Government Post Graduate College For Girls-11,Chandigarh Morphology,Cultivation ,Area of cultivation&High yielding Varieties(HYV) of Cotton(Gossypium hirsutum) Dr VISHAL SHARMA Assoc. Prof. Botany Department Government Post Graduate College For Girls-11,Chandigarh

Botanical name:Gossypium spp FAMILY:Malvaceae PART USRD:Seed hairs(Lint) Cotton is the important fibre in the world.It is obtained fron seed hairs of Gossypium spp ( G. herbaceum;chief cotton of Asia ,G.hirsutum;G.arboreum). Cotton plant is an annual or perennial shrub reaches upto height of2-6 feet.The highly branched monopodial stem bears spirally arranged palmate compound leaves and single flowers in axillary position.The fruit is capsule known as ‘boll’ having3-5 locules known as locks which bear seeds in them. The ovoid more or less pointed,curved seeds bear two types of outgrowths or hairs- the long thick and white hairs called lint and white very short hairs called Fuzz.The lint staple is the cotton fibre of commercial importance.

Cotton, the most important fibre crop of India plays a dominant role in its agrarian and industrial economy. It is the backbone of our textile industry, accounting for 70% of total fibre consumption in textile sector, and 38% of the country's export, fetching over Rs. 42,000 crores. Area under cotton cultivation in India (8.9 million ha) is the highest in the world, i.e., 25% of the world area and employs seven million people for their living.

Area of Cultivation: About 85% of the World’s total production of Cotton comes from Russia, U.S.A., China, India, Pakistan, Brazil, Mexico,Egypt and Sudan. In India, The cotton growing states are Maharashtra, Gujarat ,Karnataka, M.P., Punjab, A.P. ,Tamil Nadu,Rajasthan and Haryana Climate &Soil: Cotton is a tropical ,Kharif and rainfed crop sown in the month of June or July whereas irrigated crop is sown 1-2 months earlier (April-May).It requires a high temperature(not below 21oc) Soil: Crop can be grown on variety of soils,but it prefers a soil with good moisture holding capacity,deep soils with good humus. In,India,cotton is cultivated in the black cotton soils of the Peninsular India,red soils of the Southern India and Alluvial soils of the Indo-Gangetic plain

Climate: Cotton is primarily grown in dry tropical and subtropical climates at temperatures between 11°C and 25°C. It is a warm climate crop threatened by heath or freezing temperatures (below 5°C or above 25°C), although its resistance varies from species to species. Excessive exposure to dryness or moisture at certain stages of the plant devel-opment (lasting 5 to 7 months)maybe detrimental to cottonquality and yields,and might also kill the plant. The seeds should be planted in well-prepared moist soil with high nutrient supplying capacity. Indeed, the cotton plant is particularly weak and its moisture and nutrient uptake is remarkable. Moreover, the root system of the cotton plant is particularly developed and penetrates downward deeply (its depth can sometimes double the height of the surface stem). Accordingly, cotton should be planted in rich seedbeds that are muddy or argillaceous-sandy, where the taproot would grow downward deeply and develop under favourable conditions. Seedling emergence can occur between one week and a month after planting. During this phase (germination, emergence and seedling growth), the plant needs warm temperature and much moisture (7,000 to 9,000 m3 by hectare), which can be supplied by nature or by means of irrigation. Cotton leaves are about 12-15 cm in length and width. They develop along the main stem in a spiral arrangement. Each new leaf commonly develops 5 to 8 cm above the preceding leaf.

Cultivation: Different cultural methods are adopted in sifferent soils and climatic conditions. Deep ploughing is generally not done.Sowing is done at 4-5cm depth at 15-20kg/ha.The land is usually harrowed 2-3 times to facilitate conservation of moisture. Two common methods of sowing in India are: (1)Broadcasting method: In this method seeds mixed with mud or cowdund are sown broadcast or in rows by drills. (2)Sowing method: In this method sowing is done at suitably spaced rows The distance between the lines depends upon variety grown and the fertility of the soils and usually varies between 30 cm and 90 cm.While the American cottons are grown pure with spacing of 60-75cm,the local cottons are grown as mixed crop. After germination,the plants are thinned to 30-60cm apart in the row.During thinning operation roguing or removal of off type plants is carried on.

Rotation: In Northern India(Punjab,U.P.,&Bihar) it usually alternates with Wheat and Jowar.In the Black Cotton soil tracts of Peninsular India Jowar precedes Cotton Interculture: In black cotton soils,when plant was about 10cm high a process called interculture is practicised,which faciltates good aeration and better development of roots. Fertilizers: The application of Nitrogen is found essential for increasing the yield. Manuring is preferred at the sowing time so as to get best crop.About45-67.5kg/ha Nitrogen for irrigated crop and 22.5 kg/ha for rainfed cotton gives results.Farmyard manure(FYM) at the rate of 12 cartloads/hac is also considered to be essential for good yields. The flowering season starts from 2-21/2 months after sowing the seeds and last for the period of 8-10 wks.

Flowering generally starts one month and a half to two months after the crop is planted. Blooming will continue regularly for several weeks, even months, as long as growing conditions are suitable. After flowering, the inner part of the bloom gradually develops into a fruit (called "cotton boll"). Cotton bolls keep growing until full size (approximately 2 to 3 cm width). It will take about two months between the blooming of the flower and the first opening of the bolls. Cotton bolls burst open upon maturity, revealing soft masses of fibres. The cotton is picked either manually or mechanically. Manual picking is a very labour intensive and time-consuming task, and may be rather expensive. However, it generally produces quality lint with limited amount of trash, since cotton bolls are picked by hand as they burst open upon maturity. Cotton is harvested mechanically by cotton pickers (the most commonly used) or cotton strippers, which remove all the cotton bolls. Cotton strippers are generally used after application of a defoliant. Mechanical harvesting is faster than the manual picking of cotton. However, unwanted leaves and twins may be collected with the cotton. Cotton picked by a stripper might thus need additional cleaning (sorting of the trash) in order to obtain quality lint. Once the cotton is picked (either mechanically or manually) it is transported to a cotton gin, where the cotton fibres (lint) are separated from the cottonseeds. The cotton lint is then compacted in bales and stored

Preparation of Cotton thread: Harvesting: It begins about 6 months after sowing.Harvesting is done by hand or by machine. The seed cotton is usually picked from the open bolls.In America mechanical strippers or pickers are used Preparation of Cotton thread: (1)Ginning:The lint hairs are removed from the seed by means of ‘roller gin’.The cotton seed is subjected to a furhter ginning process and is then used either for seed or is sent in oil press for oil extraction (2)Bailing:The lint hairs got from ginning process are baled under pressurwe in bales for transporting to mills (3)Picking:In the textile mills a series of beaters and pickers fluff the fibre and frees it of foreign particles and delievers the cotton in uniform layer. (4)Lapping :Three layers of cotton fibres are combined into one (5) Carding,Combing and drawing:The short fibres are extracted,others straightened and evenly distributed (6)Twisting:The fibres are twisted into threads and ready for marketing

-The hulls are used as fertilizers;stock feed USES OF COTTON: -It is most important textile fibre.Pure cotton clothes are used allover the world. -Cotton fibre is the basic raw material for a number of cellulose Industries. -The hulls are used as fertilizers;stock feed -Cotton seed oil is a semi-drying oil and is used for cooking and soap making -The linters(fuzz) are used in manufacture of ropes,carpets,absorbent cotton etc The stalks of the cotton plant can be used as a fuel.It yields a fibre which can be used a paper making.

HIGH YIELDING VARIETIES (HYV) OF COTTON (1)MCU-5: Long Staple upland cotton,matures in165-170 days,Mean fibre length 29.0mm,Ginning outturn 34.0%,can spin count 70s,resistant to Verticillum,yield 1800 kg/hac (2)MCU-7: Cotton hybrid matures in135 days,Mean fibre length 25.0mm,Ginning outturn 33.12%,can spin count 70s,tolernat to blackarm disease,yield 1200 kg/hac (3)MCU-13: Long staple, matures in150-155 days,Mean fibre length 30.3mm,Ginning outturn 33.12%,can spin count 70s,tolernat to blackarm disease,yield 1700 kg/hac