VARIABILITY ASSOCIATION AND QUALITY STUDY IN NATIVE Dendrobium ORCHIDS
MD. ERSHADUL HOQUE
REGISTRATION NO. 23976/00214
DEPARTMENT OF HORTICULTURE AND POSTHARVEST TECHNOLOGY SHER-
E-BANGLA AGRICULTURAL UNIVERSITY DHAKA 1207
DECEMBER 2006 VARIABILITY ASSOCIATION AND QUALITY STUDY IN NATIVE Dendrobium ORCI11DS
BY
REGISTRATION NUMBER 23976/00214
A thesis Submitted to the Department of Horticulture and Postharvest Technology Sher-e-Bangla Agricultural University, Dhaka In partial fulfillment of the requirements For the degree of MASTER OF SCIENCE IN HORTICULTURE
SEMESTER: JULY-DECEMBER 2006
APPROVED BY:
Dr. Md. Nazrul Dr. Kabita Anzu-Man-Ara Islam Senior Scientific Officer Associate Professor Co-Supervisor Supervisor
Prof. Md. Ruhul Amin Chairman Examination Committee
DECEMBER 2006 CERTIFICATE
This is to certify that the thesis entitled “VARIABILITY ASSOCIATION IN NATIVE Dendrobium ORCHIDS” submitted to the Faculty of Agriculture, Sher-e- Bangla Agricultural University, Dhaka, in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN HORTICULTURE, embodies the result of a piece of bona fide research work carried out by Registration No. 23976/00214 under my supervision and guidance. No part of the thesis has been submitted for any other degree or diploma.
I further certify that any help or source of information received during the course of this investigation has been duly acknowledged.
Dated: Dhaka, Bangladesh
Supervisor Dr. Md. Nazrul Islam Associate Professor Department of Horticulture and Postharvest Technology Sher-e-Bangla Agricultural University Sher-e-Bangla Nagar, Dhaka-1205 Dedicated to My Beloved Parents
ACKNOWLEDGEMENT
All gratefulness is due to Almighty Allah, the merciful, the benevolent who has enabled me to complete this thesis successfully.
The author feels proud to express his deepest respect, sincere appreciation and immense indebtedness to his supervisor Dr. Md. Nazrul Islam, Associate Professor, Department of Horticulture and postharvest technology, Sher-e-Bangla Agricultural University, Dhaka, for his continuous guidance, constructive criticism and valuable suggestions in carrying out the research work and preparation of this thesis.
The author is very grateful to express his sincere appreciation, deepest sense of gratitude and immense indebtness to his Research Co-Supervisor Dr. Kabita Anzu- Man-Ara, Senior Scientific Officer, Landscape, Ornamental and Floriculture Division, Horticulture Research Centre (HRC), Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur 1701 for her systematic planning, kind and painstaking guidance, enocouragement, valuable suggestions and constructive criticisms in completing the research work and preparation of this thesis.
It is my privilege to express my deepest sense of gratitude, sincere appreciation and immense indebtedness to Chairman of my Advisory Committee, Md. Ruhul Amin, Professor, Department of Horticulture and Postharvest Technology, Sher-E-Bangla Agricultural University, Dhaka-1207 for his guidance, help and encouragement in conducting the research work and preparing the manuscript. The author also wishes to express his profound gratitude to his honorable teachers of the Department of Horticulture and Postharvest Technology, SAU, Dhaka-1207 for their valuable advice and encouragement.
He wishes to record his deep appreciation to Md. Sanaullah Mollah, CSO and Head, Landscape, Ornamental and Floriculture Division, HRC, BARI and S.M. Sharifuzzaman, Senior Scientific Officer, Landscape, Ornamental and Floriculture Division, IIRC, BARI, Gazipur-1701 for their cooperation, technical support, constant encouragement and time to time keen supervision during the period of research works done at the institute. It is worthwhile to mention the scientists specially Md. Kamrul Islam, Research Assistant Md. Abu Zafar Samsuddin and other personals of the Landscape, Ornamental and Floriculture Division, HRC, BARI for their cordial cooperation.
Special thanks are due to Mr. Nazim uddin, Scientific Officer, Olericulture Division of HRC, BARI for his kind help during data processing, statistical analysis and graph preparation.
The author feels indebtedness to his beloved parents whose sacrifice, inspiration, encouragement and continuous blessing paved the way to his higher education. He is also grateful to his brothers, brother in law and sister and other members of the family for their forbearance, inspirations, sacrifices and blessings.
At last but not the least, thankful appreciation is due to Syeda Fowzia Akter, Computer Operator, HRC, BARI for computer composing of the thesis.
The Author
TOPICS LIST OF CONTENTS PAGE
ACKNOWLEDGEMENTS I
TABLE OF CONTENTS 111
LIST OF TABLES IV
LIST OF FIGURES V
LIST OF PLATES V
LIST OF APPENDICES V
LIST OF ABBREVIATIONS VI
ABSTRACT IV
1 3 INTRODUCTION CHAPTER-I 12 REVIEW OF LITERATURE CHAPTER-II 23 MATERIALS AND METHODS CHAPTER-III 23 RESULTS AND DISCUSSION CHAPTER-IV Expt. 1 .Characterization of native 51 Dendrobium orchids 53 Expt. 2. Vase life of Dendrobium densiflorum 56 CHAPTER-V SUMMARY AND CONCLUSION 63 CHAPTER-VI REFERENCES
CHAPTER-VII APPENDICES
111
LIST OF TABLES
SL. TITLE PAGE No. 1. Name and source of collection of Dendrobium orchid germplasm 13
2. Vegetative characters of native Dendrobium orchids 24
3. Different categories of twenty native dendrobium orchids according to 25 vegetative characters 4. Pseudobulb characters of native Dendrobium orchids 27
5. Different categories of twenty native dendrobium orchids according to 28 vegetative characters 6. Leaf characters of native Dendrobium orchids 30
7. Different categories of twenty native dendrobium orchids according to 32 vegetative characters 8. Yield contributing characters of orchid germplasm 33
9. Different categories of twenty native dendrobium orchids according to 34 vegetative characters 10. Qualitative flower characters in native Dendrobium orchids 38
11. Pod characters of native Dendrobium orchids 39
12. Different categories of twenty native dendrobium orchids according to 40 vegetative characters 13. Root characters of native Dendrobium orchids 42
14. 42 Different categories of twenty native dendrobium orchids according to vegetative characters 15. Phenotypic and genotypic variability, heritability and genetic advance in 44 Dendrobium orchids
16. Genotypic (G) and phenotypic (P) correlations among ten characters in 47 twenty Dendrobium orchids
17. Path coefficient of flower producing character on length of spike in 48 Dendrobium orchid germplasm 18. Effect of different levels of pH and sucrose on vase life 52
IV
LIST OF FIGURES
SL. No. TITLE PAGE 1. Flower durability in native Dendrobium orchids 35
LIST OF PLATES
SL. No. TITLE PAGE 1. Pseudobulb of native Dendrobium orchid 29
2. Leaf of native Dendrobium orchid germplasm 31
3. Flower of native Dendrobium orchid germplasm 36
4. Lip diversity of native Dendrobium orchids 37
5. Pod diversity in native Dendrobium orchids 41
6. Promising genotypes of native Dendrobium orchids 50
LIST OF APPENDICES
SL. No. TITLE PAGE i Weather data during the period of experimental site (January, 2005- June, 63 2006) ii Analysis of variance of the data on different characters of 20 native 64 Dendrobium orchid genotypes
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ABBREVIATIONS EXPANSION
BARI Bangladesh Agricultural Research Institute
LSD Least Significant Difference
CRD Completely Randomized Design
CV Coefficient of Variation HRC Horticulture Research Centre °C Degree Celsius (Centigrade)
MCI Hydrochloric acid
et cil. Et alii=other people
etc. Etcetera=and others
i.e. id esl= in other words
Fig. Figure MAI Months After Interval
VARIABILITY ASSOCIATION IN NATIVE Dendrobium ORCHIDS
ABSTRACT
An investigation was carried out at the Orchidarium of Landscape, Ornamental and Floriculture Division of Horticulture Research Centre (HRC), Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur during January 2005 to June 2006. Twenty germplasms were used for characterization and evaluation in respect of different qualitative and quantitative characters to select promising line (s) as well as studies on the genetical parameters for further improvement of the crop. Durability of all the twenty gemplasm and vase life of Dendrobium densiflorum was studied with (he different levels of pH and sucrose. The results indicated the existence of wide diversity among tlie genotypes on their physio- morphological characters along with quality related characters. The genetic parameters, correlation and path coefficient analysis revealed that spike length, rachis length, flower number, flower size and flower durability were the most important traits to be selected for the development of native Dendrobium orchids. Among the different genotypes Dendrobium formosum (Di) and Dendrobium densiflorum (Dm) were the promising germplasm considering the qualitative and quantitative characters. Among the recorded characters high heritability and high genetic advance in spike length (94.00% and 98.29), rachis length (95.34% and 93.85), were recorded flower durability (94.00% and 89.00) and floret number (72.55% and 64.80 respectively) were recorded. Number of flower per plant, durability of flower and rachis length showed significant positive correlation with spike length. During the postharvest period p" 3.0 and 3% sucrose solution showed the best performance on long vase life of Dendrobium densiflorum.
Introduction
Chapter-1
INTRODUCTION
Orchids, one of the largest and important group of flowering plants, are known for their lovely blooms. There are more than 35000 species in about 800 genera (Gupta,
1997) distributed mostly in tropical and sub-tropical regions of the world covering about seven percent of flowering plants. They belong to the family Orchidaceae and are found in diverse habits and habitats, all over the world except in the dry deserts, snow peaks and cold Polar Regions (Nash, 1997). In Bangladesh, the agroecological conditions are very conducive to survival and culture of orchids. As such, different species of orchids are widely distributed in the country both in forest and non-forest areas in the country (Chowdluiry, 1975). Orchids are commonly found in Sylhet,
Rangamati, Cox’s Bazar, Rajshahi, Jessore, Sherpur, Madhupur, Tangail,
Bandarban, Sundarban, Chittagong and hilly areas of Bangladesh. They are of immense horticultural importance and play a very useful role to balance forest ecosystem (Mollah, 2001).
Orchids are marketed as pot plants and cut flowers. During the past few years, its trade has increased in volume and value throughout the world. In Asia, orchids are commercially grown in Thailand, Singapore, Malaysia, Sri Lanka, India and
Indonesia. Thailand is the largest producer and exporter of orchids and its orchid trade is worth of about 500 million dollars per year.
Dendrobium is the most popular orchid in cut flower trade in Asia for its magnificent
(lowers of great delicacy and long vase life. The genus has second largest number of species about 1600 species in the Orchidaceae family. These are distributed in
Bangladesh, India, Myanmar, Malaysia, Singapore, Indonesia, China and Japan. The cut flowers as well as pot plants of Dendrobium have high demand in USA, Japan,
Italy, Europe and Germany (Prokash, 1994). Thailand alone exports Dendrobium worth more than U S $ 12 million. However, developing countries like Malaysia,
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Singapore and Sri Lanka are contesting of catch up the international market and run the Dendrobium cut-flower industry on cooperative basis.
Majority of Dedrobium orchids under cultivation are native of tropical countries.
Bangladesh is bestowed with a wealth of orchid flora; more than 30 species of
Dendrobium orchids are available many of which are commercially important.
Moreover many of those endemic species are under serious threat of extinction due to the destruction of their habitats (Iqbal, 2006). Though, there is often a preference for hybrids in commercial markets, but beauty and quality of many local species are unique and conspicuous which can compete with the best hybrids.
The Floriculture Division of HRC, BARI, Gazipur, has a collection of more than 20 species of native Dendrobium possessing wide variabilities in respect of both plant and floral characteristics. Orchids with long cane-like stems as Dendrobium and
Epidendrum, sometimes produce little plants with roots (keikis) at the nodal region of their pseudobulbs or stems. These keikis can be separated from the parent plant and set in small pots containing compost recommended for mother plant.
Considering the above mentioned facts the present study was undertaken with the following objectives:
i. To study physiomorphological characteristics of native Dendrobium orchids.
ii. To identify a superior native orchid from twenty collected germplasm.
iii. To find out the effect of different preservatives on vase life of Dendrobium
densiflorum.
2
Review of literature
3
Chapter II
REVIEW OF LITERATURE
Orchids with their bewildering range of flowers and beautiful colour combinations provide a source of profound aesthetic pleasure to both owners and visitors (Bose el ai, 2002). Orchids are the most alluring and fascinating flowering plants. A lot of works on morphological characteristics, variability, correlation aspects as well as hybridization and tissue culture techniques for the improvement of orchid plants were done in many countries of the world. Research works in Bangladesh with respect to characterization, genetic variability, keikis production, potting media, watering, fertilization and vase life prolongation of orchids are scanty. Therefore, information available in the literature pertaining to those aspects of orchid have been reviewed and briefly presented below:
Morphological Characteristics of Orchid and related crops Bose et al.(2002) reported that the international trade of cut-flower and pot plants of orchids are dominated by hybrids of Aracnis, Aranda, A.scocenda, Caltleya, Cymbidium,
Dendrobium, Milionia, Mokara, Odonlogfoxsum, Oncidium, Paphiopedilum, Phalaenopsis and Vanda..
They also reported about a new species, Dendrobium priangane.se with white flowers, delicately scented which was found from Java. They observed that D. precenganese had white flowers which were medium delicately scented and drooping. Psudobulbs do not mature in one season but once matured they can continue to produce flowers for a long period
They noted that the width, thickness and length of capsules of D. moniliforme depicted a sigmoid pattern of development The most rapid growth of capsules took place 1-2 weeks after pollinations. Moreover, width, thickness and length of capsules reached their highest peaks at 3ul, 611' and 9Ul week, respectively. The optimum time for self pollination was 2-7 days after flowering but achieved only 10% fruit set. The optimum time for cross pollination was 1-5 days after flowering and fruit set varied between 30% to 100%.
They again noted that keiki’s are young platelets that develop either on a stem or old inflorescence. Keiki’s tend to form on many monopodial orchids (Phalaenopsis) and also on some sympodial (Oncidium, Dendrobium) orchids.
Carr and Christenson (2001) studied the characteristics of a new orchid species
Cycnoches schmidlianum and noticed that it had spindle shaped pseudobulbs; up to seven leaves which attenuated at the tapered bases; pendent lax racemes up to 25 cm long; lanceolate floret bracts, up to 12 fragrant flowers; pale green sepals; petals covered with butterscotch; brown, oblong dorsal sepals; obliquely obovate petals and
16*0.6 cm unlobed clawed lip.
Patil (2001) carried out an experiment in a greenhouse for characterization of 13 orchid species. He found that six species (Dendrobium densiflorum, Ascoccnirum apallaceum, D. nobile, Phaius lankcrvi/leae, D. pierardii and Ascoccnirum cimpuUaccum var auraniicum) and the other five species (Spalhoglollis speciosa, Aeridcs mulliflorum, 1). crepidalum, D. jeukinsii and D. primulinum) flowered during October-December and
January-April, respectively. Flowers of Spalhogloilis speciosa remained good for the longest duration (34 days) followed by D. jenkinsii (30 days). The largest flowers (13 x 13 cm) and the longest spikes (60 cm) were found in P. lankervilleae. Smallest flowers (2 x 2 cm) were recorded in Ascocetrum ampullaceum. Ascocentrum ampallaceum var. auraniicum had the highest number of flowers per plant (38) followed by Aerides multiflorum (35).
Mahanta el al. (1998) studied the variability and heritability of some quantitative characters in gerbera (Gerbera jamesonii). Ten cultivars of gerbera were evaluated for
14 characters in trials conducted at Assam Agricultural University. For all these characters, data are tabulated on range, mean, genotypic and phenotypic coefficient of variability, heritability and genetic advance. Plant height, vase life, flower size exhibited greater genetic variability and high heritability coupled with hi gh genetic advance. It was suggested that these characters could be used as selection criteria for the improvement of gerbera. Broad-sense heritability estimates were very high for all the characters except days to flower.
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They conducted an experiment for correlation and path coefficient analysis in gerbera (Gerbera jamesonii). Character association analysis among 14 different characters in a set of 10 gerbera genotypes revealed highly significant positive correlations with number of flowers/clump and leaf area at both phenotypic and genotypic levels and number of suckers at the genotypic level only. The path analysis revealed that leaf area, girth of stalk and days to flower bud opening had high direct effects. The significant positive correlation of leaf area with flower number/clump could thus be attributed to high positive direct effect of the characters.
Deka (1997) reported that the receptivity period of orchid varied from species to species (2 days in Spathoglottis plieata to 11 days in Phaius lankervillae). lie observed self incompatibility in Oncidium and Dendrobium orchids and indicated that self- incompatibility in those species was either gametic or zygotic in nature.
Prasad el a/. (2001) studied the genetic components and genotypic correlation in twenty genotypes of diverse origin of orchid genera Anoectochi/us, (joodvera, Macoodes and Zeuxine for 10 characters. They observed that spike length and plant height had the highest heritability during 1991-93 respectively. Leaves per plant, leaf diameter, and flowers per spike, spike length and length of aerial root showed positive association with plant height during 1991-92 and 1992-93. Length of flower was positively correlated with flower diameter and length of aerial root in both (he years.
However, the length of aerial root exhibited a negative correlation with leaf length and shoots per plant during 1991-92 and 1992-93 respectively.
Christenson (1995) conducted a study on orchid genera Phalaenopsis and noted that it bore several leaves at flowering and its flower consisted of a deeply 4-lobulate lip with each lobule subequal and oblong in shape.
He characterized Paraphalaenopsis genus by short internodes, terete leaves, umbellate inflorescence (densely raceme in P. serpentilingna), and flowers with spreading, undulate segments, a clawed, shallowly saccate Iabellum and a prominent callus.
Each of the two pollinia was cleft.
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Hermans and Hermans (1995) discussed the history and cultivation of Lepanthes, one of the oldest and the largest orchid genera. The genus had wide variation of flower colours and shapes. Although the flowers were often small, but their abundance makes Lepanthes worth cultivating. They noted that Lepanthes grew in a number of different habitats and locations. So, cultural requirement varied among the species.
Christenson (1994) characterized the genus Robiquetia. It had dense, pendent racemes of flowers bearing saccate lip. Flower colour varied from pure white to yellow with brown to deep reddish purple and black. It was widely distributed in tropical Asia.
Nanjan (1994) studied the association of cut flower yield with growth and floral characters in gerbera. In studies on 25 gerbera genotypes at Bangalore, cut flower yield exhibited a high level of positive and significant correlation with number of leaves per plant, weight of ray florets and days taken to flower opening. Path analysis revealed that number of leaves per plant had the greatest positive direct effect on flower yield.
Withner (1994) reported about the characteristics of Odontoglossum edwardt. The flower stalk emerged as an upright panicle of one meter or above. It had numerous fragrant flowers of three cm across and dark mauve to deep violet-purple in colour.
The bulky ovoid pseudobulbs were 8-10 cm in height, each bearing 30 to 40 cm long leaves.
Webb and Webb (1994) worked on five Dendrobium species such as, Dendrobium speciosum, D. rex, I), tarberi, 1). curvicau/e and I), pedunculatum. Those orchids were found growing along the East Coast of Australia. Their habitats spread from the coastal plains to the eastern ranges and even in hot dry inland slopes. Thick leathery but fleshy leaves were typical. The racemes were long and upright to arching.
Colour, size and arrangement of flowers varied with species. For cultivation, they required intensive light. They could be grown in cold temperate regions, being able to withstand light frost, as well as in tropical areas.
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Roh et al. (1993) reported about the vegetative shoot growth, flowering and pseudobulb development of Cymbidium ensifulium var. misericors, a miniature orchid.
They had observed that flower bud initiation occurred in early May, florets became visible in late July to early August, and full bloom occurred two weeks thereafter when grown under subtropical conditions.
Sobhana and Rajeevan (1993) investigated certain epiphytic species in central Kerala.
Flower characteristics of 41 orchid species grown at Vellanikkara were evaluated for five consecutive years in order to identify species suitable for cut flowers and pot plants.
Harper (1993) studied the hybrid orchid Multiflora phalaenopsis. He reported that its inflorescence was heavily branched with high number of (lowers. However, optimal spacing of the inflorescence prevented from overcrowding. Flowers were medium sized and white with intense maroon spotting on the lateral sepals and lip foliage was mottled.
Yukawa and Nishida, (1992) reported that Dendrobium shiraishii was vigorous in growth bearing about 10 long lasting, strikingly coloured flowers on an inflorescenc e of 28-37 cm in length The combination of blackish brown blotches on the proximal part of the petals, dellexed petals and obscurely trilobed dull red lip was not yet reported in any other species of the group. Thus, it has a considerable potential in
Dendrobium breeding program
Naskar (1900) stated that characterization is the full description of accessions by scoring a limited number of traits, which are highly heritable, easily seen by open eye. It is basically a tool for varietal description and identification of duplications.
Frankel (1989) said that evaluation may consist of nothing more than the description of the place of origin as well as the morphological and the phenological description of the
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germplasm or it may consist of information on physiological, biochemical, genetical, plant pathological or other characteristics.
Bechtel et al. (1986) observed the variability found in the orchid family was amazing.
The smallest orchids were of tiny Bulbophyllum species which were no more than a few millimeters tall while the liana-like Vanilla species that climb up the tallest forest trees reached about 30 m or more. They also stated that the giant orchid was Grammatophyllum speciosum which weighed about more than ten kilograms.
Mukherjee, (1983) reported that multiplication of Phaius by division of pseudobulbs was reported as the most suitable and popular method which produced flowering sized plants earlier than any other method.
Hegde (1981) reported that the ideal months for the propagation of Papluopecliluin fairrieanum by division were April and May when (lowering was over.
Goh (1979) reported that in some species, the differentiation of (lower primordia in the meristems occurs when stem growth ceases; (lowering in Dendrobium louisae occurred only after the termination of vegetative growth of the pseudobulbs.
Sheehan and Sheehan (1979) suggested that the optimum range of temperature for successful growing of Cymbidium and Dendrobium species was 10°C - 20°C. The range
18°C - 32°C was found optimum for successful cultivation of Phalaenopsis
Northern, (1970) suggested that Dendrobium orchids are of the highest value as cut
(lowers due to wonderful beauty and very good keeping qualities. Some Dendrobium orchid flowers last for one to three months if remained attached to the plant, and as cutflowers they remain fresh for one to four weeks.
Vase life Sultan and Farooq, (1999) suggested that cut narcissum flowers (Narcissus tazetta cv.
Kashmir Local) held in sucrose (0.15 mM) and GA3 (0.05 mM) showed an improvement in flower quality and vase life and an increase in fresh weight and water content.
Yamne el al. (1997) pretreatments with BA (upto 3 mM for 24 hours) significantly suppressed ethylene production and extended the vase life of cut florets of Lacliocat tleya and Brassocattleya hybrids. A combination of BA pretreatment and 0.4 mM silver thiosulphate spray had synergistic effect on the vase life of Cattleya hybrid
Bhattacharjee (1994) reported that vase life of the Dendrobium cut flowers were markedly increased if kept in a holding solution of 200 ppm 8 HQS and 2% sucrose.
Han, (1992) suggested that (lower spikes of Liatris spicala, harvested al the tight -bud stage, were placed in solutions containing 0-10% sucrose. Sucrose treatment significantly improved postharvest quality, with 5% sucrose resulting in an almost 2-fold increase in vase life, compared with a non-sucrose-treated control ( 1 1 8 and 6.1 days, respectively), and an increase in the length of inflorescence showing colour. In all sucrose concentrations, most (lower heads reached anthesis, compared with 27% reaching anthesis for non-sucrose controls.
Nair el al. (1991) noted that AgN03 at 100-200 mg/1 was effective in delaying senescence in Cattleya, Dendrobium, Oncidium and Rhyncos/ylis.
Zhang el al. (1991) Application of Benzyl adenine and Zeatin prolonged the life span of orchid flowers.
Ismail and Nair (1991) suggested that low concentration of (0.1-10 mg/1) Kinetin prolonged the life span of Dendrobium flowers whereas high concentration (100-1000 mg/l) decreased the life span.
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Nair (1990) reported N2 was as being “Effective for preventing fading of normal, presumably Vanda Miss Joaquim flowers in the presence of Ethylene-liberating flowers”
Thangaraj et al. (1990) studied the vase life of gerbera (Gerbera jamesonii Bolus). Freshly cut flowers of 24 accessions, placed in glass tubes with no water, were held at room temperature for 24 hours. Data were tabulated on weight loss, flower stalk bending, petal drooping, petal necrosis and vase life. The following accessions were found suitable for use as cut flowers: GJ 8, GJ 10, GJ 16, GJ 18, GJ 23 and GJ 44. In these, no flower stalk bending, petal drooping and petal necrosis were observed after 24 hours.
Gowda, (1990) suggested that the Polianthes tnberosa spikes were placed in solutions containing I or 2% sucrose and/or aluminium sulphate at 200 or 400 ppm and held for up to 12 days. The vase life was longest (12 days) in the following 2 solutions: 1% sucrose
+ 200 ppm aluminium sulphate, and 2% sucrose + 400 ppm aluminium sulphate.
Gowda and Gowda (1990) suggested that flowers of gladiolus cv. Black Jack were placed in conical flasks containing 2 and 3% of sucrose, aluminium sulfate (0.5 and 1.0
µM), aluminium chloride (0.5 and 1.0 µM) or calcium sulphate (0.5 and 1.0 µM) solution. Longest vase life (18.3 days) was with 1.0 µM aluminium sulphate, followed by
3% sucrose (17.0 days) and 2% sucrose (15.3 days). Shortest vase life (9.1 days) was found in control. The highest uptake of solution (48.0 ml) was with 1.0 µM aluminium sulphate and the lowest uptake (30.6ml) in the control. The increase in vase life due to sucrose may result from decreased moisture stress and improved water balance.
Gowda and Gopinath (1984) suggested that generally, fading makes the flowers unsalable. So, they studied orchid fading and found that potassium permanganate and brominated activated charcoal when used in the storage atmosphere delayed fading of flowers.
Ong (1982) suggested that foliar application of aluminium chloride at 500 ppm, ammonium molybdate at 100 ppm or boric acid at 1000 ppm lengthened the vase life of
Oncidinm Goldiana.
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Carow, (1981) suggested that the vase life of Phalaenopsis hybrid was prolonged by using chrysal and sucrose mixture.
Barendse (1980) in miniature Cymbidium observed marked difference in the keeping quality among 12 cultivars and use of chrysal increased the vase life.
Nowak and Vacharotayan (1980) suggested that treatment with 8-hydroxyquinoline citrate with 5% sucrose improved the flower quality and vase life of Dendrobium, Vanda, Vaudopsis, Aran/hera, Oncidium andArachnis cultivars.
Akamine (1976) suggested that Orchid flowers, though long lasting, should properly be handled to ensure maximum shelf life. Nutrients (sugar), antibacterial
[HQC, hydroquinoline sulphate (HQS) and CU], an analgesic, antipyretic and antiinflammatory (aspirin), and a number of solutions may be useful as vase-life extenders. Their effects depend on concentrations and combinations.
Materials and Methods
MATERIALS AND METHODS
The research work was earned out to study variabilities, identify morphological characteristics, keikis stimulation as well as vase life of 20 native Dendrobium orchids at the Orchidarium of Landscape, Ornamental and Floriculture Division, HRC, BARI,
Joydebpur, Gazipur during the period from January 2005 to June 2006. There were two experiments; the materials and method for each of the experiments were as follows:
EXPERIMENT 1. CHARACTERIZATION OF NATIVE DENDROBIUM
ORCHIDS
Planting materials used for the experiment
Twenty germplasm of Dendrobium native orchids were included in this study. Those were collected from different parts of Bangladesh by Floriculture Division of HRC,
BARI, Joydebpur, Gazipur.
Climate The experimental area was under subtropical climate characterized by heavy rainfall during the month from April to September and scanty rainfall during rest period of the year. Details of weather data during the growth period have been presented in
Appendix 1 The location of the site is at 24.09 N latitude and 90.26 E longitudes at an elevation of 8. 4 meter from the sea level (Anon., 1995). The orchidarium was facilitated to provide mist irrigation as and when necessary. Two ponds measuring 28 x
5 * 3 m were established within orchid house and the pond was kept full of water always to maintain the humidity in the orchidarium.
Treatments In experiment 1, the variabilities of 20 native orchid germplasm were studied. The twenty orchid germplasm were considered as the treatments of the experiment.
Scientific name and the sources of orchid germplasm are summarized in Table I.
Table 1. Name and source of collection of native Dendrobium orchid germplasm SL. No. Maine of germplasms Source of collection
D, Dendrobium formosum Srimongal, Sylhet
D2 D. farmeri Kaptai, Chittagong
D3 D. bensoni Kaptai, Chittagong
D4 D. pcirshii Kaptai, Chittagong
D5 D. monticolci Tekhnaf, Cox’s Bazar
Do D. Undeyii Tekhnaf, Cox’s Bazar
d7 D. transparens Srimongal, Sylhet
D8 D. pieardii Hill Tracts, Burma Border
D9 D. moschalum Jaintapur, Sylhet
D10 D. lermina/e Hill Tracts, Burma Border
D11 D. densiJJorum Jaintapur, Sylhet
D12 D. chrysoioxum Tekhnaf, Cox’s Bazar
D13 D. peguanum Tekhnaf, Cox’s Bazar
D14 D, longicornu Jaintapur, Sylhet
D15 D. fimbriatum Jaintapur, Sylhet
D16 D. chryscu it hem um Jaintapur, Sylhet
D17 D. miniature Jaintapur, Sylhet
D18 I), nobile Hill Tracts, Burma Border
D19 I), mulliflorum Hill Tracts, Burma Border
D20 D. bellatulum Hill Tracts, Burma Border
Design and layout of the experiment The experiment was laid out in Completely Randomized Design (CRD) with three
replications. One germplasm represent one treatment and each replication included
three plants of a germplasm.
Intercultural operations
Major disease incidence and pest infestations were not observed during the study. However, all the plants of 20 native germplasm were given similar cultural treatments throughout the year.
Collection of data Data on the following parameters were recorded from all the studied plants.
A. Plant characteristics i) Plant height
The height of the plant was measured in centimeter (cm) with a meter scale from the ground level to the tip of the growing point. ii. Number of pseudobulbs per plant Number of pseudobulbs was counted and recorded. iii. Diameter of pseudobulb (cm) Diameter of pseudobulb was determined by slide calipers and expressed in cm. iv. Hairyness of the pseudobulb
Hairyness of pseudobulb was determined by eye estimation and touching and classified either as absent or present. v. Colour of pseudobulb
Colour of pseudobulb was determined by comparing with colour chart and eye estimation, vii. Shape of pseudobulb
The shape of the pseudobulb was recorded by visual observation and classified into elongated cylindrical, lanceolate, linear, ovate, elliptic and oblong.
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B. Leaf characteristics i. Length of leaf
The length of leaf was measured by a measuring scale from leaf base to the tip and was expressed in cm. ii. Breadth of leaf
The breadth of leaf was determined by a measuring scale from one side of the middle or broadest part of the leaflet to the other side and expressed in cm. iii. Colour of leaf
The colour of leaf was determined by comparing with a colour chart and recorded as light green, green, deep green, reddish green, pinkish green etc. The leaves were observed keenly at the time of recording this parameter. iv. Hairyness of leaf
Leaf hairyness of individual plant was determined by eye estimation and classified either as absent or present. v. Number of leaves per plant The number of leaves was counted and recorded. vi. Arrangement of leaf Arrangement of leaf was observed and classified either as alternate or opposite. vii. Apex characteristics of leaf Apex character of leaf was determined by eye estimation and classified as acute, acuminate, blunt or emarginate. viii. Status of leaf at flowering stage Status of leaf at flowering stage was determined and classified either as present or absent.
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C. Flower characteristics i. Types of spike
Types of spike was determined by visual observation and recorded either as raceme or panicle. The spikes were observed keenly at the time of recording this parameter. ii. Length of spike
The spike length was noted by a measuring scale from the base upto the tip and expressed in cm. iii. Length of rachis Rachis length was determined by a measuring scale from spike base to the tip and expressed in cm. iv. Number of spike per plant Average number of spike was recorded by counting the individual plants of all germplasm. v. Number of flowers per spike
The number of flowers per spike was recorded by counting the flowers of individual spike from all germplasm. vi. Colour of flower
The colour of flower was determined by comparing with colour chart and eye estimation. vii. Colour of lip The lip colour was determined by comparing with colour chart and eye estimation. viii. Size of flower The length and breadth of flower were measured by a measuring scale and expressed in cm2.
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ix. Flower durability
Flower durability of different germplasm was recorded from the time of first floret opening to the maximum freshness of spike and expressed in days. x. Fragrance of flower The fragrance of flower was recorded by smelling and classified either fragrance present or absent.
Xi. Flowering period Flowering period of all the germplasm was recorded.
D. Pod characteristics i. Size of pod 2 The length and breadth of pod were measured by a measuring scale and expressed in cm . ii. Shape of pod
The shape of pod was recorded by visual observation and classified into ellipsoid, ovoid, globose, cylindrical and fusiform. iii. Colour of pod The colour of pod was determined by comparing with colour chart and eye estimation.
E. Root characteristics i. Number of roots Number of roots/plant was counted and recorded. ii. Length of root The length of root was noted by a measuring scale from root base to the tip and expressed in cm. iii. Diameter of root Diameter of root was noted by a measuring scale and expressed in cm.
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Collected data on plant, pseudobulb, leaf, flower, pod and root were statistically analyzed to find out the significance of difference among the treatment means. The means for all the treatments were calculated. i. Analysis of variance The analyses of variances for most of the characters under consideration were performed by F variance test. The significance of the difference between treatment means was evaluated by Least Significant Difference (LSD) test for interpretation of the results (Gomez and Gomez, 1984). ii. Estimation of simple correlation coefficient
Simple correlation coefficient (r) among germplasms was estimated with the following formula (Singh and Chaudhury, 1985).
Where, ∑= Summation
x and y two variable correlated
N = Number of observations iii. Path co-efficient: Path co-efficient analysis was done according to the procedure employed by Dewey and Lu (1959) using simple correlation values. In path analysis, correlation co-efficient is partitioned in to direct and indirect effects of independent variable on the dependent variable.
In order to estimate direct and indirect effects of the correlated characters, i.e. X 1, X2 and X3, inflorescence length Y, a set of simultaneous equation (three equations in this example) is required to be formulated as shown below-
ryX1 = Pyx1 + Pyx2 rx1x2 + Pyx3rx1x3
ryX2 = Pyx1rx1X2 + Pyx2 + Pyx3 rx2x3
ryX3 = Pyx1rx1x3 + Pyx2rx2x3 + Pyx3
Where, r denotes simple correlation co-efficient and p denotes path coefficient. Arranging them in matrix from may conveniently solve P in the above equations. Total correlation, say between x1 and y is thus partitioned as follows-
Pyx1 = the direct effect of xi on y
Pyx1rx1x2= indirect effect of x1 via x2 only Pyx3rx1x3= indirect effect of x1 via X3 only.
After calculating the direct and indirect effect of the characters, residual effect (R) was calculated by using the formula given below (Singh and Chaudhury, 1985).
P2RY = 1-∑Piy xiy. Where, P2RY = (R2); and hence residual effect,
2 R = (P RY) '/2
P,y - Direct effect of the character on length of inflorescence
r,y = Correlation of the character with length of inflorescence iv. Component of variance
The genotypic and phenotypic variance was calculated according to the following formula (Jhonson cl ct/., 1955).
σ2g=VMS -EMS r Where, VMS and EMS are the varietal and effective error means squares and r is the number of replications. The phenotypic variance (a 2ph) was derived by the following formula. σ2ph+σ2g+σ2e Where, a 2g is the genotypic variance and σ 2e is the effective error mean square.
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Estimation of genotypic and phenotypic coefficient of variation were calculated I according to Burton (1952) as follows-
Genotypic coefficient of variation (GCV) =σgx100 x Where, σ g = Square root of genotypic variance and
x = Population mean
Similarly, the phenotypic coefficient of variation was calculated by the
formula,
Phenotypic coefficient of variation (PCV) =σphx100 x
Where, σ ph = Square root of phenotypic variance
and
x = Population mean v. Heritability Heritability in broad sense was estimated.
vi. Genetic advance in per cent of mean Genetic advance in per cent of mean was calculated by the formula suggested by Comstock and Robinson (1952).
EXPERIMENT 2. STUDY ON PROLONGING THE VASE LIFE OF
DENDROBIUM
This experiment was carried out at the Landscape, Ornamental and Floriculture
Division Laboratory, HRC, BARI during the period from January 2005 to June 2006 to
study the post harvest physiology of Dendrobium densifiorum (only erect type orchid
among the 20 native orchids) flower under different concentrations of sucrose and pH
level.
Experimental Material Spikes were collected from net house-grown plants of Dendrobium densifiorum.
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Preparation of vase solution
Five hundred milliliter (ml) conical flasks were used as container. Fresh tap water used in this experiment of which pH was measured 7.0 (P 2). By adding citric acid the pH was decreased and gradually pi 1 stood at 3.0 (P|). Four levels of sucrose percentage i.e. Si 2%, S2 =3%, S.1 = 4% and S4 = control (without sucrose) were placed on respective conical flasks and dissolved by hand shaking. Then the conical flasks were marked with marker pen as P1S1, P,S2, P1S3, P1S4, P2S,, P2S2. P2S3 and P2S4.
Collection of spike The spikes were harvested when the first basal floret opened. Spikes were graded for uniformity both in length and weight. After harvesting, the spikes were carried out to the.Floriculture Laboratory of 1 IRC, BARI and fresh weights were measured. Two flower spikes were used for each treatment consisting of a 500ml conical flask containing 300 ml vase solution of given concentrations.
Treatments: There were two levels of pH and four levels of sucrose including control.
A. Levels of pH(2)
i) Low pH (3.0)-P1
ii) High pH (7.0)-P2
Ii. Levels of Sucrose
i) S1 = 2% Sucrose
ii) S2 = 3% Sucrose iii) S3 = 4% Sucrose iv) S4 = Without Sucrose (control)
Data collection Fresh weight of flowers Weight measured immediately after harvesting and before placing into conical flask.
Days taken to deterioration started Days counted when the flower started to dry.
Vase life (days) Vase life was recorded based on the senescence of the flower.
Solution uptake
The difference in weight between consecutive measurement of the conical flask + solution (without flower stick) represented the solution uptake.
Statistical Analysis
All the studies were done following simple and factorial form of Completely
Randomized Design (CRD) with three replications. The recorded data were analyzed by analysis of variance using MSTAT-C statistical package. The difference between treatment means was computed by Duncan’s Multiple Range Test (DMRT) (Steel and
Torrie, I960).
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Results and Discussion
Chapter IV
RESULTS AND DISCUSSION
EXPERIMENT 1. CHARACTERIZATION OF NATIVE Dendrobium ORCHIDS The characteristics studied included plants, pseudobulb, leaves, flowers, pods and roots of native dendrobium orchids. The physio-morphological characters like pseudobulb colour, leaf colour, flower colour, lip colour, pod colour, hairyness of leaf, hairyness of pseudobulb, etc. are important tools for the breeders, which help to identify desired genetic stocks as marker character in breeding programme The variabilities among the germplasms were estimated and discussed in this chapter under the following headings.
Plant characteristics
The plant characteristics like height, number of pseudobulb per plant, colour of pseudobulb, diameter of pseudobulb, hairyness of pseudobulb were recorded and shown in
Table 2 and 3.
Plant height Germplasm revealed marked differences in respect of plant height and it varied from 13 to 71 cm. The tallest plant (71cm) was found in germplasm Dy while the shortest plant
(13cm) was recorded in germplasm Dn (Table 2). Among the germplasm 70% attained plant height within the medium range (30 to 50 cm). About one fourth (25%) germplasm attained plant height at small range (below 30 cm) and only 5% germplasm at large size (above 50 cm) (Table 3).
Number of leaves per plant
Significant variations in respect of number of leaves per plant among the germplasms were found (Appendix II). The maximum number of leaves per plant (24) was produced by the germplasm D3 closely followed by the germplasm DK) (22). The minimum number of leaves per plant (8) was recorded in germplasm D17 (Table 2). Among the germplasm maximum number of leaves/plant was recorded by 15% germplasm and minimum number of leaves/plant recorded by 55% germplasm. On the other hand, medium number of leaves/plant was recorded by 30% germplasm.
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Table 2. Vegetative characters of twenty native Dendrobium orchids Germplasm Plant Leaf Leaf Leaf Pseudobulb Diameter of height number length breadth number pseudobulb (cm) (cm) (cm) (cm) D, 50 12 15.0 4.3 10 0.9
d2 44 17 13.2 3.7 6 1.3
d3 36 24 16.0 3.4 8 1.6
d4 19 10 11.3 3.0 5 1.4
d5 25 14 11.9 2.7 8 0.9 Dr, 24 17 9.0 4.2 15 0.5
d7 34 15 12.0 3.2 12 1.3 D8 36 20 10.4 3.6 7 3.9 D9 71 21 15.0 3.1 9 0.8 D10 40 14 15.0 2.5 1 1 1.2 D11 42 13 14.8 4.1 9 1.3 D12 29 1 1 10.4 5.2 8 4.0 D13 35 12 14.9 2.5 7 4.3 D14 39 16 13.5 2.3 10 0.8 D15 38 18 12.9 3.6 7 1.0 D16 39 O9 15.5 2.7 10 0.9 D17 13 8 3.4 0.9 10 1.5 D18 31 15 12.0 2.5 13 2.9 D19 40 18 15.0 2.9 8 3.0 D20 38 14 10.0 2.6 9 1.2
Level of * * ** * ^ X * ** significance CV (%) 23.40 1 1.91 14.22 9.45 11.55 5.68
** Significant al 0.01 level of probability
Length of leaf
As regards length of leaf, it was observed that it varied significantly (Appendix II) and ranged from 3.4 cm to 16.00 cm with the mean value of 12.56 cm. The longest leaf
(16.00 cm) was found in germplasm D3 closely followed by germplasms D16, (15.5 cm) while the shortest leaf (3.4 cm) was found in D17 (Table 2). Among the germplasm medium length of leaves/plant was recorded by 75% germplasm. On the other hand large length of leaves/plant recorded by 10% germplasm and lowest length of leaves/plant was recorded by 15% germplasm (Table 3).
Table 3. Different Categorizes of twenty native dendrobium orchids according on the basis of vegetative characters Character Germplasm Percentage (%)
Plant height (cm) Small (upto 30 cm) D17, D4, Dg, D5 and D12 25
Medium (3 1-50 cm) D18, D7, D13, D3, D8, D15, D20, D14, D16, D10, 70 D19, D11, D2 and D1
Large (above 50 cm) D9 5 Leaf number Minimum (upto 10) D]7, D4, D]2, D], D13, D11, D5, D10, D20 and 55
andD7 D18 j Medium (1 1-20) D14, D2, D6, D15, D19 and D8 30 Maximum (above 20) D9, D16, and D8 15 n Leaf length (cm) Low (upto 10 cm) D17, Dg and D20 15 Medium (11-15 cm) D8, D12, D4, D5, D7, D15, D15, D2, D14, D11, 75 I D13, D1, D9, D10 and D19;
Large (above 15 cm) D16 and D3 10 Leaf breadth (cm)
Low (upto 5 cm) D17, D14, D10, D13, D18, D20, D5, D16 ,D19, D4 50
Medium (6-10 cm) D9, D7, D3, D8, D15 and D2 30 Large (above 10 cm) D11, D6, D1 and D12 20 Pseudobulb number
Low (upto 5) d4 5
Medium (6-10) D2, D8, D13, D15, D3, D5, D12, D19, D9, D11, 75 D20, D1, D1.4, D16 and D17 Large (above 10) D10, D7, D18 and D6 20 Diameter of pseudobulb Low (upto 1.0 cm) D6, D9, D14, D], D5, D16 and D15 35
Medium (1.0-2.5 cm) D10, D20, D2, D7, D11, D14, D17 and D3 40 Large (above 2.5 cm) D18, D19, D8, D12 and D13 25
Breadth of leaf It was revealed that breadth of leaf ranged from 0.9 cm to 5.2 cm was varied
significantly (Appendix 11) with the mean value of 3.15 cm among the germplasms.
The germplasm D12 showed the highest breadth of leaf (5.2 cm) followed by
germplasm D1 (4.3 cm). The lowest breadth of leaf (0.9 cm) was observed in
germplasm D17 (Table 2). Among the germplasm large leaf breadth was recorded
by 20% germplasm and lowest leaf breadth was recorded by 50% germplasm. On
the other hand, medium leaf breadth was recorded by 30% germplasm (Table 3).
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Number of pseudobulb per plant
Significant variation was observed as to the number of pseudobulb among the germplasm under investigation (Appendix II). The maximum number of pseudobulbs (15) was obtained from the germplasm D6 closely followed by germplasm D7 (12) and D10 (11), whereas germplasm D4 had only 5 pseudobulb per plant (Table 2). Among the germplasm large number of pseudobulb/plant was recorded by 5% germplasm and lowest number was recorded by 20% germplasm (Table 3). On the other hand, medium number of pseudobulb
/plant was recorded by 75% germplasm.
Diameter of pseudobulb
It was revealed that diameter of pseudobulb varied significantly among the germplasms and ranged from 0.50 cm to 4.3 cm with the mean value of 1.73 cm (Appendix II). The germplasm Dn showed the highest diameter of pseudobulb (4.3 cm) followed by germplasm Diy (3.0 cm). The lowest diameter of pseudobulb (0.5 cm) was observed in germplasm D(, (Table 2). Among the germplasm large diameter of pseudobulb was recorded by 35% germplasm and lowest diameter was recorded by 25% germplasm (Table
4). On the other hand medium diameter of pseudobulb was recorded by 40% germplasm.
Shape of pseudobulb/plant
The pseudobulb shapes of the observed germplasm were graded into five groups viz., elongated cylindrical, lanceolate, linear, elliptic, ovate and oblong. Among the germplasm, 50% was elongated cylindrical, 15% oblong, 20% lanceolate, 10% ovate and
5 % linear (Table 5).
Colour of pseudobulb
As regards colour of pseudobulb, the observed germplasms showed remarkable variation such as green, yellow, maron, black, white and intermediate colour viz., light green, deep
green, light yellow, greenish white, creamy white etc. The variability in colour of pseudobulb of orchids is shown in plate I.
Table 4. Pseudobulb characters of twenty native Dendrobium orchids Germplasm Shape of Colour of pseudobulb Hairyness of pseudobulb pseudobulb
D, Elongated cylindrical Blackish white Present
d2 Lanceolate Green with white layer Absent D, Elongated cylindrical Dark green with shiny white streak Absent
d4 Elongated cylindrical Brown Absent
d5 Lanceolate Green with white streak Absent D6, Oblong Green with white streak Absent
d7 Lanceolate Maron Absent
Ds Elongated cylindrical Brown Absent D9 Oblong Green with white streak Absent D10 Elongated cylindrical Yellowish maron Absent D11 Elongated cylindrical Brown Absent D12 Ovate Brown Absent D13 Elongated cylindrical Light green with white streak Absent D14 Oblong Creamy white Present D15 Elongated cylindrical Maron witli white streak Absent D16, Elongated cylindrical Light yellow Absent D17 Linear Light yellow Absent D18 Lanceolate Dark green Absent D19 Elongated cylindrical Greenish white Absent
D20 Ovate Green with white layer Absent
Hairyness of pseudobulb In respect of hairyness of pseudobulb, the observed germplasms were categorized into two groups; absent and present. Only two germplasm D1 and Du had hairs of pseudobulb and absent in rest of the germplasm.
Leaf characteristics The leaf characteristics like total number of leaves per plant, length, breadth, colour, apex, hairyness, arrangement and status of leaf at flowering stage were recorded and are shown in Table 6.
CharaTabiccter 5. Different CategorizesGermplasm of twenty native dent/robin in orchids accordingPercentage on the (%) basis of vegetative characters Shape of pseudobulb Elongated cylindrical D1, D3, D4, D8, D10, D11, D13, D15, D16, D]9 50
Lanceolate D2, D5, D7, D18 20 Linear D]7 5 Oblong Do, D9, Dm 15 Ovate D12, D20 10 Colour of pscudobulb Blackish white D1, 5 Brown D4, D8,-D11, D12 20 Creamy white D14 5 Dark green D18 5 5 Dark green with shiny white D3 streak Green with white layer D2, D20, 10
Green with white streak D5, D6, D9 15 Greenish white D, 9 5 Light green with white D13 5 streak Light yellow D,6, D]7 10
Maron d7 5 Maron with white streak D15 5 Yellowish maron D10 5 Hairyness of pseudobulb
Absent D2, D.,, D4, D?, D(„ D7, Ds, D9, D10, D11, D12, D13, 90 D15, D16, D17, D18, D19, D20 Present D1, D14 10
Plate 1. Pseudobulb of Twenty Native Dendrobium Orchid Germplasm Colour of
leaf
All the germplasms were categorized into 5 groups on the basis of their leaf colour.
They were green, light green, deep green, reddish green and pinkish green. The variability in leaf colour of orchid germplasms was shown in Plate 2. Among the germplasm 40% was deep green in colour.
Arrangement of leaf Leaf arrangement of different germplasms were graded as alternate or opposite.
Germplasms D? and Dm (10%) showed opposite leaves whereas alternate leaf arrangement (90%) was present in rest of the germplasms (Table 6).
Hairyness of leaf In respect of hairyness of leaf the observed germplasms were categorized into two groups; absent or present. Only 20% germplasms D1 and D14 had hairs on leaves and rest 80% of all germplasms had no hair (Table 7).
Table 6. Leaf characters of native Dcmlrobium orchids Germplasm Leaf colour Leaf Leaf Leaf apex Status of leaf at arrangement hairyness flowering stage
D, Deep green Alternate Present Emarginate Present
d2 Deep green Alternate Absent Acute Present
d3 Deep green Alternate Absent Acute Absent
d4 Deep green Alternate Absent Acuminate Absent
d5 Reddish green Opposite Absent Emarginate Present
d6 Deep green Alternate Absent Emarginate Present
d7 Light green Alternate Absent Acute Absent
D8 Green Alternate Absent Acuminate Absent D9 Light green Alternate Absent Blunt Present D10, Reddish green Opposite Absent Acute Present D11 Dark green Alternate Absent Acute Present D12 Dark green Alternate Absent Acute Present D13 Pinkish green Alternate Absent Emarginate Present D14 Light green Alternate Present Emarginate Present D15 Green Alternate Absent Blunt Present D16 Deep green Alternate Absent Emarginate Present D17 Green Alternate Absent Acute Present D18 Deep green Alternate Absent Blunt Present D19 Light green Alternate Absent Acute Present
D20 Deep green Alternate Absent Acute Present
Apex characteristics of the leaf As regards apex characteristics of the leaves, the observed germplasms were divided into four groups; acute, acuminate, blunt and emerginate. 30% genotypes under study had emarginate type leaf apex, 10% genotypes possessed acuminate, 15% genotypes had blunt and rest 45% of genotypes had acute leaf apex. (Table 7).
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Plate 2. Leaf of Twenty Native Dendrobium Orchid Germplasm Status of leaf at flowering stage
In respect of status of leaf at flowering stage, the observ ed species were categorized into two groups; absent and present. The germplasms D3, D4, D7 and D8 (20%) had no leaf at flowering stage whereas it was present in rest of the 80 % germplasms
(Table 7).
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Character Germplasm Percentage (%) Fable 7. Different Categorizes of twenty native (Icmlrobinm orchids according on the Leafbasis colour of vegetative characters Dark green D11, D12 10
Deep green D1, D2, D3, D4, D6, D16, D18, D20 40
Green D8, D15, D17 15 Light green D7, D9, D14, D19 20 Pinkish green D13 5 Reddish green D5, D10 10 Leaf arrangement I Alternate 90 D1, D2, D3, D4, D6, D7, D8, D9, D11, Dl2, D13, D14, Dl5, D16, D17, D18, D19, D20 10 i Opposite D5, D10 II Leaf hairyness
Absent D2, D3, D4, D5, D6, D7, D8, D9, D10, D11, D12, 90 D13, D15, D16„ D17, D18, D19, D20 Present D1, D14 10
Leaf apex Acuminate D4, D8 10
Acute D2, D3, D7, D10, D11, D12, D17, D19, D20 45 Blunt D9, D15, D18 15
Emarginate D1, D5, D6, D13, D14, D16 30 Status of leaf at flowering stage
Absent D3, D4, D7, D8 20 Present 80 D1, D2, D5, D6, D9, Dl0, D11, D12, D13, D14, I D15, D16, D17, D18, D19, D2o
Flower characteristics Flower characteristics pertaining to length of spike, length ol rachis, size ol flower,
number of flower, durability of flower, colour of flower, colour of lip, fragrance of
flower, origin of spike and period of flowering were recorded and presented under
different heads.
Length of spike
Significant variation in respect of spike length was found among the germplasms.
The longest spike (29.0 cm) was produced by germplasm Dn followed by D7 (27.0 cm)
while the shortest spike (2.0 cm) was produced by D,7 (Table 8). Among the germplasm
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45% attained length of spike within the medium range (I I to 20 cm). About 20%
germplasm attained small range (below 10 cm) and 35% germplasm had large size (above
20 cm) (Table 9). Table 8. Yield contributing characters of twenty native orchid germplasm Germplasm Spike length Rachis Spike Flower Flower size (cm) length (cm) number number (cm2) D, 9.7 8.5 2.4 08 8.0
d2 17.4 11.8 3.0 14 4.4
d3 18.8 14.4 2.4 06 3.0 D4 13.7 7.3 2.5 16 2.5 D5 13.2 7.6 2.0 15 4.1
D6 8.7 6.9 2.4 14 2.5 D7 27.0 14.7 2.2 10 3.4
D8 26.5 15.0 3.0 15 3.2 D9 21.0 13.5 10 3.4 D10 23.0 10.6 2.5 12 3.6 D11 29.0 i 8.0 4.0 22 3.2
D12 19.8 1 1.0 2.5 15
D13 18.5 10.9 2.6 12 4.2 D14 5.3 3.6 2 2 08 6.9 D15 15.7 10.0 2.4 17 3.7
D16 25.8 15.4 2.5 20 4.3 D17 2.0 1.5 2.4 15 1.3 D18 21.0 14.0 2.3 14 4.2 D19 19.1 13.0 1.5 18 4.8
D20 18.0 12.3 2.5 13 5.2
Level of * * ** * * * ** significance
CV (%) 31.83 17.40 7.40 25.5 11.35
Length of rachis
Different germplasm of orchids showed significant variations in respect o f rachis length
(Appendix II). Germplasm Du showed the highest rachis length (18.0 cm) followed by Dir,
(15.4 cm) while the lowest rachis length (1.5 cm) was observed in species D17 (I able 8).
Number of spike per plant
Number of spike per plant varied significantly among the observed germplasm and ranged
from 1.5 to 4.0 with the mean value of 2.5 (Appendix 11). The maximum number of spike
(4.0) was obtained from the germplasm D11 whereas germplasm D1 produced the minimum
number (1.5) of spikes per plant (Table 9).
Table 9. Different Categorizes of twenty native dendrobium orchids according on the basis of vegetative characters Character Germplasm Percentage (%)
Spike length (cm)
Small (upto 10 cm) D17, D14, D6, D1, 20
Medium (1 1-20 cm) D5, D4, D15, D2, D20, D13, D3, D19, D12 45
Large (above 20 cm) D9, D18, D10, Dl6, D16, D7, D11, 35 Rachis length (cm) Shortest (upto 10 cm) D17, D14, D6, D4, D5, D1, D15, 35
Longest (above 10 cm) D10,, D13, D12, D2, D20, D19, D9, D18, D3, D7, 65
D8, D16, D11 Spike number
Lowest (upto 2) D19, D5 10 Medium (2-3) 85 D7, D9, D14, D18, D1, D3, D6, D15, D17, D4,
D10, D12, D16,, D2o, D13, D2, D8 Highest (above 3) D11 5 Flower number
Low (upto 10) d3, d1, d14, d7, d9 25
Medium (10-20) D10, D13, D20, D2, D6, D18, D5 D8, D12, D17, 70 D4, D15, D19, D11 Large (above 20) D,6 5 Flower size (cm2) 2 Low (upto 3 cm ) D17, D4, D6, D 3 20 Medium (3-5 cm2) 65 D8, D11, D7, D9, D10, D15, D12, D5, D13,
D18, D16„ D2, D19 Large (above 5 cm ) D2o, D14, D1 15 1
Number of flowers per spike Number of flowers per spike ranged from 6.0 to 20.0 with the mean value of 13.7.
AAmong the observed germplasm, the maximum (22) number of flowers per spike
was obtained from species D11 while the lowest number of flowers per spike (6.0) was
observed in both the species D3 and D14 (Table 9). 34
Size of flower
In respect of size of flowers, significant variations were observed among species (Appendix II).
The largest flower (8.0 cm) was obtained from the germplasms D1 closely followed by germplasm D14 (6.9 cm). On the other hand, the smallest flower (1.3 cm) was recorded from germplasm D17.
Durability of flower
Flower durability observed in this experiment varied from 8.0 to 31.0 days with the mean value of 14.5 days. The longest duration of flower (31.0 days) was found in gemplasm
D1 while the shortest flower durability (8.0 days) was recorded in D7 and D9 (Figure
1)
Fig. 1. Flower durability in native Dendrobium orchids Type of spike
The types of spike were categorized into two groups, raceme and panicle. Only the spike of germplasm Ds had panicle type spike. Rest of the germplasms had raceme type spike (Table-10)
Origin of spike
Origin of spike of different germplasm were graded as lateral or terminal. The origin of spike of germplasms D1 and D5 were terminal while rest of the germplasm was lateral. 35
Wide range of variations was observed in respect of colour of flower. The different germplasms showed different attractive colour of flowers (Plate 3). The colours of flower were categorized into white, yellow, red, blue, green and intermediate.
Fragrance of flower
In respect of fragrance of flower, the observed germplasm were categorized into two groups; absent and present. The germplasm had no fragrance in flower, whereas it was present in all germplasm (Table 10).
Lip colour
Under investigation of 20 germplasms, much more differences were observed in colour of lip (Plate 4).
Plate 4. Diversity of lip colour of native Dendrobium orchids
37
Table 10. Qualitative flower characteristics of native Dendrobium orchids Orchid Spike Spike Flower colour Lip colour Flowerin Fragrance Germplasm type origin g of flower D1 Raceme Termina White with yellow White with Fperiodebruary Present l yellow in mid - April d2 Raceme Lateral White with pink Deep yellow February Present apex and yellow with white - disc edge April d3 Raceme Lateral Pale pink with Yellow with March- Present yellow white edge May d4 Raceme Lateral Pink with purple Purple blotch March- Present with hairy May white edge D5 Panicle Termina Green with blue Bluish white March- Present l stripe May D6, Raceme Lateral Light yellow Orange- M arch- Present golden yellow April D7 Raceme Lateral White with Purple blotch March- Present with white May apex D8 Raceme Lateral Creamy white Creamy white March- Present April D9 Raceme Lateral Pale yellow with Yellow with March- Present white pinkish while May edge D10 Raceme Lateral Pale pink Pinkish March- Present yellow May D11 Raceme Lateral Golden yellow with Golden March- Present purple yellow with May two purple patches D12 Raceme Lateral Blight dark yellow Yellow- March- Present May D13, Raceme Lateral Pale Green Light Yellow March- Present May D14 Raceme Lateral White with orange Streaked March- Present red in throat orange red April with mixture of red and yellow edges D]5 Raceme Lateral Deep yellow Deep yellow' March- Present with meron May spot in mid D16, Raceme Lateral Pale yellow with Yellow March- Present orange base May D|17 Raceme Lateral Creamy white Yellowish March- Present white April D18 Raceme Lateral White with pink Pinkish white March- Absent apical half April D19 Raceme Lateral Yellow Reddish March- Present purple May D20 Raceme Lateral Creamy white Orange March- Present APril ......
39
Flowering period
Flowering periods of different observed germplasms were recorded and presented in
Table 6. The different germplasms gave flash with varying times in a year. The variability on flashing time of twenty Dendrobium orchids has been displayed in Table
10.
Pod characteristics Pod characteristics like colour, shape and size were recorded and discussed below. Pod colour
Germplasms were grouped into different categories on the basis of their colour. These were green, light green, dark green, maroon, brown, light yellow, light red etc. The different germplasms showed a wide variation in pod colour (Table I 1).
Table 11. Pod characters of native Deiulrobitwi germplasm Germplasm Pod colour Pod shape Pod size (cm2) D1 Green Ellipsoid 4.6
D2 Green Ovoid 2.8 D3, Whitish Green Ovoid 2.5 D4 Green Ovoid 2.6
D5 Green Globose 2.5
D6 Whitish Green Cylindrical 3.8
D7 Yellowish Green Ovoid 3.3
Ds Green Ovoid 3.0 D9 Light green Fusiform 3.2 D10 Green Fusiform 2.5 D11 Light Green Globose 3.0 D12 Green Ovoid 3.2 D13 Green Cylindrical 3.0 D14 Light green Ellipsoid 3.5 D15 Green Fusiform 3.0
D16 Light Green Ovoid 2 2 D17 Light Green Fusiform 1.2 D18 Pinkish Green Fusiform 3.4 D19 Light Green Cylindrical 3.2 D20 Pinkish Green Globose 3.5 CV (%) - - 59.4
1 Pod shape
The different germplasms showed a wide variation in shape of pod (Plate 5). The shape of pod
was graded into fusiform, cylindrical, ovoid, ellipsoid and globose (Table 11). Among the
germplasms 10% was ellipsoid, 35% ovoid, 15% globose, 15% cylindical and 25% fusiform.
Pod size It was observed that pod size varied significantly from 1.2 to 4.6 cm (Table 7). The maximum pod size was observed in germplasm D1 (4.6cm) followed by germplasm D6 (3.8 cm)
The minimum pod size (1.2 cm) was recorded in germplasm D17 (Table 11).
Table 12. Different Categorizes of twenty native dendrobium orchids according 011 the basis of vegetative characters
Character Germplasm Percentage (%) Pod colour
Green D1, O2, O4, D5, D8, D10, D12, D]3 and D15 45
Light green D9, D11, D14, D16, D17, D19 30
Pinkish Green D18, D2O 10
Whitish Green D3, D6 10
Yellowish Green d7 5 Pod shape Cylindrical D6, D13, D19 15
Ellipsoid D1, D14, 10
Fusiform D9, D10, D15, D17, D18 25
Globose D5, D1, D20 15
Ovoid D2, D3, D4, D7, D8, D12, D16, 35 Pod size (cm )
Low (upto 2 cm") d17 5 Medium (2-4 cm2) 90 D16, D3, D5, D10, D4, D2, D8, D11, D13, D15,
D9, D12, D19, D7, D18, D14, D20, D6, Large (above 4 cm ) D1, 5
41
Plate 5. Pod diversity in native Dendrobium orchids
Root characteristics
Root characteristics like root length, root number and root diameter were recorded and shown in Table 13.
Number of root
Variation was observed in number of root of different germplasms (Table 13). Maximum number of root was obtained in germplasm D1 (15) followed by germplasms D11 (13) whereas the lowest number of root was observed in D17 (6).
Length of root
Length of root varied significantly and ranged from 8.0 to 40.0 cm with the mean value of 30.5 cm .The longest root 40.0 (cm) was found in germplasm D7 followed by germplasms D16 (37.3 cm). The shortest root length (6.0 cm) was observed in germplasm D8 closely followed by D2 (8.0 cm) (Table 13).
Root diameter
Significant variations were observed among the germplasms (Table 13). The thickest root diameter (0.68 cm) was obtained from the germplasm D7 followed by Dig (0.50 cm). On the other hand, the thinnest root diameter (0.17 cm) was recorded from the germplasm D17.
Table 13. Root characteristics of twenty native Dendrobium orchid germplasm Germplasm Root number Root length (cm) Root diameter (cm) D, 15 35.00 0.19
d2 12 08.00 0.30
d3 10 25.00 0.20
d4 11 32.00 0.25
d5 09 34.66 0.24
D6 10 33.33 0.31
D 7 08 40.00 0.68 D8 09 06.00 0.30 D9 12 35.30 0.25 D10 11 25.00 0.30 D11 13 30.00 0.20 D 12 10 18.00 0.30 D13 08 20.00 0.20 D14 07 22.00 0.18 D15 12 32.00 0.15 D16, 10 37.33 0.28 D17 06 25.00 0.17 D18 08 17.66 0.50 D19 10 26.00 0.40
D20 12 21.00 0.35 CV (%) 6.97 14.80 5.23
Table 14. Different Categorizes of twenty native dendrobium orchids according on the basis of vegetative characters Character Germplasm Percentage (%) Root number
Low (upto 7) D,7, DI4 10
Medium (8-14) D7, D13, D18, D5, D8, D3, D6, D12, Dl6, D19, D4, 85 D10, D2, D9, D15, D20, D11 Large (above 14) D1 5 Root length (cm)
Low (upto 15 cm) D8, D2 10
Medium (15-30 cm) D18, Dl2, Dl3, D20, D14, D3, D10, D17, Dl9, D11, 50
Large (above 30 cm) D4, D15, D6, D5, D1, D9, D16, D7 40 Root diameter (cm) Low (upto 15 cm) D15 5
Medium (15-30 cm) D17, D14, D1, D11, D13, D3, D5, D4, D9, D16„ 70 D10, D12, D2, D8
Large (above 30 cm) D6, D20,D19, D18, D7 25
43
Estimate of genetic parameters in Dendrobium orchids Success of genetic improvement of any crop depends upon the extent of available variability and its subsequent skillful management towards selection of desirable type.
The analysis of variance (Appendix II) indicated the existence of significant variability for all the characters studied. The range, coefficient of phenotypic and genotype variations, heritability estimates and expected genetic advance in percent of mean (at
1%) are shown in Table 15. A wide range of variation was observed for all the 18 characters studied. The range of variation was high for spike length (2.0-29), rachis length (1.5-18.0), flower durability (8.0-31.0), leaf number (8-24), floret number (6-22) and plant height (13-71) but low for root diameter (0.17- 0.68). Orchid being a cross pollinated crop has much variation and therefore the present observation is in agreement with that as reported earlier by Sultana (2003) in orchid. Estimates of genetic parameters for each character are important for getting idea about their mode of inheritance. Such idea usually helps the breeder to make efficient selection. In the present study, a narrow difference between phenotypic and genotype coefficients of variation was noticed for spike length, rachis length, plant height, floret number and flower durability, indicating less environmental interference on the expression of these characters. Similar observations were made by Anuradha and Gowdha (1994) in gladiolus (Table 15).
A character can be improved only if it is highly heritable. The magnitude of If indicates the effectiveness with which the selection of genotypes can be made based on phenotypic performance (Johnson et a/. 1995). Out of 18 quantitative characters studied, spike length, rachis length, plant height, floret number and flower durability exhibited high heritability (Table 15). The results were in consonance with the findings of Singh and Singh (1990) in gladiolus and Sultana (2003) in hybrid orchid.
Even though the h2 values give indication of effectiveness of selection based on the phenotypic performance, it docs not necessarily mean a high genetic advance for a particular character. Heritability along with estimates of expected genetic advance, should be considered while making selection, in crop improvement only the genetic component of variation is important since only this component of h 2 serve as a useful guide to the breeder. 44
Table 15. Phenotypic and genotypic variability, heritability and genetic advance in twenty native Dendrobium orchids
Characters Range Coefficient of Heritability Genetic advance in (h2) variability (%) percent of Phenotypic Genotypic mean (at 1 %) Plant height 13 0-71.0 25.50 23.74 87.00 40.99 Leaf length 3.4-16.0 23.49 17.50 50.00 30.60 Leaf breadth 0.9-5.2 22.30 16.95 45.25 31.54 No. of 5.0-15.0 34.00 28.00 67.77 58.35 pseudobulb/plant 0.5-4.3 30.50 27.33 65.90 51.50 Diameter of pseudobulb No. of 2.0-5.0 31.44 26.58 68.63 58.27 spike/plant No. of 6.0-22.0 33.30 28.20 72.55 64.80 flowers/spike 2.0-29.0 40.45 38.00 94.00 98.29 Spike length (cm) Rachis length 1.5-18.0 36.00 35.59 95.34 93.85 (cm) I.3-8.0 30.00 25.00 64.70 54.88 Flower size (cm2) Flower durability 8.0-31.0 32.55 31.34 94.00 89.00 (days) Pod size 1.2-4.6 24.00 21.58 74.00 48.51
Root number 6.0-15.0 25.00 22.00 54.80 38.29 Root length 8.0-40.0 35.58 32.00 50.00 37.90 Root thickness 0.17-0.68 20.44 15.00 48.38 35.28
If the h2 of a character is high (80% or more), selection for this is very effective. This is because there would be close correspondence between genotype and phenotypic variances due to relatively smaller contribution of environment to the phenotype. But for character with low h2 (less than 0.4), selection may be ineffective or virtually impractical due to masking effect of environment on the genotypic effects. The characters exhibiting high h" with high genetic advance in this study were spike length (94.00% and 98.29), rachis length (95.34% and 93.85), flower durability (94.00% and 89.00) and floret number (72.55% and 64.80). This indicated addtive gene action, suggesting the possibility of improvement of these traits through selection (Burton, 1952). Similar observations were made by Prasad el al. (2001) and
45
Faroque (2003) in gladiolus and orchid respectively. The characters exhibited high h 2 along with low genetic advance (GA) in orchid were plant height (87.00% and 40.99%) and pod size (74.00% and 48.51). The high h2 coupled with low GA indicates non- additive gene action, including epistasis and dominance. Similar results were reported by Ashwath and Parthasarathy (1994) and Negi el al. (1982) in gladiolus. Other characters exhibited moderate heritability with low genetic advance.
Correlation Coefficient Character association analysis among flower and flower producing attributes revealed that all the genotypic correlation co-efficients were higher than the corresponding phenotypic correlation co-efficient (Table 16). This indicates the suppressing effect of the environment, which modified the phenotypic expression of these characters by reducing phenotypic coefficient values. Accordingly, Anuradha and Gowdha (1994) reported that the genotypic correlations were greater than the phenotypic values in gerbera. From this study, it was observed that both at genotypic and phenotypic level, length of leaves had simply positive correlation with flower number, flower size, flower durability, rachis length and spike length. On the other hand, this trait had negative association with leaf breadth; number of pseudobulb as well as spike length, breadth of leaf had negative association with leaf number and number of spike but positive association with other characters. Number of leaves had positive significant association with number of pseudobulb per plant. This indicated that number of pseudobulb will be increased with the increase of total number of leaves. Number of pseudobulb had significant but negative correlation with number of spike per plant (r=- * 0.235 ) which indicated that number of spike per plant would be increased with the decrease in number of pesudobulbs. Number of pseudobulb had also positive association with flower number, flower durability, rachis length, flower size and spike length at both genotypic and phenotypic level. Correlation coefficient revealed that number of spikes per plant had negative correlation with number of flowers per spike (Table 16). This indicated that number of flower would decrease with the increase of number of spike per plant. On the other hand, this trait had positive association with flower size, (lower durability, rachis length and spike length. The number of florets per spike recorded a positive, highly significant association with flower durability, rachis length and spike length. Bhagur 46
(1989) also reported the similar findings relating to character association and variability studies in gladiolus. The character had also shown significant but negative correlation with size of flower at both genotypic and phenotypic levels (Table 16). The results agreed with Faroque (2003) and Sultana (2003) in orchids. Durability of flower had significant positive correlation with rachis length, flower size and spike length at both genotypic and phenotypic level. This indicated that flower durability would increase with the increase of rachis length, flower size and spike length. Highly significant positive correlation was found between rachis length and spike length. Singh and Singh (1990) reported that the genotypic and phenotypic association between rachis length and spike length in gladiolus was observed to be positive and highly significant which was corroborating with the present findings. Again rachis length had negative association with flower size. This indicated that flower size would decrease with the increase of rachis length. Similar observation was reported by Lai cl al. (1985) in gladiolus. However, the correlation study revealed that selection of parents based on characters such as floret number, rachis length and flower durability were useful in breeding program.
47
Table 16. Genotypic (G) and phenotypic (P) correlations among ten characters in twenty native Dendrobium orchids Traits Leaf Leaf No. of No. of spike No. of flowers Durability of Rachis Flower size Spike
breadth number pseudobulb per per plant per spike flower length length plant Leaf length G -0.143 0.188 -0.169 0.099 0.146 0.153 0.162 0.188 -0.186 P -0.102 0.115 -0.135 0.048 0.109 0.139 0.133 0.178 -0.1 74 Leaf breadth G -0.166 0.194 -0.187 0.166 0.194 0.175 0.180 0.193 P -0.108 0.147 -0.175 0.155 0.180 0.148 0.146 0.179 Leaf number G 0.234* 0.181 0.234* 0.128 0.174 -0.175 0.165 P 0.219* 0.174 0.215* 0.105 0.115 -0.105 0.152
No. of pseudobulb per G -0.235* 0.188 0.190 0.189 0.171 0.181 plant P -0.198* 0.109 0.186 0.155 0.164 0.157 No. of spike per plant G -0.174 0.130 0.165 0.154 0.175 P -0.106 0.114 0.101 0.098 0.127
No. of flowers per G 0.408** 0.456** -0.256* 0.291* spike P 0.334** 0.364** -0.219* 0.199* Durability of flower G 0.393** 0.218* 0.420** P 0.248** 0.203* 0.315** Rachis length G -0.189 0.454** P -0.106 0.338** Flower size G -0.149
P -0.116
* Indicate 5% level of significant (using mean values) ** Indicate 1% level of significant (using mean values) Significant valus of r (5%= 0.198. 1% = 0.244)
Table 17. Path coefficient of flower producing character on length of spike in native Dendrobium orchid germplasm Traits Leaf Leaf Number of Number of Number of Number of Flowering Rachis Flower Genetic correlation breadth number leaves pseudobul spike/plant flowers/ Spike duration length size with spike length bs/plant
Leaf length -0.141 0.028 -0.001 I 0.044 -0.085 0.154 0.145 0.138 0.027 -0.186 Leaf breadth 0.312 -0.045 0.021 | -0.125 -0.003 | 0.144 0.051 0.145 0.110 -0.193 Number of -0.078 0.098 -0.050 -0.135 0.143 0.187 0.164 0.143 -0.165 0.165 leaves Number of 0.084 0.014 0.135 -0.162 0.121 0.196 0.164 0.235 0.128 0.188 pseudobulbs Number of -0.040 0.024 -0.011 -0.023 0.017 0.033 0.120 0.132 -0.015 0.175 spike/'plant Number of 0.050 0.048 0.020 0.034 0.027 0.304 0.015 0.091 -0.090 0.291 flowers/spike Flowering 0.450 0.029 -0.041 -0.056 0.042 0.031 0.445 0.113 0.003 0.420 duration Rachis length 0.282 0.015 -0.013 0.092 0.055 0.139 0.159 0.516 -0.024 0.454 Flower size -0.052 -0.027 0.057 -0.135 0.013 -0.115 -0.019 0.096 0.133 -0.149 Residual effect: 0.30
Underline figures indicate the direct effect
49
Path Coefficient Association of characters determined by correlation coefficients may not provide an exact picture of the relative importance of direct and indirect influence of each of the yield components on yield. As a matter of fact, in order to find out a clear picture of the interrelationship between flower yield and other yield attributes, direct and indirect effects were worked out using path analysis at genotypic level which also measured the relative importance of each component. Path coefficient analysis (Table 17) revealed that rachis length had the highest positive direct effect on spike length followed by durability of flower and number of flowers per spike might be due to highly significant positive correlation of spike length with the corresponding characters. The results agreed with Faroque (2003) in orchids and Tejaswini cl al. (1994) in tuberose. Among them rachis length, durability of flower and number of flower per spike had higher positive direct effect than their significant positive correlation with yield indicating that selection based on th ese characters would be effective. On the other hand length, breadth and number of leaves had negative direct effect on spike length. Similar result was found by Sultana (2003) and Faroque (2003) in orchids. Flower size had also positive direct effect on spike length but its indirect effect through other characters were mostly negative, which consequenty resulted negative correlation with spike length. Number of pscudobulb had negative direct effects though most of its indirect effects through other characters were positive which finally made insignificant negative correlation between pesudobulb and spike length. The results are in agreement with Faroque (2003) in orchids and Negi cl al. (1983) in gladiolus. The residual effect of the present study was 0.30 indicating that 70 percent of the variability in spike length was contributed by the ten characters studied in the path analysis. This residual effect towards yield in the present study might be due to other characters which were not studied, environmental factors and sampling errors (Sharifuzzaman, 1998). The path analysis indicated that rachis length, durability of flower and number of flowers per spike had contributed maximum direct effects on flower yield indicating the importance of three characters as selection indices for native Dendrobium orchid.
50
SELECTION OF SUPERIOR CLONES
> Dendrobium native orchids showed variation for all quantitative and qualitative
characters. However, coefficient of variation (cv) of the spike length, rachis length,
number of flowers and flower durability was higher (cv
> 25%) than other characters and thus considered as higher variability/diversity in
respect of those characters.
> The number of florets per plant as well as rachis length and flower durability were
reported to be desired selection criteria in increasing flower yield by Rahman et
al. (1994) and Amin et al. (2004) in orchids. The genetic parameters, correlation
and path coefficient analysis of the present study revealed that rachis length,
floret number and flower durability were the most important yield contributing
traits in Dendrobium orchids and plant selection based on those traits will be most
effective.
Based on these selection criteria such as germplasms morphological characters
and genetic association, the genotypes D. formosum (D1) and D. densifiorum (D11)
were identified as good genotypes among the twenty natives.
D, D„
Plate 6. Promising genotypes of native Dendrobium orchids
51
EXPERIMENT 2. VASE LIFE OK Dendrobium densiflonini
Days to deterioration started
The flowers for deterioration were significantly influenced by different concentrations of sucrose and pH level (Table 12). Higher days (16.0 days) was recorded for deterioration in low pH with 3% sucrose solution (PiS 2) which was statistically identical with that of low pH with 4% sucrose sohition (P,S3) for 15.4 days. The lowest time (9.0 days) was recorded in high pH (7.0) without sucrose solution (control). Low pH with 3% sucrose solution of the solution showed better performance because in low p11 with 3% sucrose solution pathogen development was reduced and water uptake was increased (Halevy and Mayak, 1976).
Solution uptake
Flower spikes placed in low pH (3.0) and sucrose solution absorbed more vase solution than those placed in high pH (7.0) with sucrose (Table 18). However, uptake was maximum (40g/spike) with 3 percent sucrose and low pH (3.0), followed by 4 percent sucrose with low pH (35.8 g/spike) as it is well known that sucrose with low pH improved water balance by maintainimng turgidity. Similar results were recorded in Gladiolus and Carnation (Halvey, 1987; Gowda and
Gowda, 1990). The spikes held in high pH without sucrose solution had the lowest solution uptake (15.9 g).
Vase life The results revealed that vase life of Dendrobium densiflorum was significantly affected by different combination of pH with sucrose levels (Table 18). The maximum vase life (19.0 days) was observed in low pH with 3 percent sucrose solution (P1S2) which was closely followed by (17.6 days) low pH with 4 percent sucrose solution. The minimum vase life (15 days) was observed in high pH (P2) without sucrose solution (S1). The extension of vase life by low pH (3.0) with 3 percent sucrose, as observed in the present investigation, accords with previous results
52
obtained in gladiolus (Murali, 1988) and roses (Nagarajaiah and Reddy,
1990). These may be due to a synergistic effect, which improved water
balance and osmotic potential, since sugar with low pH has been observed to
reduce moisture stress in spikes by affecting stomatal closure, reducing
pathogen development, preventing water loss through transpiration (Aarts,
1975; Marousky, 1969).
Table 18. Effect of different levels of pH and sucrose on vase life Treatment Days to deterioration Solution uptake Vase life started (g/stick/vase (days) days) 2% Sucrose (S1) 14.0ab 33.0bc 16.0bc
3% Sucrose(S2) 16.0a 40.0a 19.0a
pH:3.
-
0(p1) 4% Sucrose(S3) 15.4ab 35.8b 17.6ab
Without Sucrose I2.2bc 29.0c 15.7bc (S4) 2% Sucrose (S1) 11.0c 25.0cd 16.5b
3% Sucrose(S2) 13.0b 23.8d 17.0b
4% Sucrose(S3) 12.5bc 20.Ode 15.8bc
pH:7.0 (p2) Without Sucrose 9.0d 15.9e 15.0c
(S4)
.
CV% 8.75 10.28 7.54
53
Summary and Conclusion
f
53
Chapter V
SUMMARY An investigation was carried out under the shade house of experimental Farm of Landscape, Ornamental and Floriculture Division in Horticulture Research Centre at Bangladesh Agricultural Research Institute (BARI), Gazipur, Bangladesh during January 2005 to June 2006, to evaluate the physio-morphological and yield performance of 20 native Dendrobium orchids and their long vase life.
A significant variation was observed among the Dendrobium orchid genotypes in respect of observed parameters. The tallest plant was found in germplasm D9 (71 cm) while the shortest plant was recorded in D17 (13 cm). About 75% germplasm attained plant height within 30 to 50 cm. About 25% germplasm attained plant height below 30 cm. Significant variation was observed as to the various traits in pseudobulb also. The highest number of pseudobulb (15.00/plant) was obtained in
D6 Only two germplasms, D1 and D14 had hairs in pseudobulb. As regards colour of pseudobulb, the observed germplasms showed remarkable variation such as green, yellow, black, white and intermediate colours. On the other hand, 50% was elongated cylindrical, 15% oblong, 20% lanceolate, 10% ovate and 5% linear shaped pseudobulb were observed. The leaf characteristics like leave number, length, breadth, thickness, shape, colour etc. showed wide range of differences in plant types. As regards leaf apex, six genotypes possessed emarginate, two genotypes possessed blunt, two genotypes had acuminate and rest of genotypes had acute leaf apex.
It was revealed that the longest spike (29.0 cm) was produced in D11 while the shortest (2.0 cm) spike was produced by D17. The maximum number of spike (4.0) and maximum number of flowers per spike (20.0) was observed in the same genotype D11. It had attractive yellowish orange flower colour with sweet fragrance.
The maximum flower size (8.0 cm2) and durability of flower (31.0 days) were observed in germplasm D1. Its flower was scented and whitish yellow in colour. It was cross compatible
54
to native and exotic cultivars. The germplasm D2, D4, D6, D8 D14, D16, D18 and D19 showed different attractive colour of flowers. They produced medium quality flower considering flowering duration, flower number, flower size, rachis length and spike length. In respect of fragrance of flower, all the native species had fragrance.
In crop improvement only the genetic component of variation is important since this component of h2 serve as a useful guide to the breeder. The characters exhibiting high h 2 with high genetic advance in this study were spike length (94.00% and 98.29), rachis length (95.34% and 93.85), flower durability (93.59% and 88.86) and floret number (70.50% and 65.47). This indicates additive gene action, suggesting the possibility of improvement of these traits through selection (Burton, 1952). Other characters exhibited moderate heritability with low genetic advance.
The number of florets per spike recorded a positive, highly significant association with flower durability, rachis length and spike length. Durability of flower had significant positive correlation with rachis length, flower size and spike length at both genotypic and phenotypic level. Highly significant positive correlation was also found between rachis length and spike length. However, the correlation study revealed that selection of parents should be done based on characters such as floret number, rachis length and flower durability which are useful in a breeding program. Path coefficient analysis revealed that rachis length had the highest positive direct effect on spike length followed by durability of flower and number of flowers per spike which might be due to significant positive correlation of spike length with the corresponding characters.
Various level of sucrose viz. 2% (S1), 3% (S2), 4% (S3), control (S4) along with two different pH level P1 (3.0) and P2 (7.0) played vital role in prolongation of vase life in I), densifiorum. Higher days (16.0 days) were recorded for deterioration of flowers in low pH
(3.0) with 3% sucrose (P1S2). The flowers of high pH (7.0) and no sucrose solution (P2S4) showed minimum solution uptake (15.9 g/stick) as well as minimum vase life (15.0) prolongation. However, the maximum vase life (19.0 days) was observed in low pH (3.0) with 3% sucrose solution in IX densifiorum which lasted about 4 days longer than control.
55
CONCLUSION
The findings of (he study led lo the following conclusions:
> Dendrobium orchids showed variation for all quantitative and qualitative characters. However, coefficient of variation (cv) of the spike length, rachis length, number of flowers and flow er durability was higher (cv > 25%) than other characters and thus considered as higher variability in respect of those characters.
> The genetic parameters, correlation and path coefficient analysis of the present study revealed that rachis length, floret number and flower durability were the most important yield contributing traits in Dendrobium orchids. Based on this selection criterion like genotypic and phenotypic plant character, the genotypes D. formosum (D1 and D. densiflorum (D11) were identified as promising
The spike held in a solution containing 3% sucrose with pi I level 3 was most effective in
prolonging the shelf life in Dendrobium densiforum.
References
56
REFERENCES
Aarts, J. F. T. (1975). Over de howbaarheeid van suijbloemen (on the keeping quality of cut flowers). Mededelingen van de Londbouwhogeachool, Wagenigen, Holland, 57: 1- 62.
Accati, E. G. and Jona, R. (1989). Parameters influencing gerbera cut flower longevity. Acla Hori. 261: 63-68
Akamine. (1976). Postharvest handling of tropical ornamental cut crops in Hawaii. Hort Sci . 11: 25-27.
Amin, M. M. N., M. S. Mollah., S. A. Tania. M. R. Ahmed and F. N. Khan. 2004. Performance study of six indigenous epiphytic monopodial orchids in Bangladesh. J. Biol., Sci., 4 (2): 87-89.
Anonymous. (1995). Agro-climatrological data. Agroinct Division, Bangladesh Meteorological Department, Joydebpur, Gazipur.
Anuradha, S. and Gowdha, J. V. (1994). Correlation studies in Gladiolus. [In: Floriculture - Technology, Trades and Trends. (Eds.)Prakash, J and K. R. Bhandry .] Oxford and 1BH Publishing Co. Pvt. Ltd. Calcutta, pp. 285-287.
Ashwath, G. and V. A. Parthasarathy. (1994). Genetic variability in some quantitative characters of gladiolus . [In: Horticulture -Technology, Trades and Trends. (Eds.) Prakash, J. and K. R. Bhandry .] Oxford and IBM Publishing Co. Pvt. Ltd. Calcutta.pp. 288-290.
Barendes, L. V. J. (1980). Orkidsi. Vakblad Voorde Bloemisterij. 35: 25.
Betchel, H. P. C. and Lanunert, E. (1986). The Manual of cultivated Orchid Species. 3ul ed. Bath Press Co. Avon. London.
Bhagur, H. S. (1889). Studies on variability and genetical component of flowering in exotic varieties of gladiolus. Ph. D. Thesis, Kanpur University, India, pp. 55-80. Bhattacharjee, S. K. (1994). Vase life in Dendrobium orchid. Amer. Orchid Soc. Bull. 53: 390-393.
Bose, T. K , L. P. Yadav., P. Pal., P. Das and Parthasarathy, V. A. (2002).Commercial
Burton, G. W. (1952). Quantitative inheritance in grasses. Proc. 611’ Int. Grassld. Cong. pp. 277-283.
Carow, B. (1981).Vase life in Phalaenopsis.Deutscher Gartenbau. 35 : 320-322.
Carr, G. F. and Christenson, E. A. (2001). A new Cycnoches from Peru. Orchid Rev.70 (8): 748-749.
Chowdhury, M (1975) Orchid cultivation (A leaflet). Baldah Garden, Dhaka, Bangladesh.pp. 12-15.
Christenson, E. A. (1994). Robiquettia. Amer. Orchid Soc. Bull. 63 (2): 142-145.
Christenson, E.A. (1995). Paraphalaenopsis. Amer.Orchid Soc.Bull. 64 (10): I 108-1 I 13.
Comstock, R. E. and Robinson, II. F. (1952). Genetic Parameter, their estimation and significance. Proc. 611' Int. Grassland Cong. 1: 284-291.
Deka, P. C. (1997). Biotechnology and Orchid improvement. [ In: Developmental Biology and Commercialization of Orchids (Ed.) S.P. Vij.J Aff East-West Pvt. Ltd. New Delhi, pp. 18-21.
Dewey, D. K. and Lu, K. H. (1959). A correlatin and path coefficient analysis of components of crested wheat grass and production . Agron. J. 51: 515-518.
Faroque, A. A. (2003). Study on the variabilities, correlation and morphological characteristics of different local orchids. An M. S. Thesis submitted to the Department of Horticulture, BAU, Mymensingh, Bangladesh, pp. 4-90. Flowers.2"d Rev. ed. Nayaprokash, Calcutta, India.
Frankel, O. II. (1989). Principles and strategies of evaluation. [In: The use of Plant Genetic Resources. (Eds.) Brown, AM D., 11.11. Frankel., D R. Marshall and J.T. Williams], Cambridge Univ. Cambridge, pp. 245-260.
Goh, C. J. (1979). Vegetative Propagation in Orchid. New Phytol. 82 : 375-380.
58
Gomez, K. A. and Gomez, A. A. (1994). Statistical procedure for Agricultural Research. John Willey and Sons Ltd. New York. pp. 28-192.
Gowda, J. V. N. (1990). Effect of sucrose and aluminium sulphate on the post harvest life of tuberrose double. Current Res. Univ. Agril. Sci. Bangalore. 19(1). 14-16.
Gowda, J. V. N. and Gopinath, V. N. (1984). Effect of potassium permanganate and brominated activated charcoal on post harvest handling of orchids. Crop Res. Hisar 2 (1): 105-106.
Gowda, J. V. N. and Gowda, V. N. (1990). Effect of calcium, aluminium and sucrose on vase life of Gladiolus. Crop lies. Hisar. 13 (1): 255-270.
Gupta, P. D., Forkan, M. A. and Bhadra. S K (1998) Micropropagation through seeds and shoot segments in Dendrobium crcpidalum .Plant Tissue Cull. 8(1): 1-10.
Gupta,P. D. and Bhadra, S. K. (1998). In vitro production of seedlings in Cymbidium aloifolium . Plant Tissue Cult. 8 (2): 177-182.
Halevy, A. H. (1987). Recent advances in post-harvest physiology of carnation. Act. Hort. 216 : 243-254.
Halevy, A. H. and Mayak, S. S. (1979). Senescence and post-harvest physiology of cut flowers. Part I. Hort. Rev. 1: 204-236.
Han, S. S. (1992). Role of sucrose in bud development and vase life of cut Liatris spicate (L) Wild Hort Sci 27 (I 1): 1198-2000.
Harper, T. (1993). Multiflora Phalaenopsis. Amer. Orchid Soc. Bull. 62 (2): 126-133.
Hedge, S. N. (1981). Propagation of Orchid. Indian Hon. 25 : 7-9.
Hermans, J. and Harmans, C. (1995). Lilliputian adventures. Amer. Orchid Soc. Bull. 64 (10): 1088-1097.
Iqbal, N. (2006). President, Orchid Society of Bangladesh. A Personal Communication.
Ismail, A., and Nair, H. (1991). Pre and post-harvest studies on flowers of Dendrobium pompadour. Malayan Orchid Soc.Bull. 5: 43-47. Johnson, H W., Rabinson, H. F. and Comstock, R. E. (1995). Estimation of genetic and environmental variability in soyabeans. Agron. J. 47: 314-318.
Lai, S. D., Shah A. and Seth, J. N. (1985). Genetic variability in gladiolus. Prog. Hori. 17 (1): 31-34.
Mahanta, P., Choudhury, S., Paswan, L., Talukdar, M. C., and Sarma, D. (1998). Correlation and path coefficient analysis in gerbera (Gerbera jamesonii). Hori,./., 11 (2): 79-85.
Marousky, F. J. (1969). Vascular blockage, water absorption, stomatal opening and respiration of cut “Better Times” roses treated with 8-HQC and sucrose. J. Amer. Soc. Hori. Sci. 94: 223-226.
Mollah, S. (2001). Orchid (A leaflet). Floriculture Division, HRC, BARI. pp. 1-30.
Mukherjee, S. K. (1983). Orchid. ICAR, New Delhi, p. 12.
Murali, T. P (1998) Preharvest and post-harvest physiology of gladiolus. Ph. D. thesis. Univ.Agric. Sci., Banglore, India.
Nagarajaiah, C. and Reddy, T V. (1990). Effect of calcium and zinc on the vase life of open field grown cut roses cv. Queen Elizabeth. Mysore.I. Agric. Sci. 24: 233-237.
Nair, FI. (1990). Postharvest of orchids. Proc. 711' Asian Orchid Conf. Ministry of Agric. Central Res. Inst. Hortic and Directorate of Hortic. Proc. Jakarta, Indonesia, pp. 73- 89.
Nair, H., Idris, Z M. and Arditi, J. (1991). Effects of 1-aminocyclopropane-l carboxylic acid on ethylene evolution and senescence of Dendrobium flowers. Lindieyana. 6: 49-58.
Nanjan, K. (1994). Correlation studies in Gerbera. [In: Floriculture-Technology, Trades and Trends. (Eds.)Prakash, J. and K. R. Bhandry .] Oxford and IBM Publishing Co. Pvt. Ltd. Calcutta, pp. 71-75.
60
Nash, N. (1997). Use of Cocohusk in Orchids. Orchids. 66: 1268 - 1277. Naskar, S. K. (1990). Evaluation techniques and variety release in sweet potato. Second Int. training course on sweet potato production. 17-23. Sept. CTCRI, Trivandrum. India, pp. 50-57.
Ncgi, S. S., Sharma T.V.R.S., Raghava, S.P.S. and Srinivasan, V. R, (1982). Variability studies in gladiolus. Indian J. Hart. 39: 269 -272.
Northen, R. T. (1970). Home Orchid Growing. 3,d Edn. Van Nostrand Reinhold Co. New york.
Nowak, J. and Vacharotayan, S. (1980). Vadosu Liowfh Orkidsi. Prace Instytute Sadowinctwa Kwiarciarstwa, Skiemicwicach, 5: 83-93.
Ong, H. T. (1982). Effect of different concentration of aluminium chloride, ammonium molybdate and boric acid on vase life of Oncidium. Orchid Rev. 90: 264-266.
Patil, P. V. (2001). Exotic orchid. Adv. Hort. Forestry. 8: 201-203.
Prakash, D. (1994). Standardization of different containers, potting media and nutrient solution for dendrobium hybrids. Souvenir and Abstracts. National seminar on a decade of orchid research and development. T he Orchid Soc India . pp. 90- 91.
Prasad, G. V. S. S., Rao, I. V. S. and Reddy, P. V. (2001). In vitro propagation of orchid - Dendrobium 'Sonia'. Indian.I. Plant Physio!. 6 (3):284-288.
Quyu, B. S. H. (1959). Asian orchids .Trop. Agriculturist. I 15: 257-281.
Rahman, M., S. C Jana. M. R. Biswas and T. K. Chattopadhya. 1994 Genetic analysis of some characters of different orchid genera grown in the plains of homestead. Souverior and Abstracts. National seminar on a decade of orchid research and development. The orchid society of India. P. 58.
Roll, M. S., Lee, N., Lee, C. Z. and Lawson. R. IT (1993). Growth and flowering of Cymbidium ensifolim var. misericors as influenced by temperature. Acta Hort. 337: 123-130.
Sharifuzzaman, S. M. (1998). Physio morphological characteristics and yield potentials of bush bean genotypes. An M.S. Thesis submitted to the Department of Horticulture. IPSA, Salna, Gazipur, Bangladesh, pp.45-65. Sheehan, T. J. and Sheehan, M. (1979). Orchid Genera Van Nostrand Reinhold Co. New York. Singh, B. and Singh, M. (1990). Studies on variability and genetic advance parameters in gladiolus. Prog. Horl. 19 (3-4): 271-275.
Singh, R. K. and Choudhury, B. D. (1985). Biometrical Methods in Quantitative Genetic Analysis. Kalyani Publishers. New Delhi, pp. 102-138.
Sobhana, A. and Rajeeven, P. K. (1993). Foliar application of inorganic nutrient formulations in Cymbidium traceyanum. Souvenir and Abstracts . National seminar on a decade of orchid research and development. The Orchid Society of India . p. 87.
Sobhana, A. and Rajeeven, P. K. (1993). Performance of certain epiphytic species in central Kerala../. Orchid Soc. India. 7 (1-2): 31-35.
Steel, R. C. D. and Torrie, J. H. (I960). Principles and Procedures of Statistics. MC Graw Mill Book Co. Inc., New York. pp. 107-109.
Sultan, S. M. and Farooq, S. (1999). Effect of sucrose and GA.i on the senescence of cut flowers of Narcissus tazetta cv. Kashmir Local. Hort. Sci . 13 (3): 105-107.
Sultana, K. S. (2003). Study on variabilities and morphological characteristics of some hybrid orchids. An M. S. Thesis submitted to the Department of Horticulture, BAU, Mymensingh, Bangladesh pp. 10-80.
Tejaswini, N. M. and Bhat, R. N. (1994). Potential and possibilities in tuberose breeding. [ In: Florculture-Technology, Trades and Trends. (Eds.)Prakash, J. and K. R. Bhandry ] Oxford and IBH Publishing Co. Pvt. Ltd. Calcutta, pp. 313-317.
Thangaraj, T., Rajamani, K. and Thamburaj, S. (1990). A study on the vase life of gerbera (Gerbera jamesonii Bolus). South Indian Hort 38 (5): 265-267.
62
Webb, A and Webb, M.. (1994). Orchids of Australia. Amer Orchid Soc. Bull. 63 (7): 780- 787.
Witlmer, C. L. (1994). An Odyssey. Amer.Orchid Soc. Bull. 63 (4): 406-41 1.
Yamne K., Kuchii, E. N. F. and Minegishi, N. (1997). Effect of sucrose and HQS on vase life of orchid cutflower . J. Japanese Soc. Hort. Sci. 65: 801-807. Yukawa, T. and Nishida, M. (1992). Dendrobium shiraishil - a new variety of Dendrobium orchid from Irian Jaya. Lindleyana. 7 (3): 127-129.
Zhang, W., Zhang, I I., Gu, Z. and Zhang, J. (1991). Cause of senescence in nine soils of flowers. Ada Bol. Sin 33: 429-36.
Appendices
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APPENDIXE
Appendix I. Weather data during the period of experimental site (January 2005 to June 2006)
Year Month **Air temperature (0 C) Humidity (%) Rainfall(mm) Max. Min. 2005 January 24.40 12.33 86.25 0
2005 February 29.10 16.28 81.45 1
2005 March 31.92 20.70 78.53 144
2005 April 33.90 23.23 81.55 68
2005 May 32.91 23.56 84.56 137
2005 June 33.61 26.76 78.35 90
2005 July 31.81 26.15 76.55 417
2005 August 31.51 25.80 81.22 431
2005 September 31.33 25.1 1 78.00 444
2005 October 29.13 22.16 75.00 58
2005 November 28.10 17.92 85.00 44
2005 December 27.14 13.95 81.00 96
2006 January 25.27 12.00 83.45 0
2006 February 30.80 17.75 77.55 0
2006 March 32.69 19.49 8 1.25 0
2006 April 33.74 22.71 82.50 80
2006 May 34.80 25.49 81.45 406
2006 June 35.69 26.35 78.25 165
Source : Weather station. Gazipur
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Appendix II. Analysis of variance of (he data on different characters of 20 native Dendrobium orchid genotypes
Source of Degree Mean square variation of Plant Leaf Leaf Leaf Pseudobulb Diameter freedom height number length breadth number of (cm) (cm) (cm) pseudobulb (cm) Replication 2 11.25 63.50 4.85 1.43 0.45 0.16 Genotypes 16 315.81** 47.50** 22.40** 1.56** 12.26** 1.40** Error 38 5.50 6.54 3.92 0.47 2.20 0.15 ** Significant at 1% level of probability
Appendix II. Contd. Source of Degree Mean square variation of Spike length (cm) Rachis length Flower number Flower size (cm2) freedom (cm) Replication 2 11.80 0.48 14.60 0.45 Genotypes 16 301.44** 32.53** 37.85** 3.50** Error 38 9.73 3.59 5.54 0.38
** Significant at 1% level of probability
Appendix II. Contd. Source of Degree Mean square variation of Pod size (cm) Root number Root length Root diameter freedom (cm) (cm) Replication 2 0.01 10.34 4.54 0.01 Genotypes 16 0.85** 15.50** 201.45** 0.04** Error 38 0.10 7.33 15.35 0.02 ** Significant al 1% level ot probability
j
65