-- UNIT 11 CEREALS AND MILLETS 11.1 Introduction Objectives 112 Wheat 11.3 Maize 11.4 Rice 1 1.5 ' 'Rye 11.6 Oats 11.7 Sorghum 1 1.8 Barley 11.9 Triticale 11.10 Summary 11.1 1 Terminal Questions 11.12 Answers 11 .I INTRODUCTION Good food is essential for health as well as survival of human beings. Human beings depend on plants (and on animals that eat pla~~ts)for their food. The food we eat provides sub- stances needed for good health.'These nutrients provide materials for building, repairing or maintaining body tissues. They also regulate body processes and serve as fuel to provide energy. Nutrients are classified into five main groups: carbohydrates, fats, proteins, minerals and vitamins. All of these are important in the daily diet; and are obtained from different plants. , The cereal or grain crops are the most important sources of food for man and provide the basic or staple diet. They contain carbohydrates, proteins, fats, minerals and vitamins, and thus have good nutritive value. These were amongst the first plants to be cultivated or domesticated. They have been grown and used by man since ancient times. It is believed that barley and wheat were first grown in Western Asia atleast 9000 years ago. This provided the basis for civilisations of Mesopotamia, Sumeria, Babylon, Egypt, Rome, Italy and others. Similarly, rice served as the important cereal for the civilisations in Soah East Asia and rnaizd ~~~~~'$r~~~i~~~ t'lerc for civilisations in the New World. urelatcd dicotyledonous plants The ceredls not only serve as food for man, but are also important for many industrial used as cereals. The buckwhcat (Fagopyrum u~culenttrrt~).grain purposes. Cereals as well as other grasses are also used as fodder for livestock. Only a few of (Amcrran,hus spp.) the more than 10,000 species of the grass' family have been domesticated by man. and others used to a Iesstr extent arc son~etirnescelled Interestingly no new species have been introduced into cultivation during the past 2000 '~~seudoccnals.' years or more. e' Objectives After studying this unit, you will be able to know the: I o importance of food for health and survival; e most important sources of plant food; 1 e .close relationship between cereals and man; different cereal and millet crops; e origin and distribution; cultivation; botany; breeding and improvement; uses and other details pertaining to : Wheat Barley Maize Triticale. Rice Rye Oats. Sorghum Bntar~icalname: Triticum me.sitivunm Einn. Family: Poaceae Comn~ovnrlslllae : @eRun %n= 42, A B& D genonre Wheal is the world's most important food plant for more than one third of the world's population. Hundreds of millions of people throughout the world depend on foods made from the kernels (seeds or grains) of the wheat plant. It is also probably the oldest crop known it1 cultivation. Long before the beginning of agriculture, people gathered wild wheat Iba food. It is believed that agriculture originated in the Middle East when wheat was first cultivated in ancient times. There are several archeological evidences to show the presence of carbonised wheat grains at the Neolithic sites in Jarmo in northern Iraq, and in central and north eastern Europe dating back to the period 6750 B.C. to 7500 B.C. These and other observatioris suggest that wheat spread rapidly and widely throughout Asia and Europe after its domestication in the middle East. Box 11.1: Cereal --- - .- It is interesting to know that the term cereal is derived from the Greek word 'Ceres', which was the Goddess of grain, of harvest, and of agriculture in Roman mythology. She was worshipped by the fatmers and the people of Rome for her gifts. A festival called 'cerealia' honoured the Goddess each year from April 12 to April 19. In Japan, Wheat Production in Indin (in ~~iilllontoames) the ancient Shinto religion has many special ceremonies dealing with abundant harvest and good health. Here rice is the most important cereal. The festival called 'Baisakhi' (13th April) in northern India is also associated with agriculture and the first grain harvested is offered to the Gods. These and several other evidences show that there has been a very close relationship between the cereals and man since ancient times.-- 96197 69.3 There are various kinds of wheat and the most widely cultivated wheat today is called the 97.911 66.0 con~monwheat or the bread wheat. We owe much to the Russian ~otaniit~ikolai Vavilov --"- --- (1 8&7-1943) for our knowledge ofwheat. I-Ie studied more than 3 1,000 samples of wheat from different parts of the world to classify the wheats into different kinds. This knowledge was later supplemented with information from cytology, physiology and biochemistry obtained by Japanese and American scientists to provide us valuable data about the wheats of the world. It is therefore necessary to know about the taxonomy of the different wheats. This information will help us to understand the origin and distribution of different wheats. P 1.2.11 Taxci~nomy,Origin and Distribliltisal ofWllnuat Vavilov classified the different wheats into 14 species. Other wheat taxonomists recognise either more or fewer species. All the wheats are classified in the genus Triticum. This is a member of the Family Gramineae, sub family Pooideae and the tribe Triticeae. The different species of'wheat can be grouped into three categories on the basis of their cytology. Box 11.2: Cytology of wheat 7 I T11el.e are (diploid wheats having 2n = 14 chromosomes, tetraploid wheats with 2n = 28 chl~omosomes;and hexaploid wheats with 2n = 42 chromosomes. ~etafiedcytological analysis crfthese wheats also reveabd that there are 3 different genomes. The diploid wheats hivve been recognised as having the *AAQenome. The tetraploids and hexaploitls are not autoploids (i.e. possessing similar genomes to the diploid). They are alloploids with dissimihgenomes. The tetraploid wheats have the "AIBB* genome while the hexaploid wheats have the *AABBDDYgenome. This cytological knowled1;e alongwith other evidences has helped us to know about the origin and evolutioai of wheat as well as about other grasses which contributed to this evolution. The oldest krlown wheat isthe diploid wheat. There are wild and dbmesticated (cultivated) species oftl~c!sediploid wheats. The wild einkorn wheat is called Triticunl boeticum Boiss. Cercrls nnd hlillets This is a diploid wheat (2n = 14 ; AA genome) which was widespread in Western Asia. It exhibits considerable genetic variation. The cultivated einlcorn wheat called Trilicurn monococcum L, evolved from the wild type, is also diploid and has the same AA genome. It has been in cultivation since ancient times. These wheats have one grained spikelets, the fruiting stalks are brittle and fragile, and the grains remain firmly enclosed in the glunues. Very I little of this kind of wheat is cultivated today. There are several tetraploid wheats. These have originated by Hybridization betweein the diploid wheat and closely related wild grasses.They have 2 distinct genomes, the AA conlponent is obtained from the diploid wheats while the UB component was contrit~utedby the diploid grass called Aegilops spcltoides (2n = 14; BB genome). Hybridization followed by chromosome doubling resulted in the origin of the tetraploid wheats. The oldest known tetraploid wheat is called the wild emmer or Triticuru dicoccoides Koern. It is found in Palestine and Syria. From this wild emmer, the cultivated emmer or Triticum dicoccutn Szhubl must have evolved by mutation, domestication and selection. Another tetraploid uvheat called durum or Triticum dururrt Desf. also evolved from wild emmec. These tetraploid wheats were oncewidely cultivated in the Middle East. Cultivated emmer is now grown to a limited extent only, but durum is grown extensively in Italy, Spain and USA. i The most common cultivated wlleats are hexaploid, Triticum spelta Linn. and T. aestivzrnr Linn. are amongst the more important hexaploid wheats. A very large number of varieties of Triticum aestivum or breadwheat are cultivated in different parts of the world. The evolutiorl of hexaploid wheat may be summarised as follows. I T. boeoticum Ae, speltoides Ae. syuarrosu 2n = 14; D genome T, drtrum T. aestivum 2n = 28; AB genome 2n = 42; ABD genome wild cultivated 11.2.2 Wheat Cultivation Wheat is cultivated in a wide range of climates apd soilt It i: also the most widely cuhivated crop of the world. It is grown in areas from 40"s to GOON c.'~le equator having fairly dry and mild climates. Extreme heat or cold, or vely wet or very dry weather is IlarmfuI for the cro,p. 3 Thus, the weather conditions greatly influence the cultivation of wheat. Q Wheat is largely cultivated in warm temperate regions having cool winters and warn1 dry ' summers. The annual average rainfall of such wheat growing regions should be between 20 and 90 cm. The crop can be cultivated from the plains to altitydes up to 3000m above sea level. Wheat grows best on fertile clay or silt loams having adequate organic nutrients. The soil must have proper drainage as well as good water holding capacity. Wheat is grown as a major cereal crop in Russia and its adjacent regions, other European countries particularly France, Germany and Italy and in the United States, Canada, Central and South America, China, India and Australia. It is also grown in Pakistan, Turkey and Egypt. In India, there are two main wheat growing areas: (i) The Indo-Gangetic region with 7 Eeomoaic Botany Punjab; Haryana, U.P., Bihar and parts of Rajasthan; and (ii) Madhya Pradesh, South Rajasthan, Maharashtra, Andhra Pradesh and Kamataka. The crop grown in India is mainly the winter wheat and both the bread wheat as well as durum wheat are cultivated.