Wheat

Introduction | Climatic Requirement | Soil Requirement | Varieties | Cropping System
Field Preparation and Sowing | Nutrient Management | Water and Irrigation | Weed Management
Disease Management | Harvesting | Post HarvestingMiscellaneous
 
Botanical Name : Triticum aestivum
Local Name : Gahow
Hindi Name : Gehun
Family : Poaceae

Introduction
In the realm of food crops in the world, wheat (Triticum spp.) occupies the number one position. India is one of the principal wheat producing and consuming countries in the world. Its importance in Indian agriculture is second to only rice. Wheat flour based products, such as the chapatti, are part of the staple diet in most parts of India - particularly in northern India. Wheat straw is also used for feeding cattle. The Green Revolution, which was initiated in the country in the late 1960s, has had a very significant effect in increasing the yield of wheat. The output ratio of wheat to rice has steadily increased 1:3 to 4:5. Since 1991, the Ministry of Agriculture has been giving massive thrust to boost its output in the country. At present Uttar Pradesh, Punjab and Haryana are the three major wheat producing states. They account for nearly 70 per cent of the total wheat produced in the country. Though Uttar Pradesh has the highest production In India, it lags behind Punjab and Haryana in terms of productivity. Better irrigation facilities in these states are responsible for higher yield. In Haryana, 98 per cent of the area under wheat is irrigated and in Punjab the ratio is 96 per cent. However, in Uttar Pradesh, only 88 per cent of the area under wheat is irrigated. Wheat cultivation in non-traditional states including Sikkim is also being popularized by improving irrigation facilities and developing seeds suitable for cultivation in these regions.

Crop season: In Sikkim, wheat is grown during Rabi (winter) season as an irrigated/rainfed crop. The season starts with October-November and ends with March-April.

Origin and History: Wheat is being grown since pre-historic times. Wheat cultivation in ancient china traced back to 2700 B.C. and before this it was known to Egyptians and inhabitants of Switzerland. According to De Candolle wheat originated in the valley of Euphrates and Tigris and spread from there to china, Egypt and other part of the world. Some investigators believe that wheat probably originated in South West Asia specially Syria and Palestine. According to N. I. Vavilov, the origin of durum wheat was probably in the region of Abyssinia, whereas the whole group of soft wheat including bread wheat probably originated in the region of Pakistan, South-Western Afghanistan and the southern parts of mountainous Bokhara. Wheat is grown very extensively throughout the world. Russia, china, USA and India are important wheat growing countries of the world. In regards to yield per hectare U.K. ranks first followed by Germany.

The Aryans brought wheat grains to India and possibly this crop spread from its place of origin to European countries. Wheat was introduced and cultivated in United States since 17th century.

Evolution
According to an Article from “Truth About Trade and Technology”, ancient genetic tricks shape up wheat. A wild wheat (Triticum monococcum) crossed with a species of goat grass (Angilops speltoides) to produce a new form that had four set of chromosomes. Had there been just two chromosomes, the new wheat would have been like a mule sterile. However the extra chromosomes allowed the new Emmer wheat to reproduce. Emmer wheat crossed with another goat grass (Angilops tauschii) and produces new wheat, the one we know with six chromosomes.

Classification of Indian Wheat

Emmer wheat (Triticum dicoccum Schub L.)
This type was reported to be grown on a very restricted scale in south i.e. Gujarat, Maharashtra, A.P., Tamil Nadu and Karnataka, where it is known under the names Popathiya, Khapli, Ravva, Godhumalu and Samba respectively. It is preferred for granular preparation for e.g. Uppumav. This type is believed to be developed from Triticum diccoides, a wild form. It is also grown in Spain, Italy, Germany and Russia.

Macaroni wheat (Triticum durum Desf.) It is the second most important species of wheat, occupying about 14% of total wheat area. Cultivation of this type of wheat in India is considered to be very old and is confined to Central and Southern India only. It was under cultivation at one time in Punjab and W.B., but now it has been completely replaced by the Bread wheat. It is best wheat for drought conditions or under restricted irrigated conditions of Punjab, M.P., Karnataka, Tamil Nadu, Gujarat, West Bengal and H.P., it is used for semolina (Suji) preparation. The important variety of this group are Raj-911, Malavraj, Malavika, HD-4530, Jairaj, Meghdoot (HI-7483) , NP-404, Bansi etc. It is also grown in Italy, USA, Canada and Russia. It is believed that this wheat is descended from Emmer wheat. It contains 28 chromosomes.

Common Bread Wheat (Triticum vulgare Host.) It is a typical wheat of Alluvial soils of Indo-Gangetic Plains i.e. Punjab, UP, Bihar and parts of Rajasthan. The bulk of the India crop, therefore, consists of this type. The prominent varieties are K-65, K-68, C-13, PB-591, C-306 etc. It contains 42 chromosomes.

Indian Dwarf wheat (Triticum spherococcum Mihi.) This belongs to the club wheat of western countries. This is found in limited areas of M.P, U.P. of India and in Pakistan. These are characterized by very short and compact heads leaving shorter grains. They contain 42 chromosomes. These species has now practically gone out of commercial cultivation because of its low productivity and susceptibility to diseases.

Mexican Wheat (Triticum aestivum) This is the type presently grown in India in almost all the wheat growing zones from the sea level up to elevation of 3658 meters in the Himalayas. This wheat is introduced in India by Dr N.E. Borlaug of Mexico and the wheat is frequently said to be the Mexican dwarf Wheat. It is one of the most important species among the cultivated species of India which is occupying about 85% of total wheat area.

It is the bread wheat with 42 chromosomes (i.e. carriers of hereditary determinants) that has their parents- Triticum monococcum, Angilops speltoides and Angilops squarrosa, each having 14 chromosomes. Individually these parents have very poor agricultural plants but in combination they give us the king of cereals.

Crop Improvement
Work The indigenous wheat varieties being very tall, lodging and disease susceptible and low responsive to input levels had very low yield potentials therefore, it was felt necessary to evolve dwarf varieties with higher yield potentials.

A systematic and organized research on the improvement of wheat in India by breeding was started by late Sir Albert Howard and Mrs. Howard at the Imperial Agriculture Research Institute, Pusa, Bihar in 1904. Research on Breeding and Improvement Work initiated at Lyallpur in Punjab in 1907 which was shifted to Ludhiana, Punjab in 1947 after partition. Breeding of rust resistance variety of wheat was initiated at Shimla in 1934.

The crop improvement work before 1960 were all restricted to all varieties of wheat with the objective to get high yield, disease resistance, lodging resistance and grain quality. The varieties released for cultivation did not yield beyond 3000 kg per hectare. During 1960 wheat improvement work had unique break- through with the introduction of dwarf Mexican wheat from where real wheat revolution was started. The breeder are not to be satisfied with the evolution of this variety because it do not express their full yield potentials in a farmers field and thus the projected target production is not achieved. This may be correlated with several factors viz. selection of non suitable variety, inadequate inputs, untimely sowing etc. thus the main emphasis in breeding was given to produce such morphological architecture of a plant that is capable of converting electromagnetic light energy received from sun into useful yield of chemical energy for maximum production through photosynthetic mechanisms. Apart from these the introduction of draught , frost, disease and lodging resistance along with high responsiveness to applied input, thermo and photo insensitivity etc are some of the required characteristics of the newly evolved variety. IARI and Genetic Department of various research Institution and Agricultural Universities in the country are playing a leading role in the production of such varieties. In 1963 a number of dwarf wheat varieties as well as breeding materials were obtained from Dr N.E. Borlaug and experimented in several places in India. On the basis of this experimentation two varieties Lerma Rojo 64-A and Sonara 64 were released in 1965 for cultivation in irrigated areas. Through selection and breeding from the breeding materials a number of high yielding varieties like Chhoti Lerma, Safed Lerma, PV-18 etc. were released. Amber coloured hard grain high yielding dwarf varieties like Kalyansona and Sonalika were developed in India which later revolutionized wheat production in the country during early sixties. As a result of these varieties India attained self sufficiency in food grain.


In Sikkim wheat adoption experimental work started in Rabi season in 1975. A number of high yielding varieties were collected and experimented at various regional farms for proper evaluation. The variety Sonalika was introduced in large scale for cultivation to the farmers besides experimentation in Govt farms. Sonalika did well both under rainfed and irrigated conditions and gained popularity among the cultivators.


The other varieties introduced for adoption are HP-1461, Hp-1462, HP-1463 HP-1464, HP1458, HP-1459, BW-30, BW-31, BW-32, BW-33, BW-34, BW-54, BW-36, BW-37, BW-38, K-7807, K-7907, K-7928, K-7925, K-7903, K-7926, BR-223, BR-266, BR-267, BR-271, BR-277, C-306, BH-4249, U-7927, DL-129-1, DL-79-16, CPAN-1796, CPAN-1817, Kalyan Sona.

Out of these varieties Sonalika proved highest yielder both as rainfed and irrigated crop with an average yield of about 3600 to 4000 kg per hectare in Sikkim.

Area and Distribution Wheat is another cereal crop of Sikkim growing in almost all villages of Sikkim having cool winter and hot summer climate, irrespective of elevation and irrigation facilities. It is cultivated over an area of 6.38 thousand hectare. The production of wheat is recorded 9.20 thousand tones in 2005-06 and 10.36 thousand tones in 2006-07. The distribution of district-wise area and production of wheat cultivation in Sikkim is given in table below:

Table 1 District wise Area of Wheat Cultivation in Sikkim
 
 
 Sl. No.  District  Area in 000’ hectares  Production in 000’ tones  Average Yield / hectares in kg
 1.  North 0.85   0.90   1058.82  
 2.  East 1.43   2.81   1965.03  
 3.  South 2.00   3.15   1575.00  
 4.  West 2.10   3.50   1666.67  
 Total  State 6.38   10.36   1623.52  

Source: Annual progress report 2006-07, Food Security and Agriculture Development Department, Govt of Sikkim.

Use and importance

Wheat is one of the principle food crops of the world. Its importance in Indian agriculture is second to the rice. Wheat is usually ground into flour before use as food. Wheat flour based products, such as the chapatti, are part of the staple diet in most parts of India - particularly in northern India. Wheat straw is also used for feeding cattle. It is mainly used as bread in a variety of ways in different parts of the world. It is considered to be a most nutritious food crop. The germ or embryo of the wheat is relatively rich in protein, fat and several of B vitamin.


Nutritive Value

Composition of wheat flour


SL. No. Nutrient Element Whole wheat flour Refined wheat flour
1. Moisture (%) 12.2 13.3
2. Protein (%) 12.1 11.0
3. Fat (%) 01.7 0.9
4. Minerals (%) 02.7 0.6
5. Fiber (%) 01.9 0.3
6. Carbohydrate (%) 69.4 73.9
7. Calcium (mg/100g) 48 mg 23mg
8. Phosphorus(mg/100g) 355mg 12.1mg
9. Iron (mg/100g) 11.5mg 2.5mg
10. Calorific value 341 348
11. Vitamin B complex Small amount Small amount

Source: Foods that heal – The natural way to good health by H. K. Bakhru, 1996.

Botanical description
Wheat plant is annual cereal belonging to the family Graminae. It consists of the following parts:

Roots:
Wheat plant consists of two sets of roots viz. the seminal or seedling roots, that belong to embryo, are produced by the germinating seedling ( these are five in number) the second set of roots are called as clonal roots that arise from the basal nodes of the plant and form the compact vegetative mass “ crown”. The entire roots are adventitious. The second set forms the permanent root system while the seminal roots dry after about 30 days of seedling emergence.

Stem
Wheat culms or stems are erect, elastic, cylindrical, jointed and smooth. The bold joints, termed as nodes, separate the plant into section called as internodes and these nodes and internodes are differentiated when the plant starts elongating. There are five to seven nodes and the lateral branch develops from the axil of the lower leaves. The lower internodes are shorter while the upper ones are progressively longer and they are six in number at the maturity of the plant. The main culm produces branches at the base, close to the ground; called as tillers (primary) and the tillers produce additional tillers known as secondary and tertiary tillers having their own root system.


Leaves
Wheat leaves consists of two parts, the leaf sheath which encircle the stem and the blade that bends away from the stem. The juncture thickened place is called as collar and the membranous outgrowth is called ligule. The claw like appendages attached to the base of the leaf and closely clasping the sheath constitutes the auricles. The foliage arrangement on the culm is opposite.


Inflorescence
It is called as ear or a spike- a compound distichous spike, the axis bear two opposite row of lateral spikelets and a single terminal spikelet but in case of Triticum monococcum there is no terminal spikelet. The spikelet are sessile having two glumes at their base and are arranged alternately. Each spikelet is attached to a rachis node and is known as floret. The floret is composed of three stamens and a pistil which consists of ovary. The flower is closed by lemma (outer bract) and palea (inner bract). The lemma tip is extended to form awns.


Grains
The wheat seed is a caryopsis with a thin walled pericarp enclosing a single seed coat and testa is fused with pericarp. The shape is oval having a smooth and rounded dorsal surface and grooved or furrowed ventral surface at the centre. The furrow or groove is called as crease. The colour is either red white or amber. The grain consists of grain coat, nucellar epidermis, endosperm and embryo. The endosperm constitutes about 82-86% of the grain and consists of starch and gluten.

Growth Stages of Wheat Plant
 The wheat plant passes through the following four stages to complete its life cycle within a season:


Pre-establishment stage:
Pre-emergence: Sprouting of seeds by giving rise to seminal roots and coleoptiles. Emergence : Appearance of coleoptiles from germinating seeds above the soil surface.


Vegetative Stage:

Seedling:
The young plants establish larger root system in this stage. The stage may be further differentiated as one leaf, two leaves, three leaves, four leaves stages.


Crown root stage: This coincides with three or four leaf stage in plant.

Tillering stage: Plant develop crown and branch out into tillers from their base at soil surface.

Jointing stage: This is the stage at which the plant starts elongating when the nodes start developing above the crown node.

Reproductive Stage:

Booting: In this stage the upper most leaf swells out into flag holding the spike into it.

Heading: The spikes emerge out from the leaf sheath at this stage.

Flowering:
Anthesis of florets and fertilization of ovaries takes place at this stage.

Post Anthesis Stage:

Filling: The ovaries after fertilization, start elongating into seeds or ovules passing through milk, soft dough and hard dough stage.

Maturity: Colour of glumes change and kernel become fairly hard at this stage.


Introduction | Climatic Requirement | Soil Requirement | Varieties | Cropping System
Field Preparation and Sowing | Nutrient Management | Water and Irrigation | Weed Management
Disease Management | Harvesting | Post HarvestingMiscellaneous