the leaves, which spread rapidly chlamydosporia or Trichoderma harzianum resulting in defoliation. The infection on the @ 1-2 g/kg of soil. A prophylactic application stem is seen as black lesions which result in of nematicide may also be needed. blight. The symptoms on the roots appear as rotting of the entire root system. Spraying 1% Planting and management of vines Bordeaux mixture and drenching with 0.2 % Being a perennial crop, use of healthy copper oxychloride (2g/L) at monthly intervals rooted cuttings is very important for raising prevents the disease. Alternatively, 0.01% plantations. metalaxyl (1.25 g/L water) or 0.3% potas- sium phosphonate could also be used. The Preparation of land and planting standards potting mixture may be sterilized through In India, planting of wines is done in solarization. harmony with the monsoon seasons. With the receipt of the žrst rain in May-June, Anthracnose primary stem cuttings of shade trees like The disease is caused by Colletotrichum Erythrina sp., Garuga pinnata or Grevillea gloeosporioides. The fungus infects the leaves robusta or seedlings of Ailanthus malabarica causing yellowish brown to dark brown irreg- are planted in pits of 50 cm x 50 cm x 50 ular leaf spots with a chlorotic halo. Spraying cm size žlled with cow dung and top soil. 1% Bordeaux mixture alternating with 0.1% Planting is done at a spacing of 3 m x 3 m Carbendazim (2g/L) is e—ective against the which would accommodate about 1110 stan- disease. dards per hectare. The black pepper vines Leaf rot and blight can be trailed on the standards after three years when they attain sufficient height. The disease is caused by the fungus Homestead plants such as coconut, arecanut, Rhizoctonia solani and is often serious in jack, mango, drum stick, etc. can also be used nurseries during April-May when warm as black pepper standards. Dead standards humid conditions prevail. The fungus infects (dead wood, reinforced concrete columns, both leaves and stems. Grey sunken spots earthen pipes, etc.) are also being used as and mycelial threads appear on the leaves black pepper standards. and the infected leaves are attached to one another with the mycelial threads. On stems, Planting the infection occurs as dark brown lesions 3 which spread upwards and downwards. The Pits of 50 cm or still bigger, at a distance new ¬ushes subtending the points of infection of 30 cm away from the base, on the northern gradually droop and dry up. Leaf spots caused side of supporting tree are taken with the by Colletotrichum sp. are characterized by onset of monsoon. The pits are žlled with yellow halo surrounding the necrotic spots. A a mixture of top soil, farmyard manure @ prophylactic spray with 1% Bordeaux mixture 5 kg/pit and 150 g rock phosphate. Neem prevents both the diseases. cake @ 1 kg, Trichoderma harzianum @ 50 g also may be mixed with the mixture at the Nematode infestation time of planting. With the onset of monsoon, Root knot nematodes (Meloidogyne spp.) rooted cuttings of black pepper are planted and burrowing nematode (Radopholus simi- individually in the pits on the northern side lis) are the two important nematode species of each standard. infesting rooted cuttings in the nursery. Soil solarization or steam sterilization can Cultural practices be done for sterilizing the nursery mixture. As the cuttings grow, the shoots are tied The sterilized nursery mixture may be forti- to the standards as required. The young žed with biocontrol agents such as Pochonia vines should be protected from hot sun 58 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). during summer by providing artižcial shade. zinc or magnesium, foliar application of 0.25% Regulation of shade by lopping the branches zinc sulphate twice a year (May-June and of standards is necessary not only for pro- September-October) and soil application of viding optimum light to the vines but also 150 g/vine magnesium sulphate, respectively for enabling the standards to grow straight. is recommended. Adequate mulch with green leaf or organic matter should be applied towards the end of Summer irrigation north east monsoon. The base of the vines Irrigating black pepper vines during sum- should not be disturbed so as to avoid root mer (March II fortnight to May II fortnight) damage. at fortnightly interval enhances productivity During the second year, the same cultural by 90 to 100 per cent compared to unirrigated practices are repeated. However, lopping of crop. Vines are irrigated at the basin through standards should be done carefully from the hose. 50 L per vine is recommended for vines fourth year onwards, not only to regulate that have crossed 15 years of age while 40 height of the standards, but also to shade the L is enough for vines between 11-15 years black pepper vines optimally. Lopping may be age group and 30 L to vines aged between done twice (during June and September) in a 5-10 years. Spiking will be uniform in irri- year. Excessive shading during ¬owering and gated crop and most of the spikes (> 90 %) fruiting encourages pest infestations. Weed emerge in July while in rainfed crop, around regulation, base cleaning and mulching need 60% spikes emerge in July whereas the rest to be followed periodically. emerge in September. Spike length will be comparatively more in irrigated crop. Manuring and fertilizer application Diseases and their control Manuring and fertilizer application for pepper vines is to be done for proper estab- Black pepper is a—ected by many diseases. lishment and growth of plants. General rec- The important ones are listed below: ommended nutrient dosage for black pepper Foot rot disease vines (3 years and above) is NPK 50:50:150 g/vine/year. Only one-third of this dosage Foot rot (quick wilt disease) caused by should be applied during the žrst year which Phytophthora capsici is the most destructive is increased to two-thirds in the second year. of all diseases and occurs mainly during the The full dose is given from the third year south west monsoon season. All parts of the onwards. The fertilizers are applied in two vine are vulnerable to the disease and the split doses, one in May-June and the other in expression of symptoms depends upon the August-September. The fertilizers are applied site or plant part infected and the extent of at a distance of about 30 cm all around the damage. Varieties like Thevam and Sakthi vine and covered with a thick layer of soil. are tolerant to the disease. The disease can Care should be taken to avoid direct contact of be controlled by adopting integrated disease fertilizers with roots of black pepper. Organic management strategies such as phytosan- manures in the form of cattle manure or com- itation, drainage management, deploying post can be given @ 10 kg/vine during May. tolerant varieties and spraying any of the Neem cake @ 1 kg/vine can also be applied. appropriate fungicides as suggested below: Application of lime @ 500 g/vine in April-May (1) After the receipt of a few monsoon during alternate years is also recommended showers (May-June), all the vines are to under highly acidic soil condition. When bio- be drenched at a radius of 45-50 cm with fertilizer like Azospirillum is applied @ 100 g/ 0.2% Copper oxychloride @ 5-10 litres/vine. vine, the recommended nitrogen dose may be A foliar spray with Bordeaux mixture 1% is reduced by half. In soils that are dežcient in also to be given. Drenching and spraying are Crops of Kerala – An overview 59 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). to be repeated once again during August- Cucumber mosaic virus and a Badna virus September. A third round of drenching may are associated with the diseases in black be given during October if the monsoon is pepper. Virus diseases can be managed by prolonged. using virus free healthy planting material, (2) After the receipt of a few monsoon regular inspection and removal of infected showers, all the vines are to be drenched with plants and burning or deep burying of the 0.3% Potassium phosphonate @ 5-10 litres/ removed plants, spraying insecticides such vine. A foliar spray with 0.3% Potassium as 0.05% Dimethoate or Monocrotophos to phosphonate is also to be given. A second control the vectors and providing adequate drenching and spraying with 0.3% potassium nutrients including micronutrients to the phosphonate is to be repeated during August- vines. September. If the monsoon is prolonged, a Slow decline (slow wilt) third round of drenching may also be given during October. Slow decline is a debilitating disease of black pepper. Foliar yellowing, defoliation (3) After the receipt of a few monsoon and dieback are the aerial symptoms of this showers, all the vines are to be drenched with disease. The a—ected vines exhibit varying 0.125% Metalaxyl mancozeb @ 5-10 litres/ degrees of root degeneration due to infestation vine. A foliar spray with 0.125% Metalaxyl by plant parasitic nematodes. The root sys- mancozeb may also be given. tem of diseased vines show varying degrees (4) At the onset of monsoon (May-June), of necrosis and presence of root galls due apply Trichoderma around the base of the vine to infestation by plant parasitic nematodes @ 50g/vine. (This quantity is recommended such as Radopholus similis and Meloidogyne 10 for a substrate containing Trichoderma @ 10 incognita leading to rotting of feeder roots. cfu). A foliar spray with 0.3% potassium phos- The damage to feeder roots is caused by these phonate or 1% Bordeaux mixture is also to be nematodes and P. capsici either independently given. A second application of Trichoderma or together. It is necessary to adopt a combi- and foliar spray of 1% Bordeaux mixture or nation of fungicide and nematicide application 0.3% potassium phosphonate is to be given for the management of the disease. during August-September. Insect pests and their control Pollu disease (Anthracnose) This disease is caused by Colletotrichum Major insect pests of black pepper are gloeosporioides. It can be distinguished from pollu beetles, top shoot borer, leaf gall thrips the pollu (hollow berry) caused by beetles by and scale insects. the presence of characteristic cracks on the Pollu beetle infected berries. The disease appears towards the end of the monsoon. The disease can be The pollu beetle (Longitarsus nigripen- controlled by spraying 1% Bordeaux mixture. nis = Lanka ramakrishnai Prathapan & Viraktamat) is the most destructive pest of Viral diseases black pepper and is more serious in plains The a—ected vines exhibit shortening of and at altitudes below 300 m. The adult internodes to varying degrees (stunting). beetles feed on tender leaves and spikes. The leaves become small and narrow with The females lay eggs on tender spikes and varying degrees of deformation and appear berries. The grubs bore into and feed on the leathery, puckered and crinkled. Chlorotic internal tissues and the infested spikes turn spots and streaks also appear on the leaves black and decay. The infested berries also occasionally. The yield of the a—ected vines turn black and crumble when pressed. The decreases gradually. Two viruses namely term pollu denotes the hollow nature of the 60 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). infested berries in the vernacular language The infestation is more severe during the of Kerala State of India, Malayalam. The post monsoon and summer periods. Clip pest infestation is more serious in shaded o— and destroy severely infested branches. areas in plantations. The pest populations Spray Dimethoate (0.1%) on a—ected vines; are higher during September-October in repeat spraying after 21 days to control the želd. Regulation of shade in plantations the infestation completely. Initiate control reduces the populations of the pest in the želd. measures during early stages of pest infes- Spraying Quinalphos (0.05%) during June- tation. In nurseries spraying neem oil (0.3%) July and September-October or Quinalphos or Neemgold (0.3%) or žsh oil rosin (3%) is also (0.05%) during July and Neemgold (neem e—ective in controlling the pest infestation. based insecticide) (0.6%) during August, September and October is e—ective for the Bush pepper management of the pest. Rooted lateral branches grown as bushes are known as bush pepper. Bush pepper can Top shoot borer be raised as potted bushes or želd grown The top shoot borer (Cydia hemidoxa) is bushes. Bush pepper yields green pepper a serious pest in younger plantations in all throughout the year and the fresh yield black pepper areas. The larvae bore into ten- per bush can be up to 1 kg after 3 years of der terminal shoots and feed on internal tis- planting. sues resulting in blackening and decaying of a—ected shoots. Fully grown larvae are grey- Organic black pepper production ish green and measure 12-15 mm in length. For certižed organic production of black When successive new shoots are attacked, the pepper, at least 18 months the crop should growth of the vine is a—ected. The infesta- be under organic management. In new plan- tion is higher during July to October when tations the žrst crop of pepper can be sold numerous succulent shoots are available as organic, as the yielding starts from third in the vines. Spray Quinalphos (0.05%) on year. To convert an existing plantation to tender terminal shoots; repeat spraying at organic, a conversion period of 36 months is monthly intervals (during July-October) to set for perennial crops. The conversion period protect emerging new shoots. may be relaxed if the organic farm is being established on a land where chemicals were Leaf gall thrips not previously used, provided sufficient Infestation by leaf gall thrips (Liothrips proof of history of the area is available. It is karnyi) is more serious at higher altitudes desirable that organic method of production especially in younger vines and also in is followed in the entire farm; but in the case nurseries in the plains. In severe cases of of large extent of area, the transition can be infestation, the growth of younger vines and done in a phased manner for which a conver- cuttings in the nursery is a—ected. Spray sion plan has to be prepared. Dimethoate (0.05%) during emergence of The entire pepper holding can be con- new ¬ushes in young vines in the želd and verted to organic production when pepper cuttings in the nursery. is grown as sole crop. When grown in a mixed Scale insects cultivation system, it is essential that all Among the various scale insects recorded the crops in the želd are also subjected to on black pepper, mussel scale (Lepidosaphes organic methods of production. Black pep- piperis) and coconut scale ( Aspidiotus per as a best component crop in agri-horti destructor) cause serious damage to black and silvi-horti systems, recycling of farm pepper vines at higher altitudes and also waste can be e—ectively done when grown to older cuttings in nurseries in the plains. with coconut, arecanut, co—ee, rubber etc. Crops of Kerala – An overview 61 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

As a mixed crop it can also be intercropped Use of biopesticides, biocontrol agents, with green manure/ legume crops enabling cultural and phytosanitary measures for e—ective nutrient built up. the management of insect pests and diseases In order to avoid contamination of organ- forms the main strategy under organic sys- ically cultivated plots from neighboring tem. Management of pollu beetle by Neemgold non-organic farms, a suitable bu—er zone (0.6%) spray at 21 day intervals during July- with dežnite border is to be maintained. October, shade regulation and management In smallholder groups, where the pepper of scale insects by removing severely infected holdings are contiguous, the isolation belt branches and spraying Neemgold (0.6%) or is needed at the outer periphery of the entire žsh oil rosin (3%) are recommended. group of holdings. Pepper grown on this iso- Application of biocontrol agents like lation belt cannot be treated as organic. In Trichoderma or Pseudomonas multiplied in sloppy lands adequate precaution should be suitable carrier media such as co—ee husk taken to avoid the entry of runo— water and or coir pith compost, well rotten cow dung chemical drift from the neighboring farms. or quality neem cake may be done regularly to keep foot rot disease in check. To control Management practices fungal pollu and other foliar diseases spray- For organic production, traditional vari- ing of 1% Bordeaux mixture may be done eties adapted to the local soil and climatic restricting the quantity to 8 kg copper per conditions that are resistant or tolerant to hectare per annum. Application of quality diseases, pests and nematode infection should neem cake mentioned earlier along with the be used. All crop residues and farm wastes bioagent Pochonia chlamydosporia will be like green loppings, crop residues, grasses, useful to check the nematode population and cow dung slurry, poultry droppings etc. avail- thereby slow decline of the disease. able on the farm can be recycled through Certiœcation composting, including vermicomposting so Certižcation and labeling is usually done that soil fertility is maintained at high level. by an independent body to provide a guarantee No synthetic chemical fertilizers, pesticides that the production standards are met. Govt. or fungicides are allowed under organic sys- of India has taken steps to have indigenous tem. Farmyard manure may be applied @ certižcation system to help small and mar- 5-10 kg/vine along with vermi/leaf compost ginal growers and to issue valid organic certif- @ 5-10 kg/vine based on the age of the vine. icates through certifying agencies accredited Based on soil test, application of lime/dolo- by APEDA and Spices Board. The inspectors mite, rock phosphate/bone meal and wood appointed by the certižcation agencies will ash may be done to get required quantity of carry out inspection of the farm operations phosphorus and potassium supplementation. through records maintained and by periodic When the dežcient conditions of trace ele- site inspections. The grower has to document ments become yield limiting, restricted use of all the details with respect to želd map, želd mineral/chemical sources of micronutrients history sheet, activity register, input record, and magnesium sulphate are allowed as per output record, harvest record, storage record, the limits of standard setting or certifying pest control records, movement record, equip- organizations. Further, supplementation of oil ment cleaning record, labeling records, etc. cakes like neem cake (1 kg/vine), composted Documentation of farm activities is must for coir pith (2.5 kg/vine) or composted co—ee acquiring certižcation especially when both pulp rich in potassium and suitable micro- conventional and organic crops are raised. bial cultures of Azospirillum and phosphate Group certižcation programmes are also solubilizing bacteria will improve fertility. available for organized groups of producers 62 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). and processors with similar production sys- days required when following the traditional tems located in geographical proximity. practice and removes extraneous impurities Harvest and post-harvest management like dust from the berries. Harvesting Pepper has a moisture content of 65 to 70 Black pepper takes about 7-8 months after per cent at the time of harvest, which should ¬owering to reach full maturity. In India the be brought to safer levels of 10 per cent by ade- crop is harvested during December-January quate drying. The green colour of matured in plains and January-April in the high pepper is due to the presence of chlorophyll ranges of Western Ghats. Harvest starts pigment. During drying, enzymatic brown- when one or two berries turn yellow. The ing sets in and the phenolic compounds are spikes are nipped o— by hand and collected oxidized by atmospheric oxygen under the in bags. Normally, single pole bamboo ladder catalytic in¬uence of the enzyme phenolase is used as a support for harvesting. and eventually the product turn black. Recent advances in product diversižcation have necessitated harvesting of the berries Sun drying is the conventional method fol- at di—erent stages of maturity. The level of lowed for drying of black pepper. The despiked maturity required at harvest for processing berries are spread on concrete ¬oor and dried into di—erent pepper products is given below: under sun for 3-5 days to bring the mois- Product Stage of maturity at harvest Canned pepper 4-5months Dehydrated green pepper 10-15 days before maturity Oleoresin and essential oil 15-20 days before maturity Fully mature and 1-2 berries start turning from Black pepper yellow to red in each spike Pepper powder Fully mature with maximum starch White pepper Fully ripe

ture content below 10 per cent. Dried black Post-harvest processing pepper with high moisture content (>12 %) Post-harvest processing operations fol- is susceptible to fungal attacks. Mycotoxins lowed for black pepper involve threshing, produced by fungal attack render the product blanching, drying, cleaning, grading and unžt for human consumption. In order to packaging. During processing care should get quality dry product, pepper berries are be taken to maintain quality during each spread on clean dry concrete ¬oor, bamboo step of operation. Though manual threshing mats or PVC sheets and dried in the sun for is more common, mechanical threshers with a period of 4-6 days. Average dry recovery capacities varying from 50 kg/h to 2500 kg/h varies between 33-37 per cent depending on are available which can thresh quickly and the varieties and cultivars. provide cleaner products. The threshed and dried black pepper The quality of the black pepper can be has extraneous matter like spent spikes, improved by a simple treatment of dipping the pinheads, stones, soil particles, etc. mixed mature berries taken in a perforated vessel in with it. Cleaning and grading are basic oper- boiling water for a minute before drying. This ations that enhance the value of the produce processing technique imparts uniform colour, and help to get higher returns. Cleaning on a reduces the microbial load and helps to dry small scale is done by winnowing and hand the product within 3-4 days as against 5-6 picking which removes most of the impurities. Crops of Kerala – An overview 63 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Packaging or in jute bags. The bags are arranged one Organically grown black pepper should over the other on wooden pallets after laying be packaged separately and labeled. Mixing polypropylene sheets on the ¬oor. di—erent types of pepper is not good from a commercial point of view. Ecofriendly Uses packaging materials such as clean gunny Black pepper is traded as whole dried bags or paper bags may be adopted and the corns, white pepper, powder, extracts, spice use of polythene bags may be minimized. blends and mixtures. Apart from its use as Recyclable/reusable packaging materials a spice and ¬avouring agent, black pepper shall be used wherever possible. has antimicrobial, antioxidant, anti-in¬am- matory and antitoxic properties. It also has Storage carminative, digestive, antioxidant and Black pepper absorbs moisture from antidepressant properties. Black pepper air during rainy season when there is high is also a remedy for skin diseases, ¬u and humidity and may result in mould and congestion, cough and cold, dental problems, insect infestation. Before storage it is to be vitiligo, dandru— and even cancer. Besides, dried to less than 10 per cent moisture. The it is diuretic and diaphoretic. Black pepper graded produce is bulk packed separately in is one of the most common spices used in multi-layered paper bags or woven polypro- di—erent cuisines around the world. It is used pylene bags provided with food grade liners in both the whole and grounded form. 64 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Biology and cultivation of cardamom, the queen of spices V.V. Radhakrishnan Genetics and Plant Breeding Division, Department of Botany, University of Calicut, Kerala – 673635, India.

Cardamom (Elettaria cardamomum the hilly terrains of Western Ghats and the Maton) is a large, perennial, herbaceous rhi- portion south of the Palakkad gap came to be zomatous monocot, belonging to the family known as Cardamom Hills. The cultivation Zingiberaceae. It is a native of the moist of cardamom in India was actively taken up evergreen forests of the Western Ghats of by the erstwhile Travancore Government in southern India. The cardamom of commerce 1823 AD. During 19th century, the Britishers is the dried ripe fruit (capsules) of cardamom established cardamom plantations and plant. This is often referred as the ‘queen of started its systematic cultivation. Cardamom spices’ because of its very pleasant aroma and is cultivated in Kerala, Karnataka and Tamil taste, and is highly valued from ancient times. Nadu states of India. Most of the cardamom It is grown extensively in the hilly regions of growing areas in Kerala are located in the South India at elevations of 800-1300 m as an districts of Idukki, Wayanad and Palakkad. undercrop in forest lands. Cardamom grows In Karnataka, cardamom is grown in Coorg, luxuriantly in forest loam soils, which are Chikmagalur and Hassan districts and to a generally acidic in nature with a pH range lesser extent in North Kanara district. In of 5.5 - 6.5. The crop thrives well in regions Tamil Nadu, cardamom cultivation is located which receive well distributed annual rainfall in certain localities in Pulney and Kodai hills. of 1500 - 2500 mm with a mean temperature Kerala has 57% of area and contributes 88% of 15oC to 30oC and relative humidity of 75 - of production; Karnataka 36% of area and 7% 90%. Cardamom prefers well drained soils of production, while Tamil Nadu has 7% of rich in organic matter and it does not tolerate area and 5% of production. In India the area water logging. under cardamom has come down drastically over the last three decades from 1,05,000 ha Cardamom is one among the major spice during 1987-88 to 70,080 ha during 2016- crops originated in India. Earlier, carda- 17, while production has gone up from 3,200 mom was a minor forest produce and there tons during 1987-88 to 19,625 tons in 2016- was no organized cultivation. The system of 17. During the period, the productivity has cardamom collection from naturally growing increased from 47 kg/ha to 254 kg/ha. plants continued till 1803 at least, but in later years the demand became too large, and Habit large scale organized cultivation started in The cardamom plant is a 2-4 m tall herba- India as a secondary crop in co—ee planta- ceous perennial with branched subterranean tions. But its cultivation spread rapidly in rhizomes from which several leafy shoots Crops of Kerala – An overview 65 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). arise, forming a clump. Leafy shoots have aromatic and about 3 mm long with a thin a limited life span; the žrst year is mainly mucilaginous aril. for vegetative growth, the second year for reproductive growth (¬owers and fruits), and Types/cultivars the third year a senescence and death stage. Based on the nature of panicles and New buds are formed from the base of the old shape and size of capsules, three natural shoots in the žrst and second yearേ and thus cultivars have been observed in cardamom in a clump, old shoots, young shoots and buds namely Malabar, Mysore and Vazhukka. The can be seen in varying numbers. Flowers cultivar Malabar having prostrate panicles are borne on erect, prostrate or semi-erect (panicles spreading on ground) is widely (¬exuous) in¬orescences depending on the grown in Karnataka, while the cultivar variety. Mysore, characterized with erect panicles The leaves are lanceolate in shape and is extensively cultivated in Kerala and parts lamina tapers into a sharp tip and are 25-90 of Tamil Nadu. The cultivar Vazhukka, a cm long and 5-15 cm wide. Leaves are dark natural hybrid between Malabar and Mysore green and shiny on the upper surface and types with distinct semi-erect (pendent) pan- pale green on the lower surface. The lower icles, is the most popular cultivar in Kerala. surface of the leaf could be smooth (glabrous) or pubescent (hairy) depending on the variety. Propagation The in¬orescence arises from the base of the Production of planting material leafy shoots and is 45-120 cm long. Flowers Propagation by vegetative means through are borne in racemes, they are hermaphro- suckers is the most preferred method. dite, zygomorphic and about 4 cm long and Production of planting materials from seeds 1.5 cm wide. The calyx is tubular green and and through tissue culture is also practiced. shortly three toothed and persistent. The Seedling propagated plants may not be true corolla tube is as long as the calyx tube, with to its parent type due to the presence of cross narrow spreading pale green lobes. pollination in the crop. In Kerala, suckers Flowers have an attractive petalloid are used for raising cardamom plantations. labellum which is made of modižed stamens, Sucker multiplication is taken up from the about 1.8 cm long with an undulating edge. žrst week of March to the žrst fortnight The labellum is white in colour with violet of October. The site is selected in open, streaks radiating from the centre. There is gently sloping well drained areas near a only one functional stamen which has a short, water source. Trenches of 45 cm width, 45 ¬at, broad žlament with a longer anther and cm depth and convenient length are taken connected with a short crest. The inferior across the slope or along the contour at 1.8 m ovary consists of three united carpels with apart. They are žlled with equal quantity of numerous ovules in axile placentation and a humus rich top soil, sand and cattle manure. slender style with a small capitates stigma Mother clumps identižed for planting mate- which sits on the top to the anther along the rial production are uprooted partially, leav- crest. Flower initiation takes place in india ing some part in the želd itself for future along with the onset of south west monsoon perennation. The roots are trimmed and during the month of May. From initiation the suckers separated so that the minimum to full bloom it takes 25-35 days, and from planting unit consists of one grown up tiller bloom to maturity, 110 to 140 days. The fruit and a growing young shoot. They are planted is a trilocular capsule, ovate-globose, dark at a spacing of 1.8 m x 0.6 m in filled up green to pale green in colour. On ripening trenches. Sufficient mulch is provided. the capsule turns yellow in colour; it contains Overhead shade and sufficient irrigation 15-30 seeds which are dark brown, angled, are provided during summer months and 66 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). the shading material is removed with the planted in high rainfall and irrigated areas. onset of monsoon rains. Application of DAP A spacing of 1.8 cm x 1.8 cm is suitable for and MOP enables better establishment and Karnataka state of India. Immediately after growth. On an average 20 to 30 suckers per planting, the plant base should be mulched initial planting unit can be produced within well with available dried leaves to protect soil one year of planting. Care should be taken from erosion and conservation of soil mois- to identify and collect mother clumps only ture. Weeds are potential competitors in the from areas totally free from viral diseases. consumption of water and nutrients which will depress the growth of cardamom. Two Field planting and management to three rounds of hand weeding at the plant Before taking up planting, želd should base during May, September and December/ be made ready. For planting in a new area, January and slash weeding in other areas ground should be cleared and if it is a replant- are advisable. The weeded material can be ing area, old plants should be removed. Shade used for mulching. regulation, terracing and preparation of pits Judicious irrigation during summer should be done during summer months. months ensures increase in yield by at least Shade regulation is one of the important prac- 50%. Irrigation is required generally from tices in cardamom plantations. It should be February to April but at times from January carried out during summer (March-April) in to May depending upon the availability of the new planting areas and during May-June rainfall. In cardamom growing areas of after the receipt of summer showers in the Tamil Nadu, where the South-West monsoon existing plantations. If there is thick shade is not very e—ective, irrigation during March- due to dense branches and bigger leaves, August is advisable. This is the period during chopping o— of branches should be done to which development of young tillers and pan- provide žltered light up to 40 to 60 percent. icles takes place and if plant su—ers during Cutting braches from all the sides ensures this stage, yield will be reduced drastically. a balanced canopy. South-western slopes Irrigation can be done through di—erent should be provided with more shade than methods such as hose irrigation, sprinkler north-eastern slopes. Shade trees should irrigation and drip irrigation depending upon have small leaves and tap root system and the facilities available in the plantation. Hose in summer they should not shed leaves. irrigation can be done at weekly intervals In areas having medium and steep slopes, at the rate of 20-30 L per clump depending soil preparation is di—erent from that of gentle on the clump size. In the case of sprinkler, slopes. In sloppy areas soil loss due to ero - irrigation equivalent to 35-45 mm rain at sion should be prevented for which planting fortnightly interval is recommended whereas should be done in terraces. Terraces should in drip irrigation water at the rate of 4-6 L be made across the slope at required distances per day can be given. depending on the spacing adopted. Pits of Forking the plant base to a distance of 90 cm x 90 cm x 45 cm are prepared before 90 cm and to depth of 9-12 cm is found to the commencement of monsoon and about enhance root proliferation and better growth one third of the pit is žlled with top soil and of plants. As far as possible, the entire plan- one third with 1:3 mixture of organic manure tation and particularly the plant base are to and top soil. Suitable planting materials be kept under mulch to reduce the ill e—ects are selected and planted in the already pre- of drought. Removal of old tillers and dry pared and žlled pits and plants should be leaves, known as trashing, is to be carried protected from wind by staking. For Mysore out once in a year after completion of žnal and Vazhukka cultivars plant to plant dis- round of harvest and these materials can tance can be 3 m x 3 m or 2.4 m x 2.4 m when also be used as mulch. Earthing up is not Crops of Kerala – An overview 67 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). required in a normal plantation, but due to with semi-erect panicles are suited for low soil erosion or mismanagement, at times it density planting and intensive management is noticed that the top soil covering the plant practices (1000 plats per hectare). base is washed away and the rhizomes and roots are exposed and in such situations, Selection earthing up of the plant base with top soil Clonal selection is generally practiced in is recommended during December-January. cardamom and it is based on both qualitative and quantitative characters. Initial selection Crop improvement in cardamom for desirable traits is made from In spite of its prominence in world trade the planters’ želd and wild habitats. Selection from time immemorial, systematic research is made based on some passport characters on cardamom was initiated in India only in identižed in the descriptor for the crop. In 1944. Much information on scientižc manage- order to isolate promising clones, germplasm ment of cardamom cultivation has been gen- collections are subjected to initial evaluation erated by now. Primary mandates of carda- studies. Selection in cardamom for high yield mom research in India are crop improvement, and superior quality capsule was initiated development of agrotechniques, development a few decades ago. Though some cultures of strategies for integrated nutrient, pest were isolated earlier they did not become and disease management and development popular among the planting community. of post harvest techniques. As many as six Systematic evaluation of germplasm acces- research organizations are at present engaged sions carried out after 1980s has resulted in in research on improvement of cardamom the identižcation and release of a few elite in India. Over the last thirty years, there clones having high yield potential and good has been a drastic reduction to the tune of quality capsules. 30% in the area under cardamom in India due to various reasons but the production Hybridization has gone up many folds owing to the large The most popular cardamom cultivar scale cultivation of improved varieties suited namely ‘Vazhukka’ is presumed to have to di—erent agroclimatic situations coupled evolved as a result of natural cross between with adoption of high production technology. cv. Malabar and cv. Mysore. Breeding in car- Use of genetically superior planting damom is aimed at evolving recombinants material and cultivation adopting improved which are superior with regard to yield and agrotechniques is the most accepted means to quality of capsules. In cardamom, both inter- enhance crop productivity. Since cardamom generic and intervarietal hybridizations were is amenable to both sexual and vegetative carried out but the results of the former were propagation, methods such as selection, not encouraging. Intervarietal hybridization hybridization, mutation breeding, poly- was successfully carried out using di—erent ploidy breeding and tissue culture are used varieties/cultivars of cardamom for produc- as measures for genetic upgradation of the ing high yielding heterotic recombinants. planting materials. Cardamom is cross pol- Evaluation of these hybrids enabled in the linated, and large variability exists in seed- isolation of over half a dozen high yielding ling progenies. The chromosome number of heterotic recombinants with a yield of above cardamom is 2n=48. Selections and hybrids 1000 kg/ha. have mainly been made for yield improvement and resistance to pests and diseases. Plants High yielding varieties and selections with medium stature and prostrate panicles Various research institutions working on are more suited for closer planting (3000 the crop improvement aspects of cardamom plants per hectare) whereas robust plants have released a number of elite, location 68 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). specižc and high yielding clones having a yield heating. Maturity of capsules and the curing potential of above 450 kg/ha (rain fed) and temperature in¬uence the colour and quality superior capsule characters. Prominent among of processed cardamom. During curing, a them are detailed in the table given below. temperature range of 40-45oC is maintained In addition to this, there are several during all the stages of drying which helps high yielding clones selected by cardamom in good retention of green colour. Gradual o farmers. The most popular and widely cul- increase of drying temperature to 50-60 C tivated among them is ‘Njallani green gold’ in the last two hours of curing enables easy which has very high yield potential and good removal of ¬oral remnants during polishing. quality characters. Other prominent farmer During curing, if temperature exceeds the selections are Palakkudi, Panikulangara, Vali threshold levels, capsules develop brownish green bold, Elarani, PNS Vaigai, Vander car- streaks due to heat injury. An increase in damom, Kalarickal bold, Pulari, Pappalu, drying temperature also results in loss of oil Arjun, etc. Even though fourteen improved from the seeds. A traditional žrewood based and location specižc varieties of cardamom curing house consists of a furnace for burning have been developed and made available to the wood, ¬ue pipes for conveying the hot air farmers by various research institutes work- and drying racks for stacking the trays. The ing on the crop, many farmers still depend capsules are evenly spread as a single layer on promising landraces for cultivation. on the trays. After stacking the trays on the racks in the drying chamber, the curing Harvesting and processing room is closed. Hot air generated by burning Cardamom plants start bearing two or žrewood in the furnace is circulated through three years after planting suckers or seed- the ¬ue pipes, which are placed a few centi- lings respectively. The capsules ripen within meters above the ¬oor. This process enhances a period of 120-135 days after its formation. the room temperature to 45-55oC, which is Harvesting period commences from June- maintained for a period of 3-4 hours. During July and continues till January-February this period, capsules sweat and give o— the in Kerala and Tamil Nadu. In Karnataka, moisture. The drying process is facilitated harvesting begins in August and prolongs till by opening the ventilators for sweeping out December-January. Usually harvesting is the water vapour generated from the drying done at an interval of 30-40 days. The cap- capsules. Exhaust fans are also used for the sules are harvested when they attain physi- speedy removal of moisture. After complete ological maturity, which is indicated by dark removal of water vapour, the ventilators are green colour of rind and black coloured seeds. closed and temperature inside the chamber Harvesting of ripened capsules is avoided as is again maintained at 45-55oC for a period it leads to the loss of green colour and also of 18-24 hours. In the žnal stage of curing causes splitting of capsules during curing process, the temperature is further raised process. Immature capsules on processing to 60-65oC. The temperature is raised to yield uneven sized, shriveled and undesir- hasten the cleaning process by which debris ably coloured produce. Freshly harvested like stalks attached to the capsules can be capsules are washed in water to remove the removed easily. Temperature inside the soil particles and other dirt adhering to it curing chamber is maintained around 65oC and to get good quality commodity. Storage to avoid splitting of the capsules and also to of capsules after harvest for longer duration prevent the loss of volatile oil. Under these adversely a—ects quality of the end product. conditions, it is possible to obtain high quality green cardamom in about 24-30 hours. Curing of cardamom is the process by which moisture of freshly harvested capsules Efficient and highly automated carda- is reduced from 80 to 10-12% through indirect mom driers have been developed and are Crops of Kerala – An overview 69 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Major varieties of cardamom developed in India (kg Yield potential / ha) Special Sl. Selection/ Area of Cultivar distinguishing Source No. Variety adaptability characteristics

An early ma- turing profuse- ly ¬owering va- South Idukki ICRI (Spices riety, medium zone of Kerala, Board), Mylad- 1 ICRI - 1 Malabar sized panicle where the umpara, Idukki, 660 with globose, rainfall is well Kerala- 685553, extra bold, distributed India dark green co- loured capsules Performs well Vandanmedu under irrigat- and ICRI (Spices ed conditions. Nelliampathy Board), Mylad- Suitable for 2 ICRI - 2 Mysore of Kerala and umpara, Idukki, 760 higher altitude. Anamalai and Kerala- 685553, It has medium Meghamalai of India long and parrot Tami Nadu green capsules. Early maturing Regional Sta- type, non-pu- Cardamom tion, ICRI (Spic- bescent leaves, 3 ICRI - 3 Malabar growing tract es Board), 600 oblong bold, of Karnataka Saklespur Kar- parrot green nataka, India capsules. An early ma- Adapted to turing vari- Lower Pulney ety adaptable hills of Tamil Regional Sta- to low rain- Nadu. Suitable tion, ICRI (Spice fall area. Me- ICRI - 4 for low rainfall Board), Thad- 4 Malabar dium size pan- 460 (TDK- 4) area (1500 iankudisai, icle, globose mm) and Tamil Nadu- bold parrot having similar 624 212, India green capsules. agroecological Non pubescent conditions. leaves. Hybrid variety, early bearing, ICRI (Spices high yield, high Kerala and Board), Mylad- oil content deep 5 ICRI - 5 Malabar parts of Tamil umpara, Iduk- 2000 green a bold Nadu ki, Kerala – capsule, moder- 685553, India ately talent to rot disease. 70 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). (kg Yield potential / ha) Special Sl. Selection/ Area of Cultivar distinguishing Source No. Variety adaptability characteristics

Regular yield- er, high oil content, deep ICRI (Spices green long bold Kerala and Board), Mylad- 6 ICRI - 6 Malabar capsule, mod- parts of Tamil umpara, Idukki, 1900 erately tolerant Nadu Kerala- 685553, to rot patho- India gens trips, bor- er and drought. Hybrid variety, Cardamom ICRI (Spices early bearing, growing areas Board), Mylad- high yield, high 7 ICRI - 7 Malabar of Wayanad umpara, Idukki, 1400 oil content deep District of Kerala-685553, green a bold Kerala India capsule. An early ma- turing vari- ety with slight- Cardamom Res. All cardamom ly ribbed light Station (Kera- growing tracts green capsules. la Agri. Univer- 8 PV - 1 Malabar in Kerala and 500 Short panicle, sity), Pampad- parts of Tamil close racemes, umpara, Kera- Nadu ellipsoid to la-685556, India elongate capsules Cardamom Res. High yielder, Station (Kera- deep green long la Agri. Univer- 9 PV - 2 Vazhukka bold capsule, Kerala 1200 sity), Pampad- high dry recov- umpara, Kera- ery percent. la-685556, India Crops of Kerala – An overview 71 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). (kg Yield potential / ha) Special Sl. Selection/ Area of Cultivar distinguishing Source No. Variety adaptability characteristics

Compact plant, suit- able for high density plant- Zonal Hort. Res. ing. Tolerant Traditional Station (Uni- to hairy cat- cardamom versity of Hort. Mudigere erpillars and 10 Malabar growing Sciences), Mudi- 275 - 1 white grubs. Malanad areas gere, Karnata- Short pani- of Karnataka ka- 577 132, cle, oval bold, India pale green cap- sules. Tolerant to thrips and shoot borer. Suited for cul- Suited for Zonal Agri. Res. Mudigere tivation in 475 11 Malabar Karnataka Station, UAS, - 2 valleys in (Valley areas) Mudigere Karnataka An early ma- India Institute turing vari- of Spices, Re- All cardamom ety suitable for search, Carda- IISR, growing tracts high density mom Research 12 Suvasini Malabar of Karnataka 400 planting long Centre, Appan- (CCS- 1) and Wayanad panicle, oblong gala, Karna- of Kerala bold, parrot taka- 571201, green capsules India Resistant to rhizome rot disease, Suit- IISR Cardamom Kodagu, North IISR ed for hot spots Research Cen- Wayanad, 13 Avinash Malabar of rhizome rot tre, Appanga- 850 Hassan and (RR- 1) and leaf blight la, Karnataka- Chikmagalur diseases. High 571201, India quality elongat- ed capsules IISR Cardamom IISR Kodagu, North Research Cen- Vijetha Tolerant to Wayanad, 14 Malabar tre, Appanga- 650 (NKE Katte disease Hassan and la, Karnataka- - 12) Chikmagalur 571201, India 72 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). being widely used with alternative sources social functions and celebrations are not com- of fuels such as kerosene, Liquid Petroleum plete without serving Gahwa or Arab co—ee Gas, diesel or with combination of fuels. (cardamom ¬avoured co—ee). It is believed Such improved systems have the advantage that this drink cools down body heat in a of retaining high quality of produce with country where extreme heat is a regular fea- respect to colour and duration of curing is ture of daily life. It is also believed to aid in also substantially reduced to 16-18 hours. digestion and is said to be an aphrodisiac. Dried capsules are polished either manu- Indian cardamom is low in fat, high in pro- ally or with the help of machines. Polishing tein, iron and vitamins B and C. In India it is is carried out by rubbing the dried capsules used as a masticatory and also in ¬avouring in hot state against a hard surface. The culinary preparations. Cardamom seeds are polished produce is subsequently graded chewed after meals to ward o— foul smell and based on quality parameters such as colour, as a mouth freshener. Recently, in India, a weight per volume, size and percentage of variety of cardamom ¬avoured products have empty, malformed, shriveled and immature come to market such as biscuits, chocolates, capsules. After grading, cardamom capsules health drinks, milk, cheese and so on. It is are stored. The capsules are stored at a also used for making garlands in India and moisture content of less than 10 percent to Arab countries for special occasions. retain the original parrot green colour and Conclusion to prevent mould growth. Use of 300 gauge Till now world demand for cardamom black polythene lined gunny bags improves has been increasing commensurate with efficiency of storage. It is advisable to store the growth in production and due to this the dried cardamom in wooden boxes at room there has been no slump in world market and temperature, preferably in the curing houses. entire production is consumed in the same Uses year without much left over. In the last žf- teen years world production of cardamom has The major use of cardamom on a world- increased almost three times and similarly wide basis is for culinary purposes in the consumption also. Cardamom economy in form of capsules or in the ground form. In the Western Ghat region of India supports a Asia, cardamom plays an important role in sizeable proportion of small farm sector and the preparation of a variety of spiced rice, agricultural labour and there is an urgent vegetable and meat dishes. Cardamom can need to improve and sustain the production add a lingering sparkle to many dishes, both and productivity of the crop. There should traditional and modern. International trade be concerted attempts to achieve a quan- in cardamom is dependent on the demand tum jump in productivity not only through created by specialized applications that have high yielding varieties but also through the evolved in two distinct markets namely the process of constraint alleviation mainly in Arab countries of the Middle East and in respect of drought, pest and diseases. There Scandinavia. Cardamom gives a warm, com- is immense potential and technological fea- forting feeling and it is responsible for the sibility to increase cardamom yield in India peculiar and exotic ¬avour of Bedouin co—ee. and as the global requirements are growing, In the Middle East, religious ceremonies , the future seems to be bright for India. Crops of Kerala – An overview 73 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Biology and cultivation of vanilla, the prince of spices V.V. Radhakrishnan Genetics and Plant Breeding Division, Department of Botany, University of Calicut, Kerala – 673635, India.

Vanilla is a tropical orchid cultivated to cultivation there since 1945. Late in 1960, extract its pleasant ¬avouring principle. It preliminary investigations on the cultiva- belongs to the family Orchidaceae. Though tion aspects of vanilla were initiated at the over 110 species have been described, only Research Station at Ambalavayal in Wayanad three are important as source of the ¬a- District of Kerala. Highly impressed by vouring agent vanillin. They are Vanilla the results, a few enthusiastic planters of planifolia Andrews, Vanilla pompona Schiede Wayanad District took up the cultivation of and Vanilla tahitensis J.W. Moore. Of these, this unique crop. The Government of Kerala Vanilla planifolia is the most preferred also initiated a small scheme at Cheengeri at commercially and hence widely cultivated. Ambalavayal for settlement of tribals through Vanilla is a native of Mexico and Central cultivating vanilla over an area of two hect- America. Congenial conditions for the growth ares. However, these initial attempts did not of vanilla were available in several parts of succeed due to various reasons like lack of the world, but introduction of this plant as a proper care, continued technical support and plantation crop was not possible because of proper marketing arrangements for the pro- the absence of specižc agents for pollination. duce. Nevertheless, these plantations served It was Edmond Albius, a former slave, who as source of planting material for vanilla found out a practical method for artižcial development programmes initiated by various pollination which is still being practiced. This agencies in the recent past. discovery of the method of artižcial pollina- tion of ¬owers and amenability of the crop to Climate and soil vegetative propagation paved the way for com- Vanilla needs a warm and wet tropical mercial cultivation of vanilla in many coun- climate. It grows well on a variety of soils tries. The major vanilla growing countries ranging from sandy loam to laterites provided are Indonesia, Madagascar, Mexico, Tahiti, the soil is loose and friable with high organic Comoro Islands and Reunion. Uganda, Tongo, matter. It ¬ourishes well in partial shade of French Polynesia and India grow vanilla on a about 50%. It can be grown from sea level limited scale. The history of introduction of to over 1500 m above mean sea level in a vanilla into India appears to be obscure since temperature range of 25 to 32oC. Moderate no authentic information on this subject is slope and good drainage help its easy estab- available. According to the record available lishment. The ideal growing condition for with the Fruit Research Station at Kallar/ vanilla is moderate rainfall evenly distrib- Burliar in the Nilgiris, vanilla has been under uted throughout ten months of the year, with 74 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). dry spells during ¬owering and harvesting extend throughout the length of the ovarian period. cavity.

Habit Support plants/standards Vanilla is a herbaceous perennial vine, Being a climber, vanilla requires a support climbing up trees or other supports to a height or standard for climbing. Low branching of 10-15 m by means of adventitious roots. trees with rough bark and small leaves are In cultivation it is trained to a height which preferred as support trees. If the support will facilitate hand pollination and harvest- tree selected is a leguminous one it can add ing. Long, whitish, aerial adventitious roots, nitrogen to the soil. A few of the common sup- about 2 mm in diameter, are produced singly port trees suitable are Glyricidia maculata, opposite the leaves and adhere žrmly to the Plumeria alba and Erythrina lithosperma. support plant. The roots at the base ramify Support trees are planted at least six months in the humus or mulch layer. The stem is prior to planting of vanilla for successful long, cylindrical, succulent and branched. It establishment. Cuttings of 1.5 to 2 m length is 1-2 cm in diameter and is dark green and with 4 to 5 cm diameter are used for planting photosynthetic with stomata. The internodes in žlled pits of about 30 cm x 30 cm x 30 cm are 5-15 cm in length. Leaves are large, ¬at, size at a spacing of 2.5 m between rows and ¬eshy, sub sessile, alternate and oblong-ellip- 2 m within a row. About 1600 to 2000 plants tic to lanceolate. They are 8-25 cm long and are accommodated in one hectare area as 2-8 cm broad. The tip is acute to acuminate a pure crop. However, in optimally spaced and the base somewhat rounded. Venation coconut or arecanut gardens, the number of is parallel and the veins are distinct. The plants will be lower than this. It can be cul- petiole is thick, short and canalized above. tivated as an intercrop in coconut, arecanut and other similar farms. The stout racemose in¬orescences are axillary, usually simple but rarely branched. Propagation and planting They are usually borne towards the top of Vanilla is propagated mainly by shoot vine and are 5-8 cm long with usually 10-26 cuttings, as seed propagation is very diffi- ¬owers opening from the base upwards. The cult. The length of cuttings is to be adjusted rachis is stout and 4-10 mm in diameter. depending upon availability of planting The bracts are rigid, concave and persistent. material. However, cuttings with less than Flowers are large, waxy, pale greenish yel- 30 cm length should not be used for planting low, bisexual and zygomorphic. The sepals directly in the main želd. If longer cuttings and petals look alike and they are commonly are planted, they will grow faster and usually called perianth lobes or tapels. The lower come to ¬ower in the third year after plant- petal is short, broad and it is modižed into ing. Strong, healthy and actively growing a labellum. The lower part of the labellum vines are to be selected as planting material. envelops a central ‘column’ (gynostemium). They should be cut into pieces of about one The tip of the column bears a single stamen metre length with the bottom three or four with two pollen masses (pollinia) covered by leaves removed and kept in a shady place for a cap or hood like structure called ‘rostel- a week to loose water content. The portion lum’, which prevents natural pollination. of a vine which has once given yield is not The slender stalk like portion is the ovary, useable for planting. The cuttings are planted which is 4-5 cm in length. A cross section close to the base of the support tree by laying of the ovary of an opened ¬ower shows three the 3-4 basal nodes from where leaves have carpels, three pairs of žbrovascular bundles, been removed on the soil surface and gently and three pairs of placentae. The placentae pressing these nodes to the soil or putting Crops of Kerala – An overview 75 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). sufficient soil to cover the nodes. While trained from one support tree to the other planting, the basal cut end portion of the within the same row by planting additional cutting is kept just above the soil surface supports in between or on horizontal bars to avoid chances of decay. The top end of connecting two main support trees. Trailing the cutting is to be tied to the base of the or coiling is an important cultural operation support tree gently so that the new sprout as it induces ¬owering. produced from it will eventually climb on them. The ideal time for planting is when Flowering and pollination the weather is neither too rainy nor too dry. Depending upon the altitude of the culti- Under South Indian conditions planting can vated area, ¬owering occurs from December be done between August and October. to May and it takes 45-60 days from the ini- tiation of in¬orescence to ¬owering. If lon - After care ger cuttings are used for planting, ¬owering Vanilla loves organic matter and decom- commences in the third year after planting. posed mulch as they are the main source of Generally one ¬owering occurs in a year. nutrients for the plants. Easily decomposable Removal of growing shoot tips one or two organic matter is applied around the plant months prior to ¬owering season induces base three or four times in a year. Spraying profuse ¬ower production. In¬orescences one percent 17:17:17 NPK complex on the foli- are formed in the axils of leaves on stems age and stem has been found to be benežcial of the previous year’s growth. Twenty or to enhance the growth of vines. Irrigation more ¬owers are found in an in¬orescence. at the rate of two to three litres of water per The stigma is physically prevented from plant in the initial years of growth is neces- coming in contact with the anther by a ¬ap sary. Any operation done in the plantation like structure known as rostellum as men- should not disturb the roots, which are mainly tioned earlier. This makes artižcial hand conžned to the mulch and surface layer of soil. pollination a must for production of beans. In The support tree should be allowed to form Mexico and Central America where vanilla branches to di—erent directions to have an is indigenous, to a lesser extent the ¬owers umbrella shaped appearance about 150 cm are pollinated by Melipona bees and hum - above the ground. From the time of initial ming birds. Elsewhere, hand pollination is planting, the vines attached to the support unavoidable for fruit set. Hand pollination are to be allowed to grow upward. However, if can be easily resorted to with pointed bamboo they are permitted to grow up on the support splinter or tooth pick. With it, the rostellum tree itself, it will rarely blossom so long as it is is lifted up and the overhanging anther is growing upward. Moreover hand pollination pressed against the stigma with the thumb will also be very difficult to be carried out. which ensures smearing of the pollen over Therefore, the vines are allowed to grow up the stigma. The ideal time for pollination to a height of 1.2 to 1.5 metres and allowed is between 6 a.m. and 1 p.m. The fruit set- to hang down on the branches. Such vines ting percentage is found to be the maximum should be brought back to the ground and a when pollination is carried out at 8 a.m. and portion of it placed under the mulch. Later thereafter it shows a decreasing trend as it is coiled again on the same support tree. pollination is delayed. Stigma receptivity Thus the vine should be looped up and down is reported to be for 24 hours. Each ¬ower adjusting the height in such a way that it is lasts for a day only and so pollination should not more than the shoulder height of workers. be carried out on the same day. The ¬ow - This makes operations such as pollination, ers, which are not fertilized, fall o— within harvest and pruning easy and will make the a day or two. It is reported that the size of crop more productive. Vanilla vines can be the beans has a direct positive correlation 76 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). with the amount of pollen deposited on the gives the best quality beans. This method stigma. Normally eight to ten ¬owers located is simple and consists of four stages. on the lower side of the in¬orescence and not more than 10 to 12 in¬orescences in a vine Killing or wilting are pollinated in a plant. The remaining The beans after cleaning are dipped in o ¬ower buds are nipped o— to reduce strain hot water (63 to 65 C) for three minutes to on the vine. If this restriction is not prac - stop the vegetative phase of mature beans tised, dežnitely the beans will be smaller in and or the initiation of enzymatic reactions size. Once fertilization takes place, the ovary responsible for the development of aroma. elongates rapidly for 45 days and full length Killing is indicated by the development of and girth of the bean is attained within 75 brown colouration by the bean. days. Depending upon the elevation of the Sweating cultivated area, the bean takes nine to ten It is done to further raise the temperature months to reach full maturity. The fruit of the beans. The beans are made to sweat by (pod) is a capsule and in trade it is known exposing to hot sun light for about one and a as a bean. The bean is pendulous, narrowly half hours once in a day on a raised platform cylindrical, obscurely three angled, 10-25 cm erected at about 75cm to 100 cm above the long and 5-15 mm in diameter. It becomes ground. This is to be followed immediately aromatic on processing. The vanilla bean after killing. After keeping in sunlight the contains thousands of seeds which are very beans are wrapped in a woolen blanket and minute, black in colour and globose in shape. stored in wooden boxes. Keeping in sunlight Around 50 to 65 mature beans of 15 cm or and the other steps are to be repeated for more length can make one kilogram of fresh 8 to 10 days depending upon local climatic beans. The recovery of dry bean is about conditions. During this operation, the beans 20% of fresh weight. acquire a deeper brown colouration and Harvesting and processing become quite supple, and the development The fresh vanilla beans do not have any of an aroma becomes perceptible. At the ¬avour or aroma because vanillin and other end of the sweating period, the weight of the chemical substances responsible for impart- beans will be around half of the initial weight. ing the peculiar fragrance and ¬avour are not present in free form at the time of harvesting. Slow drying During the process of curing, free vanillin It is done by spreading beans on wooden is developed in the beans as a result of a racks in a room at ambient temperature. series of enzymatic actions on several glu- The period of slow drying can be 20 to 25 cosides. Simultaneously, various aldehydes, days wherein the beans will further loose aromatic esters, protocatechic acid, benzoic moisture very slowly and become more pliable acid, vanillic acid and anisic alcohol are also and capable of being twisted onto the žngers. formed and all these compounds together While slow drying, the relative humidity of give the fragrance of natural vanilla well the room should be kept at more than 70% by distinguishable from synthetic vanillin. hanging moistened cloths or keeping water Immature beans are dark green in colour. in trays below the racks. When the beans When the beans are ready for harvest, they are ready for conditioning after slow drying, will have a pale yellow tinge at the distal their weight will be around one third of the end. Fully matured beans are harvested original weight. for curing or processing. Though di—erent methods of processing vanilla beans are Conditioning followed in vanilla growing countries, the The beans are sorted out depending on Bourbon method, practised in Madagascar length and bundled into 50 or 100 and tied at Crops of Kerala – An overview 77 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). both ends. They are packed in butter paper, share of natural vanillin is likely to increase cellophane paper or polypropylene bags and to a great extent. stored in airtight containers to allow full development of aroma and ¬avour. The van- Constraints illin content of properly cured beans would In view of rising demand for natural be around 2.5 to 3% with moisture content products, the prospects of vanilla cultivation of 20 to 25%. are wide. But the production of vanilla in India is very less. Vanilla cultivation has the Yield problems of availability of improved varieties, The yield of vanilla varies depending on restricted adaptability to high humid area, the age of vines and the method of cultivation. poor seed germination, hindered self polli- Under reasonable level of management, the nation, etc. By evolving suitable varieties average yield of a middle aged plantation and introducing cultivation in coconut and would be about 250 kg of cured beans per arecanut gardens, production of vanilla can hectare. The yield may decline after 12 or be increased in the country. 13 years of planting and so replanting is to be done at this stage. Prospects of Indian vanilla Of late vanilla cultivation is gaining Uses importance in our country mainly due to Vanilla is one of the expensive spices the R & D e—orts of the Spices Board, an traded in global market. The substance autonomous organization under Ministry of chie¬y responsible for the fragrance, ¬avour Commerce & Industry, Government of India. and pleasant aroma of the vanilla beans is Considering the good demand for natural vanillin (C8H8O3). Vanilla essence is largely vanillin extracted from vanilla beans in the used in the preparation of ice creams, choc- international market, the Spices Board has olates, bakery products, puddings, pharma- initiated programmes for its development. ceuticals, liquors, perfumes, soaps, etc. With The area under cultivation has steadily the advent of chemical technology to produce increased since 1990. The area which was vanillin, various types of vanillin such as only a few hectares has increased to over ethyl vanillin, synthetic vanillin, other 1000 hectares by now. There is a big mar - natural ¬avours and secondary metabolites ket for vanilla essence in India but today have taken over the use of natural vanillin. almost entire vanilla essence used is syn- Nevertheless, natural vanillin is still the most thetic. Considering the growing international preferred as a spice for ¬avouring food owing market and the possibility to use natural to its delicate aroma with pleasant taste. vanillin in our country, there is a bright World over, there is an increasing trend for future for vanilla cultivation in India in the use of natural products and therefore the years to come. 78 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Biology and cultivation of grain amaranths V. Prajitha and J.E. Thoppil Cell and Molecular Biology Division, Department of Botany, University of Calicut, Kerala-673635, India.

“Amaranth - thou art immortal and dost one of the answers to coming dry seasons. never fade, but bloomest for ever in renewed It can dežnitely ensure global health and youth” were the words of rose to amaranth food security in future. Hence this plant can according to Aesop, the Greek story teller. rightly be considered as a food from the past Amaranth has always been in the lime- for the future. light as a crop for farmers and as a topic of The word ‘amaranth’ in Greek means interest for researchers. The plant gets its ‘everlasting’ and in fact, the crop has endured. name from the Greek word amaranthon mean- To assure a small annual supply of this ing ‘unfading’ or ‘immortal’. Interestingly, crop, traditional farmers have continued this plant has been a favourite of poets too. to grow small plots of the grain each year. The beauty of its unfading ¬owers was even Furthermore, the distinctly beautiful appear- referred to by famous poets like John Milton, ance of amaranth has helped to prevent the Francis Thompson, Samuel Taylor Coleridge crop from slipping into obscurity. and John Keats. In the poem ‘The Hound of The small seed size of amaranth might Heaven’ (1893), Francis Thompson even goes have been a partial cause for the reduction a step further to compare God’s love to “an of amaranth cultivation in some areas. As amaranthine weed”. No words can express a small seeded crop, it requires greater the beauty and popularity of this leafy and attention in the early parts of the growing grain crop than those mentioned above. season when compared to a larger seeded The question why this crop has attained crop like maize. The cultivation of grain global attention, points to its peculiar proper- amaranth is now in the process of expanding ties, mysterious origins and current agricul- in a number of countries. Grain amaranth tural development. And, it is increasingly pop- research at Rodale Research Center (RRC, ular with gardeners who žnd it fascinating for Pennsylvania, USA) focuses on three areas: its ease of cultivation, colourful appearance germplasm preservation and utilization, the and diverse uses in the kitchen. Owing to development of improved lines and outreach its wider adaptability, low production cost and information dispersal. Over the past ten and high nutritional value, it played a major years, RRC has sent seeds of segregating role in wiping out malnutrition and hunger accessions and improved lines of grain ama- amongst the poorest populations in Africa in ranth to researchers of over 70 countries. the past 20 years. It serves as a poor man’s Many of those countries now have internally vegetable. There are evidences for this plant funded amaranth projects of their own. The being grown from prehistoric times. A plant American Amaranth Institute (AAI), which grown as a food crop 1000 years ago could be has been organized to promote research Crops of Kerala – An overview 79 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). and development in amaranths, is working Mayas considered amaranth as their staple closely with many other research institutions food together with maize and beans. It is to develop standards for amaranth seed one of the traditional food plants in Africa certižcation. used to wipe out malnutrition within poor Farmers are developing innovative tech- segments of the population. It was one of niques to žnd ways to produce grain ama- the most important crops of America before ranth economically. As a result of their inge- Spanish colonialists conquered it and further nuity, the supply of commercially available cultivation of the crop was banned. Amaranth amaranth has increased to the point where was žrst introduced as an ornamental plant th several food companies are producing ama- to Europe in the 16 century. Di—erent species ranth products which can be purchased in of Amaranth spread throughout the world th th th many stores in the USA. The rising demand during 17 , 18 and 19 century. In India, for amaranth food products will require a China and even under the harsh conditions substantial increase in amaranth production of Himalayas this plant became an important during the coming years. grain and/or vegetable crop. After the arrival of the Spanish Conquistadors in Mexico in the There are reports from collaborating early 1500s, amaranth almost disappeared in researchers that there are substantial plant- the Americas as a crop until research began ings of grain amaranth in Mexico, Kenya on it in the U.S. in the 1970s. In the mean- and China to produce grain for export, as time, amaranth had spread around the world well as for domestic use. Even though sev- and became established for food use of the eral advancements are being made in the grain or leaves in places such as Africa, India development of grain amaranth species, it and Nepal. In the past two decades, amaranth is important to stress that many research has reiterated to be grown by a much larger questions and developmental opportunities number of farmers around the world in China, still exist for those who wish to make an Russia, parts of Eastern Europe and South impact on the expansion of this crop. America and is re-emerging as a crop in Mexico. Amaranth was grown as a grain crop Origin and distribution in the U.S. in the late 1970s. The valuable Amaranth is a very old cultivated crop characteristics of amaranth grain, combined believed to have originated in the American with its adaptation to a wide range of grow- continent. It has been a staple food in ing areas, make it a very promising crop for Mesoamerica for thousands of years, žrst the future. At present amaranth is grown collected as a wild food and then domesti- in the USA, South America, Africa, India, cated at least as early as 4000 BC. About China and Russia. The Czech Republic is the 60 species are native to the Americas, most important grower in Europe (approx. whereas less numerous are the species 250 ha). The largest area of the grain-type originally from Europe, Africa and Asia. amaranth is in China, where 150,000 ha are The most widespread species are native reportedly grown for forage use. Amaranthus to North, Central and South America and is the most popular leafy vegetable in india, these are Amaranthus cruentus, A. cauda- mostly cultivated in Kerala, Tamil Nadu, tus and A. hypochondriacus. The species A. Karnataka, Maharashtra, Andhra Prasesh cruentus and A. hypochondriacus are native and Telangana. of Mexico and Guatemala and A. caudatus is widely distributed both in South America Botany and India. This species developed as one of The genus Amaranthus belongs to the the staple foods for the ancient inhabitants monoclamydous family Amaranthaceae of the Andean region. The Aztecs, Incas and and consists of 60–70 species, 40 of which 80 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). are considered native to the Americas. Over set seeds at a smaller size during short days. 400 varieties within these species are found Grain types may produce yields comparable throughout the world in both temperate and to rice or maize [2,500 kg/ha]. tropical climates. The three grain ama- Amaranth is a quantitative short day ranth species viz. Amaranthus caudatus L., plant, which is an advantage in the sub- Amaranthus cruentus L. and Amaranthus tropics where the generative stage is delayed hypochondriacus L. are cultivated in Mexico, during summer. Amaranths like fertile, well Central America and the Andean highlands drained alkaline soils (pH > 6) with a loose of Southern America for several thousand structure. The mineral uptake is very high. years. The species have gained high popu- Flowering of Amaranthus species can start larity in the Indian subcontinent as well. 4–8 weeks after sowing. However, the growth These amaranth grains are highly rich in and development patterns are highly variable protein and the essential amino acid lysine. from one species/cultivar to the other and In recent years these have received global may also depend on photoperiodism, altitude attention, being a quality protein crop that and cultivation practices. Overall, the three can stand remarkably well against abiotic grain species have a longer growth period stress under marginal management prac- than weedy species. tices. One motivating factor for the initiation In the Amaranthus genus, several species of the amaranth research evolves from the are weeds, a few are ornamentals, some are perceived need to broaden the food base by leafy vegetables and some are having forage the utilization of underutilized food materials. use potential. Grain amaranths are 2 to 8 feet Amaranth is one of the 23 tropical plants tall, but the most commonly grown variety recommended for studies aimed to enhance ‘Plainsman’ (a hybrid of A. hypochondria- food quality in the tropics. cus x A. hybridus) is usually 5 to 6 feet tall. Grain amaranths are herbaceous annuals Plainsman has a single unbranched stem, with upright determinate growth habit. They with a large mass of tiny maroon ¬owers are tall (0.5–2 m) and moderately branched clustered in an in¬orescence at the top of from a main stem or unbranched and develop the plant. Grain heads of ‘Plainsman’ range dense panicles at the tip of the stem. They from 4 to 12 inches in length and 2 to 8 inches are characterized by large to moderately in width. Grain amaranths vary in ¬ower, large complex in¬orescences comprising of leaf and stem colour, but maroon or crimson aggregates of cymes. Most amaranth spe - colour is common in these plant parts. Some cies are monoecious and a few are dioecious. varieties have green ¬owers and others are The ¬owers can be terminal or axial, but are golden. Some of the deep crimson varieties always organized into glomerules within the can be very striking when in full bloom. A in¬orescence. Within the glomerules the žrst few small clusters of ¬owers may occur at the ¬ower is generally staminate and the later žrst few leaf axils below the head. ¬owers are pistillate. The grain, vegetable, ornamental and The ¬owers show 5 tepal lobes, 5 stamens weedy types do have some distinct variations. and unilocular superior ovary. The seeds The leaves and grains of all types are edible show variable seed coat colour. Vegetable and equally nutritious. The seed or grain of amaranths can be easily distinguished from the grain type is of a pale colour, varying grain amaranths by in¬orescence features from o—-white to pale pink. The seeds of the like mostly or exclusively axillary glomerules vegetable, ornamental and weedy types are or short spikes, origin of ¬ower bud from leaf black and shiny. Both types are edible and axil, 3 tepal lobes, 3 stamens, brownish black may be used as ¬our sources, but if the black seeds and indeterminate growth habit. They seed types are mixed in the pale types, it is form ¬owers and seeds along the stems and often considered as adulteration. The grain Crops of Kerala – An overview 81 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). amaranths are characterized by having dis- light weight, but not otherwise adapted for coid grains with well di—erentiated folded wind dispersal. ¬ange region and seed coat colour other than Several investigations are going on to black or brownish black. So the seed character gather phylogenetic relations among the three is very useful in demarcating vegetable, grain species of grain amaranth to provide infor- and weed amaranths. mation for breeding experiments, germplasm Amaranth has a ‘C-4’ photosynthetic path- conservation e—orts and decision on evolution- way as in the case of other cereals, which ary patterns in the grain types. Hybrid devel- enables it to be uniquely efficient in uti - opment programmes from crosses between lizing sunlight and nutrients at high tem- these species have been carried out to žnd peratures. It is more drought resistant than out the genetic relationship between them. maize and thrives in 30–35°C temperatures Interspecižc crosses have been made and it and tolerates poor fertility also. Amaranth has been found that that A. cruentus is closer can be cultivated in some areas where farm- to A. hypochondriacus than to A. caudatus. A. ers have limited options, especially in those caudatus is also closer to A. hypochondriacus areas with limited rainfall. The drought than to A. cruentus. tolerant characteristics of amaranth make it a prospective dry land crop for farmers in Cytogenetics semi-arid areas. Amaranths as C4 plants, The genus Amaranthus is characterized grow rapidly under a variety of unfavorable by small sized chromosomes with indistin- abiotic conditions, including drought stress, guishable secondary constriction, satellites, heat stress, high salinity, etc., making them etc. and this fact has restricted the cytoge- uniquely suited for subsistence agriculture. netical studies of this crop. The taxonomy of In botanical terms, grain amaranth is not the genus Amaranthus has also been confus- a true cereal because it is a dicotyledonous ing due to the extreme range of phenotypic plant. Hence they are referred to as ‘pseudoce- plasticity among the species and the possible reals’, as their seeds resemble in function introgression and hybridization involving and composition those of the true cereals. weedy and crop species. Amaranth seeds are small (1-1.5 mm diame- Karyomorphological studies in ter), lenticular in shape and weight per seed is Amaranthus are scarce, probably due to 0.6-1.3 mg. The grain structure of amaranth higher number of small sized chromosomes. di—ers signižcantly from that of cereals such Updated data have indicated that there are as maize and wheat. In amaranth seeds, the two basic chromosome numbers such as embryo or germ, which is circular in shape, x=8 and 9 in the family Amaranthaceae. surrounded by the starch rich perisperm and The genus Amaranthus is tribasic, because together with the seed coat represents the three gametic numbers viz., n = 14, 16, and bran fraction, which is relatively rich in fat, 17 were reported previously. The gametic protein, vitamins and minerals. Seed produc- number n=17 seems to be originated from tion in grain amaranth varies with growing n=16 through primary trisomy. In some cases conditions. Seed production per plant could be both 16 and 17 can occur in the same species. estimated from plant height and basal stem Based on cytogenetic analysis of interspecižc diameter. The size and weight of the seeds hybrids, it has been proposed that the species vary between the populations of the same with 2n=32 are polyploids (basic number x=8) species, between the individuals of the same and that x2=16 is a derived basic number. populations and even between seeds on the The basic number x2=17 would have appeared same plant. Seed dispersal is accomplished later by primary trisomy. A study pertaining by wind, water, birds and animals and also to the karyological details of the three grain by human activities. Amaranthusseeds are amaranths viz., A. caudatus, A. cruentus and 82 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

A. hypochondriacus has revealed the diploid holds a collection of about 520 accessions of chromosome number as 2n=32, 34 and 32. 18 amaranth species. The breeding objectives of grain Crop improvement amaranths include raising yield, increasing Grain amaranths are pseudocereals that harvestability and developing properties played an important role as human food in like lodging resistance, reduced seed shat- the ancient civilizations of America. Current tering, seedling vigour, uniform maturity, interest in amaranths resides in the fact synchronous drydown of the plant and that they exhibit high nutritional value, seedhead, reduced leažness in the green head C4 photosynthetic pathway, great amount of area, reduced plant height, pest resistance/ genetic diversity and phenotypic plasticity. tolerance, tolerance to damping o—, larger Amaranths are predominantly self-pollinated seeds, good nutritional prožle of seed (high with varying amounts of outcrossing. By seed protein), tolerance to cold, etc. growing amaranths in isolation, it is possi- ble to control the amount of outcrossing for Four grain amaranth varieties registered the development of true to type lines from in Crop Science are ‘Montana 3’ (‘MT 3’), segregating accessions within a few genera- ‘Montana 5’ (‘MT 5’), ‘Amont’ and ‘Plainsman’. tions of selection. Many selections have been Several lines have been developed by RRC, made from the segregating accessions in an NU-World Amaranth and AAI, and have e—ort to create uniform lines. Seeds from the been widely distributed and tested. All of amaranth accessions have been distributed to the registered cultivars trace to materials thousands of researchers and farmers around developed by the RRC. The cooperative the world. The germplasm collections at var- amaranth breeding programme between ious institutes such as RRC, AAI, CAAS, the RRC and the University of Nebraska INIFAP, UNSAAC/CICA, NBPGR, etc. are started in 1992 resulted in the release of the backbones of varietal improvement pro- the variety ‘Plainsman’. Breeding objectives grammes aimed at developing agronomically for ‘Plainsman’ development included early acceptable lines using classical plant breeding maturity, light seed colour and short plant and selection methods. Amaranthusis well height. ‘Plainsman’ matures in 110 days suited to ex-situ conservation because the after planting in some of the planting areas. seeds are long lived and small. Evaluation tests in Nebraska, Colorado, Missouri, Minnesota and South Dakota Identižcation and preservation of germ- indicated that ‘Plainsman’ was one of the plasm are necessary for maintaining genetic most promising amaranth cultivars for the diversity, studying local genetic material in United States. It became popular due to its order to choose ecotypes having high nutri- relatively high yield potential, lodging resis- tional interest in their place of origin, and tance, limited seed shattering, seed colour initiating breeding programmes. RRC has and early maturity. got approximately 1,400 accessions mostly represented by A. cruentus, A. hypochondri- In India, a grain amaranth variety named acus, A. caudatus, A. tricolor and A. dubius. ‘Annapurna’, a cultivar of A. hypochondriacus The Amaranthus germplasm collection of the has been developed through selection in India. Plant Introduction Station (USDA, USA) Annapurna’s average grain yield is 22.3q/ includes approximately 3,000 accessions. ha. The whitish creamy seeds of Annapurna The National Botanical Research Institute contain about 14.5% protein and it shows (NBRI, India) has one of the best collections of excellent popping quality. It shows the follow- amaranth germplasm in the world with over ing plant and yield characters: plant height: 2,500 accessions referable to 20 species. The 220-225cm; ¬owering: 75 days; maturity: 140- World Vegetable Center (AVRDC, Taiwan) 145 days; stem: stout, generally unbranched, Crops of Kerala – An overview 83 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). ridged; foliage: leaves broad, dark green, lan- stems are interesting vegetables suitable for ceolate (24 cm x 12 cm); in¬orescence: long soups, salads and other dishes, used across (70 cm), green, compact with terminal and Africa, Asia and the Americas. A. dubius, lateral spikelets; test weight: 0.8-0.9 g/1000 A. cruentus and A. tricolor are adapted for seeds; seed colour: cream white. growth as leafy vegetables in areas with hot Other varieties developed are ‘Pastevnyi climate, especially in the hot humid tropics. 1’, ‘Turkestan’ and ‘Ural’ of Russia; A. cru- The leaves are a good source of carotene, entus variety ‘Anden’ of South America and iron, calcium, ascorbic acid, vitamins and ‘Noel Vietmeyer’, ‘Oscar Blanco’ and ‘Alan proteins. In Africa and the Caribbean, Garcia’, released from selection programmes amaranth is commonly eaten as a pot herb, in Peru. with individual leaves picked o— the plants periodically. The leaves of both the grain and The cultivated species of grain amaranth vegetable types may be eaten raw or cooked. are monoecious. Conventional and modern Amaranths grown principally for vegetable methods of hybridization have been used use have better tasting leaves than the grain to improve grain amaranths. Recently the types. A dark seeded strain of A. cruentus potential for the development of hybrids has L. is commonly cultivated as a vegetable in been advanced by the identižcation of gene West Africa. markers. Markers can be used to identify and discard self-pollinated plants in the The food value of grain amaranth was F1 generation. In addition, markers allow recognized by the people of Mexico, Peru and breeders to avoid the process of emasculation Nepal long before any nutritional analyses when making crosses. The identižcation of had been conducted. Because it is easy to three sources of cytoplasmic male sterility digest, amaranth is traditionally given to paved the way for additional hybridization those who are recovering from illness or techniques. Genetic investigations have been a fasting period. Amaranth is used as an conducted in India to learn more about the ingredient primarily in bread, pasta, baby traits which control yield, including harvest foods, instant drinks, etc. For such purposes index, yield per plant and weight per 1000 seeds have to undergo processing through seeds. There have also been some unique boiling, swelling, flaking, extrusion, puff- investigations to identify the mode of inher- ing, roasting, grinding, sprouting, etc. The itance of traits that a—ect the nutritional most common product is ¬our and whole ama- characteristics of the grain. ranth seeds in breads, musli bars, porridges, pastas, biscuits, cookies, etc. In Mexico, grain Uses and economic importance amaranth is popped and mixed with sugar The demand for food is increasing, not only solution to make a confection called ‘alegria’ to meet food security for growing populations, (happiness). A traditional Mexican drink but also to provide more nutritious food, rich called ‘atole’ is made from milled and roasted in good quality proteins and nutraceutical amaranth seeds. In India, A. hypochondria- compounds. Amaranth is a valuable nutri- cus is known as ‘rajgeera’ (the King’s grain) tious foodstu— with high production potential. and is often popped to be used in confections The edible parts are the seeds, leaves and called ‘laddoos’ which are very similar to tender stems. They are non-grass, broad- Mexican ‘alegria’. In Nepal, amaranth seeds leaved plants that produce small seeds on are eaten as a gruel called ‘sattoo’ or milled a sorghum like head. The grain is a pseudo into a ¬our to make chapattis. cereal consumed in various parts of the world Grain amaranth species are cultivated due to its higher dietary benežts. exclusively for seed production in the U.S. The amaranth species as a group is used and other regions of the world. The attraction for a wide variety of purposes. Leaves and of the crop to both earlier civilizations and 84 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). modern consumers is the highly nutritious of its distinctive characteristics. The most golden seed. The most studied nutritional intriguing is the microcrystalline starch in aspect concerning the food value of grain amaranth seed, which is about one-tenth the amaranth is the identižcation of the limit- size of corn starch particles. The small size ing amino acids of the protein component. of the starch could be of value in both food The crude protein content of selected light and industrial uses. seeded grain amaranths has been reported Amaranth grain contains 6 to 10% oil, to range from 12.5 to 17.6%. The grain is which is found mostly within the germ. The reported to have high levels of lysine, a nutri- lipids are rich in tocotrienols and squalene, tionally critical amino acid, ranging from which are natural organic compounds 0.73 to 0.84% of the total protein content. positively involved in lowering low density Lysine is an amino acid which is dežcient in lipoprotein blood cholesterol. Amaranth other grains. Its high lysine content makes it lipids are characterized by a high degree particularly attractive for use as a blending of unsaturation, which is desirable from a food source to increase the biological value nutritional point of view. Linoleic acid is the of processed foods. The high protein content, most abundant fatty acid followed by oleic acid the well balanced amino acid prožle, high and palmitic acid. Another interesting compo- content of fat, žbre and minerals all make the nent of amaranth oil is squalene, a terpenoid grain amaranths candidates for a renewed compound ubiquitous in the unsaponižable major role as world food source. Grain spe- fraction of cereal grains, used in medicines cies of Amaranthus are not only richer in and cosmetic industry. Amaranth seed oil protein content than other cereals but also contains approximately 6% of squalene a their properties for human diet are closer to considerably higher amount than usually nutritional perfection. found in oils from other cereal grains. Its Amaranth is valued for the positive chem- importance as a food constituent resides in its ical composition of seeds that does not con- ability to lower cholesterol levels by inhibiting tain gluten/prolamin, a composite of storage its synthesis in the liver. Plant sterols (phy- proteins, stored together with starch in the tosterols) are another group of biologically endosperm of various grass related grains. active components present in pseudocereal Consumption of gluten rich grains will cause lipids. Phytosterols, which cannot be absorbed celiac disease in sensitive individuals. The in the human intestine, have very similar individuals, who are allergic to wheat, use structure to cholesterol and they inhibit substantial quantities of amaranth grain and intestinal cholesterol absorption, thereby žnd that they can substitute amaranth for lowering plasma total and low-density lipo- wheat without an allergic reaction, since protein (LDL) cholesterol levels. Total sterols amaranth is gluten free. in amaranth lipids can represent approxi- Starch is the major part of carbohydrate mately 20% of the unsaponižable fraction in grain amaranth and starch granules are with the predominant sterol present being small (1-3 mm), polygonal in shape, with chondrillasterol. high swelling power and is easily degrad- Amaranth which produces a large amount able by alpha-amylase. Amaranth starch of biomass in a short period of time can be is highly stable during freezing and highly used as a forage crop for domestic animals. resistant to mechanical stress. There is a Several cuttings can be made per growing distinctive gel characteristic to the starch season. The forage use of amaranth is estab- and both waxy and non-waxy starch gran- lished in both the tropic and temperate zones. ules have been identižed. Interest has been In many tropical areas, where amaranth is expressed in specialized food and industrial consumed as a vegetable, amaranth stover applications for amaranth starch as a result is fed to livestock after several harvests. Crops of Kerala – An overview 85 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Amaranth forage has succeeded as an ani- cardiovascular diseases, regular consump- mal feed in the temperate zone of China. In tion reduces blood pressure and cholesterol Peru, stover is grazed or milled for use as a levels, while improving antioxidant status feed supplement after the seed heads have and some immune parameters. In Ethiopia, been hand harvested. In the U.S., animals A. cruentus is used as a tapeworm expellant. always used to eat wild amaranth, but not In Sudan the ash from the stems is used as a as a deliberately managed forage. wound dressing and in Gabon heated leaves Many amaranths have become popular are used on tumours. ornamental plants and are found worldwide. Some types of amaranths accumulate Examples include brightly coloured A. tricolor toxic levels of oxalate and nitrate when grown ‘bedding plants’ and A. caudatus ‘love lies under conditions of stress. The occurrence of bleeding’ plants with beautiful drooping rope phenolics, saponins, tannins and phytic acid like in¬orescences. The enchanting beauty of (a well-known inhibitor of iron absorption and the vividly coloured leaves, stems and seed other minerals), in the whole grain has also heads in an amaranth želd is a sight which been reported. Some studies suggested that evokes emotions that other crops cannot give. thermal processing of amaranth, particularly in moist environment, prior to its preparation Studies have shown that as pseudocereals, in food and human consumption may be a amaranths represent good sources of min- promising way to reduce the adverse e—ects of erals, vitamins, dietary žbre and natural amaranth’s antinutritional and toxic factors. dyes. Contents of minerals depend on species and growing conditions. Amount of calcium Future prospect of grain amaranth and magnesium are higher than amounts Amaranth is a versatile crop with a long in other cereals. The anthocyanin (reddish) history of domestication and use. To date pigments in amaranth ¬ours and vegetable only a modest amount of research and plant appear to have great potential for compet- breeding have been done with this plant, ing with sugar beets as a source of natural, mostly with the grain types. Amaranth is non-toxic red dyes. Seeds are good source of an important plant to diverse human popu- vitamins mainly Vitamin B and E. Polyphenol lations around the world, but its use could be compounds have been extensively researched greatly enhanced through further breeding in the last decade for health promoting prop- and research. With the diverse collection of erties such as their role in the prevention of germplasm available, rapid progress could degenerative diseases which include cancer be made with a minor investment in screen- and cardiovascular diseases. The main phe- ing and breeding projects. Investigations by nolic compounds found in amaranth seeds amaranth researchers and farmers around are ca—eic acid, p-hydroxybenzoic acid and the world have provided a solid foundation ferulic acid. for further development of this valuable crop In addition to nutritional properties, plant. Additional research is needed to better grain amaranths are already known for dežne the feeding values, potential toxicity their high medicinal value. Several stud- problems and possible cultivation strategies ies have shown that amaranth seeds or oil of both utilized and underutilized grain ama- may benežt those with hypertension and ranth species. 86 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Biology and cultivation of coffee V.B. Sureshkumar Regional Co–ee Research Station, Narasipatnam, Andhra Pradesh-531116, India.

Co—ee is the most popular beverage and with suitable intercrops is now widely being a very important commodity. Among the popularised in Andhra Pradesh, Odisha and traded commodities in the global market, north-eastern states to check deforestation oil is the žrst, co—ee the second, natural and sustain the livelihood of the tribal people gas the third and gold the fourth in posi- of these regions, as these areas are found tion. Co—ee is cultivated from 25o North to suitable for co—ee. In India, presently co—ee 25o South of the equator in Africa, South is cultivated in an area of around 4.5 lakh East Asia and Central and South America. hectares with average annual production Global production of co—ee is around 96.32 above 3 lakh tonnes. lakh tonnes presently. Brazil is the major India exports around two third of its pro- producer, sharing one third of global pro- duction. Major quantity is exported to Italy, duction. Out of the total global production, Belgium, Turkey and Russian Federation. more than 90% is produced in developing India’s co—ee exports generated revenue of countries. Nevertheless, major quantity is Rs.5600 crores during 2016-17. being consumed in developed counties. In India co—ee is cultivated mainly in Botany the hilly tracts of Karnataka, Kerala and Co—ee belongs to the family Rubiaceae. Tamil Nadu. Co—ee based farming systems Co—ee is the most economically important Production of coŠee in major produc- genus of the family. There are about 100 spe- ing countries (MT) cies of co—ee. But Co¡ea arabica (Arabica co—ee) and C. canephora (Robusta co—ee) are Countries Arabica Robusta Total the two economically important species and Brazil 2736000 630000 3366000 are cultivated on large scale. C. liberica (tree Vietnam 66000 1536000 1602000 co—ee) is also cultivated to a small extent in some regions. Co¡ea arabica is tetraploid Columbia 876000 0 876000 (2n=44) and it is the major variety cultivated. Indonesia 78000 558000 636000 If untopped, Arabica grows like a small tree Honduras 444000 0 444000 to a height of over 30’ (9m) but on regulation Ethiopia 391200 0 391200 through training/pruning it looks like a small bush. Co¡ea canephora is diploid (2n = 22) India 94980 217020 312000 and the second largest cultivated species. Others 1363320 641340 2004660 It is robust in growth compared to Arabica. Total 6049500 3582360 9631860 Without training/pruning it also becomes a Crops of Kerala – An overview 87 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Area and production of coŠee in diŠerent in Robusta it is about 9 to 11 states of India months. Area under coffee Production of coffee (Metric Co—ee fruit is a drupe State (Hectares) tonnes) with ¬eshy pericarp (fruit Arabica Robusta Total Arabica Robusta Total skin) having deep red colour Karnataka 108845 135940 244785 70510 151235 221745 in general. Below the fruit skin lies the mucilaginous Kerala 4228 81642 85870 2140 61125 63265 layer surrounding the hard Tamil Nadu 29513 6094 35607 11850 4485 16335 parchment cover containing Andhra & 75327 267 75594 10400 50 10450 the co—ee bean of commerce. Odisha Normally each fruit con- NE States 5903 1598 7501 100 105 205 tains 2 beans, elliptical or Total 223816 225541 449357 95000 217000 312000 egg shaped, with the seed coat known as silver skin. tree. Due to cross-pollination, wide ranging Sometimes abortion of one variation within the population is observed. ovule due to non-fertilization leads to the Both Arabica and Robusta are perennial formation of a single seed, the ‘pea-berry’. evergreens. They have prominent vertical Occasionally 3 or more seeds may be seen stems with horizontal branches in pairs due to the presence of more than one ovule opposite to each other, known as primaries. per locule. The upright shoots, arising from the stem is Co—ee consists of a stout central root grow- known as ‘suckers’ or ‘water sprouts’. These ing 0.5 m to 1 m depth with 4 to 8 axial roots. grow more profusely when the plant is topped. The lateral roots grow more or less parallel to These orthotropic suckers are used in vege- the soil surface to a distance of 1.2 m to 1.8 tative propagation. The shape of co—ee leaf m from the trunk. The feeder roots are seen is usually elliptical. The length and breadth in larger numbers in the surface soil. The of co—ee leaf vary considerably depending on concentration of the feeding roots increases the species, shade intensity and cultivation from the centre towards the periphery. In practices. Arabica feeder roots are the highest at the Flower buds appear at the leaf axils of 30-60 cm layer and in Robusta they are con- mature wood and sometimes on green wood centrated in the žrst 30 cm layer. as in¬orescence. Four to six in¬orescences Climatic factors suitable for co‚ee are produced per axil, each in¬orescence cultivation containing up to 5 to 6 ¬owers depending For successful establishment and eco- on various in¬uencing factors. Under South nomic production of co—ee a variety of factors, Indian conditions the mature buds blossom climatic as well as edaphic, must be optimal. in the dry months of February to April, seven As co—ee is a perennial crop and economic to ten days after receipt of the žrst summer life span of a plantation ranges from 40 to showers or irrigation. Arabica is predomi- 70 years depending upon variety. Selection nantly self pollinated with di—erent degrees of a proper site is imperative to make it pro- of natural cross pollination in contrast to ductive and prožtable.The optimum altitude Robusta, which is strictly cross pollinated. for Arabica co—ee is 1000-1500m (3250-5000 Pollination occurs within 6 hours after ¬ower- feet) and for Robusta co—ee is 500-1000 m ing under bright light. Wind, gravity and bees (1600-3520 feet). help pollination. The process of fertilization is completed within 24 to 48 hours of pollination. The term aspect is used to describe the In Arabica, period of development from ¬ower slope of the land in relation to the direction of to ripe fruit is about 6 to 8 months, whereas the position of the sun in the morning hours. 88 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

In general, north, east and north-east aspects bases. A deep soil provides a larger volume are ideal for both Arabica and Robusta. for root proliferation to explore water and However, the desirable aspect depends on nutrients. Co—ee soils in India belong to the the altitude. Absence of adequate shade and red and lateritic soil groups. The organic direct exposure to sunlight in the afternoons matter status and soil pH as prevailing in can destroy the chlorophyll, resulting in leaf most of the hilly and forest soils of South yellowing and berry blotch particularly in India are favourable for co—ee. Slightly acidic the presence of a heavy crop. A block with soil (pH 5.8 to 6.0) is the most favourable for gentle slope lesser than 15% is ideal for co—ee. root growth. For Arabica, the optimum temperature Propagation of co‚ee range is 15°C to 25C. For Robusta, a higher Though coffee could be propagated temperature range of 20°C to 30oC is ideal. through seed as well as vegetative parts, Though it can withstand an occasional fall seed propagation is common and easy. But of temperature up to 7°C, long periods of in the case of cross-pollinated Robusta and even 15°C interfere with the physiological hybrid Arabica, seed progenies tend to be processes. Frost damage is caused by a highly segregating unlike in self-pollinated fall in the temperature of the co—ee tissues Arabica. below the lethal limit of 3°C. Compared to Arabica Robusta is more susceptible to low Seed propagation temperature. Selection of mother trees, collection of fruits Since co—ee is, by and large, a rainfed and preparation of seeds crop, rainfall is of fundamental importance The selected mother plants must be for cultivation of all the species of co—ee. For healthy, free from diseases and good yield- Arabica, a rainfall of 1500-2000 mm (60-100 ers with lesser number of defective beans, inches) and for Robusta, 1000-2000 mm (40- pea berries and ¬oats. The block where the 80 inches) is required. More than the quan- mother plants are identižed should be free tum of the rainfall, equitable distribution is from ‘o—-type’ plants. To get seeds of Arabica very essential. Blossom showers of 25-50 mm true to type and to avoid cross pollination (1-2 inches) and backing showers of 50-75 mm advance blossom irrigation is given to the (2-3 inches) for Arabica in March-April and selected plants/blocks. Ripe but not over ripe almost the same quanta of rainfall for Robusta fruits, perfect, free from disease are picked during February-March are indispensable from the selected plants, washed with clean for successful blossom and fruit set. Early water and ¬oats are removed. The same day, showers without backing showers or very the berries are carefully pulped using a hand late showers cause physiological disorders. pulper. After removing the remaining cherry Failure of these summer showers results skins, the slimy beans are again stirred in in crop loss unless irrigation is provided. clean water and any left-over ¬oats are Apart from timely summer showers, a well removed. All damaged, deformed, small and distributed rainfall during the developmen- discoloured beans are discarded. The beans tal and ripening stages of the berries, i.e., are then mixed with žnely sieved wood ash, from June onwards till October-November evenly spread to a thickness of about 5 cm is necessary for a good crop. The optimum and allowed to dry slowly in shade. They are relative humidity for Arabica is 70-80% and stirred twice or thrice a day to facilitate uni- Robusta is 80-90%. It is ideal to plant co—ee form drying. After drying for 5 days, excess under shade so as to get 50% of day light for ash is rubbed o— and packed. It is desirable Arabica and 70% of day light for Robusta. to treat the seed evenly with a fungicide like Co—ee prefers deep, well drained, loamy Bavistin 50 WP (1 g/kg) or Vitavax 75 WP soil with plenty of humus and exchangeable (0.66 g/kg) to protect the seeds from fungal Crops of Kerala – An overview 89 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). infection. Dried seeds should be sown at the The soil used should be free from nematodes. earliest possible as the co—ee seed looses via- The bags are arranged in rows of 10 and the bility on storage. number of rows could be multiples of 10. The bags are secured žrmly without crumpling Nursery site and artiœcial shade using binding wires or long bamboo splits The site selected for nursery should be with suitable props driven into soil. either a ¬at land or a gentle slope with a good water source nearby. Coir mats or synthetic Transplanting nursery mats capable of providing varying While transplanting to the poly bags ade- intensity of shade from 50% to 75% shade quate care should be taken not to damage or cover can be used for shade. Precaution should bend the roots. Before lifting the seedlings be taken to roll up the mats during continuous from the germinating bed it is watered to rain to ward o— diseases. loosen the soil. The seedlings are gently lifted using a sharp wooden splinter. Using the Primary bed same splinter a small hole of 2 cm width and The primary nursery bed is just a raised enough depth to accommodate the root is platform of sieved loamy soil with enough made in the centre of the bag and the seedling organic matter or jungle soil free from nema- is placed in the hole with the collar region todes, stones, clods or plant debris. Sand could at the same level as found in the primary be mixed to improve drainage. The bed should bed. Deep planting results in collar rot. The be free draining. The primary bed could be transplanted seedlings are gently pressed of 1 m width, 15 cm height and length of with the thumb and fore-žnger and watered any convenient size. Seeds are sown imme- immediately. The seedlings will be ready with diately on receipt as germination gradually 5 to 6 pairs of leaves in about 4 or 5 months decreases. The seeds are placed about 2.5 cm after transplanting. apart and 1 cm deep, facing ¬at side down- After care wards, by gently pressing with the thumb. The young seedlings in the polybags may Deep sowing is avoided. After lightly covering die due to ‘damping o—’ if the soil is too wet, the seeds with soil, the entire bed is covered especially in areas of heavy rainfall. Also with paddy straw to conserve moisture and the seedlings should not be allowed to wilt. warmth. Watering, preferably using a water The frequency of watering depends upon the can, is done once a day. Germinating co—ee climatic conditions. In addition to ‘damping seeds are sensitive to extremes of soil mois- o— ’ disease, water stagnation or tight packing ture. If the soil dries out after germination, may induce iron dežciency, which is easily the seeds die and if the soil becomes too wet identižed by the interveinal chlorosis (retic- then the seeds may rot. After sprouting, the ulation) or whitening of the emerging leaves. straw is removed and when the seedlings Making additional holes in the bag to improve reach ‘topi’ or ‘soldier’ stage, they are ready drainage helps reduce the symptoms. for transplanting. The seedlings must be hardened o— by Secondary polybag bed progressive removal of the shade over a period In the secondary bed, polybags žlled with of weeks as sudden exposure to sun will cause soil media are arranged for transplanting leaf loss and delay the development. The the seedlings. For this, polybags of 6”x9” (23 seedlings should not be kept in the polythene cm x 15 cm) size and150 gauge thickness bags for more than 6-7 months as the roots are used. Holes are provided on lower half get bent or twisted. of the polybags for adequate drainage and If the growth of seedlings is not satis- aeration. Soil mixture of sieved jungle soil, factory, application of supernatant liquid of FYM and sand in the ratio of 6:2:1 is used. cow dung slurry is recommended to enhance 90 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). growth. Alternatively, urea solution of 0.5% Pre-treatment of the cuttings concentration (50g urea in 10 litres of water) could be applied two months after transplant- Before planting in the propagation ing, once in a month. About 4 litres of the trenches, the cuttings are immersed in 0.2% urea solution will suffice 1sq.m. area. To Bavistin solution (1g of Bavistin in 250 ml boost up the seedlings in case of delayed of water) for a minute to avoid any fungal transplanting, spraying of 50 ml of Planožx/ contamination followed by dipping the bases Agrona or 60 ml of Cytozyme plus in 200 of the cuttings in IBA (Indole Butyric Acid) litres of water with 1 kg of urea may be taken solution for 5-10 seconds. For single node cut- up when the seedlings put forth 4 to 5 pairs ting 5000 ppm IBA (500 mg IBA dissolved in of leaves or one month before želd planting. 50 ml. alcohol and made up to 100 ml. with water) is used for basal dipping whereas for Vegetative propagation terminal cuttings and mallet cuttings 1000 Vegetative propagation assumes greater ppm IBA (100 mg of IBA dissolved in 50 ml importance in cross pollinated species like alcohol and made up to 100 ml with water) Robusta or hybrids as there is no guarantee is used. that the seedlings raised from the seeds are true to the mother plants. In co—ee, clones are raised mainly from shoot. Planting of cuttings and arranging in propaga- tion trenches Propagation by cuttings The treated cuttings are planted in poly- In co—ee, only the vertical shoots i.e., suck- bags, individually, containing soil mixture (6 ers (orthotropic growth) are used for vegeta- parts sieved jungle soil, 3 parts sand and 1 tive propagation as the horizontal branches (plagiotropic) are unsuitable. Selection of part FYM). The bags are arranged in propa- mother plants to take cuttings is similar to gation trenches of 1 m width, 0.5 m depth and that of seed propagation. Three types of cut- of convenient length. The trenches are covered tings are used for vegetative propagation viz., with transparent polythene sheet (500 gauge) (i) single node cutting, (ii) terminal cutting over a supporting frame in a semi-circular and (iii) mallet cutting. hood shape allowing enough space above the cuttings. As in the case of seedling nursery, i) Single node cuttings the propagation trenches are arranged under Three to six month old suckers (preferably overhead artižcial shade. To drain o— rain pencil thickness of 1cm) are selected from the selected mother plants and single node water narrow drainage channels are provided semi-hardwood cuttings of 10 cm length are around the trenches. Adequate moisture cut from each sucker with a basal slant cut level/humidity is maintained by watering and top horizontal cut at internodal region. A once or twice a day. After rooting in about 3 pair of leaves, cut to half their size, is retained months, the polythene sheet is removed and at each node. the rooted cuttings are allowed to harden under the nursery shade before planting out. ii) Terminal cuttings The cuttings could be collected and planted The terminal portion of the sucker after during the rainy season (June-August). In the taking the single node cuttings is collected case of Robusta, rooted cuttings of di—erent and a slant cut is given at the base to use as mother plants should be mixed for e—ective terminal cuttings. pollination and fruit set. Rooted Robusta iii) Mallet cuttings clones give uniform yield as well as quality Mallet cutting is 45-60 day old sucker compared to seedling progenies. Further, detached from the mother plant with a piece they generally come to bearing earlier than of woody bark, using a sharp knife. seedlings. Crops of Kerala – An overview 91 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Common nursery diseases soil should be thoroughly dried under sun, Damping o‚ (collar rot) before use. This disease caused by Rhizoctonia solani Cockchafers (white grubs) is aggravated by excessive moisture in the Use of thoroughly dried and sieved soil soil. Providing proper drainage and timely and cattle manure prevents cockchafers transplanting reduce the incidence. In case which a—ect the root system. It can also be of severe incidence, spray Carbendazim at prevented by installing traps during žrst 0.05% a.i.(1g/1L) or Captan or Dithane at summer showers to kill the trapped adults. 0.4% a.i. (5 g/L). Cut worms, wire worm, crickets, aphids, loop- Brown eye spot ers and caterpillars With Cercospora co¡eicola as the caus- As weeds harbour many of these pests ative agent, this disease becomes acute under which feed on co—ee seedlings, the nursery inadequate shade. Providing adequate shade should be kept weed free. In case of severe followed by spraying of Captan or Dithane infestation, spraying o fEkalux 25 EC @ 2 or Ferbam at 0.4% a.i. (5 g/l of water) or car- ml or Metacid 50 EC @ 1 ml in one litre of bendazim at 0.05% a.i. (1g/lL of water) once water gives good protection. in 30 days helps reduce the incidence. Field planting Stem necrosis Once the area is selected for planting cof- It is caused by Myrothecium roridum and fee, clearing of land is attended to with simul- is seen in seedlings during monsoon season. taneous arrangements for raising nursery. Disease infects both stem and leaf. Infection causes brown discolouration on the stem and Clearing of land necrotic spots on the leaves. Seedlings start Generally it is recommended that some of wilting and gradually die. Judicious irriga- the big, standing trees are retained during tion, removal and destroying of a—ected seed- clearing of land to provide initial shade to the lings and spraying propiconazole at 0.02% newly planted young plants. After extracting (Tilt at 0.8 ml/1 L of water) at monthly inter- the remaining undesirable trees, a thorough vals from May to August are recommended cover-digging to a depth of 1’ (30cm) is given to control the disease. and all the roots and stones are removed followed by incorporation of the underground Stem-wasting disorder (Kondli) vegetation. Adequate ‘žre-path’ is maintained This is a non-parasitic disorder resulting all around the estate during dry months to from toxicity of copper fungicides sprayed on prevent spread of forest žre. After clearing the young plants in the nursery during inclement land, the next important work to be attended weather. A—ected plants show constrictions to is soil conservation measures as soil ero- at the žrst or second node from the base. sion is a serious problem in the high rainfall The plants become lean and lanky and easily areas of co—ee growing hilly tracts. Contour snap o— at the constriction. Use of organic bunding and terracing are e—ective in slopes. fungicide instead of copper fungicides, to Planting in the œeld control nursery diseases avoids this disorder. Tall selections like Sln.3, Sln.4, Sln.5, Common nursery pests Sln.6, Sln.8 and Sln.9 should be planted at 7’ Nematodes (Pratylenchus coeae) x 7’ (2.1 m x 2.1 m) and semi-dwarf selections The soil for the nursery should be thor- like Chandragiri should be planted at 6’ x oughly checked for nematodes before use and 6’ (1.8 m x 1.8 m). Spacing recommended for only nematode-free soil should be used. If Robusta selection Sln.1R (S.274) is 10’ x 10’ (3 presence of nematodes is suspected, the sieved m x 3 m) and for SIn.3R (CxR) is 8’ x 8’ (2.4 m 92 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). x 2.4 m). In south-west monsoon area, where that it could be slowly raised to accommodate planting is done in June, pits could be taken the growing young plants. Along with co—ee in March-April after the summer showers seedlings, both permanent and temporary and kept open for weathering. In north-east shade trees are planted. Once the temporary monsoon area where planting is taken up shade is able to give adequate protection, during September, pits are taken in June at the huts are removed and additional mulch the onset of South-West monsoon rains. A pit is placed. Care is taken to see that the huts of 45 cm x 45 cm x 45 cm is recommended. do not suppress the seedlings. If the shade is The back-žll in the planting pit should be a inadequate and plants are exposed to hot sun, mixture of top soil, well decomposed, dried the young plants may succumb to leaf spot and cockchafer free FYM along with 30 g of disease caused by Cercospora co¡eicola. It is rock phosphate one month prior to planting always advisable to žll up the gaps caused for the žlled up soil to settle down. As ade- by the death of young plants in the initial quate soil moisture is essential for initial or gestation period itself, otherwise it will establishment, planting is taken up as soon be very difficult to fill up the gaps later as the monsoon starts. In south west monsoon as supply plants have to struggle to survive zone, planting is done in August, whereas in under the established plants or shade trees, the north east monsoon zone, it is just after due to root competition. the žrst showers of the north east monsoon in September. Replanting and rejuvenation grafting Disease free and healthy seedlings are The economic productivity of Arabica (tall planted in the marked and already closed pits. cultivars) starts declining around the age of The bottom most portion of the nursery bag 25 years and that of Robusta around 60 years. (1 cm) containing the seedlings is chopped But there are instances where Arabica over o— and the polythene bag should be removed 30 years and Robusta over 50-60 years doing invariably. After placing the seedling in the well under proper crop husbandry. When it hole made to accommodate the bag just before is felt that bringing back the productivity of planting, it is žrmed up using the feet. Care older co—ee by improved farming practices is taken to plant the seedlings a little above is not possible, replanting with the same the soil surface to give allowance for possible cultivar or improved strain is thought of. sinking and to avoid collar rot in case of water Conversion of an old block into a new block stagnation. Hot sunny days, very wet days is brought about by replanting, interplanting and windy days are not desirable for planting. or interlining. Planting in sticky soils is to be avoided. Replanting Aftercare This process consists of complete uproot- As swaying of seedlings in windswept ing of old co—ee and replanting with improved areas delays establishment, two stakes are cultivars, after fresh line marking in confor- inserted criss-cross against the wind direc- mity with spacing for the new cultivar. This tion with the plant in the cross junction. is the best method to convert an old block Mulching with dry leaves is done around into a new one. The newly planted young the plant to a distance of 1’ (30 cm) from the plants will not have any competition from stem to prevent washing o— of the soil around established co—ee. Moreover, being in a block the plant. Immediately after the cessation of of young materials, the plants are likely to rain, the plants are protected from hot sun get better attention. Young shade trees are and cold night with small huts of coconut retained while old shade trees, which have thatches or loosely knit open bamboo baskets. grown unwieldy, are removed as young co—ee The huts are žxed with stakes in such a way struggles to come up under huge shade trees. Crops of Kerala – An overview 93 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Interplanting are planted simultaneously between the rows This method involves planting of seedlings as in the case of interplanting. The suckers of selected plant material in between rows will yield from second year onwards and the of existing old co—ee. Only the spacing of old crop on the suckers will always be heavier co—ee or its multiple can be adopted for the than the exhausted old co—ee. By the time three or four crops are taken from the suckers, new material as the old stand is not disturbed. the young co—ee would have developed fully A few branches of the existing old co—ee cov- and started bearing some crop. Now the old ering the seedlings are clipped o— to allow plants with suckers are completely uprooted. more light and air. The growth of co—ee will be extremely slow and the branches tend to Rejuvenation grafting be elongated without enough secondary and Whenever a plant becomes less productive tertiary development due to severe competi- due to mechanical damage or serious disease, tion from existing old co—ee. The old co—ee is it is removed and replaced by new material. removed gradually. As the grower continues Sometimes, the ‘o—-type’/’passenger’ plants to get some income from the old co—ee without are also replaced to increase productivity of any gestation period this method is popular unit area. Removing the unproductive plants in many small holdings. and planting new material are costly and time consuming. Moreover, there will be a Interlining gestation period of 4 to 5 years resulting in In this method alternate rows of old co—ee less income. To overcome these problems, reju- are eliminated and new plants are planted venation of the unproductive plants through in the old rows. The spacing within the row grafting is advocated. The rejuvenated plant is ¬exible but not between the rows. When comes to bearing at least 2 years earlier than the young coffee has grown sufficiently, conventional replanting. But grafting should the middle row of old co—ee is uprooted and not be attempted on very old plants or plants replanted with the new material. By following whose productivity has been reduced due to this method the planter gets some income root damage. from half of the area, while the other half The unproductive plants are collar pruned gets rejuvenated. at 1’ (30 cm) above the ground level during In case of interplanting or interlining, it March/April, after the summer showers. is always advisable to take pits early enough Suckers come out in 1 to 1½ months and to allow weathering for at least 2 or 3 months among them, 2 to 3 healthy suckers are before žlling in and planting. By doing so the retained removing the rest. During the mon- cut ends of the roots of the surrounding old soon rains in June, suckers of the same age co—ee will all dry up and so will not extend and thickness, allowed in desirable plants, into the pit for at least some time enabling are collected and single noded scions are the young plants to get a chance to establish prepared. A vertical slit (cleft) of 1.5 to 2.0 and grow. Secondly, the pit should be deeper cm is made in the stock suckers arising from and bigger than the usual pits, at least with the collar pruned plant after cutting o— the 2½’ (75 cm) diameter and 2½’ (75 cm) depth. suckers at 5 to 8 cm height. The single noded Thirdly, while žlling the pits, well decom- scion sucker is fashioned into wedge shape of posed cattle manure should be added. 1.5 to 2 cm and inserted into the stock. The graft portion is tied with a polythene strip. Interplanting with rejuvenation The grafts are covered with polythene bags Here, the old plants are collar-pruned and to prevent rotting. When union takes place two to three suckers are allowed. New plants in 1 to 2 months, the polythene strips are 94 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). removed. As the grafting success is only 65 An ideal shade tree should have long life to 70%, 2 to 3 suckers are grafted to be on as that of co—ee and it should not be brittle the safer side. leading to breakages of branches during heavy winds. It should have a spreading habit Shade trees and shade management and bear feathery leaves to give a žltered Shade trees shade and not casting too dense a shade, In India shade is inevitable for economic branches may spread at a height several feet production except in some Robusta planta- above co—ee. It should not be a host for any of tions where the soils are deep and fertile with the serious pests and diseases of co—ee and assured irrigation facilities. Many parts of should not compete with co—ee for moisture the co—ee regions in the world, such as Brazil, and nutrients. The leaves should provide good Hawaii, Indonesia, Kenya, Vietnam, etc., grow mulch and it should give valuable timber. co—ee without shade on commercial basis. Shallow rooted shade trees compete with cof- But in India majority of the plantations are fee for soil moisture. Since no single species under rain-fed conditions and hence co—ee is of tree has all the desired qualities, a mixed recommended to be planted under shade. The shade consisting of di—erent long standing recommended spacing for permanent shade permanent trees and temporary shade trees is trees is 40’ x 40’ (12 m x 12 m). In new clear- advocated for co—ee. The shade trees in co—ee ing, for every two co—ee plants one temporary plantations are grouped into two categories shade tree (dadap) is planted. Shade trees viz., temporary and permanent based on their must provide 50% shade in Arabica and 30% size, nature of growth and longevity. shade in Robusta, as only 50% and 70% of The temporary shade trees are planted day light is considered optimum for Arabica to provide immediate shade for the young and Robusta co—ee respectively. plants. Dadap (Erythrina lithosperma) is a Shade reduces light intensity, helps to popular and widely used temporary shade. overcome physiological problems like die- Calliandra (Calliandra calothyrsis), Castor back and ¬oral malformations, narrows down (Ricinus communis), Sesbania sp., Gliricidia diurnal variation, and enhances photosyn- sp., etc., could also be used to provide shade thetic activity and net assimilation rate. It initially to the young plants and to supple- also protects the plants from hot sun, strong ment nitrogen. Solanum sp. is also being used wind, hailstone, cold temperature and frost as a temporary shade in some of the areas. damage and decreases incidence of diseases Ficus species (F. virens, F. racemosa, F. and pests in co—ee. Planting shade trees in microcarpa, F. nervosa, F. retusa, F. tsjahela), co—ee helps better root growth by reducing Artocarpus integrifolia (jack tree) and Albizzia soil temperature, supplies enough quanti- species, are popular permanent shade trees ties of major and minor nutrient elements to commonly maintained in co—ee plantations. sustain average crops, adds nitrogen to the Trees like Cedrela toona, Dalbergia latifolia, soil through the root nodules of leguminous Pterocarpus marsupium, Syzigium jambo- shade trees. Further, shade also suppresses lana, etc. are also recommended for co—ee weed growth, especially perennial grasses, plantations. In majority of the plantations in increases soil biomass through leaf shed- South India, silver oak (Grevillea robusta) is ding/shade-lopping and addition of mulch the predominant shade tree. In strict sense, preserves soil organic matter by inhibiting silver oak is not an ideal shade tree, as its rapid decomposition of organic residues and leaves do not easily get decomposed and the brings down soil erosion by protecting the soil dry leaves create a potential žre hazard in from lashing rains. It indirectly a—ects the low rainfall areas. As the spine like leaves quality of beans and increases longevity of get stuck on to the plants, black rot may get co—ee plants by reducing overbearing. accentuated in high rainfall areas. Further, Crops of Kerala – An overview 95 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). the branches of silver oak are not spreading in single-stemmed co—ee mainly to reduce the nature. In spite of these demerits, silver oak menace of white stem borer in Arabica and to is popular among the small growers for its have an easy bush management in Robusta. quick growth, timber value and its suitabil- In single stem training system, the verti- ity as standard for training pepper. African cally growing main stem is allowed to reach shade tree (Maesopsis eminii) is another fast a certain height and the apical growth is growing shade tree seen in co—ee plantation clipped (known as topping or capping) just in India. It is a soft-wood tree and the large 2” (5 cm) above the node of the recommended branches cannot withstand heavy wind and height. One of the top most primaries is also hence is not recommended for planting in removed to prevent possible splitting of the co—ee plantations. main stem due to heavy crop load. Topping is done to reduce the apical dominance and Time and mode of shade regulation to encourage strong lateral growth of the Shade trees require regular pruning primaries. The žrst topping forms the žrst and thinning to prevent shade becoming tier. After 4 to 5 crops, when the plants start excessive. Shade regulation is preferably closing in, one healthy sucker from the main done immediately after harvest but before stem, just below the top most primary pair pruning of co—ee plants to enable removal is allowed to grow. One healthy sucker is 1 of broken/damaged branches of co—ee as a allowed and when this sucker reaches 4/2 feet 1 result of falling of shade tree branches during (1.35 m) in tall Arabica and 5/2 feet (1.65 m) lopping. If dry weather prevails during the in Robusta, the apical portion is clipped to post-harvest period, shade regulation is develop formation of the second tier. In the commonly taken up just before the onset of case of semi-dwarfs, toping is recommended south west monsoon. In young clearing the at 3’ to 5’ (0.9 m to 1.5 m). Suckers arising shade canopy is maintained at a low level of from the main stem are removed periodically. about 4 to 5 m above the ground. In estab- Multiple stem system is common in many lished plantations, lower canopy branches are of the African and Latin American countries. removed and upper canopy of the permanent Various methods such as cutting, bending trees is maintained at a height of 10 m to 14 (agobiada), angle planting and multiple plant- m height. Removal of lower canopy branches ing are available to have multiple-stem co—ee. prior to monsoon facilitates air circulation, But cutting the main stem to produce multiple reducing atmospheric humidity. Reduced stem is common. After 3 or 4 crops, when the atmospheric humidity discourages build-up main stem attains good girth, it is stumped of disease causing pathogens. (collar-pruned) at about 1’ (30 cm) from the Bush management ground level giving a smooth slanting cut. A strong frame work with healthy crop- After a few weeks when suckers sprout, 3 ping branches is a pre-requisite to obtain healthy suckers at di—erent heights around prožtable crop year after year in a perennial the stem are selected and retained removing fruit bearing crop like co—ee. Maintaining the others. When the suckers bear 4 to 5 a proper balance between vegetative and crops, the exhausted suckers are removed reproductive phases without impairing the one at a time in a year with simultaneous health of the plant is achieved by proper allowing of new sucker. bush management which involves training, In co—ee, pruning is generally means pruning and handling. removal of excess vegetative growth. Main Training basically refers to allowing objectives of pruning are to minimise bien- the plant to have a single stem or multiple nial bearing tendency and consequent risk stems. In India, it is most common to žnd of die-back during over-bearing, to remove 96 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). unwanted dead, diseased and over-aged the soil, which anchors plant and supports branches and to provide a micro environ- its life, is also equally important. Hence, an ment within the plant for maximum crop integrated nutrient management involving production but minimum spread of diseases/ chemical fertilizers, organic manures, foliar pests. The process of pruning involves feeding, bio-fertilizers and vermi-compost removal of criss-cross branches and branches comes a long way for efficient nutrient growing vertically upwards or towards the management. Since organic manures have main stem, removal of exhausted, lean and negligible N, P and K contents, application of lanky branches having a few cleft of leaves chemical fertilizers is inevitable in intensive at the end, broken and dead wood, removal economic farming systems. But equal impor- of suckers and secondary laterals arising tance should be given for organic manures to from the žrst nodes on the primary adja- save the dying soils of the tropics and to sus- cent to the main stem and removal of whippy tain higher productivity. While chemical fer- tilizers supply the needed nutrients, organic branches touching the ground. Remove all manures, serving as soil amendments, add vertical growth arising from the primaries/ life and make the soil more conducive for secondaries; otherwise, these growths are plant growth. converted into special branches known as ‘gourmandisers’, being in an advantageous Availability of adequate essential nutri- position of getting good sunlight and aeration, ents in balanced proportions throughout the yielding a good crop at the cost of the adja- life of co—ee is essential for economic pro- duction. Inadequacy of any one of the major cent growth below. Cut the whippy secondary fertilizer elements (N, P & K) or the secondary branches close to the primary so that no stub nutrients (Ca, Mg & S) or unavailability of is left to interfere with the development of any micro nutrient/trace element (Fe, Mn, replacement. Excessive pruning or exces - Zn, Cu, B, Cl and Mo) adversely a—ects plant sive removal of foliage is detrimental and growth. Recycling of the entire shade tree reduces the crop production. Removal of all litter, co—ee leaf, pulp etc., contributes 84-95 non-bearing branches is not advisable as kg N , 40-42 P2O5 and 108-123 kg K2O per ha., every bearing branch should be supported which may sustain a shade-grown low crop, it by non-bearing branches. There is a close rela- may not be sufficient to support a higher tionship between the number of ¬ower buds crop under lesser shade canopy. Nutrients and number of leaves in a bearing branch. brought in by the leaf fall are essentially the Generally pruning is taken up immediately nutrients recycled from the soil and, hence, after the harvest to remove the exhausted addition of nutrients to soil is essential to and undesirable wood. When a plant is in a compensate the crop removal of atleast the state of die-back it needs all the available major nutrients. foliage and it should never be pruned other than removing the dead wood. While pruning Fertiliser recommendation for bearing is essentially a knife work, handling involves co‚ee no cutting but just breaking and removal of Based on experiments on crop removal the dead/diseased wood and suckers by bare (35 kg. N, 5-7 kg P2O5 and 37-45 kg K2O for hand. Handling and desuckering are carried every tonne of clean co—ee), plant bio-mass out 3 or 4 times a year. requirement, fertiliser use efficiency and release of nutrients from soil sources, the Nutrient management general basic recommendation is 10 kg N, 5

In any perennial crop, the health of the kg P2O5 and 10 kg K 2O for every 100 kg of plant is very important to produce crop year clean co—ee harvested up to an yield level after year. At the same time, the health of of 500 kg clean co—ee per acre (1250 kg/ Crops of Kerala – An overview 97 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). ha). Soil testing or soil fertility evaluation Method of fertilizer application in scientižc farming needs little emphasis. The root system of bearing co—ee extends Fertilizer recommendation supported by soil to more than 3’ (90 cm) in all sides from test values avoids ion-antagonism (suppres- the stem and the entire želd is matted with sion of uptake of one nutrient element due roots in an established plantation. Hence, the to the presence of other element(s) in excess) most e—ective method is to apply fertiliser and helps economising fertilizer dose. In cof- in broad circular band, but 1’ (30 cm) away fee, the basic recommendation is subject to from the stem. After application, the mulch 10-25 % increase or decrease based on soil is disturbed to make the fertilizers come test values. in contact with the soil. The soil moisture dissolves the water-soluble fertilizers and Fertilizer recommendation for young the dissolved nutrients percolate down due co‚ee to gravity. Foliar feeding is recommended to Unlike bearing coffee, young coffee supplement soil application of nutrients to requires more P in readily available form meet the higher nutritional requirement of a for profuse rooting and hence P is recom- bumper crop, to rectify nutritional disorders, mended on par with N and K in 1:1:1 ratio to supplement micro-nutrient demand and to in water-soluble granular form. Complex fer- help plants in the event of root damage due tilisers like 17:17:17 or 19:19:19 @ 60 g in one to disease (root rot) or pests (nematodes/root split during 1st year, 120 g in two splits during mealy bugs). When the yield exceeds 1250 kg/ second year, 180 g in three splits during 3rd ha in Arabica and 2 tonnes/ha in Robusta, year and 240 g in four splits during 4th year 2 foliar sprays, one during late April and is recommended for young Arabica co—ee. another in October-November help overcome For Robusta twice the dosage of Arabica is the crop strain. recommended. Time of fertiliser application Organic manures It is advisable to apply fertilizers when In co—ee the importance of organic matter there is sufficient moisture in soil. Keeping in soil hardly needs any emphasis. Organic in view of the peak demand periods of co—ee, manure improves soil structure facilitating 4 split applications are recommended. Under gaseous exchange and drainage, increases Indian conditions, the žrst application in the water holding capacity and CEC, enabling March coincides with ¬owering/fruit set, the the soil to retain more soil moisture and the 2nd split in June feeds the developing berries, applied nutrients, binds the soil particles thus the 3rd split in September helps maturation reducing the soil erosion and fulžls the entire of berries and makes up the leaching losses requirement of the micronutrients and creates and the 4th split in November compensates the a favourable environment for the microbial mobility of nutrients from foliage to matured activity which is essential for conversion of crop and also prepares the plants to overcome many of the nutrients into available form.1 1 the ensuing drought period after harvest. to 1 /2 tonne of dried, cockchafer free FYM In the case of 3 splits, the fertilizers could should be applied any time in a year when be applied in March, June and September. there is sufficient moisture in the soil When only two splits are envisaged as in and when the soil conditions are suitable the case of low yield, the 1st split could be for forking in the manure. in March and the 2nd split in September. If rock phosphate is included in the schedule it Soil acidity and liming should be broadcast and forked in one single Under South Indian conditions co—ee is application in March along with the 1st split known to come up well in soils of pH around of N and K. 6.0. Liming is recommended when soil pH 98 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). goes below 6.0. Application of lime should (ii) to break up any hard pans, which might be carried out based on evaluation of soil restrict the entry of water into the soil and samples, as excess lime application causes (iii) to open up the soil for gaseous exchange reduced availability of phosphorus and and penetration of water deep into the root micronutrients. Higher calcium content in zone. But soil cultivation is not advocated in the soil due to excessive application of lime co—ee plantations excepting the cover digging may also hinder the uptake of potassium and done in the new clearing before planting to magnesium due to ion-antagonism. Generally loosen the compact soil and to remove the the quantity of agricultural lime (CaCO3) weeds to facilitate faster growth of the young recommended varies from 0.5 to 2 tonnes plants. The advantages of organic mulching per acre. Whenever magnesium dežciency is are many. It protects the soil surface from suspected, equivalent amounts of žnely pow- the impact of rain, increases inžltration of dered dolomite (CaMgCO ) may be applied. 3 2 rainfall and reduces run o—, conserves soil Generally liming is done after harvest. Since moisture and surface soil, suppresses weed moisture is essential for most of the chemi- growth and it protects the soil from hot sun cal and biological reactions, lime is applied and cold nights thus maintaining optimal soil when adequate moisture is present in the temperature for continued microbial activ- soil. However, at least a month’s gap between fertilizer application and liming is desirable ity and root growth. Additionally, mulching to prevent the possible interaction between improves soil structure, avoids formation of the fertilizers and liming materials. Lime ‘cap’ and facilitates rain water acceptance, is to be broadcasted throughout the planted adds organic manure on decomposition and area and thoroughly incorporated for proper provides most of the needed micronutrients, contact and reaction with the soil matrix. spreads rain water and avoids gully forma- tion, increases soil nitrates, reduces soil Weed management acidity and helps reduce chlorosis. For young In a fully established co—ee plantation co—ee seedlings, mulching should be provided under shade, where no gaps are generally immediately after planting. Mulching takes seen consequent to full coverage of the can- care of soil erosion and weed growth. opies, or in želds fully covered by mulch, Another soil conservation measure is to weed growth is not a problem. However, in grow a cover crop. It helps to conserve soil, new/young clearings or in poorly established smother out weeds and enhance biomass estates without adequate shade, where more in soil. In high rainfall area particularly of open patches are commonly seen, weed in Robusta where spacing is large, cover growth does pose problems. Slash weeding, crop helps to a greater extent. Sometimes clean weeding by scraping the soil using farm food crops like ginger are cultivated till the implements and chemical weeding are com- co—ee canopies close in. But any crop which monly practiced to control weeds. Glyphosate involves soil cultivation is not preferable in is generally recommended for co—ee plan- co—ee. An ideal cover crop or inter crop should tations. Spraying of gramoxone @ 500 ml not compete with co—ee for nutrients, water per barrel of 500 litres has been found to be or light. Nor should they interfere with the e—ective to control the dicots and glycel @ cultural operation. 1200 ml per barrel of 200 litres controls all types of weeds. With addition of urea @ 2 kg In order to prevent soil erosion in sloppy per barrel, the quantity of weedicide could areas it is recommended to dig cradle pits of be reduced to half. 30 cm width, 45 cm depth and 150 cm length across the slope in staggered manner. By the Soil conservation measures end of monsoon cradle pits get žlled with Soil cultivation such as scu¿ing and dig- fallen leaves and weed slashing and act as ging is generally done (i) to control weeds compost pits and helps in conserving the soil Crops of Kerala – An overview 99 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). moisture. Cradle pits can be cleared by the proceed at a faster rate than Arabica and a end of monsoon once in two or three years. larger number of ¬ower buds attain matu- rity by about January-February. Receipt Intercrops of sufficient rainfall (25-40mm) triggers Growing compatible perennial crops in ¬owering. A period of moisture stress before a mixed farming system, particularly in ¬owering is benežcial in bringing about the small grower sector, is quite common concentrated flowering. Flower opening in co—ee. Almost all the co—ee tracts in occurs in 8-10 days after receipt of rainfall/ India have pepper as a mixed crop trained irrigation. Flowering in co—ee is controlled on the shade trees. Silver oak is an ideal by a hormonal mechanism. This hormone live standard for pepper. But pepper is also could be ‘gibberellin’ or a chemical related to trained on temporary dadaps as well as huge ‘gibberellic’ acid. The pollen tube in Robusta permanent jack trees. In addition to pepper, takes about 8-12 h to reach the ovary and orange and banana are also being cultivated about 26-36 h for union of gametes under as an intercrop by the planters of Pulneys in normal healthy blossom. Fruit set in co—ee Tamilnadu. Annuals like ginger, turmeric is in¬uenced by plant health, timely blossom and elephant foot yam etc., are cultivated in showers, severity of drought prior to blossom young co—ee plantations in Kerala. This helps and the weather conditions prevailing on the in controlling the weed growth. Intercrops day of the blossom. Debilitated plants due to bring in additional income in the gestation over-bearing, severe disease incidence and period of co—ee, in addition to smothering of inadequate nutrition adversely a—ect fruit weed growth. Any intercrop involving soil set. Very late blossom showers may result in cultivation is not preferred as it leads to soil poor set, particularly if preceded by severe erosion in hilly terrains. Sinceover 98% of drought conditions. the growers are in the small grower sector, Premature berry drop is a common feature without adequate žnance for intensive cul- every year. But the percentage of loss may tivation, a diversižed cropping system with di—er from year to year depending on seasonal co—ee as the base crop is always advisable conditions varying from as low as 10% to as as an insurance against price ¬uctuations. high as 50%. Apart from seasonal factors, berry drop may be due to physiological factors Physiology of co‚ee like carbohydrate dežciency or imbalance For successful management of the plan- between carbohydrates and auxins during tation the knowledge on in¬uence of envi- the development of berries. Continuous water ronmental factors and cultural practices on logging (‘wet feet’ condition) aggravate berry yield is essential. Although co—ee grows con- drop. Under South Indian conditions fruits of tinuously, the growth is slow during summer Arabica mature 8 to 9 months after ¬owering and winter months. During heavy rainfall and fruits of Robusta mature 10 to 11 months also growth is retarded. Immediately after after ¬owering. summer rains or the heavy monsoon rains Fruit ripening is not uniform in co—ee, in growth is rapid. Production of new ¬ushes spite of almost simultaneous blossom in all and extension of growth in terms of number nodes/branches. Endogenous production of of nodes and leaves are important to serve ethylene, facilitated by more sunlight, helps as cropping wood for the succeeding years. ripening. Exogenous application of ethylene Generally, co—ee in India seems to come also hastens ripening. Since exogenous eth- to ‘¬oral phase’ by September. Flower buds in ylene induces early senescence leading to Arabica usually develop in succession during pre-mature leaf shedding, growth hormone September to February/March. In Robusta, is needed to o—set senescence. To hasten rip- initiation and di—erentiation of ¬ower buds ening in Arabica 100 ml of ethephon and 100 100 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). ml of Hormonal in 200 litres and for Robusta carbohydrates. Apart from depletion of car- 50 ml of ethephon and 100 ml of Hormonal in bohydrates, faulty fertilization and moisture 200 litres of water is recommended. 500 ml dežcit during June to August also cause these of solution is required for an Arabica plant disorders. Arabica at lower elevation with and 660 ml of solution is required for Robusta overbearing is prone to produce more black plant. Ethephon solution may be sprayed on beans. Proper management such as judicious the fruits when about 10% of natural ripening pruning, optimum shade regulation, adequate is seen. Ethephon spray hastens ripening and timely manuring, regular bordeaux by 2 to 4 weeks. sprays to control leaf rust and avoiding die- Bean size is partly genetically deter- back help reduce black bean formation to a mined and partly modižed by environmental greater extent. conditions. The potential size of the bean Drought management is determined by the mother tree but the For successful blossom and good yield 25 ultimate size is determined in the period of to 40 mm rainfall or equivalent irrigation rapid expansion following the pin-head stage is required for Arabica during March and and re¬ects the availability of soil moisture for Robusta during February. Inadequate at this time. Hence, adequate rainfall during or uneven distribution of rainfall causes June to August is important in berry develop- drought conditions a—ecting the growth of ment. The size is also determined by certain the plant as well as yield. Drought man- cultural methods such as pruning, mulching agement envisages selection of drought and fertilizer applications. tolerant material or increasing the solute Due to genetic as well as physiological/ concentrations in plant through foliar sprays environmental factors, many bean disorders of nutrients. Sln.9, Sln.10, Sln.4 and Sln.5B are seen in co—ee. Failure of endosperm to are relatively drought tolerant among pop- develop and žll the integument results in ular co—ee selections. In the case of Robusta empty beans. This is mostly a physiological all the recommended cultivars are drought problem. However, it is caused by genetic susceptible. Maintaining adequate shade, factors also. Empty beans occur frequently providing mulching during summer months in hybrids of two species having di—erent and irrigation are the methods to mitigate the chromosome numbers. Occurrence of elephant e—ects drought in co—ee plantation. Spraying beans and triage are genetic aberrations. A of nutrient mixture containing 1 kg super single cavity in the ovary with two embryos phosphate, 750 g MOP and 1 kg ZnSO4 in is called as elephant beans and it usually 200 litres of water at 45th day after the last break up during hulling. Three beans develop rainfall and again 30 to 45 days after the in a single fruit is called as ‘triage’. When žrst spray @ 1L per plant found to minimise one of the integuments does not develop and the drought e—ect and increase yield is rec- the other one occupies the whole berry, a ommended to tide over the drought. round bean known as ‘pea berry’ is formed. In general, co—ee in India is a rain-fed crop Though genetic factors are more responsible, grown under varied climatic conditions with inadequate pollination in¬uences formation rainfall ranging from 1000mm to 3500mm. of pea berry. The percentage of pea berries A rainfall as low as 40” (1000 mm) is suf- range from 10 to 30. Higher percentage of ficient for normal production, provided it is pea berry is not desirable. well distributed and received on time. About 1 Black ‘jello’ beans are formed due to 1 to1 /2” (25-40 mm) of rainfall as ‘blossom poor žlling of endosperm occurring during showers’ in February for Robusta and in the growth of endosperm. But ‘black’ bean March for Arabica are essential for ¬owering formation is due to low accumulation of and fruit set. Same quantity of rainfall 15-20 Crops of Kerala – An overview 101 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). days after blossom as ‘backing showers’ are cracks and crevices; v) swab the main stem required for fruit set. To ensure adequate and thick primaries prior to ¬ight periods water supply for ¬owering/fruit set and to once in April-May and once or twice in tide over any unprecedented drought during October-December (depending on the degree berry development, irrigation is being pro- of infestation) with 10% lime solution; vi) if vided wherever adequate water sources are infestation is in the initial stage wrap the available. stems with sheets of gunny bag and spray chlorpyriphos+cypermethrin combination Pest management @1.2 ml/litre or chlorpyriphos 50EC-1.5 ml Co—ee in India experiences huge loss due + cypermethrin 1.2 ml or chlorpyriphos 25EC to serious pest problems like white stem 3 ml + cypermethrin 1.2 ml per 200 litres borer in Arabica and mealy bug and shot of water; vii) spray the main stem and thick hole borer in Robusta. In fact, over 80% of primaries with neem kernel extract for good potential trouble from pests can be avoided control of the pest. by sound methods of cultivation in a suit- able environment. The stable environment Co‚ee berry borer (Hypothenemus hampei) of a co—ee plantation makes it particularly favourable for the practice of integrated pest The co—ee berry borer is another serious management (IPM) involving chemical, cul- pest of co—ee. It is exclusively monophagous tural and biological control. and requires co—ee berries for feeding and breeding. The adult berry borer bores into the White stem borer (Xylotrechus quadripes) berries through the navel region. Tunnelling White stem borer is a serious pest of co—ee, and oviposition occur only in hard beans. The causing major loss to co—ee in India. Adult mother beetle lays about 15 eggs and eggs Female beetles deposit eggs in the cracks and hatch in about 10 days. The larvae feed on crevices and under the loose scaly bark of the the beans, making small tunnels. A typical main stem and thick primaries, preferring pin hole at the tip of the berries indicates the the plants exposed to sun light. Hatched out presence of the pest. In case of severe infesta- grubs feed in the corky portion just under tion, 30 to 80% of the berries may be attacked, the bark and splits. Infested plants show resulting in heavy crop loss. Proper adoption externally visible ridges around the stem of cultural and phytosanitary measures is and exhibit symptoms like yellowing and foremost in the management of co—ee berry wilting of leaves. However, such plants are borer. Timely harvest is very important. No less productive, yielding more of ¬oats. Later, berries should be left over, either on the plant the larvae enter into the hardwood and make or on the ground. Spreading gunny bags or tunnels in all the directions. In some cases, polythene sheets on the ground, during har- the tunnels may extend even into the roots. vest will help to minimise gleaning. Maintain After about 10 months adult emerges out by optimum shade and good drainage. Dipping cutting an exit hole in the bark. infested berries in boiling water for 2-3 min- Control measures suggested are i) main- utes kills all the stages inside. Drying co—ee tain optimum shade on the estates; ii) trace to the prescribed moisture level (parchment the infested plants prior to ¬ight periods 10.5%, cherry 11.5%) prevents breeding of (i.e, during March and September); iii) col- beetles in stored co—ee. lar prune the infested plants, uproot if the borer has entered into the root, and burn Shot-hole borer (Xylosandrus compactus) the a—ected parts; iv) remove the loose scaly The shot-hole borer is a major pest of bark of the main stem and thick primaries Robusta co—ee. Adult beetle usually attack using coir glove or coconut husk to get rid of green succulent branches. After entering 102 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). into the twig through the shot-hole made on with Ekalux 25 EC @ 300 ml or Folithion the underside, female makes a longitudinal 50 EC @ 300 ml or Lebaycid 1000 @ 150 ml tunnel and lays as many as 50 eggs. The or Kerosene 4 litres in 200 litres of water, milky white larvae feed on the Amborsia. using a sapperlot/gator sprayer; iv) if the roots Life cycle is completed within 4 to 5 weeks. are infested, drench the soil near the root The incidence of pest reaches the peak during zone with any one of the above insecticides September to January, and gradually declines (other than kerosene) at the same dosage during the dry period. The buildup could and add 300 ml of Plantvax 20 EC or 160 g be severe under heavy shade. Withered o— of Bayleton 25 WP in 200 l water, if fungus dried branches with shot-holes indicate the association is noticed; v) bio-control: if P. citri presence of the pest. The attacked branches is predominant, release, 17,500 to 25,000 par- dry up fast, as tunnelling limits the ¬ow of asitoids initially and 5,000 to 7,500 in the sap. Leaves above the point of attack fall subsequent years until control is achieved. prematurely. The terminal leaves wilt, droop And if other species of mealy bugs dominate, and dry up. Severe infestation results in the then release 10,000 to 15,000 of the predator, loss of considerable number of productive Cryptolaemus montrouzieri. branches. Due to the mode of attack and concealed nature of the pest, insecticide Green scale (Coccus viridis) applications do not provide any economically Green scale is a summer pest, prolifer- feasible control. However, the incidence of ating during hot dry weather. The insect shot-hole borer could be e—ectively contained sucks sap from the tender parts, congregating by adopting the following measures: i) prune down on the under surface of leaves close to the a—ected twigs 2 to 3 inches beyond the the midrib and veins, on the green shoots, shot-hole and burn from September onwards, spikes and berries. Heavy loss of the sap as soon as the žrst symptoms of attack like causes debility or even death of the plant. drooping of leaves is noticed, and continue The infested leaves may curl up and tender as a routine measure at regular intervals; ii) twigs droop. The honeydew excreted by the remove and destroy all the unwanted/infested scale forms a layer on the leaves and acts suckers during summer as the pest prefers as a medium for the growth of the “sooty to breed in the suckers during dry period; mould”. This hinders photosynthesis, thereby iii) maintain thin shade and good drainage. weakening the plant. Host plants and ant Mealy bug (Planococcus citri and P. lilacinus) association are almost same as that of mealy bugs. Control measures recommended for Mealy bugs are small, soft bodied green scale are: i) controlling ants as in the insects attacking co—ee and a wide variety case of mealy bugs; ii) removing and burning of crops. Adult female is wingless, the oval weeds which harbour the scales; iii) spraying body clothed with a mealy secretion in the the a—ected patches with quinalphos 25 EC form of small, white threads. Each female (Ekalux) @ 120 ml or Dimethoate (Rogor is capable of laying 100 to 1000 eggs. Life 30 EC) @ 170 ml in 200 L of water using a cycle is completed in about a month. Mealy gator/ sapperlot sprayer along with 200ml bugs multiply rapidly during hot weather. of any wetting agent. For grown up plants Infestation becomes severe in summer. dimethoate (Rogor 30 EC) may be used at a Intermittent showers and irrigation help in dosage of 600ml in 200 L of water. the build up of the pest. Excessive removal of shade in Robusta plantations often leads Brown scale (Saissetia coeae) to ¬are up of mealy bugs. Control measures Brown scale is a sucking pest seen in suggested are: i) maintain adequate shade; co—ee, active during summer months. The ii) control ants; iii) spray the a—ected patches life history and symptoms follows the same Crops of Kerala – An overview 103 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). lines as those of green scale in general. The closely one behind the other. They drop down honey dew feeding ants are seen with brown on silken threads from shade tree to co—ee scale also. Like other sucking pests, this also during September/October. During this stage has a wide range of host plants like citrus, (paratrooping stage), the caterpillars may get Guava etc. Control measures recommended dispersed by wind. Out breaks usually occur are: i) control of ants as in the case of mealy in a cycle of 3 to 4 years. Cardamom and bugs; ii) removing and burning weeds which shade trees like Bischoa javanica, Syzygium harbour the pest; iii) spraying the a—ected jambolana, Eugenia jambolana and Erythrina patches with quinalphos (Ekalux 25 EC) @ lithosperma are hosts of caterpillar. In order 300 ml in 200 L water along with 200 ml of to control the incidence of hairy caterpillar any agricultural wetting agent. recommended control measures are: i) col- lect and kill caterpillars; ii) collect and burn Cockchafer or white grub (Holotrichia spp.) pupae from January to May; iii) install light Adults of cockchafers are reddish brown traps in June/July for collecting and killing beetles. They feed on leaves of crop plants moths. or forest trees and the adults emerge from March to June after the žrst summer shower. Root lesion nematode (Pratylenchus coeae) After mating, female beetle lays eggs in the Though there are several species of soil. The hatched out creamy white grub feeds nematodes attacking co—ee, the root-lesion on roots. They are serious pests in new clear- nematode, Pratylenchus co¡eae has been ings and replanted areas. Grown up co—ee found to be highly destructive to Arabica plants normally withstand the attack. The co—ee. P. co¡eae lays eggs in the root lesions. young plants (1 to 5 years old) attacked by Development from egg to adult takes about white grubs show yellowing of leaves and a month. Nematodes feed and destroy the stunted growth. Such plants will wilt and die cortical parenchyma cells of the tap root, sec- in summer period. Attacked plants can be ondary roots and feeder roots. As a result, easily pulled out as they are left with only the the outer layer of the tap root and secondary tap root. In order to control the pest following roots peel o— and the feeder roots are lost, recommendations are made: i) collect and impairing water and nutrient absorption. kill the grubs encountered while taking up P. co¡eae causes ‘juvenile foot-rot’ of young digging and other farm operations; ii) install Arabica plants and die-back or ‘spreading light traps after the žrst summer showers decline’ of bearings plants. Nematodes during March-June and kill the trapped spread to other areas through implements, adults; iii) apply Thimet 10 G at the dosage rain water, plants from infested nursery and of 20 g per plant. soils from a—ected blocks. Exposure of soil in the nursery to sun, using sieved jungle soil Hairy caterpillar (Eupterote spp.) and FYM and avoiding of bringing seedlings It is an important pest of Arabica co—ee. from nematode infested areas are the mea- The adult of hairy caterpillar is a brownish sures to control nematode in the nursery. yellow moth, emerges in June/July. Eggs While in želd, uprooting and burning the are laid in clusters of 100 to 150 on the a—ected plants, digging pits of 2’ x 2’ x 2’ under surface of the leaves of shade trees. size and exposing the soil to sun for one year Caterpillars of E. canaraica start feeding on prior to planting, keeping the pits weed-free, leaves one or two days after hatching. They planting the infested area with Robusta (if feed on leaves and cause severe damage by suitable) or Arabica-Robusta grafted plants denuding the plants. Badly a—ected plants (Arabica scion grafted on to Robusta root take 2 to 3 years to recover. They are gre- stock) are recommended to avoid the incidence garious and migrate from branch, moving of nematode. 104 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Minor pests disease is observed throughout the year, peak Co—ee bean beetle (Aracerus fasiculatus) period being August to November. Pale yellow is a pest of beans in storage and also a—ects spots appear on the lower surface of infested co—ee berries in the želd. Drying the co—ee leaves, later turning orange yellow powdery to the prescribed moisture level and storing mass consisting of uredospores. Severely in well ventilated godown is suggested to infested leaves fall prematurely. Sln.3 (S.795) avoid this pest. Snails (Ariophanta solata) and Sln.12 (Cauvery) are highly suscepti- are active during S.W. monsoon feeding on ble to the disease. Growing of rust tolerant leaves of co—ee and dadap. It is controlled Arabica varieties like Sln.5 (S.2931), Sln.9 by picking and dipping in hot water or salt (S.2790) or Chandragiri, avoiding cultivation solution. Liming and application of ash repels of susceptible Arabica cultivars in lower alti- snails. Red borer ( Zeuzera co¡eae) a—ects tudes of less than 2000 feet and providing co—ee by boring into the young stem and optimum shade, etc., are recommended as primaries. The larva is reddish and hence preventive measures. For susceptible culti- the name. A—ected branches should be cut vars any one of the systemic fungicides like and burnt. Thrips are minute organisms, triademefon @ 0.02% a.i., (Bayleton 25WP) @ less than 1 mm in size. They damage leaves 160g or hexaconazole @ 0.01% Contaf( 5%EC by lacerating the leaf tissues. As damage is @400 ml in 200 L of water) during March more in exposed areas during dry weather, and September/October and spot spray of optimum shade should be maintained to triademefon @ 0.02% a.i., (Bayleton 25WP) control thrips. Termites also cause crop loss @ 160g during break in monsoon (August) in co—ee. Locating the termite colonies and are recommended. Additionally, apply freshly destroying the queen, placing Aluminium prepared Bordeaux mixture on the under phosphide tablets (2 per mound) or pouring surface of leaves before the onset of South- 60 ml of Chlopyriphos 20 EC help to control West monsoon (May-June) as a prophylactic termites. measure.

Diseases of co‚ee Black rot (Koleroga noxia) Like pests, diseases also cause consider- Black rot is the second important disease affect- able loss in crop if left unchecked. All the dis- ing both Arabica and Robusta, during the monsoon eases of co—ee recorded in India are caused by period. It is very common in all the coffee tracts, parasitic fungal pathogens. Arabica is more under the influence of heavy monsoon. It brings a susceptible to diseases than Robusta. In the crop loss of 10 to 20%. Continuous monsoon rain case of integrated diseases management use with saturated atmosphere of 95 to 100% RH, thick of tolerant cultivars and more attention to shade and valleys sheltered from sunlight are the upkeep of the plants in vigour play vital roles favourable factors for this disease. The black rot as natural enemies are rare, unlike in the pathogen infects leaves, developing berries and case of pest management. young shoots. The most striking symptoms are blackening and rotting of leaves, developing ber- Co‚ee leaf rust (Hemileia vastatrix) ries and young twigs. Affected leaves get detached Co—ee leaf rust is the most disastrous dis- from branches and hang down by means of slimy ease of co—ee, caused by the fungus, Hemileia fungal strands. When the affected parts get dried, vastatrix. This fungus infects only the foliage white web of mycelium will be visible. Thinning of the genus Co¡ea. Wet weather during May of shade in the endemic blocks before the onset to November, intermittent rains and sun- of monsoon, centering and handling, cleaning of shine, mist or rain during the dry weather bushes by removing dead/dry branches, suckers, from December to March are favourable to removing dried leaves fallen on the canopies and the disease. In the South-West monsoon zone spraying Bordeaux (2kg CuSO , 2kg CaO in 200 ₄ Crops of Kerala – An overview 105 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

L of water) on both leaves and berries before the root disease is seen only in Arabica and it is onset of monsoon are should be carried out prior conžned to Giris area in Chikmagalur and to the commencement of monsoon to prevent the Yercaud region in Tamil Nadu. All these dis- disease. In affected blocks, it is advised to remove eases are caused by fungi. Brown root disease the affected leaves and berries, and spray 0.03% (stump rot) is caused by Fomes noxius, red carbendazim (Bavistin 120 g/200 l water). root disease is caused by Poria hypolateri- tia, black root disease by Rosellinia bunodes Co‚ee trunk canker (Ceratocystis ƒmbriata) and Rosellinia arcuata and santavery root Generally the disease a—ects the plants disease is caused by Fusarium oxysporum. aged above 10 years. Plants will be weak with Brown, black and red root diseases spread to no foliage formation with irregular lesions neighbouring plants through root contact of on the main stem. Ultimately branches start infected stumps or plants. These also attack wilting and lead to the death of the plant. dadaps, silver oak and many other shade Uprooting and destroying the a—ected plants, trees. The shade tree stumps and wooden avoiding bark injury to the plants and treat- logs in the farm are the main source of these ing the a—ected plants with carbendazim are diseases. Arial symptoms are almost same in the measures suggested to control the disease. all these cases. A—ected plants show gradual yellowing of leaves and defoliation followed Pink disease (Corticium salmonicolor) by death of the plant. In case of brown root Results in pink encrustation of branches. disease, thick brown encrustation with fun- Infected branches may shed their leaves and gal mycelium is seen near collar region of entire branches may dry up and die. A—ected the root and in the case of red root disease plants show pink encrustation of the fungal root system shows red encrustation covered growth. Spray 0.5% Bordeaux mixture as with soil, whereas in the case of black root a prophylactic spray and in endemic blocks disease, on the stem near the ground level spray carbendazim 0.03% (120 g/200 litres fan-shaped black fungal mat with pellet like of water) to control the diseases. fructižcations are seen. Anthracnose (Colletotrichum gleosporioides) In the case of brown, red and black root This results in twig dieback, stalk rot of diseases, management practices are the same. berries/leaves and brown blight of leaves. In order to control the spread of the disease Twig dieback is noticed during October to žrst thing to be done is isolating the a—ected May, stalk rot of berries/leaves is observed plants and adjoining four plants with 2 feet during monsoon and brown blight of leaves deep and 1 feet wide trench. Soil removed is observed in exposed blocks. Maintain from the trench should be put into a—ected adequate shade to prevent twig dieback area. Other measures to be adopted are and brown blight of leaves. Prevent water uprooting the severely a—ected plants with logging and provide good drainage to prevent the roots, burning and then applying 1 kg stalk rot. Spray 0.5% Bordeaux mixture as of CaO in the pit, drenching the soil with a prophylactic spray and in endemic blocks 0.4% Bavistin 50 WP (8 g/ L of water) at 3 spray carbendazim 0.03% (120g/200 litres of L per plant or 0.3% Vitavax 75 WP (4 g/L of water) to control the disease. water) when wilting is just seen, applying organic manure @ 10 kg per plant, remov- Root diseases ing the stumps of shade trees immediately Brown root disease, red root disease, black or ring-barking before felling the trees to root disease and santavery root disease are prevent infection and avoiding of carrying of the four types of root diseases noticed in cof- soil/plant material from a—ected area. New fee. Among these, žrst three root diseases are seedlings should be planted only after about seen both in Arabica and Robusta. Santavery 6 months after taking control measures. 106 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

In the case of Santavery root disease the SH9 either in single or in combination are symptoms are sudden wilting, yellowing of responsible for resistance in co—ee plants leaves followed by defoliation and death to the leaf rust. Of these SH1, SH2, SH4 and of plants. Roots show brown to pinkish SH5 are found in Ethiopian Arabicas, SH3 colour when cut open. Favourable factors in C. liberica and SH6, SH7, SH8 and SH9 are for Santavery root disease are low or high found in the inter-specižc hybrid of Robusta soil temperature, poor physical conditions of x Arabica, Hybrido de Timor (HDT). soil, moisture stress, inadequate shade and In India research programme on co—ee wounds on the roots. In order to control the was initiated during 1925. Prior to the estab- Santavery root disease uprooting and burning lishment of research department, some of of the dead/dying plants, planting grafted the innovative planters had developed co—ee plants (Robusta as stock and Arabica as scion) selections namely Coorgs, Chicks and Kents. in a—ected blocks, applying 10 kg FYM/plant, Over the last nine decades, Central Co—ee correcting the soil acidity to pH 6.0-6.5 and Research Institute has established a germ- drenching the soil with 0.4% Bavistin 50 WP plasm of around 360 Arabica accessions and (8 g/l of water) or 0.3% vitavax 75 WP (4 80 Robusta accessions including exotic and g/l of water) @ 3 litres per plant are recom- indigenous collections. Through its research mended. Further, optimum shade should be programmes CCRI has released 13 Arabica maintained in the blocks and plants should and three Robusta selections. be kept in healthy condition by providing adequate quantity of fertilizers and organic Arabica selections from India manures. Sln.1 was developed by selection from the progenies of a natural hybrid of C. arabica x Co‚ee improvement C. liberica and Sln.2 was developed by S.31 Co¡ea arabica and Co¡ea canephora x S.22. Initially both these selections were are the two commercial varieties cultivated popular but later were withdrawn due to worldwide. Among these, Co¡ea arabica is bean defects. In order to overcome the bean preferred in the market as it is superior in defects of Sln.1, it was crossed with Kents quality with enticing aroma and low ca—eine and and Sln.3 was developed. Sln.3 was a content. Nevertheless, Co¡ea arabica is sus- high yielder and renowned for its quality and ceptible to leaf rust disease and the dreaded very popular among growers as S.795. Later, pest, white stem borer. Though Robusta is it became susceptible to new races of co—ee resistant to co—ee leaf rust and white stem leaf rust. Sln.4 was developed from compos- borer, aroma is less and taste is bitter com- ite Arabica collections from Ethiopia namely pared to Arabica. Moreover, Robusta is rela- Cioccie, Agaro and Tafarikela. Cioccie and tively susceptible to drought. Hence, the main Agaro are tolerant to leaf rust. Tafarikela focus of the breeding programme in Arabica is is susceptible. Nevertheless, Tafarikela is to evolve varieties having resistance to co—ee tolerant to drought. Sln.4 was later used to leaf rust and white stem borer, whereas in develop improved selections. Robusta, the objective is to evolve varieties Sln.5A and Sln.5B were developed by with high aroma, better taste and drought crossing indigenous inter-specižc hybrid tolerance. (Devamachy) with S.881 and S.333. It is However, Arabica is being more consumed, widely cultivated in Andhra Pradesh. Sln.5B, of high value and major focus of research which was developed by crossing Devamachy programmes is to evolve Arabica varieties with S.333, is a high yielder with improved having resistance to co—ee leaf rust. Studies bean size, better cup quality and with high conducted in di—erent countries in this line želd tolerance to leaf rust. It is popular have indicated that nine major genes SH1 to in all Arabica growing regions. Sln.6 is Crops of Kerala – An overview 107 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). an inter-specižc hybrid between Robusta Robusta selections from CCRI Sln.1R (S.274) with Kents Arabica. Sln.6 is Robusta selection 1R was developed by also a popular selection grown in all Arabica mass selection. Bean size and yield potential regions, due to its želd tolerance to leaf rust, is higher compared to old Robusta. It is being improved bean size and cup quality. Sln.7 was cultivated all over Robusta growing regions. developed as an attempt to exploit high den- Later through further selection Sln.2R sity planting by exploiting the dwarf mutants. (Balehonnur Robusta series) was developed. Dwarf mutant ‘San Ramon’ was crossed with It is collection of di—erent 17 Robusta clones S.795, and the resultant hybrid was crossed (BR series). Out of these, mixture of superior with Agaro and again the hybrid was crossed clones, BR-9, BR-10 and BR-11 was recom- with HDT. The dwarfs among the progenies mended for planting for better pollen compat- were utilised for high density planting. It is ibility and higher fruit set. Robusta selection drought tolerant but a late ripener. Presently Sln.3R was developed by crossing Sln.1R with it is cultivated only in certain marginal areas. Co¡ea congensis. Hybrid was superior in bean Sln.8 was developed by pureline selection size and improved cup quality. Yield was on from Robusta x Arabica inter-specižc hybrid par with S.274. Bush size is compact and it Hybrido de Timor. It is a moderate yielder. is suitable for high density planting. It is tolerant to leaf rust and is a popular selection. Sln.8 being tolerant to leaf rust was Harvesting further crossed with Tafarikela, an introduc- Fruits attain maturity within 8 to 9 tion from Ethiopia, which is drought tolerant. months after flowering in Arabica and The hybrid is drought hardy, with improved within 10 to 11 months after ¬owering in bean size and renowned cup quality and was Robusta. Mature fruits should be carefully released as Sln.9. This variety is popular and harvested and processed to prepare the com- cultivated in all Arabica regions in India. mercial product called green beans. Careful handling of co—ee and correct processing Sln.10 is a double cross hybrid of Catura techniques adopted at the estate level are x Cioccie and Catura x S.795. Catura is a the most important steps which determine high yielding variety, but, highly susceptible the quality of the end product viz., the co—ee to co—ee leaf rust. Sln.10 became suscepti- beverage. Faulty and unclean processing will ble to virulent races of leaf rust. Sln.11 is cause ‘o—tastes’ in the co—ee cup. an inter-specižc hybrid of C. liberica x C. eugenoides. It is highly tolerant to leaf rust For the preparation of both parchment and drought, but with small bean size and is a and cherry co—ees, picking of the right type moderate yielder. It performs well in marginal of fruits is an essential part of processing. areas of Andhra Pradesh. Sln.12, popularly Co—ee fruits should be picked as and when known as Cauvery, is an interspecižc hybrid they become ripe. Under-ripe and over-ripe between Catura and Hybrido de Timor. It fruits will a—ect the žnal quality of co—ee, the is a high yielder with bold bean size and former tending to produce ‘immature’ beans compact bush. It was resistant to leaf rust and the latter ‘foxy’ beans. While picking for about 10 years after release. But later it and transporting picked co—ee to the drying became susceptible to new races and it was yard, damage to the co—ee fruits should be replaced by other popular selections. Later avoided. Green cherries should be carefully Sln.13 (Chandragiri) was released by crossing sorted out before taking the ripe fruits for Villa Sarchi (mutant of Burbon) and Hybrido pulping. The green cherries may be dried de Timor. It is tolerant to all known races separately for the preparation of cherry co—ee. of leaf rust and bean size is bold. It is being It is advisable to wash and dry frequently cultivated in all Arabica regions of India. the bags used for collecting the harvested 108 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). fruits. Bags in which fertilizers, pesticides 2. Treatment with alkali: Removal of muci- and fungicides are stored should never be lage by treatment with alkali takes about used for this purpose. ½ an hour for Arabica and ¾ to 1 hour for Robusta. The wet parchment obtained after Primary processing pulping is drained to remove excess water Co—ee is processed in two ways (1) wet and is spread out in the vats uniformly. It processing, by which plantation or parch- is furrowed with wooden rakes and 10% ment or washed co—ee is prepared and (2) solution of caustic soda (Sodium hydroxide) dry method, by which cherry or unwashed is evenly applied into the furrows using a co—ee is prepared. rose can. About 1 kg of Sodium hydroxide dissolved in 10 litres of water is sufficient Wet processing (preparation of parchment to treat 25 to 30 forlits of parchment. The co‚ee) a) Pulping parchment is agitated throughout and soaked for about half an hour. When the parchment Preparation of co—ee by the wet method no longer appears slimy, it should be washed requires pulping equipment and adequate thoroughly with clean water, repeatedly two supply of clean water. After harvesting, the to three times. fruits should be pulped (removal of skin) on In this the same day so as to avoid fermentation 3. Removal of mucilage by friction: method, the pulped parchment coming out commencing before pulping. Fruits are fed of the pulper is fed into the ‘aqua washer’. to the pulper through a siphon arrangement The aqua washer removes the mucilage by to ensure uniform feeding and to separate friction and the mucilage is washed away by lights and ¬oats from sound fruits. Uniform the water passing through the machine. Thus feeding ensures proper removal of skin and the parchment coming out of the machine prevents cuts and choking of the pulper discs. is free from mucilage. It is washed again The pulped parchment passes through a sieve in the vats once or twice and then taken up where the unpulped fruits and fruit skins are for drying. separated. Passing the parchment through a grading sieve will also help in separating c) Soaking the large and small sized beans. The skins Overnight soaking of wet parchment in separated by pulping should be removed from clean water helps to improve the colour of the vats. the parchment. d) Washing b) Removal of mucilage On completion of fermentation, the The mucilage on the parchment cover can parchment is thoroughly washed with water be removed by 3 methods which are as follows: repeatedly in the vats till all the mucilage is removed. 1. Natural fermentation: The wet parchment obtained after pulping is kept heaped in vats e) Drying of parchment co‚ee and allowed to undergo natural fermentation Soon after the parchment co—ee is washed, brought about by bacteria. The pectin and the excess water should be drained on spe- non-reducing sugars present in the mucilage cially constructed raised platforms or on are digested by the bacteria and the muci- perforated galvanized sheets. Surface drying lage is rendered soluble after about 36 to 48 is best carried out in trays provided with a hours. In the case of Arabica, the mucilage wire-mesh bottom. The co—ee may be turned breakdown is completed in about 36hours frequently to facilitate quick drying and to and in the case of Robusta, fermentation prevent cracking of the parchment skin. In will be completed only by 72 hours. rainy weather, the trays may be kept under Crops of Kerala – An overview 109 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). polythene covered erections. In the evening, co—ee. The dried co—ee parchment should be co—ee should be protected against mist. The packed in clean gunny bags and stored in surface drying in trays may take about 24 godowns on wooden dunnage. After drying, to 48 hours. co—ee should be stored in a well ventilated After surface drying, the parchment is store house. Fertilizers, pesticides or insecti- spread over clean tiled or concrete drying cides should not be stored together with co—ee ¬oors. The parchment should be spread to a as co—ee beans readily pick up foreign taints. thickness of 7 to 10 cm and dried slowly. Rapid Perfect cleanliness should be maintained all drying of washed co—ee at this stage causes through the di—erent stages of processing the parchment skin to split, which may lead right from picking till the co—ee is žnally to discolouration of the beans. Stirring and despatched to the curing works. turning over of the parchment co—ee once an Out turn hour is necessary for uniform drying. The parchment should be heaped and covered with Out turn is a scale or a unit indicating polythene sheets early in the evening, until ratio of ripe cherry to dry parchment, dry the next morning. The cover may be removed cherry or clean co—ee. Approximate ripe and co—ee spread again the next day. Sun cherry to clean co—ee ratio in case of Arabica drying of parchment co—ee may take about is 17 to 19% and in case of Robusta, the ratio 7 to 10 days under bright weather conditions. is 19 to 21%.

Dry processing or preparation of cherry co‚ee Secondary processing For the preparation of cherry co—ee, fruits Milling should be picked as and when they ripen. Removal of parchment skin and silver skin When harvesting is done by one stripping, it from parchment co—ee and husk from the is preferable to do so when 50% of the crop is cherry co—ee is called milling. After milling ripened. Greens and unripe fruits should be skin and parchment peels are removed by sorted out and dried separately. The fruits winnowing and then clean co—ee is subjected should be spread evenly to a thickness of to grading. about 8 cm on clean drying yards. It is desir- Grading able to dry on tiled or concrete drying yards. Co—ee should be stirred at least once an hour. Both Arabica and Robusta can have round The cherry co—ee may be heaped and covered beans, called pea berry (PB) or ¬at seeds every day in the evenings and spread again called ¬ats. Pea berry is separated manually the next morning. The co—ee is dry when a or mechanically using PB band separators. žstful of cherry when shaken gives a rattling Flats are then classižed into A, B or AB sound and a sample forlit records the same according to the size of seeds. The di—erent weight on two consecutive days. The cherry types and grades of co—ee released for export co—ee would be well dried after 12 to 15 days. are Plantation AA, A, B and C, Arabica cherry Each lot of cherry should be bagged separately PB, AB and C, Robusta cherry PB, AB and in clean gunny bags. C and Robusta parchment PB, AB and C. After completion of grading, garbling (sorting) Packing and storing co‚ee is done to remove defective and discoloured Approximate moisture content in ripe beans then clean co—ee (green co—ee) is stored cherry is 65%. After processing and drying, in ventilated godown for marketing. co—ee should be dried to optimum moisture level. Drying is complete when beans are Cup quality evaluation dried to a moisture level 10.5% in case of Cup quality of co—ee is in¬uenced by parchment co—ee and 11.5% in case of cherry variety, agronomic practices, climatic factors, 110 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). primary processing, secondary processing, the consumers demand for unique co—ee with roasting, grinding and brewing. To main- žner qualities, growers are identifying co—ees tain quality, care should be taken right from of unique origin and special characteristics choice of varieties, cultivation, processing and and processing it with utmost care to promote brewing. Cupping is the method of systematic as specialty co—ee. Monsooned co—ees from evaluation of aroma and taste characteristics. India are renowned specialty co—ee fetching Cup quality evaluation is done by expert cup premium price in the global market. Apart tasters at quality evaluation laboratories. The from this, estate co—ees, organic co—ees and green co—ee is roasted at 205oC in a suitable variety co—ees are promoted by growers of roasting machine till it turns to golden brown India. colour. Roasted beans are then ground in grinding machine to prepare coarse powder. Indian œlter co‚ee Fresh powder is then put in a porcelain cup Indian žlter co—ee is a special co—ee and brewed with 250 ml boiling water (around preparation. Put 10 g (1 tablespoon) co—ee 95oC) and allowed to settle for 5 minutes. powder to the upper unit of the co—ee žlter, After removing the ¬oats at a palatable insert plunger and make the co—ee powder temperature co—ee is tasted for its quality. a uniform bed. Pour 150 ml freshly boiled Specialty co‚ees water over the plunger. Allow it to brew for Specialty co—ees are exceptional co—ees, žve minutes. Golden brown aromatic liquid better in quality compared to normal co—ee will drip into the lower unit of the žlter. Pour either in taste or in visual appearance or both. out the extract from the lower unit into the Deca—einated co—ee, organic co—ee, high alti- cups. Add 100 to 125 ml fresh hot milk into tude co—ees, single origin co—ee (estate co—ee) the extract and add sugar to taste. Indian and variety co—ees are specialty co—ees. As žlter co—ee is ready. Crops of Kerala – An overview 111 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Biology and cultivation of tea V.V. Radhakrishnan Genetics and Plant Breeding Division, Department of Botany, University of Calicut, Kerala – 673635, India.

The beverage prepared from the dried leaves of m above the mean sea level. Most of the tea estates the tea plant is the most popular non-alcoholic drink are located in slopes having 10%-33% gradient. of the common man. Commercial tea is obtained Origin and distribution from three species of the genus Camellia belonging Tea is considered to be native of China. to the family Theaceae namely Camellia sinensis Some workers consider it belonging to North (L.) O.Kuntze (China type), Camellia assamica East India and adjoining part of Burma. (Masters) Wight (Assam type) and Camellia assam- Tea has its principal area of distribution in ica ssp. lasiocalyx (Planch ex Watt) Wight (Cambod the South East Asia ranging from Nepal to type), which are known to produce commercially Formosa and Japan. Three important types acceptable tea. Among the three species Camellia of cultivated tea tea namely China type, sinensis is the most commonly grown. Man’s first Assam type and Cambodia type are seen in use of tea plant as a pleasant beverage dates back these areas. Some other workers consider to early days of human history. The tea leaf has that tea originated somewhere in the lower to undergo several physical and chemical changes Tibetan mountains. before it can be rendered fit for consumption. Based on the method of manufacture, commercial tea is Types of cultivated tea classified as (a) green tea (b) black tea and (c) oolong China tea (Camellia sinensis (L.) O. Kuntze) tea. The most popular value added product is instant China tea grows into a big shrub, about tea, a water soluble product of black tea. Today, tea 1-3 m in height, with numerous stems arising is drunk all over the world and as each year passes from the base of the bush near the ground more tea is being produced and consumed. India level, giving rise to a dome shaped bush when continues to be the world’s largest exporter of tea, fully grown. Leaf blades are generally leath- and more cups of tea are drunk throughout the world ery and dark green. Marginal veins of the leaf because it is a good tranquilizer and at the same are generally indistinct. Flowers are borne time acts as a mild stimulant. The original habitat singly or in pairs in the cataphyllary leaf of the tea plant is Southeast Asia with warm wet axils. All the žve sepals are persistent and summer and dry cold winter. Tea is a rain fed crop. leathery. Petals are 7 to 8 in number, cup It requires a rainfall of about 150 cm per annum. The shaped. Ovary white, densely hairy, three O temperature range required is between 13 C and locular. Stigma is apical, capsule 1 to 3 loc- 30°C. Relative humidity should be around 80% but ulate, containing 1 to 3 seeds. not less than 40% and the area should not be prone to frost and heavy wind. Tea plant requires strong Assam tea (Camellia assamica (Masters) Wight) acidic soil with pH between 4.5 and 5.5. At present Assam tea grows in to a small tree with commercial cultivation of tea extends from 44°N a vertical branching system and a distinct to 34°S. It enjoys the elevation of 300 m to 2500 trunk, sometimes up to one third of the height 112 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). of the tree. The tree generally grows to a While preparing the land for new planting, height of about 10 m to 15 m. Leaves are measures to conserve soil and water must be typically dependent and thin glossy with more borne in mind. Provisions for boundary, con- or less acuminate apex and distinct marginal tour and leader drains to facilitate draining veins. Leaf blades are mostly broadly elliptic, of the surplus water and prevent soil erosion 8 to 20 cm long and 3.5 to 7.5 cm wide. Flowers are made, besides staggered trenches. In the are single or in pairs developing from the case of new planting, to avoid the incidence cataphyllary leaf axils. Sepals are 5 to 6 in of root diseases, after felling the trees, root number, unequal, leathery and persistent. system is removed to the extent possible. Petals are 7 to 8 in number, white and devoid Burning of jungle growth is not advisable of any pigmentation. Ovary is three locular. as ash being alkaline will increase the pH Style typically three. Stigma linear. Fruit of soil. In the case of replanting, old shade and seed more or less same as in China type. trees are removed leaving the young ones in the želd. The land is leveled into an even Cambod tea (Camellia assamica ssp. lasiocalyx slope to facilitate easy cultural operations and (Planch, ex Watt) Wight) proper drainage. A pit size of 30 x 45 cm2 is Cambod tea reaches a height of about 6 to recommended for tea planting. However, in 8 m. Leaves are more or less erect, glossy and clayey soil and drought prone areas, deeper yellowish-green when young and light green pits are advisable. Aluminium sulphate at at maturity. Size of the leaf is intermediate the rate of 100 gm per pit is applied and between those of Assam and China types thoroughly mixed with soil if the soil pH is and leaves are generally elliptic. Ovary 3 to more than 5.5. The polythene sleeves are 4, sometimes 5 locular. Styles 3 to 5, free. cut and removed without damaging the roots while planting. Planting is completed Fruit and seed similar to other varieties. in June, where the plantations receive the Planting and aftercare South West monsoon while it is advisable Tea is propagated either through seeds to complete it in September in areas under or by clonal methods. Seeds are viable up North East monsoon regime. to six months and prior to sowing, seeds are Training of young tea put in water and only the sinkers are used and ¬oaters rejected. Seeds germinate in4-6 Proper training of young tea plant is nec- weeks and the cracked seeds are transplanted essary to achieve good canopy cover, proper in polythene sleeves. Polythene sleeves of development of frames and more number of 10 cm width and 30 cm height are used for plucking points per unit area. Centering or raising seedlings in the nursery. A mixture cutting the leader stem is the žrst agronomic of jungle black soil with sand in the ratio of practice executed after planting the tea plant 1:1 is žlled in the bag. Approximately 2 kg in the želd. Centering o—ers release from of soil-sand mixture is needed per sleeve. apical dominance and induces laterals. It Top 10 cm of the sleeve is žlled with red should be done four to six months after plant- soil in order to induce proper rooting. The ing during favourable climatic conditions. seedling will be ready for planting in the The žrst plucking after centering is termed main želd in nine months of time. Clonal as tipping and two tier tipping for proper planting materials are prepared from single spread is recommended in training of young node cuttings, multiple node cuttings or by tea plants. First tipping at 35 cm height for tissue culture. Clonal cuttings are planted in increasing the tertiaries and second tipping polythene sleeves for germination and after at 50 cm to induce the density of plucking germination they are planted in the main points is suggested. Tipping should be done želd as in the case of seedlings. at green and semi hard wood portion and Crops of Kerala – An overview 113 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). the tipped in material must contain only Plant protection 3-4 leaves and a bud. Crop shoots produced Pests after two tier tipping have to be removed The major pests that infect the tea plant periodically. Mother leaf plucking during include root pests, stem borers and leaf pests. lean periods and level plucking during The major root pests are nematodes and high plucking months are recommended to cock chafer grubs. Nematodes are micro- ensure the sustained productivity and health scopic worms infecting roots resulting in the of young tea and it is essential for better development of knots or galls. A—ected roots frame development. Cutting the branches become defunct. Plants exhibit chlorosis and of tea bush at a pre-determined height and stunted growth. In nursery, heat treatment a t a specižed interval is known as pruning. is practiced to control the nematodes. The This important operation is carried out to soil sand mixture is spread on a GI sheet maintain the convenient height for plucking, and heated from below. Optimum tempera- to induce more vegetative growth, to remove ture is 60-80oC. Chemical treatment with the dead and defective wood and to remove Carbofuran 3G 20g per cubic feet of soil is knots and interlaced branches. Pruning of also e—ective. Neem cake @ 2kg per bush is young tea plants is carried out normally recommended in the želd. in žfth year, which is known as formative Cock chafer grubs (Holotrichia sp.) žnd pruning. If tea plants are left unpruned, access to the nursery either through the they will grow as high as 30 feet. soil or through undecomposed farmyard Tea is a shade loving plant and therefore manure. The grubs damage the bark and roots of young plants leading to their death. planting shade trees and their management Heat treatment of soil and use of granular is considered as a routine cultural operation insecticides are recommended. in tea plantations. The best permanent shade tree for tea plantation is silver oak (Grevillea The red co—ee borer ( Zeuzera co¡eae) and robusta). Tea requires only sparse shade and the polyphagous borer Sahyadrassus mala- hence the optimum stand of shade is retained baricus are the major stem borers infecting based on growth of the tree, altitude of the tea. The red co—ee borer bores the young stem of the plant and the larvae tunnel down- garden and other aspects of the želd. ward and make holes at intervals to eject excreta and wood particles. Thick branches Manuring are preferred by Sahyadrassus malabaricus. Tea responds to manuring and it has been The borers make holes in the stem and cover estimated that to produce 100 kg of made tea, the entrances with a frassy mat formed from tea plant utilizes on an average 10.2 kg of N, chewed wood and silk. To control stem borers, the a—ected stem region is cut and removed 3.2 kg of P2O5 and 5.4 kg of K2O. Manuring in tea starts from the nursery stage itself. and Quinalphos is applied using ink žllers. Once they strike roots at about 4 months after The holes are covered with clay paste also. planting, 30 g of soluble mixture ( Ammonium The major leaf pests are mites, thrips phosphate 35 parts, Potassium sulphate and and tea mosquito bugs. Mites like pink mite Magnesium sulphate 15 parts each and Zinc (Acaphylla theae), purple mite (Calacarus car- sulphate 3 parts) is dissolved in 10 L of water inatus), red spider mite (Oligonychus co¡eae), and is applied with rose can for about 900 scarlet mite (Brevipalpus australis) and yellow plants. Manuring in tea depends on many mite (Polyphagotarsonemus latus) infect tea. factors like age of the plants, organic and If infestation is high, Dicofol, Quinalphos nutrient status of the soil, soil pH, nature of or Monocrotophose is sprayed. Scirtothrips pruning and želd potential of the tea bushes. bispinosus is the major thrip infecting tea. 114 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

These thrips prefer young leaves and buds. attached to the stem for some time. The roots Both adults and larvae feed on the plants and are covered with black strands of mycelia, cause lacerations of tissue which appear as more or less woolly in appearance, which run streaks. The leaf surface becomes uneven, longitudinally along the surface of the root curled and matty. The feeding marks on and sometimes unite to form a network. The the unopened buds appear as two parallel above diseases can be managed by preventing lines on the leaves. Chemical treatment with their occurrence and spread by eradicating Phosalone, Monocrotophos, Quinalphos or the pathogen. Soil drenching with certain Dimethoate is recommended. The tea mos- fungicides and soil application of biocontrol quito bug Helopeltis theifera infects tender agents are e—ective in controlling them. leaves and buds and causes dark brown colour. Charcoal stump rot is caused by Ustulina Spraying of Thiodan 35 EC at appropriate zonata. The presence of white or cream dozes is recommended. coloured delicate fan shaped patches of myce- lium and irregular black double lines on the Diseases wood surface of the root are the characteristic There are root diseases, stem diseases and symptoms. The dead bushes are uprooted stem diseases that infect tea. The major root and disposed o—. The area is then sprayed diseases include red root disease, brown root with 1%^ Copper oxychloride. Replanting is disease, root splitting disease, Xylaria root done only after 1-12 months. Violet root rot disease, black root disease, charcoal stump is caused by Spaerostilbe repens. The a—ected rot, violet root rot and Diplodia root disease. bush exhibits a debilitated appearance. The Red root disease is caused by Poria hypolat- leaves become thin, yellow and drooping. The eritia. The disease can be easily identižed by bark of the root becomes deep violet to inkish the characteristic mycelial strands that the violet in colour. Improvement of drainage to fungus forms on the surface of the root. The take away excess water, forking of still soil fungus spreads very fast but kills the bush to increase aeration and improvement of soil slowly. Brown root disease is caused by Fomes conditions by green manuring, mulching and noxius. The roots get encrusted with a mass application of compost will help in recovery. of soil, sand and small stones to a thickness Botryodiplodia theobromae causes Diplodia of 3-4 mm, which cannot be easily washed o—. root disease. The failure of the bushes to In advanced stages of the disease, the wood recover after pruning or die back of new of the root turns soft and spongy with honey shoots formed after pruning is the initial comb like reticulation. Armilaria mellea symptom of the disease. The bushes show causes root splitting disease in tea. The most a weak appearance with unhealthy frames characteristic symptom of the disease is the and small leaves. Application of an adequate development of longitudinal cracks in the fertilizer to help the bushes to put on vigorous bark. When the bark of the root is lifted, growth is the remedial measure proposed. a thick mat of white mycelium can be seen. The stem diseases include collar can- Xylaria root disease is caused by Xylaria s p . ker and thorny stem blight. Collar canker The very žrst symptom of the disease is the in tea is caused by Phomopsis theae. The retardation of growth. The a—ected plants main symptoms of the disease are chlorosis, remain dormant with absolutely no ¬ush cessation of growth, profuse ¬owering and growth. The a—ected roots are covered by canker on stems. To control the disease, typical black, ribbon like compact strands of remove the a—ected portion by pruning to fungal hyphae that almost completely cover the healthy wood and apply copper fungicides the root surface. Black root disease is caused to cut ends. Soil drenching with systemic by Rosellinia arcuata. Diseased bushes die fungicides and soil application and wound suddenly and the withered leaves remain dressing with biocontrol agents are e—ective. Crops of Kerala – An overview 115 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Thorny stem blight is caused by Tunstallia gained further importance due to massive aculeata. The characteristic feature of this uprooting of old seed grown sections to be disease is the formation of thorny projections replaced with a few popular clones such as on the stem. These thorny projections are the UPASI 9, UPASI 3, ATK, TRF 1, CR 6017, apices of the fructižcations of the pathogen. SA 6, etc., which will lead to narrow genetic The severely a—ected bushes are uprooted base. If genetic variability of such areas are and burnt to avoid risks of further spore not collected and conserved now, they will production. Soil drenching with fungicides be lost forever. Such an alarming situation and wound dressing with biocontrol agents of the tea germplasm in India leads us to provide good control of the disease. intensify the e—orts of collecting the genetic Blister blight caused by Exobasidium diversity and conserving and utilizing the vexans is the major leaf disease in co—ee. same. The wide bush-to-bush variation in The fungus a—ects only young succulent any želd of seed grown tea will be apparent leaves and stems. Translucent spots occur to any observer but the extent of variability within 3 to 10 days and well developed lesions is perhaps not fully realized until yields or are seen within two weeks. The lesions are yield components of a large number of bushes sunken on the upper surface and convex at are recorded separately. the lower surface. A—ected leaves are dis - Selection torted and irregularly rolled. The disease can be controlled e—ectively by spraying a Di—erent workers have suggested selec- combination of COC and Nickel chloride at tion criteria for yield and yield related char- a regular interval of 5-7 days. acters in tea. Size and surface area of a bush in a mature tea želd are the criteria Crop improvement recommended for estimating yield by Visser Introduction, selection and hybridiza- (1969). A positive correlation between yield tion are the mainstay of the improvement and leaf size was observed by Satyanarayana programmes for superior planting material and Sharma in 1982. In a mixed population in any crop. The žrst e—orts to improve the where chinary bushes also exist, selection for tea plant started by way of introduction and leažness will tend to be biased in favour of the selection of superior jats. The žrst scientižc shrubby China type. In general, such bushes attempt to select improved tea in Northeast will be less productive in areas where large India was made by Stiefelhagen brothers in leaf Assam type bushes can be grown. Leaf 1860 by establishing standard sources of the size, which is related to size and weight of tea seeds. The seed grown plants are not shoot, has also been used as a yield criterion. uniform as they are genetically diverse. In Correlation between leaf size, leaf number some cases the yield and quality are unpre- and yield were also observed. dictable but the planters wanted uniform From South India, in 1966, Venkataramani plantations and as a result clonal method clearly pointed out that seedling plants in of propagation came to existence. a population exhibit tremendous variation Genetic resources programme is one of amongst themselves with regard to di—erent the priorities in crop improvement research. characters. It is not therefore surprising to The priority areas should be viewed primarily assume that some of the variations are such from three di—erent angles namely collection as to adopt the plants possessing them better of variability, evaluation of collected cultivars to the conditions in which they grow. It is a and conservation. The old seed grown tea common knowledge that in a tea želd, some populations are highly heterogeneous and bushes are attacked less by fungi, mites etc., thus are the gold mines of genes. The need and that some bushes recover quickly from for collecting tea germplasm in India has pruning than others. The advantage of such 116 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). variations is to be exploited scientižcally. of the annual crop is gathered, and a second When the selection programme was started in ¬ush in September to December when about UPASI-TRF, prime importance was given to 35 to 40 per cent of the annual crop is har- yield and quality. Resistance to blister blight vested. Commercially, tea may be divided and mites received only secondary consider- into three basic classes namely black or fer- ation because immunity or high resistance mented, green or unfermented and oolong or to blister blight and quality do not go hand semi-fermented. Besides these three types, in hand. In practice no one selection could instant tea, a water soluble form of black tea be really resistant to all pests and diseases is also manufactured in limited quantities. and a selection that is satisfactory for yield There are žve principal operations in the and quality might not highly or totally be preparation of black tea and they are: susceptible to the most common pests and diseases. It has been pointed out that selec- Withering tion of the mother bush is the most import- About 75 per cent of the fresh weight of ant and that the future of the vegetatively a fresh tea leaf consists of water even on propagated progeny would greatly depend on a dry day and nearly half of this has to be initial selection. But the combination of high removed before the žbres of the leaf and crop yield and outstanding cup qualities is stalk will stand the strain of rolling without likely to occur only very rarely breaking up. The leaf is spread thinly over withering racks arranged one above the other Vegetative propagation of tea horizontally, and allowed to remain there for The genetic makeup of perennial crops is 12 to 18 hours to lose its excessive moisture. highly heterozygous and the unique charac- Sometimes, heated air is forced over these teristics of such plants are lost if they are racks if the atmosphere around is humid. propagated by seed. For commercial purposes The leaf slowly and evenly becomes soft and it is essential to have certain desirable char- ¬accid and ready for rolling. acters such as high yield, good quality and resistance to pests and diseases. Since seed Rolling/leaf maceration propagation does not ensure the availability Rolling imparts the characteristic twist of plants true to the parent, the propagation to the leaf, breaks the leaf cells, and exposes of superior varieties has to be done through the juices to the air for fermentation to set vegetative means in tea. in. After half an hour’s rolling the leaf is removed in aluminium trolleys to a sifter Harvesting and processing and roll breaker. The movement causes the Harvesting in tea involves the collection of broken leaves and žne particles to fall below young growing shoots comprising the apical and the rest is taken out after rolling. The bud, the internodes and two or three leaves latter is again rolled for the second time with immediately below it, which constitute the increased pressure. After the second roll, all crop. Collection of two leaves and a bud is the leaves still more or less green and ¬accid known as žne plucking while harvesting are transferred to the fermenting drum. three leaves and a bud is termed as light plucking. In order to increase labour pro- Fermentation ductivity and to harvest entire crop during During fermentation, the tannin in tea is the high cropping months, shears have been partly oxidized and the leaf changes colour introduced and used. Motorized machines are and turns bright coppery red. The rolled also used for harvesting. In India, plucking leaf is spread on tiles or aluminium or glass is carried out throughout the year. Even sheets and the oxidation which has com- then, there are two big ¬ushing periods, menced during rolling continues. The period from April to May when about 25 per cent of fermentation generally extends from three Crops of Kerala – An overview 117 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). to three and a half hours, but this includes this method, the leaves are rolled inside the rolling time as well. As a general rule, the rollers and as a result of the pressure exerted shorter the fermentation, the more pungent by the rollers the leaves are crushed and the the liquor is, and the longer the fermentation sap gets smeared on the leaf surface. the softer the liquor and deeper the colour. CTC tea Drying or œring CTC stands for cutting, tearing and curl- After the leaf changes its colour, the ing. Here, rollers are designed in such a way leaves are subjected to drying or žring. The that the leaves get cut, teared and curled in essential function of this process is to arrest the process. The product is called CTC tea. further oxidation of the leaf and to remove all moisture excepting a small amount of roughly Instant tea 3 to 5 per cent. The drying machine is the Powder tea, which is also known as instant largest machine required in a tea factory. The tea is manufactured in separate factories. To automatic tea drier is a large steel oven inside make the powder, an ordinary tea infusion which the leaves travel slowly to the bottom is evaporated and dried; the powdered solid while hot dry air is continuously forced into matter thus obtained serving as a product the oven. Careful regulation of temperature to be infused again. is essential, as excessive heat will scorch the Green tea leaves while lack of it will result in improper Green tea can be broadly classižed in to drying. Generally, the process known as žrst two categories: Pan or Chinese green tea and žring removes only three-fourth of the total Sencha or Japanese green tea. The essential moisture of the fermented leaves. After a di—erence between the two is that pan tea period of cooling, they are fed into another is half fermented and in sencha the green drier and the latter known as second žring leaf is steamed as soon as it is received for removes the remaining moisture and the tea processing to activate the enzyme polyphenol from this second drier is the žnished product. oxidase and then dried in stages till it reaches Grading and sorting a moisture content of 34%. On the other hand, pan tea is allowed to ferment slightly Grading is carried out on mechanically and roasted in a hot pan to prevent further oscillated sieves, similar to those used in fermentation. In both the methods the green the green stage, and žtted with meshes of colour of the leaf is preserved throughout the appropriate size. It is the essence of good manufacture and the end product is green. manufacture that teas should be sorted daily and not exposed to the air. After sorting tea Grades of tea is graded and given various names such as There are di—erent grades attributed to Orange Pekoe, Pekoe, Fannings and Dust; processed tea based on the method of process- but these are only indicative of size and not ing, size of the granules and also the quality of quality. Finished grades are stored in of the tea. The major grades of orthodox tea airtight bins until a sufficient quantity is are whole leaf, broken, fannings and dust. accumulated to žll a consignment. The major grades of CTC tea are broken, fannings and dust and in the case of green Di‚erent methods of tea processing tea the major grades are whole leaf, broken, Orthodox tea fannings and dust. All the above types are Orthodox teas are manufactured using further classižed in to further grades based orthodox rollers in the process of rolling. In on the size of the leaf/granule/dust. 118 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Biology and cultivation of natural rubber P. M. Priyadarshan Former Deputy Director, Rubber Research Institute of India, Kottayam- 686009, Kerala, India.

Natural rubber has been an essential stability to latex at basic pH, whereas latex commodity not only for the tyre industry coagulates at low pH. but also for more than 50,000 products that Natural rubber is produced in South East hold elasticity as an attribute. Natural Asia (92%), Africa (6%) and Latin America rubber is produced from over 7,500 plant (2%). The main producing countries are species distributed among 300 genera of Thailand (4.17 million t in 2014, account- seven families, namely Euphorbiaceae, ing around 37% of global output), Indonesia, Apocynaceae, Asclepiadaceae, Asteraceae, Malaysia, India, China, Vietnam and also Moraceae, Papaveraceae and Sapotaceae. The Sri Lanka, Brazil, Liberia, Côted’Ivoire, prime source of natural rubber worldwide Philippines, Cameroon, Nigeria, Cambodia, is Hevea brasiliensis (Willd. Ex. A. de. Juss. Guatemala, Myanmar, Ghana, Democratic Müll-Arg.). Among the alternate sources of Republic of Congo, Gabon, Bangladesh, Laos rubber available, Parthenium argentatum and Papua New Guinea. Hevea rubber is Gray and Taraxacum kok-saghyz Rodin are depicted in ancient religious documents from currently exploited commercially on a small Mexico dating back to AD 600 and has a long scale in semi-arid regions and temperate history before domestication. However, the regions respectively. discovery of vulcanization (heating rubber The molecule of natural rubber is a cis with sulfur) by Charles Goodyear in1839 1,4 polyisoprene [(C5H8)n] where n may resulted in explosive advancements in product range from150 to 20,00,000, and is the end manufacturing. product of around 21 biochemical steps. Production of a molecule requires at least The latex found in the inner bark of H. 48 hours. Shaving of bark of the tree (tap- brasiliensis is obtained by tapping (shaving ping) yields rubber latex from the turgid the bark with a sharp knife) and collection laticifers of the bark and the ¬ow of latex of latex in cups. Addition of an acid, such ceases upon plugging of the laticifers that as formic acid, solidižes rubber. The solid- happens as a natural phenomenon after ižed rubber can then be pressed between 3 to 4 hours of latex ¬ow.Latex is a white twin rollers to remove excess water to form cytoplasmic colloidal suspension containing sheets. The sheets are commonly packed in mainly rubber particles and some non-rubber bales for shipping. Rubber is also commonly particles, organelles, proteins and serum. transported in the form of concentrated latex Latex particles are negatively charged on derived through centrifugation. The strip of their surface and latex has a plasticity index latex coagulated on the tapping panel (lace) (pI) between 3 and 5. This confers a colloidal and the lump left out in the cup (cup lump) Crops of Kerala – An overview 119 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Some rubber yielding plants other than Hevea brasiliensis Common Scienti˜c name Distributional range name Castilla elastica Panama AMERICA (Mexico, Central America, Western Sessé rubber tree South America)

AFRICA (Micronesia, Northeast Tropical Africa, West East Tropical Africa, West Central Tropical Ficus vogelii African Africa, West Tropical Africa, South Tropical (Miq.) Miq. rubber tree Africa, South Africa, Western Indian Ocean area) Funtumia AFRICA (East Tropical Africa, West Central Lagos silk africana (Benth.) Tropical Africa, West Tropical Africa, South rubber tree Stapf Tropical Africa) Manihot glaziovii Ceara AMERICA (South America) Muell.Arg. rubber Holarrhena ¥oribunda (G. False AFRICA (West Central Tropical Africa, West Don) Durand & rubber tree Tropical Africa) Schinz AFRICA (Northeast Tropical Africa, East Funtumia Lagos silk Tropical Africa, West Central Tropical Africa, elastica Stapf rubber West Tropical Africa) Indian Ficus elastica ASIA-TROPICAL (India, China, Malaysia) rubber Roxb. plant Parthenium NORTHERN AMERICA (South Central U.S.A., Guayule argentatum Gray Mexico)

Taraxacum kok- Russian ASIA-TEMPERATE (Russia, China) saghyz Rodin dandelion

Cryptostegia Palay ASIA (India) grandi¥ora R. Br. rubber that form the ‘scrap’ of commerce also fetches last decade. Mainland Southeast Asia and income to the planter. Southwest China represent the epicentre of Hevea rubber nowadays is cultivated as far rapid rubber expansion. north as 25o North (Yunnan province, China) and as far as 21o South in Brazil. The main History of domestication production zone conžned between 15 o N and History of Hevea recapitulates the S. Strong international demand for natural names of žve distinguished men: (i) Clement rubber is driving expansion of industrial scale Markham (of the British India Office); and smallholder monoculture plantations, (ii) Joseph Hooker (Director of Kew Botanic with >2 million ha established during the Gardens); (iii) Henry Wickham (naturalist); 120 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

(iv) Henry Ridley (Scientižc Director of for research on H. brasiliensis. Ridley devel- Singapore Botanic Gardens); and (v) R.M. oped an improved method of tapping rubber Cross (Kew gardener), with Kew Botanic trees that resulted in better yield of latex. His Gardens playing the nucleus for rubber innovation revolutionized the region’s econ- procurements and distribution. As per omy. The arrival of 22 seedlings in Singapore directions of Markham, Wickham collected did not create the Malaysian plantations 70,000 seeds from the Rio Tapajoz region of overnight. The price of co—ee had been high the Upper Amazon (Boim district) and trans- due to production problems in Brazil but, ported the collection to Kew Botanic Gardens by the mid 90s, these problems had been during June1876. Seeds reached Kew on 14th of overcome whilst fungal disease was attacking June 1876. Unlike popularly believed, this was the Malaysian plants. In 1895, upon advice not a corrupt evasion of law, as an official from Henry Ridley, Tan Chay Yan planted 43 statement Borracha no Brasil in 1913 says it’s acres of Hevea on his estate at Bukit Lintang only a goodwill of Government of Brazil. Of the in Malacca and the Kindersleys planted fur- 2899 seeds germinated, 1911were sent to the ther 5 acres in Selangor. These were the žrst Botanic Gardens, Ceylon (now Sri Lanka), commercial rubber estates in Malaysia and, during 1876, and 90% of them survived at as the co—ee market collapsed, more and more the Henarathgoda Botanical Garden. During planters turned to rubber. September 1877, 100 Hevea plants specižed as Signižcant development on the propaga- ‘Crossmaterial’ were also sent to Ceylon. In tion of Hevea rubber occurred after 1910. June 1877, 22 seedlings not specižed either The contribution to propagation and breed- as Wickham or Cross, were sent from Kew to ing of Hevea made by P.J.S. Cramer (Bogor, Singapore, which were distributed in Malaya Indonesia) during 1910–1918 is note worthy. and formed the prime source of 1,000 tap- He made a trip to the Amazon and succeeded pable trees found by Ridley during 1888. in getting seeds of Hevea spruceana and Hevea Mixture of Cross and Wickham materials guianensis. Cramer also conducted experi- might have occurred, as the 22 seedlings were ments on va r iations observed in 33 seedlings unspecižed. One such parent tree planted imported from Malaysia in1883 from which during 1877 was available in Malaysia even the žrst clones of the East Indies were derived. after 100 years. The rubber trees covering Along with van Helten, a horticulturist, he millions of hectares in South-east Asia are could standardize vegetative propagation by believed to be derived from very few plants 1915. The žrst commercial planting with bud- of Wickham’s original stock from the banks grafted plants was undertaken during 1918 of the Tapajoz. After a review of the history of in Sumatra’s eastcoast. Ct3, Ct9 and Ct38 rubber tree domestication in East Asia, one were the žrst clones identižed by Cramer. would draw the conclusion that the modern Commercial ventures gradually spread with clones have invariably originated from the the introduction of bud grafting and ‘genera- 1911 seedlings sent to Ceylon during 1876. tive’ and ‘vegetative’ selection methodologies Also, Charles Farris could transport some were simultaneously used that resulted in seedlings to Kolkata in India (erstwhile seedlings and grafted clones. Calcutta) during 1873. Hence, the contention The žrst introduction of rubber to India that the modern clones were derived from was during 1873 from Ceylon (now Sri Lanka) ‘22seedlings’ is debatable. when 28 Hevea plants were planted in the Developments in domestication of rubber Nilambur Valley of Kerala state in South after 1880 commenced in Singapore Botanic India. During the period 1880–1882, plan- Gardens. Under the direction of Henry tations on an experimental scale were raised Nicholas Ridley, who took over as Director in di—erent parts of South India and the o f SBG in 1888, the garden became a centre Andaman islands. Hevea was žrst introduced Crops of Kerala – An overview 121 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). to Vietnam in1897 by the French, but was Hevea shows seasonal flowering in rejuvenated only after 1975 because of the response to alternation of seasons. In the long lasted war. northern hemisphere, March–April is the main ¬owering season, and a short spell Botany of Hevea brasiliensis of secondary ¬owering prevails in August– Hevea is easily recognizable from its September in many areas. It seems reason- characteristic trifoliated leaves. The genus able to presume that geographic location has a is basically composed of 10 species: H. brasil- bearing on whether the trees ¬ower during the iensis, H. guianensis, H. benthamiana, H. secondary season. While it ¬owers and sets pauci¥ora, H. spruceana, H. microphylla, seeds during both the seasons in Malaysia, the H. rigidifolia, H. nitida, H. camporum and southern parts of India experience ¬owering H. camargoana . Seven species are found in in March and April only. In north east India, the upper Rio Negro region, considered to Tripura state experiences ¬owering and seed be the center of origin of the genus. Hevea set during both the seasons, but seeds are brasiliensis is found in Southern areas out- less viable during the secondary season. The side of this center, in the upper Rio Madeira, appearance of female ¬owers takes 10–12 days where žve other species are represented. It more than male ¬owers (dichogamy), and, due has generally been assumed that the species to incomplete protrandry, some of the male are freely inter-compatible. Consequently, ¬owers emerge after the appearance of female Hevea species might be considered as a spe- ¬owers. In Manaus and São Paulo (Brazil), cies complex, due to the absence of a strict which are located south of the equator, Hevea barrier to recombination between species. Many e—orts led to the identižcation of certain ¬owers only during September–October. types which were formerly presented as other In¬orescences are borne in the axils of the possible species. H. paludosa was identižed basal leaves of the new shoots that grow out in Brazil in 1905 and is often considered as after wintering. The in¬orescence is a many an 11th species. branched, shortly pubescent panicle bearing All Hevea species have 2n = 36 chromo- ¬owers of both sexes. The larger female ¬ow- somes, with the exception of one triploid ers are borne at the end of the central axis and clone of H. guianensis (2n = 54) and the main branches while the smaller and more existence of one genotype of H. pauci¥ora numerous male ¬owers appear on other parts with 2n =18. Although Hevea behaves as a of the panicle. Flowers are greenish yellow, diploid, it is believed to be an amphidiploid (2n with a bell shaped calyx having žve triangu- = 36; x = 9) that stabilized during the course lar lobes but no petals. Such pentamerous of evolution. Similar to other tropical trees, ¬owers and a tricarpellary ovary are typical Hevea normally takes 4–5 years to attain the of the Euphorbiaceae and the alternation of reproductive stage. Though the capacity to vegetative and reproductive phases with the ¬ower is retained thereafter, the periodicity formation of in¬orescences at the end of the and the quantitative importance of ¬owering dry season implies a tight control of ¬owering vary from clone to clone, as in other tropical time. Staminate ¬owers have ten anthers trees. Rubber tree is monoecious, with lateral arranged over a staminal column in rows of in¬orescences (branched panicles) bearing žve each. The pistillate ¬ower consists of a both staminate and pistillate ¬owers that three celled ovary with three short sessile appear in the last phase of the defoliation– stigmas. For each pistillate ¬ower, about 70 refoliation process during wintering. Rubber staminate ¬owers are found. reaches maturity when it attains 50 cm trunk girth (tappable girth) at 125 cm height, so Hevea appears to be obligatorily insect as to harvest latex. The immature phase of pollinated and predominantly cross fertil- rubber is around six to seven years. ized. The strongly scented ¬owers of mature 122 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). in¬orescence attract insects (pollinators) that pressed against the endosperm and enclose are mostly midges and ants of the families the plumular end of the axis of the embryo. Heleidae and Ceratoponoidae. The viability The endosperm, which forms 50–60% of the of pollen grains can be as high as 90%, but weight of the seed, contains semi-drying oil on average is only about 50%. Due to incom- which can be used as a rather poor substitute plete protrandry, Hevea clones may undergo for linseed oil. If seeds are not sown in 10–15 assortative mating. Clones that have early days, they lose viability on storage as a result anthesis of female ¬owers will preferentially of the production of hydrocyanic acid (HCN). get pollinated by clones wherein female ¬ow- ers are yet to emerge. So, in a multi-clone Vegetative growth of the plant population, possibility of random mating can Growth in the length of stem is discontin- always occur. However, due to incompatibility uous, with rapid elongation of an internode barriers among clones and issues relating towards the end of which a cluster of leaves to fruit set, seed set may not occur in the is produced. This will be followed by a rest expected rate. period for the scale leaves to develop around Fertilization occurs within 24 h after the terminal bud. This sequence is repeated pollination and unfertilized female ¬owers and leaves are produced in whorls separated quickly wither. Clones vary greatly in ¬ower- by bare stem. Young scions of bud grafts ing, fertility and fruit set. This ranges from elongate internodes for 2–3 weeks followed near sterility to proližc fertility. There is no by a rest period. Although the elongation of evidence of self incompatibility. The mature stems is intermittent, their girth increases fruit is a large three lobed capsule, 3–5 cm continuously. New ¬ushes in the mature tree in diameter, having a woody endocarp and a appear at any time of the year. The spirally thin, leathery mesocarp, and contains three arranged trifoliate leaves hang downwards seeds. The fruit reaches its maximum size in approximately parallel to the petioles and about 80–90 days and the endocarp becomes are reddish or bronze in colour and gradually woody in about 110 days. The endosperm become green. The angle with the petioles matures in about 130 days and the cotyledons will now be increased to 180°, in which posi- get pressed to the endosperm. Thereafter, tion they remain until they senesce. The the moisture content of the capsule wall mature laminae are shiny dark green on declines when the fruit is about 140 days their upper surfaces and paler, glaucous so that the dry capsules dehisce explosively green below. Leaves are trifoliate and gla- into six pieces with dispersal of seeds up to brous, arising on petiolules with long petioles 15 m from the tree. (about 15cm) bearing extra ¬oral nectaries Seeds are large (3.5–6.0 g) and ovoid with at the point where petiolules merge. Nectar the ventral surface slightly ¬attened. The is secreted only on the new ¬ush of leaves seed coat, or testa, is hard and shiny, brown during ¬owering. The lea¬ets are elliptic or grey brown with numerous darker mottles or obovate with the base acute and the apex or streaks on the dorsal surface, but a few acuminate; they have entire margins and or none on the ventral side. The hilum can pinnate venation. Clones can be identižed be seen as a shallow, approximately circular through a closer examination of the archi- depression on the ventral surface and the tecture of leaves. micropyle is adjacent to it. A papery integu- ment lines the inner testa and encloses the Wintering endosperm, which žlls the seed. The embryo Trees of more than 4 years exhibit defolia- is situated in the middle of the endosperm tion or ‘wintering’, a term used to describe the with the radicle pointing towards the micro- annual shedding of senescent leaves which pyle. The two white, veined cotyledons are renders the trees wholly or partly lea¬ess Crops of Kerala – An overview 123 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). for about 15–20 days. Defoliation is followed rubber growing areas. The principal way of by terminal bud bursting in 15 days and the achieving high productivity has been the expansion of new leaves in a week. There development of high yielding clones with used to be a yield depression during defo- desirable characteristics through rigorous liation and more markedly during refolia- breeding and selection. Supplementary tion. In areas experiencing a dry period, the approaches to achieve greater productivity duration of wintering tends to be short and have been the determination of an optimum refoliation is completed fast, thus minimizing tapping schedule and soil management to yield reduction. Most of the non-traditional maintain fertility. All these parameters a—ect rubber growing areas above 15°N fall under the overall growth and physiology of trees. this category. There are marked di—erences Before the rubber tree can produce between clones in wintering behaviour. A few latex, it needs to attain maturation of the tend to shed and replace part of their foliage leaves, the organs of photosynthesis. Leaves simultaneously over a relatively long period attain maturity in around 35–40 days after and may thus show no very obvious signs of emergence. In addition to phytohormonal wintering, while at the other extreme some equilibrium, leaf maturity can be regarded become completely lea¬ess for a time. The in terms of CO2 balance and the maturity majority are intermediate between these leads to a series of characteristics such as extremes. leaf expansion, chlorophyll accumulation and formation of photosynthetic apparatus (photo- Root heterogeneity and stock–scion systems I and II and carboxylative enzymes), interactions stomata, cellwall and supporting structures. A major part of rubber breeding effi - The dry matter increase in rubber tree leaves ciency can be attributed to the grafting is directly related to the balance between technique which enables the multiplication of CO assimilation from photosynthesis and elite genotypes at the level of the bud-grafted 2 its release by respiration. During the juvenile part (aerial part of the tree). Unfortunately, phase, the CO balance in the rubber tree cloning the whole tree (aerial part and roots) 2 is especially a—ected by signižcantly higher for the development of single component clonal respiration. The higher respiration rates trees by the cutting technique (self-rooted that occur in the juvenile phase seems to marcots and mist-propagated cuttings) indicate a higher metabolic activity (growth generates a high ratio of uprooting due to respiration), during which energy released is lack of tap root and inadequate anchorage. required to synthesize structural compounds Notwithstanding, a bud-grafted population and chlorophyll. To reach net photosynthe- has a high level of homogeneity and should sis, the young leaves need to increase the exhibit intra-clonal variation in yield to a concentration of CO . minimum. 2 Ecophysiology of rubber Propagation systems Rubber planters are under permanent As in any other tree species, Hevea is pressure to raise land productivity while also multiplied by both seeds and vegetative protecting the environment as a result of: means. There are di—erent kinds of rubber (i) decrease in the amount of cultivable land; seeds such as: (i) legitimate; (ii) illegiti- (ii) the change in human lifestyles increasing mate; (iii) ordinary; (iv) monoclonal; and (v) the demand for rubber; and (iii) environmen- polyclonal. Among these, monoclonal and tal issues generating a demand for natural polyclonal seeds are produced in specially rubber over synthetic rubber. This increasing raised plantations. The other types of seeds demand has prompted rubber cultivation are collected from commercially established to be rapidly expanded into non-traditional plantations. 124 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Polyclonal (polycross) seeds, which are are made on two sides of a bud, 1.5 cm apart. hybrid seeds, are produced in plantations Then, two horizontal cuts are made connect- called polyclonal seed gardens. In these gar- ing the lower and upper ends of these cuts. dens, several clones are planted intermixed Latex is allowed to ooze out and meanwhile s o as to maximize cross pollination. Clones incisions are made around neighbouring buds planted in these gardens should possess of the same bud wood. When the oozing of desirable characters such as: (i) high yield; latex stops, it is wiped o— and the bud patch (ii) disease resistance; (iii) vigour; (iv) ability marked out by the four cuts is stripped o—. to produce good seedling families; and (v) The inner side of the bud patch is examined profuse production of seeds. All the clones for the presence of the core of the bud, which should preferably ¬ower simultaneously. appears as a slight projection. If that is not Vegetative propagation of rubber is carried present, the bud patch should be discarded. out mainly by bud grafting. Propagation The bud patch is then gently placed in the bud through rooted cuttings is possible in rub- grafting panel after lifting the ¬ap. Due care ber but is not generally practiced due to must be taken not to injure the cambium. The unsatisfactory development of the root sys- panel is bandaged using a polythene strip. tem, especially the taproot. The principle Bandaging should commence at the bottom involved in bud grafting is the replacement and move upwards in a close tight spiral that of the shoot system of a genotype with that of can end with a knot. It requires 15–20 days another more desirable genotype. The method for the bud patch to heal and form part of of bud grafting adopted is a modižed form the stock. The presence of green colour on of the forket method of patch bud grafting. the bud when the bud is scratched indicates In this process, a patch of the bark of the initial success of bud grafting. seedling plant (stock) is replaced by a bud patch taken from the clone to be multiplied Latex production and harvest (scion). A thin žlm of polythene is wound Latex is a colloidal suspension. It is a over the bud patch for water proožng. After stable dispersion (emulsion) of polymer 21 days, the polythene is taken o—. The bud micro-particles in an aqueous medium. It patch gets attached to the stock permanently is a complex emulsion consisting of proteins, and becomes a part of it. The stock is then alkaloids, starches, sugars, oils, tannins, res- cut o— above the bud-grafted portion and the ins and gums that coagulate on exposure to grafted bud develops into a new shoot (scion) air. Besides rubber particles, latex contains and then into a two part tree. sub-cellular elements like lutoids, plastids, Depending on the colour and age of the the Fre-Wyssling particles whose role is not buds, three main types of bud grafting are clearly understood and ribosomes. However, practiced. These are: (i) brown (conventional); neither the nuclei nor the mitochondria are (ii) green; and (iii) young bud grafts. In the expelled during tapping. žrst method, older buds having a brown colour Latex usually contains 25% to 50% dry are used, while in the other two, tender green matter, 90% of which is made up of rubber. buds are utilized. Depending on the part Tapping causes loss of cell constituents from of the stock where bud grafting is carried the laticifers. Hevea rubber is a macromole- out, the classižcation would be: (i) base bud cule formed by chains of 5-carbon isoprenic grafting; (ii) crown bud grafting; (iii) over units – the cis 1,4 polyisoprene (C5H8)n where bud grafting; and (iv) high bud grafting. The n may range from 150 to 20,00,000. This bud patch used for brown bud grafting has high molecular weight polymer is formed a length of about 5 cm and a width of about from sequential condensation of isopentenyl 1.5 cm. For preparing the bud patch, two diphosphate (IDP) units. IDP is a common parallel vertical cuts having a length of 5 cm intermediate for the production of numerous Crops of Kerala – An overview 125 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). classes of isoprenoids produced in plant vessel rings. Hence, when the tree is tapped, kingdom. These units are the precursor of latex thus exuding originates not only from numerous other natural isoprenic substances the latex vessels of the trunk that are cut, (sterols, carotenoids, etc.). A close study of but also from connected latex vessels of the its structure has shown that the isoprenic same latex vessel ring that are uncut, but bonds are mainly of the cis form; less than that lie within the proximity of the ‘drainage 0.2% is in the trans form and these make the area’ of the tapping cut. Similarly, tapping žrst ‘geranyl geranyl’ links in the polyiso- panel turgour pressure has a bearing on the prene chain. The average molecular weight changes in the drainage area as a whole. is between 2,00,000 and 8,00,000. On tapping, release of pressure occurs to a Laticifers are the major locations of rubber greater extent in the latex vessels than in biosynthesis. Numerous classes of isoprenoids the surrounding tissues. This results in a are produced through IDP as a common inter- rapid elastic expulsion of latex ¬ow through mediate. The mevalonate (MVA) pathway has the vessels along the pressure gradient. The been the conventionally studied pathway gradient is highest near the cut and becomes for isoprenoid biosynthesis since the 1950s. smaller with increasing distance away from This cytosolic pathway of rubber formation the tapping cut. Latex ¬ow ceases after two was demonstrated through incorporation of hours when plugging happens by the bursting radiolabelled pathway intermediates such of lutoids. The early tapping systems slowly as mevalonate and 3-hydroxy-3-methylglu- evolved into the modern systems largely by taryl coenzyme A (HMG CoA) into rubber. reducing the number of cuts and the fre- Recently, the plastidic I-deoxy-D-xylulose quency of tapping. 5-phosphate/2-C-methyl-D-erythritol 4-phos- There is a need to open trees for tapping phate (MEP) pathway is being considered as as soon as the required minimum girth has a possible alternative route for rubber biosyn- been obtained. While the budded trees have thesis. The expression of l-deoxy- D-xylulose cylindrical trunks and can be opened at a 5-phosphate synthase (DXPS) in Hevea latex height which tappers can reach without any and leaves suggests that the MEP pathway aid, seedling trees are conical with a bigger exists in the laticifer and therefore could girth at the base of the tree and hence, a provide an alternative means of generating lower height of opening is recommended. With IDP for cis-polyisoprene synthesis. conventional tapping the recommendation is Latex ¬ow rate and the changes in tap- to open bud-grafted trees for tapping with a ping panel turgour pressure have a direct girth of 46 cm and above (when 70% of the relation with the anatomical aspects of the trees have attained) attained at a height of laticifer system. The latex vessels (laticifers) 1.5 m from the ground. For seedling trees, the are arranged in concentric cylinders among convention is to open when a similar girth is the phloem tissue. Elongated laticifer cells reached at a height of 75 cm from the ground. are laid down in each cylinder end to end The latex vessels in the bark traverse from with their end walls dissolved, thus form - bottom left to top right at an angle of 300 ing sets of continuous articulated tubes. in an anti-clockwise direction. Hence, a cut These cylinders appear as rings in a cross from the high left to low right will severe a section, known as ‘latex vessel rings’. Lateral greater number of latex vessels which lead to connections between adjacent latex vessels the current practice of sloping cut from high within the same ring occur, and the laticif- left to low right on all spiral cuts. Similarly, erous system is thus made up of a complex 25o slope is preferred for seedling because network of interconnected vessels gaining it results in lesser bark consumption and a the name ‘anastomosing latex vessels’. There smaller area of bark that will be lost when are no connections between adjacent latex the cuts reach ground level without much 126 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). loss of yield. Further, the presence of a thick Rubber products can be manufactured corky layer in bark provides a channel for either from dry rubber or from latex. Dry the ¬ow of latex. Since the bark thickness rubber products are generally made by mould- is less in bud-grafted trees, the latex may ing, calendaring or by extrusion methods. over¬ow the sides of the tapping cut with a Latex products are made by dipping, casting 25o slope; which is an additional reason for or by extrusion. Dry rubber products like having 30o slope in bud-grafted trees. When door mats, bushes and even tyres are made the tapping cut approaches the base, a new by moulding. Thin products like microcel- cut on the opposite panel can be similarly lular sheets are made by calendaring and opened. Tapping Panel Dryness (TPD) is products like rubber hoses are made by a syndrome encountered in rubber trees, extrusion methods. An automobile car has characterised by spontaneous drying up of more than 500 parts made of rubber starting the tapping cut resulting in abnormally low from bushes, beadings, wipers to tyres. Latex yield or stoppage of latex production. products like rubber bands, balloons, gloves, condoms etc. are made by dipping the moulds Post-harvest processing in compounded latex whereas foam products Tapping of a rubber tree is preceded by like mattresses are produced by casting and clearing the tapping panel, and the tree lace latex threads are made by extrusion method. and the lump remaining in the cup are col- After shaping, the products are vulcanized lected by the tapper before tapping the tree. by heating in sunlight or in hot air ovens. This lump and lace are dried and pressed Products and processes generating ancil- to form 25/50 kg blocks. These fetch a com- lary income paratively lower price commercially, but can Hevea honey and wood are the two supple- form raw material for the production of crepe mentary income generating sources that can and block rubber. Such blocks are used for raise signižcant income from rubber planta- manufacturing tyres. The collected latex tions. Neither male nor female ¬owers secrete is diluted with twice the quantity of water nectar, but it is secreted by the extra-¬oral and 1% Formic acid is added to coagulate nectaries (on young leaf petioles and ¬eshy the rubber. After coagulation, the ‘rubber scales of young shoots). Over the years, honey slabs’ are passed through rubber rollers to bee rearing saw major vicissitudes due to squeeze the water out. Popularly, in addition non-availability of bees many a times. In to using smooth and ribbed rubber rollers, India, there was a rehabilitation measure automated sheeting batteries are also used through the introduction of Apis mellifera for higher efficiency. Rubber sheets thus with a reported average yield of 60 kg/hive/ formed are smoked and dried in the smoke year compared to 19.46 kg/hive/year for the house and made into bales. Latex as such is popular Indian honey bee viz., Apis cerana not generally used for making products due indica. On an average, 15 to 20 A. cerana to its low dry rubber content (DRC). 100 g indica hives can be placed per ha and the of latex contains only 30 g to 32 g of rub- average yield is 12 kg/hive/year. The honey ber depending on the season. Latex can be ¬ow period of rubber plants ranges from subjected to centrifugation using specially January to March and during this period designed latex centrifuges that can yield honey bees collect large quantities of nectar latex with 60% DRC, popularly known as from the extra ¬oral nectaries. cenex. Double centrifuged latex is also used Rubber wood is composed of žbres, ves- for making specižed latex products. Latex sel elements, axial parenchyma and rays in can also be concentrated by creaming process. di—erent proportions similar to that of other Crops of Kerala – An overview 127 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). hardwood species. The žbres are lignižed or traditional environment, RRIM 600 seems partially lignižed and are 1.1 mm to 1.5 mm to be the universally accepted clone for all in length and about 22 µm in thickness and non-traditional areas of the world. the vessels are small to moderately large with Natural pollination was the basis of ‘ran- one to four pores per mm2. The structure dom seedling populations’ and of ‘mother-tree and distribution pattern of pores enhance seedlings’. Natural pollination was exploited the chemical impregnation capacity of rubber by creating polyclonal seed gardens with the wood during preservative treatments. The best mixed clones, planted in isolated sites lumen of the pores is usually žlled with bal- in order to protect them from outside pol- loon like parenchymatous outgrowths called len. Natural pollination in seed gardens can tyloses which are a characteristic feature of lead to a certain amount of selfed seedlings rubber wood. For temporary protection, a dip with potential inbreeding. R ecombination treatment with a number of insecticides and breeding programme is practiced in rubber by fungicides is carried out. In long-term, the controlled hand pollination for the production wood preservatives are allowed to penetrate of full-sib families, followed by three selection deep into the timber for complete preserva- stages viz., Seedling Evaluation Trial (SET), tive penetration either through dip di—usion Small Scale Clonal Trial (SSCT) and Large process or pressure impregnation process. Scale Clonal Trial (LSCT). The process is cyclical, with the best clones becoming can- Crop improvement didates for recombination in the next cycle. From around 500 kg/ha in primary clones The aim of a breeding programme in rub- to more than 2500 kg/ ha in the best current ber is to derive a clone with enhanced dry clones, rubber breeding has come a long way rubber yield and if possible, with improved primarily due to recombination breeding secondary attributes like resistance to dis- and selection of clones under RRIM and eases and high/low temperature stresses. The PB series. RRIC 100 series released in Sri efficient use of the available genetic vari - Lanka during 1970s is yet another example. ability in the form of clones is further augmented Much of the hybridization work in Malaysia through bud-grafting. However, the longtime (RRIM, Prang Besar), Indonesia, India, Côte needed for genotype evaluation and low seed d’Ivoire, Brazil, Thailand and Vietnam fur- set are added constraints for the production of ther strengthened the array of hybrid clones. recombinants. The main source of modern These clones are known for their adaptability clones is the Wickham population with to specižc hydrothermal/agro-climatic sit- much low genetic variability. Of late, con - uations. At least 16 primary clones played certed efforts to integrate new Amazonian major role and can be considered as prime wild population o—er new vistas for the pro- progenitors of many modern clones. Many duction of new clones. valuable recombinants must have been lost While considering planting in a new area during the course of assortative mating of that may be suboptimal for rubber growth primary clones and of hybrid clones followed the best plants to use are polyclonal seedlings by subsequent directional selection for yield to ensure maximum stand development, sac- under varied geo-climates. The breeding pol- rižcing yield since these areas are a—ected icy has been mainly to cross ‘the best with by stress conditions. However, evaluation the best’ (GAM, Generation-wise Assortative of established clones gives quick informa- Mating), with strong emphasis on precocious tion on what clones are suitable for a new yield in selection within Wickham material. area. While the rubber producing countries But it could be considered to take more advan- have selected vivid clones suitable to their tage of genetic analysis and of quantitative 128 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). estimation procedures, especially for the 510), Tjirandji (Tjir1, Tjir16), Waringiana assessment of clonal general combining abil- (War4), etc. are the prominent ones. Some ity (GCA) for growth and latex yield improve- major clones developed from the important ment. Breeding for disease resistance has to rubber research institutes around the world take account of specižc aspects related with include IRRI clones (Indonesia, Indonesian host-pathogen interactions. Rubber Research Institute (clones IR), MDF The aforesaid breeding scheme is of the clones (clones collected in the Madrede Dios, past, and lately, Hevea breeding has been Peru by Firestone), RRIC clones ( Sri Lanka, compelled to undertake drastic reduction in Rubber Research Institute of Ceylon), RRII the years consumed for completing a breeding clones (India, Rubber Research Institute cycle and for derivation of clones. SSCTs and of India), RRIM clones (Malaysia, Rubber LSCTs are well avoidable. The scheme pro- Research Institute of Malaysia), RRISL clones posed here is to start with SETs comprising (SriLanka, Rubber Research Institute of hybrid seedlings. The course normally fol- Sri Lanka), RRIT clones (Thailand, Rubber lowed is to evaluate through test tapping and Research Institute of Thailand), RRIV clones select the best yielding seedlings. Presuming (Vietnam, Rubber Research Institute of that a seedling can never re¬ect the yielding Vietnam), etc. attribute during adult stage this step needs to It is difficult to provide yield data for be suitably modižed. The families of hybrid di—erent clones which successively emerged seedlings are to be raised in closer spacing (2 or 3 m) and allowed to attain tappable girth. in clone recommendations since there has These seedling trees are to be evaluated with been no standard for characterizing the yield a reference clone. (Selections from such eval- level of the clones over time in the successive uations are to be further laid under clonal experimental programmes. The mean annual -1 nursery, only to reconžrm the yield potential). yield over 10 tapping years with 550 kg ha The high yielding seedling trees are to be for unselected Wickham seedlings, 1175 kg -1 made bud-wood points, only to have enough ha for PilB 84 (selected in the 1920s), 1425 bud-grafted plants for block level commercial kg ha-1 for RRIM 501 (1928–1931), 2000 kg evaluations. Once the yielding potential of ha-1 for RRIM 600 (1937–1941) and 2125 kg the clonal derivative is conžrmed under block ha-1 for RRIM 712 (1947–1958) are the records trials, the clone is set for recommendation. available. Deriving clones at dežnite inter- When a normal breeding cycle takes 35 to 40 vals is challenging to the breeder, for which years, through skipping SSCTs and LSCTs, režnements in the methodology followed to the scheme proposed can complete a breeding reduce breeding cycle time and to assess the cycle in 17 years. yielding potential are prime. Rubber clones are denominated with a žrst part in letters (abbreviation of the ori- Biological constraints and their gin) and a second part in numbers. A list of management denominations with their emblematic clones It is noteworthy that unlike other clonal that were developed during the žrst half of the species, Hevea is not a—ected by viral dis - 20th century, such as AVROS (AV49, AV255, eases. Apart from South American leaf AV352, AV2037), Bodjong Datar (BD5, BD10), Blight (SALB), other diseases of economic Djasinga (Djas 1), Glenshiel (Gl1), Gondang importance are the Gloeosporium leaf disease Tapen (GT1), Kali Djeroek (KD1), Landb. Mij. (Colletotrichum gloeosporioides), powdery mil- Oud Djember (LMOD 53), Lands Caoutch dew (Oidium heveae), and the Phytophthora Bedrijf (LCB 1320), Pataroeman (Pat 190), leaf fall (Phytophthora spp.). Clonal speci - Pilmoor (PilD 65), Prang Besar (PB 186), žcity is evident towards resistance to these Proefstationvoor Rubber (PR 107=LCB diseases. Crops of Kerala – An overview 129 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

South American Leaf Blight (SALB - chlorothalonil (Daconil), triforine (Saprol) and caused by Microcyclus ulei) that is singu- triadimefon (Bayleton) are found promising larly devastating is a stress factor limiting in small-scale trials. the yield of Hevea. It has played and still Abnormal leaf fall is the most destruc- plays a major role in the history and in the tive disease in India and occurs during the geographic distribution of rubber industry in southwest monsoon months of June, July and the Americas. On one hand it prevents Latin August. It infects pods, leaves and tender America from developing rubber cropping in shoots causing heavy defoliation and die-back all the otherwise favourable climatic condi- of tender twigs. The žrst report on this dis- tions, and on the other hand it represents a ease from India was in 1910 from estates permanent major threat to the crop in Asia near Palapilly, in Trichur district, Kerala and Africa. Some amount of breeding work, state. In due course, the disease spread to mainly based on back cross technique has all other rubber growing districts. Rainfall been undertaken in the past to incorporate is the most important predisposing factor for resistance to these diseases in high yield- the initiation and spread of the disease. In the ing clones. Resistance sources appear to be traditional rubber cultivated areas of India, a absent in high yielding Wickham population, continuous spell of 250 to 350 mm rain for 7 but rather frequent within the Amazonian to 10 days without intermittent hot sunshine, germplasm. Conidia and ascospores cause with minimum and maximum temperatures infection and both are equally important in within the range of 220C to 250C and 260C completing the disease cycle. Rain plays an to 300C respectively and relative humidity important role in the spread of leaf blight. It (RH) above 90% are most congenial for the is believed that rain is the most e—ective dis- outbreak of the disease. Under such conditions seminator of large masses of spores and wind of low temperature and very high atmospheric is the chief means of dispersal. Outbreaks humidity, the disease spreads rapidly and of leaf blight occur when the daily tempera- assumes epidemic proportions. Under normal ture is below 220 C for longer than 13 h, RH monsoon, the disease starts by the middle of over 92 per cent for a period longer than 10 June and reaches the peak by the middle of h and rainfall above 1 mm per day for the July. However, when monsoon is late, very previous seven days. The fungus can a—ect heavy incidence is noticed from the middle petioles, green stems, in¬orescences and of July to middle of August. Di—erent species fruits. But the most obvious infection is on of Phytophthora are reported to be causing young leaves on the abaxial surface of four to pod rot, bark rot, patch canker and leaf fall nine day old, expanding tender leaves. They diseases of rubber in various countries. The appear as greyish-black lesions covered with species most common in the traditional areas olive-green powdery sporulating masses. The meadii. causal fungus Microcyclus ulei (P. Henn.) von is P. Prophylactic spraying of rubber Arx & E. Muller (Dothidella ulei P. Henn.) is plants with 0.75 per cent Bordeaux mixture is specižc to Hevea species only. Several plant the very popular method. It was noticed that protection operations are being carried out addition of 0.5 per cent zinc sulphate to 0.5 per for controlling this disease. Aerial spraying cent Bordeaux mixture could give adequate (8 -10 rounds) is done using benomyl 300 g, protection and reduce the cost of spraying by thiophanate methyl 200 g or mancozeb 2 kg about 35 per cent when compared to spraying in 30 L water per ha at intervals of 7 to 10 with 0.75% or 1% Bordeaux mixture. days. For fogging 200 g thiophanate methyl Powdery mildew disease was žrst reported or 1 kg mancozeb are being used in 6 to 8 L from Indonesia. Tender leaves at the brown of agricultural spray oil per ha at intervals of or light green stage are highly suscepti- four to seven days. Systemic fungicides like ble. The presence of dull cool weather with 130 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). intermittent light showers during refoliation tridemorph (Calixin 0.6/ha) or mancozeb predisposes the plants to severe disease (Dithane M45 1.5-3 kg/ha) are recommended attack. Prevalence of mist, dew and cloudy for Corynespora control in Indonesia. days with 75 to 80 per cent relative humid- ity are favourable for disease development. Biotechnology and genomics Early wintering clones usually escape from The attainment of yield plateau and prev- the disease because the climatic conditions alent intra-clone variations in the yield of during their refoliation period are not favour- Hevea prompted researchers to tackle these able for the disease development. Late win- problems through employing the modern tools tering clones are usually severely a—ected. of biotechnology. However, higher yield alone The optimum temperature for germination, would not encourage cultivation of Hevea, infection and sporulation ranges from 250C since the species is sensitive to biotic and to 300C. The fungus is disseminated by air- environmental attributes and physiological borne conidia. The peak sporulation is around disorders. The long breeding cycle and the noon. Oidium heveae Steinm an obligate large size of the crop also make breeding time parasite is responsible for the disease. Leaf consuming. Biotechnology applied to Hevea fall due to powdery mildew adversely a—ects can be discussed under two headings: (i) invi- the growth and yield of rubber trees. Dusting tro culture; and (ii) molecular breeding. While with sulphur gives e—ective control of powdery in vitro culture deals mainly with regener- mildew disease. Spraying wettable sulphur is ation and propagation, molecular breeding preferred only in nurseries and young rubber includes identification, characterization, plantations as repeated spraying in mature introduction and expression of novel genes. areas is expensive and impracticable. Sulphur The emergence of genomics has overshad- dust having a minimum of 70% sulphur is owed the relevance of in vitro culture. The generally used for dusting. The dust should conspicuous reason for this is that in vitro be dry, free ¬owing and should pass through culture was attempted by several laborato- 325 mesh sieve (particle size 40 microns). ries worldwide, but progress had been very Dusting is done at the rate of 11-13 kg/ha at minimal as the techniques envisaged could an interval of 7 -10 days. Three to six rounds not be commercialized successfully. On the of dusting are usually required. other hand, genomics worked meticulously Corynespora cassiicola (Berk. & Curt.) Wei that could make inroads into the intricacies is an important plant pathogenic ascomycete of Hevea culture and development faster than causing the damaging Corynespora Leaf Fall any other branch of science. (CLF) disease. A small secreted glycoprotein Experimentation with in vitro culture of named cassiicolin was previously described rubber commenced during the 1960s with as an important e—ector of C. cassiicola. Chua in 1966 attempting to derive callus Corynespora causes leaf spot and leaf fall cultures from the plumule tissues of seed- diseases. First reported in India from see- lings. The e—ects of osmotic concentration, dling nurseries, it was then reported from carbohydrates and pH of the culture media Malaysia, Nigeria, Indonesia, Sri Lanka and were also studied. Later, the RRIM took Thailand. The disease has now been found the initiative of undertaking large scale in almost all rubber growing regions. The tissue culture work through maintaining environmental factors favouring disease deve- callus cultures from various explants. It lopment are high humidity, a temperature of expanded to somatic embryogenesis and 280C to 300C, humid air and cloudy weather. micro-propagation through stem explants. Spraying of benomyl, mancozeb, captan or While anther culture was employed to achieve propineb is recommended for a—ected nursery purelines žrst and exploitation of heterosis plants. Four to žve rounds of spraying with thereafter, micro-propagation and somatic Crops of Kerala – An overview 131 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). embryogeny were used to generate homoge- conditions. However, this procedure, which neous populations. Although research on in is expensive, did not appear to guarantee vitro culture commenced nearly 45 years ago, increased efficiency, nor was it a means even after rigorous experimentation, these for rescuing rare progenies. areas are still in their infancy due to short Somatic embryogenesis in rubber is comings towards commercial applicability. becoming standardized in di—erent labo- Expectations of better performance of these ratories worldwide as an efficient system multiplication techniques are based on three for plant regeneration from cells. At the considerations: (i) cloning the root system same time e—orts have been made to trans- would generate new and more homogeneous form Hevea cells in order to increase genetic root stocks or monogenetic clones; (ii) selection variation in a targeted way and complement of clonal roots would improve the exploitation plant breeding e—orts with the possibility of of existing genetic variability; and (iii) use modifying already selected high performing of rejuvenated clonal plant material would clones with specižc genes (addition or inac- potentially provide important agricultural tivation), while avoiding meiotic recombina- attributes towards higher growth, latex yield tion. However, in the short term, genetic and resistance to wind and dryness. transformation is becoming a powerful tool The Rubber Research Institute of Ceylon for investigating how the rubber genome (RRIC) was the žrst to carry out culture of functions with the assistance of targeted anthers to raise haploid plants. However, mutations. the žrst plants from Hevea pollen were made available by Chen during 1977 at the Baoting Conventional rubber breeding takes Institute of Tropical Crops, Hainan, China. more than 25 years to develop a new clone, Since then, at least four laboratories in China but genetic transformation is the quick took the lead in researching production of alternate method to introduce desirable haploid plants in vitro. Research on this line genes. The žrst transformation report in remained inconclusive. Attempts towards pro- Hevea brasiliensis was published in 1991, toplast culture and fusion were carried out through Agrobacterium mediated transfor- using young immature leaves, using discs of mation. In 2003 Rubber Research Institute pith in the apical part of young green shoots of India reported successful development and or anther calli. Protoplast-derived calli devel- establishment of transgenic rubber plant oped somatic embryos. Subsequently, they with SOD gene for their further evaluation. germinated in to plants on the same medium. Unfortunately, due to issues related to ethics, Fusion of protoplasts was aimed at hybridiz- till date none of these transformed genotypes ing di—erent Hevea species for breeding resis- has been taken to the planter’s želd for com- tance to SALB. Not much headway was made mercial evaluation or utilization. in this line of work. In vitro germination of Genomic technologies were taken up by mature and immature zygotic embryos issued various research groups working with Hevea, from hand pollination has been considered in order to increase knowledge and also as a way of improving the success rate of to identify new targets for breeding and/ genetic recombination in rubber. Good results or complementing genetic transformation, (90% success in germination) were achieved and to assist rubber breeders in various only for immature embryos that were at least strategies. Derivation of draft genome is 3–3.5 months old after fertilization. It also the ‘trendy research’ of late. As Heveagenome appeared that immature seeds of this age has now been published four times, yet not could be germinated in vivo under controlled everyone comes up with the same žndings. 132 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Biology and cultivation of teak T.K. Hrideek, Suby and M. Amruth Kerala Forest Research Institute, Peechi, Thrissur, Kerala-680653, India.

Tectona grandis, L.f. popularly known as in the 19th century in India by the British teak, is a tropical hardwood tree belonging East India Company stands as a testimony to the family Verbenaceae. It is native to to the unique qualities of the teak timber South and South East Asia mainly to India, which still makes it popular. Myanmar, Laos, Indonesia and Thailand. Teak wood is one among the highly valued Context of organised teak planting tropical timbers in the world. It is exten- During the 17th and 18th centuries, there sively raised as monocrop plantations within were increased and organized efforts made and outside its natural range in tropical (by the formation of joint-stock trading areas of Central and South America, East companies) by European political powers and West Africa and Carribean. The word for acquiring a monopoly in the maritime teak derives from Tamil tekku, Malayalam trade in spices with the Asian and South East thekku and Portuguese teca. In India, teak Asian hinterlands. This gradually culminated grows well in natural forests of central and in the political domination over these lands south India i.e., from North Madhya Pradesh and maritime domination of trade. One of up to South Kerala. Teak timber fetches a the crucial determinants of maintaining very high price in the market because of its maritime dominance in trade and war was characteristic grain, colour, strength and owning strong and durable seafaring vessels. durability; hence the practice of establishing Traditionally it was the Oak timber which was teak plantations is in vogue wherever the available in abundance in Europe that made soil and climate support its growth. In India, it possible to construct dependable naval fleet regular teak plantations were successfully for the British. Search for a substitute for oak established from 1842 under the initiative of timber ensued by the end of 18th century, as the British East India Company, and this is the oak forests of Europe run out of timber. considered as the first successful attempt to Teak emerged as a suitable substitute and grow teak plantations across the globe. The soon there were missions set up to see how period previous to British dominance has the huge demand for teak timber for build- seen a restriction on the extraction of teak ing large ships can be satisfied. Some of the timber. Most obvious control was taxation provinces had conservators posted to oversee and prohibition of its use for construction extraction and supply of the teak timber to other than by the elites of society. So teak the Bombay Docks where ships for the East came to be known as a royal timber and a India Company were built. Though forests of vehicle of exertion of political power in the Malabar and Burma came to a sharper focus society. The provocation for teak planting in terms of timber extraction, soon there was Crops of Kerala – An overview 133 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). a realization that initial calculations of the These developments had manifold conse- inexhaustible quantity of extractable teak quences: žrst of all, teak was very much at timber in these forests are wrongly founded. the center of the newly emerging science of As a result, there were several attempts made tropical forestry in all its diverse dimensions to cultivate teak as a monocrop plantation, and aspects. Secondly, teak had a place in the especially in localities where teak was found newly emerging institutions of forestry in the growing well in natural forests. One such 19th century such as the Forest Department locality was Nilambur in Kerala which and much later the Forest Research Institute. belonged to the Malabar district of Madras Research and development activities on teak Presidency which was under direct rule of productivity contributed to an astonishingly the Company. So e—orts were on to estab- voluminous literature in silviculture, ento- lish a teak plantation in Nilambur in Kerala mology, forest pathology and wood science from early decades of 19th Century. The and technology which still continues to grow. then Malabar collector Canoly who directly Thirdly, all these colonial anxieties around oversaw the experiments was assisted by Mr. this beautifully grained native wood had Chathu Menon. As there existed no previous made it a globally valued and sought after documentation and standardization of meth- commodity. ods on every aspect of plantation development Major variants of teak including induced seed germination, mass There are many variants in teak di—eren- production of seedlings, spacing and plant- tiated in terms of their characteristic wood ing, tending and thinning, everything had quality including texture, colour and grain. to be developed from scratch through trial The factors triggering this variation could and error. At the end of numerous unsuc- also vary widely including the phenotypic cessful attempts, the žrst successful Teak expression in response to provincial environ- plantation in the history emerged by the mid mental factors like climate and soil. Some 19th century in Nilambur. These plantations of these variants such as Nilambur teak belonged to the batch planted in 1840s by Mr. (Malabar teak), Konni teak, Middle American Chathu Menon and Mr. Conolly who were teak, Western African teak, Godavari Teak, instrumental in standardizing the methods of Burmese teak, etc. are the well known names teak planting and were considered originators in the world’s timber Industry. There are a of the plantations of teak and founders of total of 23 types of teak woods in India and tropical forest plantation forestry. Between the major ones are the following. two decades from 1842 to 1862, Mr. Chathu Menon raised more than a million teak trees 1. Nilambur teak: It is also known as in the Nilambur Valley. Malabar teak. This variant grows faster than others, yields larger log dimensions Though developments in iron ore process- and contains straight grain with golden ing and metallurgy contributed to the design yellowish brown color, often with darker and building of superior quality ships than streaks. those built with teak, the heavy demand for teak continued due to the large scale expan- 2. Adilabad teak: It grows in Rajulmaddugu sion of the railway network where sleepers locality of Andhra Pradesh. It is known made of teak were preferred due to its dura- for its rose coloured heartwood, attrac- bility and physical properties. As the British tive texture and fetches high price. crown which assumed political domination 3. CPT (Central Provincial teak): This is (following the mutiny of 1857) had perceived a close-grained and slow grown teak railway expansion as a matter of internal grown in the drier zones of central India. security as it enabled troop movements, teak It has a deep colour, twisted or wavy continued to be a matter close to maintaining grains give the attractive appearance political dominance. and fetches a higher price. 134 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

4. Dandeli teak: It is a slowly grown teak material, riverine alluvium on the ¬ood- grown in Dandeli area (Karnataka, plain of Chaliyar River, well-drained soil India) and the wood is with close grain and pronounced and alternating wet and and dark colour. dry seasons are the characteristic features 5. Godavari teak: This variant is native of the Nilambur valley that determine the to Godavari region in Andhra Pradesh. characteristic phenotypic expression. This The wood is especially with great orna- locational advantage of Nilambur was a factor mental value owing to its grain. for choosing it as a site of raising plantation in the early 19th century. The peculiarities of 6. Konni teak: It is also a slowly grown Nilambur teak have resulted in obtaining it teak with close grain and darker colour a unique GI (Geographical indication) status. grown in the Konni area of Kerala state Normally bark of the teak tree has a dark of India. brown colour, and that of the Nilambur teak Other than these well-known Indian teak is of golden colour. As mentioned above, the wood variants used for making furniture, precisely alternating wet and dry seasons there are several other species of teak wood help the formation of a clear annual ring. This which are imported to India. The most pop- results in attractive grains and characteristic ular among the imported teak wood is the design of the teak wood. The soil characteris- Burma teak (also called Myanmar teak), tics of the Nilambur valley is thought to have which has a rich golden brown colour and a decisive role rendering a golden hue to the straight grain pattern. Myanmar accounts for wood. Nilambur teak with its heartwood rich almost 1/3rd of the total teak production in with teak oil protects it from fungal and pest the world. African and South American teaks infestations. The chemical named Caoutchouc such as Ghana teak and Columbiana teak are is the reason for this oil secretion. This was also used in making furniture. Teak wood the reason why teak wood was chosen for originating from other South Asian countries making large seafaring vessels in the past. such as Indonesia (Java teak), Thailand, and Nilambur teak has less sapwood and it has Malaysia also žnd their ways in the market. high durability. Presence of Tectoquinone and Naphthoquinone provides immunity from Teak provenances in Kerala termite damages and infestation from insects There are several teak provenances and fungus even in the wet weather. As the identižed across the globe wherever teak growth is faster Nilambur teak is considered has a natural population. A provenance is more productive than other teak provenances. ‘the geographical source or place of origin A single instance that the Nilambur teak con- from which a given lot of seed or plants are tinues to be the choicest wood that goes into collected’; the provenance is also ‘material the making of the British luxury car Rolls- from such a source or origin; often restricted Royce despite the fact that Teak is grown to imply material from a specižed race.’ in more than 70 countries stands testimony Nilambur, Konni, Vazhani, Parambikulam, to the unquestioned supremacy of Nilambur Thamaravellachal and Arienkavu are the teak. However, there is a concerted e—ort to well-known provenances in Kerala. Among be made to protect the genetic base of the these, the Nilambur and Konni teak are well natural teak of Nilambur as it is fast eroding. known for their colour and quality. Konni teak: Konni teak is a well known Nilambur teak: The Nilambur teak is provenance in the international wood market. sought after stock right from the colonial This once enjoyed the same degree of popu- period itself due to its structural charac- larity as did the Nilambur teak in the timber teristics and unique design of the trunk. market. By the mid 19th century Ayilyam The presence of deeply weathered parent Thirunal, the king of Travancore Princely Crops of Kerala – An overview 135 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

State made attempts to raise teak plantation Properties of teak wood in the Konni region of the state, for the teak The properties of teak wood which make from the region was already recognized for it attractive in timber market are mainly the its unique qualities. Travancore went ahead durability, strength and comparatively low with expanding the teak plantations that it weight. Teak wood has a low proportion of had successfully established with a regular softwood. Hardwood is golden in colour and annual target žxed on the land areas to be then it darkens as it gets older, which can brought under the teak planted each year. be reverted to the original when polished. From 1920s the expansion of teak plantations Annual rings of the tree are very promi- received a boost in the Travancore state as nent which increases the aesthetic value Taungya was introduced as a technology of the timber. In some cases more than one for raising large scale plantations of teak. annual ring is produced in a year and are The authorities of Travancore had perceived known as pseudo rings. These pseudo rings teak planting as a progressive enterprise and provide better appearance and help to fetch long term investment for the state and had a higher price for the timber. The newly cut made e—orts to adopt new technologies and wood produces a distinct aroma that is com- know-how in expanding their plantation parable to the smell of leather. The chemical base. By the last decades of the 19th century, composition of extracts from teak is complex Travancore had many experienced officials from Nilambur appointed as assistant con- and almost all the anthraquinones (e.g. servators who oversaw planting in Konni. 2-methyl anthraquinone) found in the wood Top officials such as Diwan Ramayankar are e—ective against termites. Tectoquinone and British residents used to visit Konni is another characteristic metabolite similar to evaluate state e—orts in improving teak to anthraquinone. The compounds such as plantations. Konni teak fetched the high- Naphthoquinone (1,4-naphthoquinone) pres- est price in the international market due to ent in teak wood helps to resist fungal attack. its dark brown hue and sharp grain from The oil in the teak wood makes it termite annular rings compared to the Burma and proof and resistant to borers. This oil when Nilambur teaks. Apart from this, the pres- applied to other timber logs increases their ence of a larger percentage of Tectoquinone durability. The reason behind the oil produc- and Naphthoquinone makes Konni teak more tion is a chemical caoutchouc as mentioned resistant to scratch rims and fungus and before. The soil and climate in¬uence the ensure its longevity. The characteristics of strength of the teak wood. It is well estab- local weather and soil along with the genotypic lished that teak grown on the west coast is content of the provenance probably determine much better than the one grown in central these features of Konni teak. The growth India. The wood gains strength as it attains rate of Konni teak is low when compared to an age of 50 and compared to wood from teak grown in other places. After Nilambur middle portion of the tree bottom and top the natural forests of Konni has a denser portion has higher strength. stock of teak. Since selection and clear felling was intensely practiced in this forest tract Breeding strategies for teak as elsewhere in the state up to a few decades Though research on various aspects of back, the depletion of natural teak forests silviculture teak began way back in 19th has severely a—ected the genetic diversity of century when the žrst plantations were teak. So conservation of the genetic diversity attempted, organized programmes for con- and stock of the Konni teak available in the servation and improvement of the genetic early plantations and natural forests in the stock of teak in India began only by 1962 region is a major concern. by the Forest Research Institute, Dehradun. 136 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Subsequently, in Kerala also similar e—orts In the procedure, the žrst step is Plus Tree were made from 1979 under the supervision Selection. A plus tree is a phenotypically of Kerala Forest Research Institute, Peechi. outstanding individual with a number of Genetic improvement of teak focused mainly desirable traits. While selecting plus trees on identifying phenotypically superior trees of teak, each superior tree is compared with from its various natural growing regions and at least 5 trees within a radius of 50 meters deploying them as vegetatively propagated from the plus tree. During the process of clones in seed orchards. selecting plus trees, the main objective is to The aim of tree breeding for timber is select trees for higher productivity without to improve the growth rate and tree form giving any consideration for wood quality. so that higher volumes, the larger length of The main criteria for selecting plus trees are clear bole and straight grained timber are i) superiority in terms of height and length available in short rotation. It is also aimed of clear bole ii) superiority in terms of girth to minimize the quantity of low grade timber at breast height (gbh) iii) straightness, iv) due to branch knots, ¬utes, buttress, spiral absence of bumps, ¬utes, epicormic shoots, grain and blisters. Resistance to defoliator buttresses, twisting, etc v) narrow compact and skeletoniser insect attack is also a desired crown with light branches vi) absence of feature. Concurrent improvement in the afore- diseases and other defects. mentioned features cumulatively contributes to the increased productivity of forest land Assessment of plus trees for selecting elite tree and improved quality of timber for market. During the process of selecting an elite tree from plus trees, wood quality is also Kerala is one of the prime teak grow- considered additionally as a key parameter ing states of India. Attempts to genetically since it is the preferred feature in the timber improve the planting stock were made as market. Hence it is necessary to study the early as 1961 when Kedharnath and Mathews di—erent wood properties such as density, did the žrst selection of plus trees of teak. grain, colour, etc. To achieve the selection Fifty trees, outstanding in growth and stem of elite trees, progeny test or clonal evalua- form designated as plus trees were selected in tion may be used. These tests also provide di—erent teak growing areas of Kerala using information on genetic variance, heritability check tree method. Later in 2004, another 61 of characters and genetic combining ability. new plus trees were selected from Thenmala, Recently Kerala Forest Research Institute Konni, Malayattur, Thrissur, Parambikulam, together with Institute of Forest Genetics and Nilambur, Wayanad, Vazhachal and Kannur Tree Breeding has initiated a programme to Divisions. The status of these plus trees was identify elite trees from plus trees. evaluated recently and it was found that most of the trees had lost markings; some Seed production of them were felled or fallen and not feasible The use of improved seed or plant mate- to identify them in the natural forest tract. rials is essential to increase the growth and At present, as per records 94 plus trees are quality of plantations. Large quantities of available in Kerala which includes 31 plus quality seeds are required for the planting trees selected during 1980-82. of teak; to meet up the immediate demand, Characters of plus trees seed stands and seed production areas are The characters used to identify the plus identižed and maintained. To obtain such trees are not aimed to capture the expression improvements, seed production areas and/ of their phenotypic and genotypic features or seed orchards are required. which can be used for the scientižc improve- Seed production areas: A Seed Production ment of the stock based on genetic principles. Area (SPA) is a converted plantation or a Crops of Kerala – An overview 137 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). natural stand of teak for seed production. In genetic improvement programmes of teak. this process plantations with trees showing It is assumed that the o—spring developed superior vigor and growth compared to the through random mating among the superior adjoining areas are selected and converted types would also be genetically superior. The to seed production areas after the removal of main purpose of establishing seed orchard inferior trees. The SPAs seem to be the most is to mass produce such genetically supe- practical short term option for improved seed rior seeds, which are easily accessible and production programmes. An abundance of collectable. improved seeds can be achieved within one Silvicultural practices in teak year of establishment of an SPA. Through Site selection the SPA option, the gain in volume of grow- The planting site has a strong e—ect on ing stock in plantations is 5-15% over the the growth, development and wood quality of routine seed sources. At present, Kerala has teak plantations. The productivity of a plan- around 1500 ha of plantations designated tation can be greatly improved through the as teak SPAs. selection of a correct site for the plantation Clonal seed orchards: Clonal Seed Orchard programme. It is noted that the teak distri- (CSO) is another option of seed source estab- bution pattern in its natural range is discon- lishment. It is a plantation of mixed pop- tinuous or patchy. Size, quality, density, and ulation derived from plus trees, designed, the form of teak trees vary from one location established and managed for seed production to another. There are several factors which purposes. Clones of plus trees are used as a control the distribution and growth pattern source of planting material for the orchard. of the species. The major factors include the Usually, bud material is used and clone amount and distribution of rainfall, moisture, banks are established by grafting the buds soil and light. to stocks raised from locally available seeds. Teak grows naturally in a wide range of The establishment of clone banks facilitates climatic conditions, from the very dry (500 the subsequent collection of seed and bud mm/year) to the very moist (up to 5,000 mm/ material from the plus trees and ensures that year). Under very dry conditions, the tree the genetic material is available from them is usually stunted and shrubby. Under very even if the plus trees themselves are lost. Very moist conditions, the tree is large and ¬uted recently KFRI has developed a technology to and usually behaves like a semi-evergreen produce clones using epicormic buds of teak species; the wood quality is poor in terms of without grafting. This method helps to avoid colour, texture and density. For the production the problems due to graft incompatibility. of high quality wood with optimum growth, Generally, the CSO starts producing seeds rain fall should be between 1200 mm and at 10-15 years and its initial gain is about 2500 mm with a marked dry season of 3-5 25% over the base population. months. Seedling seed orchard (SSO): Seed Soil: Teak grows best on deep, well drained orchard is fundamentally a collection of phe- alluvial soils derived from limestone, schist, notypically superior and diverse individuals gneiss, shale and some volcanic rocks such as of a species, which is silviculturally managed basalt. Conversely, the species performs very to produce phenotypically and genotypically poorly on dry sandy soil, shallow soil, acidic superior seed crop through the process of soil (pH < 6.0) derived from laterite or peat bog open pollination. Establishment of seed and on compacted or waterlogged soil. Teak orchards using superior clones from diverse soil is relatively fertile with high calcium, regions has been an important strategy of phosphorus, potassium, nitrogen and organic 138 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). matter contents. Studies have indicated that plantation is increased (from base popula- teak requires relatively large amount of cal- tions) by 5-25%, depending on types of seed cium for its growth and development and teak source and planting site. The best period to has been named as a calcareous species. The collect seeds is November to March and seeds amount of calcium content in the soil is also are collected from Teak SPAs. used as an indicator of teak site quality. The optimum pH range for better growth and Propagation quality is between 6.5 and 7.5. Seed propagation Light: One of the important factors which Teak seed processing mainly comprises of a—ect the growth of teak is the availability cleaning, grading and supply/storage of qual- of light. Hence, it requires a high intensity ity seeds. As the žrst step in seed cleaning of light for its growth and development. Teak the feathery calyx is removed by rubbing the needs 75-95% of light intensity in a day for seeds in a gunny bag. The separated frag- its normal growth. ments of calyx are removed by winnowing. The seeds are then size graded using a seed Other factors: Apart from rainfall and grader. Fruits below 9 mm size are discarded. moisture, soil and light intensity, other fac- In order to get optimum and uniform germi- tors such as temperature and elevation also nation from teak seeds, pre-sowing treatment play important roles in limiting the distri- is essential. The most common and widely bution and growth pattern of the species. It accepted method of ‘alternate wetting and is known that teak grows well under warm drying’ is followed. In this the graded seeds and humid conditions. A series of studies in are soaked in moist gunny bags during nights controlled environments have indicated that and spread out in the open for sun drying on the optimum temperature for growth and the following day; the procedure is repeated development of the species is 27-36°C. This for seven consecutive days. Termite aided range of temperature is normal within teak’s mesocarp removal is another pretreatment tropical range. Teak poorly tolerates cold and method used for seed germination in teak. frost conditions during winter period. Under The teak seeds are spread on a tray and the frost conditions, seedlings and saplings placed in a termite infested area. The ter- are severely damaged and they die, which mites enter the tray and feed on the mesocarp is one reason why the species cannot grow in about 2 weeks. These seeds are sown in at elevations. the nursery beds. Seed quality Nursery practices: Raised beds (30 cm The success of planting programmes high, supported with split areca stems) of depends not only on site quality but also on 10 m x 1 m are formed. Sand and soil mixed the genetic quality of the planting materi- with FYM form the top layer. Sowing is done als. Although the growth and yield of the after the bed is watered. Usually, sowing is plantation can be largely improved through done by the broadcast method or dibbling in site selection, stem quality (i.e., straightness, April-May. Seed rate is 3-5 kg of seeds per persistence of stem axis, branching, ¬owering, bed. After sowing, the seeds may be pressed etc.) is strongly controlled by genetic make into the beds. A thin layer of soil also can be up. The use of improved seeds (i.e., from sprinkled to cover the seeds. The beds are seed production areas, seed orchards and also mulched with green leaves to reduce plus trees) is essential in the improvement evaporation losses. One-year-old seedlings of growth, stem quality and other characters of 1-2 cm (thumb thickness) at the thickest of the plantation. It has been estimated that portion below the collar are uprooted from by using such improved seed, the gain in mother beds and used for making stumps. growth and/or volume of production in the Stumps with 15-20 cm of root at 2-3 cm of Crops of Kerala – An overview 139 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). stem prepared with a sharp knife are com- propagation of selected plus trees. In this monly used for planting. Teak seedlings can technique, shootlets are produced under lab- be produced in shorter duration by using poly- oratory condition and are then transferred to thene bags or root trainers. Three to four glasshouse conditions for rooting. The rooted month old teak seedlings are pricked out from shootlets or plantlets are transplanted for the germination beds into polythene bags (30 stock production. cm x 20 cm) in the month of March/April. Spacing Poly bag seedlings: In this, before germi- The initial spacing of seedlings adopted nating the seeds, soil, sand and dry dung or in teak plantation varies (1.8 m × 1.8 m to compost mixed in 3:2:1 proportion is žlled in 4 m × 4 m) depending on many factors like polythene bags and seeds are sown. After 90 site quality, cost of establishment, thinning days seedlings are ready for planting. regime, small wood utilization and planting 2. Clonal propagation: This method system (e.g. agroforestry, intercropping etc.). was developed by Kerala Forest Research However, site quality seems to be the priority Institute. Usually, epicormic buds from plus factor directing the size of spacing in the trees are used to prepare clonal plantlets. To teak planting programme. Under the dry site prepare vegetative rooted cuttings, branches conditions, where the initial growth rate of the plantation is poor (e.g. < 1.0 metre per with appropriate size are collected from the year in height), close spacing of 2 m × 2 m lower part of the crown of trees and brought to is the most suitable. Conversely, the initial laboratory/mist chamber as soon as possible spacing can be wider up to 4 m × 4 m, for and these are allowed to produce epicormic cost reduction, under good site conditions. 3 shoots. After 20 days epicormic buds are m × 3 m spacing also has been recommended. collected at the ‘three leaf stage’ and leaves However, in areas where wider spacing is are removed carefully. Cuttings of about 20 required for the application of agroforestry cm in length and 1.5 to 2 cm diameter are systems or machine weeding, the 4 m × 2 m made using a sharp knife. The basal end of spacing is used. the cutting is dipped in water immediately to prevent air bubbles entering the vascu- Planting time lar system as it may later interfere with the Planting time has a signižcant role in absorption of growth regulating substances determining the survival and growth of teak to be administered at the next stage. Indole plantations, especially when stump plant- 3-butyric acid (IBA) is used as a rooting ing is practiced. The most suitable planting hormone. The treated cuttings are planted time for teak is soon after the arrival of the in root trainers žlled with vermiculite and monsoon showers or at the beginning of the are kept in a humidity chamber at 95% RH. rainy season. Phenological development After about 15-20 days, epicormic shoots pro- studies showed the importance of planting duce roots. The rooted epicormic shoots are time, especially on growth. Teak has only transferred to poly bags žlled with potting one growth ¬ush period throughout the year. mix and hardened in the mist chamber for Shoot growth which starts soon after the žrst 10-15 days. shower (late April) reaches its peak at the beginning of the rainy season (May-June), 3. Micropropagation: Apart from SPAs thereafter it declines sharply in the middle and CSOs, tissue culture is another option of the rainy season (July-October) and ceases for mass supplying of genetically improved during the dry season (November-April). materials for planting programmes of this It is also recommended that teak may be species. This technique of propagation has planted just prior to, or during the growth been developed successfully for commercial ¬ush period, i.e., between May and early June, 140 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). depending largely on the arrival of the žrst removed. The yield obtained during thinning monsoon rain. operations is termed as thinning yield. The trees that remain after the di—erent thin- Weeding nings are felled at the rotation age of the Teak is a light demanding species and its plantation in an operation called žnal felling. growth and development are reduced sharply This is a clear felling. The rotation age is the under poor light conditions. Teak is very sus- age of the plantation when it is žnally felled. ceptible to weed competing for nutrients and light. Hence, intensive weeding is necessary Major pests of teak during early establishment of the plantation, Insect damage is a serious problem in i.e., 1-3 years. Six or seven weedings may be teak plantations. This is especially so where necessary during the žrst two years. intensive farming is practiced, e.g. in well irrigated plantations. The most common Thinning insects that cause severe damage to plan- Key determinants in the proper develop- tations are defoliators and stem borers. ment of teak trees are well-timed thinning and pruning. Thinning refers to the removal Defoliators of underperforming trees in the plantation Defoliators are insect larvae and they which is cut and sold prematurely, thus cause severe defoliation and, hence, reduce allowing the best trees to continue develop- growth rate, apical dominance and seed ing fully with more space and soil nutrients. production capacity of the trees. The most Meanwhile, pruning refers to the cutting of important defoliators in¬icting severe dam- the side branches o— the main trunk of the age in teak plantations throughout the tropics trees while they are growing. This is done are Hyblaea puera Cramer (Hyblaeidae) and to ensure straight and high quality logs. Eutectona machaeralis Walker (Pyralidae). Initially, there will be 2500 seedlings in a Outbreaks of these insects may occur 2 to 3 hectare when seedlings are planted in 2 m x 2 times during the growing season. After the m spacing. The seedlings are densely stocked outbreaks, especially of Hyblaea puera, the in this manner to encourage seedlings to grow plantation growth rate may be reduced by as straight and develop a straight bole. As the much as 75%. Control of outbreaks of these canopy develops thinning is performed. There insects requires the application of chemicals are two types of thinning — mechanical and Bacillus thuring- silvicultural. Thinning is carried out nor- and biological agents like mally at 4, 8, 12, 16, 20 and 24 years of age. iensis. Hyblaea puera nucleopolyhedro virus The žrst two thinnings at 4th and 8th years (HpNPV) is a biocontrol agent developed by are called mechanical thinning where trees Kerala Forest Research Institute against in the alternate diagonals and in a straight Hyblaea puera. row respectively are removed. Stem borers In žrst thinning half of the saplings Stem borers cause severe damage in young are removed (i.e., 1250 assuming that 2500 plantations (1-5 years old). Damaged trees seedlings are planted) and in the second may die back or top break causing reduction thinning from the remaining, a half of the in growth rate and stem quality. The most saplings (625) are removed. After the second damaging stem borer in young teak planta- mechanical thinning, distance between the tions is the red or co—ee borer Zeuzera co¡eae saplings increases to an average of 4 m. The Nietner (Cossidae). In old plantations, i.e., subsequent four thinnings are called silvicul- over 10 years, it is the beehole borer Xyleutes tural thinnings or normal thinnings where ceramicus which proves to be most damaging. stunted and poorly grown trees are selectively It causes severe damage to the standing trees Crops of Kerala – An overview 141 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). and also reduces the value of timber. At grows well on moist sites. To produce high present, there are no practical chemical or quality timber trees, the site should have biological methods for controlling outbreaks pronounced dry period of 3-5 month duration. of the beehole borer. Silvicultural treatments The typical teak soil is deep, well drained, and such as weeding, control burning, thinning alluvial with high calcium, organic matter and intercropping are the only methods which and other elemental content. The soil pH is can reduce the insect populations. 6.5-7.5. Teak is a light demanding species. Major diseases of teak As a result, intensive weeding in 1-5 year Teak su—ers from a large number of dis- old plantations is very important. eases and disorders. Diseases a—ecting teak A large quantity of improved seeds can be are broadly grouped into diseases of wider obtained through establishment and man- occurrence, serious diseases of restricted agement of Seed Production Areas and Seed occurrence and potentially serious diseases. Orchards. Clonal propagation in vivo and by Foliage diseases like leaf spot and leaf blight tissue culture is a viable option for mass pro- caused by Phomopsis tectonae, P. variospo- duction of quality planting stock. Appropriate rum, Phoma glomeratum, P. eupyrena and and timely silvicultural management must Colletotrichum state of Glomerella cingulata be carried out to improve both the growth are widely distributed in teak stands. Teak rate and quality. foliage rust caused by Olivea tectonae occurs Due to various reasons which include throughout the range of distribution of teak Government policies of conversion of teak in India and causes severe premature defolia- plantations to natural forest for wildlife tion of the a—ected plants. The phanerogamic conservation needs, soil depletion due to parasite Dendrophthoe falcata var. pubescens continuous rotation of monoculture teak causes severe damage to the teak stands, plantation, etc., there is a perceptible decrease especially in older ones. Serious diseases in the area and quality of teak plantations of restricted occurrence include root, butt in Kerala. The current low production of and heart rot diseases and die back caused timber and low productivity of plantations by Phialophora richardsiae associated with do not match with the high demand for teak an insect borer, Alcterogystia cadambae. wood. An alternate strategy could be to pro- Potentially serious diseases a—ecting teak mote cultivation of teak in the homesteads stands include pink disease caused by and farm holdings along with other crops. Corticium salmonicolor, bacterial wilt caused Retaining teak in the homestead is an age by Pseudomonas tectonae and stem canker old practice in Kerala homesteads, but it and die back caused by Phomopsis tectonae. leaves a lot desired in terms of developing Among these, the pink disease has emerged suitable packages and protocols for teak based as a serious threat to young teak stands, agroforestry practices, with better input of especially those raised in high rainfall areas. improved planting materials, information, Conclusion institutionalization and market integration. Teak plantations have been widely estab- Yet another alternative is to promote planta- lished throughout the tropics with the main tions of teak in private lands as monocrop or objective to producing high quality timber. mixed stands if not planting at small scale. Three main factors a—ect growth and quality Teak is also a suitable tree when it comes to of the plantation: site quality, seed supply and seeking additional revenue to the grower in silvicultural management. Site quality has a terms of carbon žnancing. Developing teak direct e—ect on the growth and development cultivars suitable for these planting situations of the plantation. The rotation age can be in homestead and small scale plantations is greatly reduced through site selection. Teak a challenge to breeders. 142 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

Conservation and propagation of dasamula group of medicinal plants A.V. Raghu Kerala Forest Research Institute, Peechi, Thrissur, Kerala-680653, India.

India has an impressive wealth of now sold in the ‘health food shops’ all over the medicinal plants, almost all of them native world including the developed world. to the country. More than 7000 species are Ayurveda has long been the main system reportedly used for medicinal purposes, most of health care in India, although western of them being exploited recklessly for the medicine has become more widespread espe- extraction of drugs. It will be prudent to study cially in urban areas. About 70 percent of the science and status of indigenous medicinal India’s population live in rural areas; about plants for evolving efficient strategies for two thirds of rural people still use ayurveda conservation and management. Medicinal and medicinal plants to meet their primary plants are viewed as a possible bridge between health care needs. Ayurveda and variations sustainable development, a—ordable health of it have also been practiced for centuries care and conservation of the vital biodiver- in Pakistan, Nepal, Bangladesh, Sri Lanka, sity. Importance of medicinal plants is still Tibet, etc. Currently, about 5,000 products growing although it varies depending on the are included in the “pharmacy” of ayurvedic ethnological, medical and historical back- treatments. Historically, plant compounds ground of each country. Medicinal plants are have been grouped into di—erent categories also important for pharmacological research according to their e—ects. For example, some and drug development, not only when plant compounds are thought to heal, some to constituents are used directly as therapeutic relieve pain and some to promote vitality. agents, but also when they are used as basic Ayurvedic plants have been classižed in to materials for the synthesis of drugs or as mod- several groups like dasamula, dasapuspa, els for pharmacologically active compounds. tribhala, trikatu, etc. which are used in com- In recent times, however, due to the increas- bination for di—erent purposes. ing realization of the health hazards and toxicity associated with the indiscriminate Dasamula group of medicinal plants use of synthetic drugs and antibiotics, there Dasamula (ten roots) is one of the best has been a renewal of interest in the use of known drug group of classic ayurveda. The plants and plant based drugs throughout the drugs include vilva, kasmari, syonakah, world. According to WHO, the resurgence of patala, agnimanthah, prsniparni, saliparni, public interest in traditional medicine is on brhatidvayam (two plants) and goksurah. It the increase because of a sweeping green is a special combination of ten plants with wave and a large number of plant drugs are the ability to act on a wide range of health Crops of Kerala – An overview 143 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). problems, those caused by both vata and cm in height with a short woody stem and kapha. The ten plants include žve herba- numerous prostrate branches with soft grey ceous plants known as laghu panchamula hairs; leaves unifoliolate, alternate, stipulate, and žve trees known as bruhat panchamula. lea¬et ovate-acute, 14 cm x 10 cm; ¬owers Desmodium gangeticum (Linn.) DC. (Family: small, pink in terminal elongate racemes; Papilionaceae), Pseudarthria viscida (Linn.) calyx campanulate, hairy outside, with W. & A. (Family: Papilionaceae), Solanum triangular teeth; corolla papilionaceous, melongenea var. insanum (Linn.) Prain. exserted; stamens diadelphous; ovary sessile, (Family: Solanaceae), Solanum violaceum many ovuled, style žliform, incurved, stigma Ortega (Family: Solanaceae) and Tribulus capitate; fruit compressed, moniliform, 6-8 terrestris Linn. (Family: Zygophyllaceae) seeded. The drug is a good cardiotonic, useful are used as the source of laghu panchamula in the treatment of cardiac disorders. It is hot, and Aegle marmelos (Linn.) Corr. (Family: sweet, diuretic, laxative and nervine tonic. Rutaceae), Gmelina arborea Roxb. (Family: It overcomes corruption of tridosa, burning Verbenaceae), Oroxylum indicum (L.) Vent. sensation, fewer, cough, difficult breathing, (Family: Bignoniaceae), Stereospermum colais dysentery, thirst and vomiting and is useful (Dillwyn) Mabb. (Family: Bignoniaceae) in vatarakta, insanity and ulcers. and Premna corymbosa Rottl. (Family: 2. Pseudarthria viscida Verbenaceae) as the source of bruhat pan- Kerala physicians have by and large chamula in South India. Many of these plants accepted Pseudarthria viscida as the drug are red listed. source of saliparni. However, some publica- As per the text Sarngadhara Samhita, tions equate it with the two species of Uraria, dasamula nourishes the lean, stimulates namely Uraria lagopodioides and Uraria vitality and gives progeny to the childless. picta. Pseudarthria viscida (Linn.) W. & A. It is an excellent tonic for convalescence (Family- Papilionaceae), the drug source of and general debility. It is used in the form saliparni, is a perennial viscid pubescent of asava, arishta, avaleha, churna, ghruta, semi-erect di—use undershrub, 60-120 cm long kwath and taila. It is also used as the basic with slender branches, more or less clothed ingredient in many other preparations. with whitish hairs; leaves 3 foliae, terminal Dasamula is a popular health tonic, benež- lea¬et rhomboid-ovate, acute, 8 cm x 8 cm, cial to gastric, respiratory, cardiovascular, laterals obliquely ovate-acute or rhombiform, nervous and urino genital systems of the body. subcoriaceous; ¬owers small, pinkish white It is digestive, carminative, stomachic, anti- in long terminal branched racemes; calyx 2 spasmodic, analgesic, expectorant, cardiac, lipped, campanulate, hairy outside, 4-teethed; antirheumatic, antihelmintic, restorative corolla exerted, stamens diadelphous; ovary and is a rapid cell rejuvenating tonic. The subsessile with many ovules. Style incurved, plants coming under this group are described stigma capitate; fruit densely viscid-hairy, below brie¬y. ¬at, linear-oblong, one celled legume; seeds 4-6, compressed, brownish black. Saliparni Laghu panchamula is bitter, hot, tonic, aphrodisiac and promoter 1. Desmodium gangeticum of body tissues. It is strength giving and it Desmodium gangeticum is used as the overcomes intermittent fever, vata, urinary drug source of prsniparni in Kerala. However, diseases, tumours, oedema, burning sensa- some materia medicas consider Uraria lagop- tion, di¯cult breathing and toxic conditions. odioides and Uraria picta as the drug source of prsniparni. Desmodium gangeticum (Linn.) 3. Solanum melongena var. insanum DC. (Family- Papilionaceae) is a sub erect, Solanum melongena var. insanum and di—usely branched undershrub, 90 cm-120 Solanum violaceum are considered as the 144 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). source plants of the drugs coming under 5. Tribulus terrestris brhatidvayam in Kerala. However, other Tribulus terrestris is the source plant of species of Solanum like Solanum virginia- the drug goksurah. However, Pedalium murex num are also considered as drug source of is also used as the source plant of this drug brhati somewhere. Solanum melongena var. somewhere. Tribulus terrestris Linn.(Family- insanum is a much branched, very prickly, Zygophyllaceae) is an annual or perennial grey-pubescent undershrub; leaves simple, prostrate herb with many slender, spreading alternate, ovate or elliptic-ovate, acute, 7-12 branches up to 90 cm in length, commonly cm x 6-8 cm, oblique at base, irregularly lobed, found throughout India, up to an altitude of stellate-pubescent, prickly along the nerves; 5,400 m. Leaves are simple, pinnate, oppo- ¬owers purple, 1-4, extra-axillary; calyx lobes site, lea¬ets 4-7 pairs, almost sessile or with 5, lanceolate, thick stellate-pubescent; corolla very short petioles, oblong, entire, to 1.7 cm x rotate, deeply žve cleft, lobes 5, triangular; 0.5 cm, villous; ¬owers bright yellow, solitary, stamens 5, free, epipetalous; ovary villous; extraaxillary; sepals 5, free, linear-acute; berry oblong-globose, 3 cm across, fruiting petals 4, free, golden yellow, obovate, rounded calyx enlarging. Root, fruits and leaves are at apex; stamens 10, inserted at the base of the useful parts. Brhati is reported to be an annular lobed disc, žlaments free; ovary constipating, digestive, acrid and bitter. It sessile, hairy, 5-celled, style short, stigma helps vitiated tridosas and cures dyspepsia, 5 lobed; fruit 5 angled, spinous, tuberulate, fever, respiratory and cardiac disorders, skin schizocarp, separating into 5 cocci, each with ailments, vomiting, ulcers and poisonous a pair of spines on them; seeds several in each coccus with transverse partitions between a—ections. them. Flowers and fruits are seen almost 4. Solanum violaceum throughout the year. Flowering starts within Solanum violaceum is the second mem - 20-35 days and the fruit matures in 14 days ber of brhatidvayam. Solanum violaceum after the formation of seed. Ortega (Family- Solanaceae) is an armed shrub; leaves simple, alternate or sub-op- Bruhatpanchamula posite in unequal pairs, grayish green, ovate 1. Aegle marmelos or oblong, sinuately lobed, 9-3 cm x 6-9 cm, Aegle marmelos is the source plant of vilva. base oblique or unequal sided, stellately It is an armed tree with axillary straight wooly or downy beneath, prickly along the spines single or paired and three foliolate mid nerve; ¬owers pale purple, regular in alternate leaves. The North Indian and South 8-10 ¬owered, extra-axillary racemes; calyx India varieties show some morphological cupular, lobes 5, triangular, thick, prickly; di—erences. The North Indian variety is corolla rotate, deeply 5 cleft; stamens 5, free, taller with larger leaves and fruits and it žlaments very short, anthers oblong-lanceo- has been reported that the large fruited forms late; ovary glabrous, style stellately pubes- are tetraploid. Aegle marmelos (Linn.) Corr. cent; berry globose, smooth, light green, (Family-Rutaceae) is a spiny tree sparsely variegated with dark green when young distributed throughout India on the plains and orange-yellow when ripe. Root, fruits and in the hilly tracts up to 1300 m elevation. and leaves are the useful parts. Brhati is The plant is a medium sized armed deciduous reported to be constipating, digestive, acrid tree with straight, sharp, axillary thorns and and bitter. It helps vitiated tridosas and cures yellowish brown shallowly furrowed corky dyspepsia, fever, respiratory and cardiac dis- bark. Leaves are alternate, 3-foliate, lea¬ets orders, skin ailments, vomiting, ulcers and elliptic, lanceolate or oblong-obovate obtuse, poisonous a—ections. terminal one 4.5 cm x 2.5 cm, lateral ones Crops of Kerala – An overview 145 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). smaller, glabrous, margin sub crenulate; and antihelminthic. The ¬owers are sweet, ¬owers white, sweet-scented in axillary refrigerant, bitter, astringent and acrid, panicles; calyx tube copular, lobes 4 or 5; and are used in treating leprosy and skin petals 5, white, oblong, thick, gland-dotted, diseases. The fruits are acrid, sour, sweet, spreading; stamens many, inserted around refrigerant, bitter, astringent, aphrodisiac, the disc; ovary ovoid, 10-celled with many trichogenous, alterant and tonic. They are ovules; berry ovoid, 8 cm x 6 cm, woody; seeds used for promoting the growth of hair and many. It is useful in diarrhoea, dysentery, for anaemia, leprosy, ulcers, constipation, dyspepsia, stomachalgia, cardiopalmus, strangury, leucorrhoea and colitis. vitiated conditions of vata, seminal weak- ness, uropathy, vomiting, intermittent fever, 3. Oroxylum indicum swellings and gastric irritability. The leaves Oroxylum indicum is the source plant of are astringent, laxative, febrifuge and expec- syonakah. The plant is a tree with large torant, and are useful in ophthalmia, deaf- opposite bipinnate leaves. Oroxylum indicum ness, in¬ammations, catarrh, diabetes and (L.) Vent. (Family-Bignoniaceae) is a medium asthamatic complaints. The tender fruit is sized deciduous tree with soft light brown bitter, astringent, antilaxative, digestive and bark with corky lenticels. Leaves are very it promotes digestion and strength, overcomes large, 90-180 cm long, 2-3 pinnate with 5 or vata, colic and diarrhoea. The ripe fruits are more pairs of primary pinnae, rachis very astringent, sweet, aromatic, cooling, febri- short, cylindrical, swollen at the junction fuge, laxative and tonic and are good for the of the branches, lea¬ets 2-3 pairs, ovate or heart and brain in dyspepsia. elliptic acuminate, glabrous; ¬owers large, pale purple, in long terminal racemes; calyx 2. Gmelina arborea large, leathery, oblong, campanulate, trun- Gmelina arborea is the source plant of cate; corolla large, ¬eshy; fruits ¬at capsules, the drug kasmari. The plant is a moderate up to 1 m long, tapering to both ends, woody; sized unarmed deciduous tree with simple seeds very many, ¬at winged all round except opposite leaves. Gmelina arborea Roxb. at the base. The fresh root bark is soft and (Family- Verbenaceae) is an unarmed mod- juicy and cream yellow to grey in colour. It erate sized deciduous tree 15-20 m in height is sweet, later becoming bitter. On drying, with whitish grey corky lenticellate bark. the bark shrinks, adheres closely to the wood Leaves are simple, opposite, long-petioled, and becomes faintly žssured. Roots, leaves, broadly ovate-acuminate, glabrous, green fruits, seeds and bark are the useful parts of above, soft, fulvous tomentose beneath; this plant. The roots are sweet, astringent, ¬owers showy, yellow tingled with brown bitter, acrid, refrigerant, anti-in¬ammatory, outer side, in dense terminal pendunculate anodyne, aphrodisiac, expectorant, appetiz- panicles; calyx campanulate, pubescent out- ing, carminative, digestive, antihelminthic, side; corolla tube short; fruits ¬eshy ovoid constipating, diaphoretic, diuretic, antiar- drupes, orange yellow when ripe, seeds hard thritic, febrifuge and tonic. They are useful and oblong. The whole plant is used as medi- in vitiated conditions of vata and kapha, cine. It is astringent, bitter, digestive, cardio- in in¬ammations, dropsy, sprains, neural- tonic, diuretic, laxative and pulmonary and gia, hiccough, cough, asthma, bronchitis, nervine tonic. It promotes digestive power, anorexia, dyspepsia, ¬atulence, colic, helmin- improves memory, overcomes giddiness and thiasis, diarrhoea, dysentery, strangury, gout, is useful in burning sensation, fever, thirst, vomiting, leucoderma, wounds, rheumatoid emaciation, heart diseases, nervous disorders arthritis and fever. The leaves are stomachic and piles. The roots are acrid, bitter, sweet, and anodyne and are useful in stomachalgia, stomachic, tonic, laxative, galactagogue ¬atulence, cephalalgia, ulcers, splenomegaly 146 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). and vitiated conditions of vata. The tender elliptic-ovate, acute, 5-9 cm x 3-6 cm, irreg- fruits are expectorant, carminative and sto- ularly toothed, thin, coriaceous, dark green machic, and are useful in cough, bronchitis, and shining above, dull below; ¬owers small, dyspepsia, ¬atulence, colic and leucoderma. greenish white in many ¬owered, terminal, short-peduncled, corymbiform, cymose pan- 4. Stereospermum colais icles; calyx cupular, persistent, becoming Stereospermum colais is used as the slightly larger and saucer shaped in fruit; drug source of patala in Kerala. However, corolla obliquely funnel shaped, 4 or 5 lobed; Stereospermum suaveolens is being used as stamens 4, žlaments hairy at base; ovary the drug source in some other parts of India. 2 or 4 celled, 4 ovuled, style linear, end- Stereospermum colais is the white ¬owered ing in a shortly bižd stigma; fruit globose species and Stereospermum suaveolens is drupe, 4 mm across, black when ripe. Root, red flowered. Stereospermum colais root bark and leaves are used in medicine. (Dillwyn) Mabb. (Family: Bignoniaceae) is a Agnimanthah is reported to be acrid, bit - large deciduous tree. The branches and leaves ter, astringent, cardiotonic, carminative, are pubescent. Leaves are opposite, impar- laxative, stomachic and tonic. It improves ipinate; lea¬ets 7-9, 7-15 cm x 4-7 cm, thin, digestive power and is useful in constipation, coriaceous, obovate to lanceolate, acute or fewer, heart diseases, neurological diseases rounded, often unequal sided at base, acute to and rheumatism. It overcomes kapha and caudate-acuminate at apex, entire or shortly vata disorders, anaemia, piles, oedema, serrate; ¬owers fragrant, yellow with reddish poison, anasarca and abdominal diseases. veins in lax terminal cymose panicles; calyx Traditionally, this drug is highly valued for campanulate, glabrous; corolla bilabiate; sta- its anti-in¬ammatory property. mens 4, žlaments with a tuft of wooly hairs; capsule pendulous, 4-angled or ribbed, 30-40 Conservation and propagation cm x 1 cm. Roots, leaves, ¬owers, fruits and In the case of dasamula destructive col- seeds are the useful parts of the plant. The lection of drugs is severe since roots are the roots are bitter, astringent, arid, anodyne, sources of active compounds. Hence, research appetizer, constipating, diuretic, lithontrip- towards either genetically improving the tic, expectorant, cardiotonic, aphrodisiac, species for higher production of the active anti-in¬ammatory, antibacterial, febrifuge component or increasing the production of and tonic. They are useful in vitiated condi- the compounds under in vitro culture condi- tions of vata, dyspepsia, diarrhoea and renal tions is essential. The commercial demand of and vesical calculi. dasamula is presently fulžlled by wholesale suppliers through rural and tribal collectors 5. Premna corymbosa residing in/ near forest areas. Due to deple- Premna corymbosa is used as the drug tion of natural ¬ora and increased demands, source of agnimanthah However, Ayurvedic need for systematic cultivation and large scale Formulary of India suggests Clerodendrum multiplication has been realized recently and phlomides as the real source of the drug and hence taken up for studies. Premna corymbosa as the substitute. Some Today many medicinal plants face extinc- workers opine that these two can be used tion or severe genetic loss, but detailed infor- as substitutes for each other as they have mation is lacking. For most of the endangered similar properties. Premna corymbosa is a medicinal plant species no conservation action small sized tree with simple opposite and has been undertaken. There is an urgent need aromatic leaves. Premna corymbosa Rottl. to conserve the dasamula group of plants (Family-Verbenaceae) is a small sized tree; since they may become extinct if the reck- leaves highly aromatic, simple, opposite, less exploitation continues. The best way to Crops of Kerala – An overview 147 Gregor Mendel Foundation, Calicut University, Kerala, India (2018). ensure the conservation and availability of increased the speed of germination as well medicinal plants is to propagate them using as germination percentage. advanced techniques. In the case of rare, Stereospermum colais shows poor germi- endangered or over exploited plants, prop- nation percentage (25-30%) even under nurs- agation and cultivation is the only way to ery conditions and this can be overcome by provide material without further endangering sowing the seeds immediately after extract- the survival of those species. Cultivation has ing the seeds. Mature fruits collected directly pharmacological advantages over wild col- from the trees before dehiscing were suitable lecting. Wild collected plants normally vary for achieving good germination. Germination in quality and composition, due to environ- on direct sowing on a seedbed is efficient, mental and genetic di—erences. In cultivation, technically less demanding and cost e—ective this variation and the resulting uncertainty of the therapeutic benežt are much reduced. in all the species. This can also help for the The plants can be grown in areas of similar step-by-step transplantation to potted soil climate and soil, they can be irrigated to and the subsequent hardening of seedlings. increase yields and they can be harvested Large scale production of these species using at the right time. Cultivation also greatly seeds is an easy and reliable method and it reduces the possibility of misidentižcation will help to increase the resource availability and adulteration. for pharmaceutical use and at the same time help in conservation of these species. In situ conservation in the natural habi- tats is the best method. But, due to climate Vegetative propagation change and anthropogenic in¬uences, nat- The goal of vegetative propagation is to ural wild habitats of medicinal plants are produce progeny plants identical in genotype getting devastated rapidly. Hence the only to a single source plant. Vegetative propaga- alternative is ex situ conservation. Moreover, tion through stem cuttings and air layers can conventional methods of propagation adapted be carried out in Premna corymbosa. by the natural populations of medicinal plants help them to increase their population size Stem cuttings very slowly only. Under the circumstances, Propagation through stem cuttings is standardization and improvement of propa- an easily cost e—ective propagation method. gation techniques and growing them under Many new plants can be obtained in this way human care is very essential to meet the in a limited space from a few stock explants. growing demands of medicinal herbs. The It is inexpensive, rapid, and simple and does žrst step in this direction involves sourcing not require the special techniques necessary and handling of propagules or propagates. in grafting, budding or micropropagation. Seed propagation, vegetative propagation In addition to this parent plant is usually and in vitro propagation protocols are being reproduced exactly, with no genetic change. developed in medicinal plants and dasamula group is not an exception. Air layering Layering is a form of rooting cuttings in Seed propagation which adventitious roots are initiated on a Seed propagation can be carried out in stem while it is still attached to the plant. all the members of dasamula except Premna The rooted stem (layer) is then detached corymbosa. Seeds can be germinated in and transplanted, and becomes a separate nursery beds. In some of the plants like plant on its own roots. Layering is valuable Gmelina arborea and Stereospermum colais to produce a relatively small number of large pre-treatment of the seeds with water soaking sized plants of a special cultivar in an outdoor 148 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018). environment with a minimum of propagation underpins the use of all other biotechnologies facilities. in conservation and use. The advantages of In P. corymbosa quick and higher rooting being able to multiply a given genotype with was observed in all the layers just after 15 relative ease, with a low risk of introduc- days of layering. On an average, 20 roots ing or reintroducing pathogens, and with a per layer with an average length of 10 cm low risk of genetic instability, need not be were observed on the 30th day of layering. emphasized in this technique. In vitro prop- Absence of callus was also noted on the lay- agation protocols for dasamula species like ers. Encouraging results may be due to the Aegle marmelos, Gmelina arborea, Oroxylum favourable climatic condition that prevailed indicum, Stereospermum colais, Solanum vio- in the locality. All the layered plants estab- laceum, and Tribulus terrestris have been lished in the nursery very well. Furthermore, developed. However, further standardization the proposed method is convenient, practical of the protocols for their large scale utilization and suitable for large scale propagation of is the need of the hour. Moreover, the herbal this species. pharmaceutical industry should come forward to accept such new developments in science In vitro propagation so that e—ective conservation, propagation In vitro propagation not only facilitates and utilization of the rare and endangered large scale production of the plant, but also medicinal plants become more e—ective. Crops of Kerala – An overview 149 Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

List of contributors 1. Ms. Surekha Y. Pawar 7. Dr. K.S. Ananda Research Scholar, Principal Scientist & Head, Genetics and Plant Breeding Central Plantation Crops Research Division, Department of Botany, Institute Regional Station, University of Calicut, Vittal, Kerala - 673635. Karnataka - 574243 2. Dr.K.T. Chandramohanan 8. Dr. M.K. Rajesh Assistant Professor & Head, PG Principal Scientist, Department of Botany, Crop Improvement Division, Government Brennen College, Central Plantation Crops Research Thalassery, Institute, Kerala - 670106 Kasaragod, 3. Mr. T.S. Jishinprakash Kerala - 671124 Research Scholar, Plant Biotechnology Division, 9. Dr. B. Sasikumar Department of Botany, Former Principal Scientist & Head, University of Calicut, Crop Improvement & Biotechnology Kerala - 673635 Division, 4. Dr. A. Yusuf Indian Institute of Spices Research, Kozhikode, Assistant Professor, Plant Kerala - 673 012 Biotechnology Division, Department of Botany, 10. Dr. V.V. Radhakrishnan University of Calicut, Professor, Genetics and Plant Kerala - 673635 Breeding Division, Department of Botany, 5. Dr. K. Samsudeen University of Calicut, Principal Scientist, Kerala - 673635 Crop Improvement Division, 11. Dr. V. Prajitha Central Plantation Crops Research Research Scholar, Institute, Cell and Molecular Biology Division, Kasaragod, Department of Botany, Kerala - 671124 University of Calicut, Kerala - 673635 6. Dr. N.R. Nagaraja Scientist, 12. Dr. John E. Thoppil Crop Improvement Division, Professor, Central Plantation Crops Research Cell and Molecular Biology Division, Institute Regional Station, Department of Botany, Vittal, University of Calicut, Karnataka - 574243 Kerala - 673635 150 Crops of Kerala – An overview Gregor Mendel Foundation, Calicut University, Kerala, India (2018).

13. Dr. V.B. Sureshkumar Forest Genetics & Tree Breeding Deputy Director, Department, Regional Co—ee Research Station, Kerala Forest Research Institute, Narasipatnam, Peechi, Andhra Pradesh - 531116 Thrissur, Kerala - 680653 14. Dr. P.M. Priyadarshan Former Deputy Director, 17. Dr. M. Amruth Rubber Research Institute of India, cientist, Kottayam, S Sociology Department, Kerala - 686009 Kerala Forest Research Institute, 15. Dr. T.K. Hrideek Peechi, Thrissur, Scientist, Kerala - 680653 Forest Genetics & Tree Breeding Department, Kerala Forest Research Institute, 18. Dr. A.V. Raghu Peechi, Scientist, Thrissur, Extension & Training Division, Kerala Forest Research Institute, Kerala - 680653 Peechi, 16. Ms. Suby Thrissur, Research Fellow, Kerala - 680653 This book contains essays on the most important crops of Kerala State of India like rice, coconut, arecanut, pepper, cardamom, vanilla, coffee, tea, rubber and teak which have formulated the destinies of the people of Kerala from time to time, an essay on grain amaranths which are often referred to as the newly emerging food crops and another essay on dasamula group of medicinal plants which are familiar to any ker- alite as the source materials of the ayurvedic medicinal combination dasamula.