In this article we will discuss about the varieties of cotton.
Research efforts, since the formation of AICCIP in 1967, have led to the release of around 250 cotton varieties and hybrids for the different cotton growing tracts of the country and development of economical and ecofriendly package of practices for realising enhanced productivity.
World class cotton varieties and hybrids like Suvin, DCH 32, NHH 44, TCHB 213. DHB 105. LHH 144, Shresth, LRA 5166, Anjali, Surabhi, MCU 5, MCU 7, MCU 13, HHH 287, Abhadita, HD 324, DHH 11, H 4, H 6, H 8, AAH 1, RG 8, RAJ, DH 9, PKV Hy-2 and scores of others with higher yield, special characteristics and suitable to low cost production technologies have all been released over the years suiting to the textile needs and bringing net profit to the fanning community in the country.
During the IX Plan period (1997-2002), 23 hybrids and 40 varieties have been released for commercial cultivation catering to the needs of the various agroclimatic regions of the country.
During the period 2000 to 2010, several high yielding cotton varieties and hybrids have been released for commercial cultivation through AICCIP catering to specific needs and possessing special characteristics. Most of these varieties/hybrids are capable of yielding 1800-2500 kg ha-1. Cotton hybrids/varieties recommended for different states are given in Table 19.1.
Hybrid Seed Production:
The conventional method of hand pollination and emasculation is most popular in India. Doak method (thumb nail) of crossing is practiced in hybrid seed production.
Male and female plants arc grown in shallow furrows (30 cm deep). Female parents are spaced 2.0 m apart while male parents at 1.0 m espacement. Delinted seeds are sown at the rate of 2-3 seeds per hill. Seed production plots receive around 15 t ha-1 of FYM with a fertiliser dose of 250 N, 125 P2O5 and 125 K2O kg ha-1. Gaps if any are filled using seedling grown in polythene bags/ tubes. Around 70 labourers per day are required ha-1 for hand emasculation, crossing and bagging at peak flowering period.
Emasculation and bagging of female parent bud is better done during evening hours (3-6 PM), while they are pollinated on the subsequent day in the morning (8-11 AM) or even up to 11 AM. Emasculated flower is bagged with red tissue paper or red straw tube. After pollination, red bag or tube is replaced with white bag or tube. Pollen of the male flowers is collected and kept under protection in covered trays. A thread is tied at the base of the pedicle for easy identification of pollinated flowers. All missed flowers must be removed.
Coloured Cotton:
Natural coloured cottons are in existence in all shades from white to black. As per the historical documents, blue, purple, pink, green and brown cottons were in cultivation in coastal Peru. In Mexico, wild trees of brown cottons are called Coyoqui and yellow cotton as Coyuche. They are still spun by tribals in Mexico.
In India, brown cottons of G.hirsutum and G.arboreum are grown in some remote areas of Kakinada in Andhra Pradesh and Tripura. Naturally coloured cottons are environmentally friendly as they are sold at premium price. They do not fade on washing. The greatest disadvantage of coloured cottons at present is that they yield less and fibres are short with low strength, low micronaire value and low maturity coefficient.
Genitically Engineered Cotton:
Several cotton cultivars with fair amount of tolerance to sucking pests have been developed. However, tangible resistance to most important pest, the bollworm, has not been obtained in breeding. That is the reason for looking towards the genetically engineered (GE) cotton plants widely known as B.t (Bt) cotton due to the delta – endotoxin gene from an ubiquitous soil bacterium Bacillus thuringiensis for solution to manage bollworms.
The technology is well established in cotton growing countries of the world. The GE cotton accounts for 12 per cent of the total of 44 M ha under different GE crops of the world. Recent multilocation trials with GE cotton hybrids in India show that it is superior to conventional hybrids in respect of reduced pesticide consumption and increased cotton yield.
Their economic superiority coupled with biological and environmental safety would offer an excellent opportunity to fit into the IPM system for cotton fanners with inheretently excellent fibre properties.
Bt Cotton:
According to Central Institute for Cotton Research (CICR), Nagpur, Gene Campaign during three years of field studies on Bt cotton cultivation showed that India’s Bt cotton technology itself is faulty and will fail to protect cotton farmers from the bollworm. The study recommends additional pesticide sprays since the Bt technology fails to provide adequate protection.
The principal findings of Gene Campaign’s field studies indicated no significant pesticide savings in India. Gene Campaign studies had found that protection offered by Bt cotton hybrids lasts only up to about 90 days, after which the effect wears off. The CICR study also reports that protection falls off after 110 days because the Bt gene does not express properly after that.
Another feature of the Bt cotton hybrids reported by Gene Campaign was the premature dropping of cotton bolls. Early investigations (1997-98) in the US also revealed boll dropping in Monsanto’s GM cotton.
The CICR scientists have shown that the Indian Bt cotton technology, being used by all agencies, is flawed. Bt cotton hybrids being produced in India were unstable and unpredictable, the result of faulty technology in which gene expression is variable, showing declining levels of Bt toxin in the same season.
This means that since the Bt cotton does not provide adequate protection, farmers must use chemical pesticides to protect their crops. This is in consonance with Gene Campaign’s findings that the Mahyco-Monsanto cotton failed to protect against bollworm, fanners had to use chemical pesticides, hence savings on pesticide were not significant.
According to CICR study, the Bt technology being used in India is not suited for cotton cultivation since the pest profile is very different to the pest profile in the US. Since Bt technology was developed for the cotton pests in the US, it is unlikely to work for us here. Now the CICR study has very clearly shown that Bt cotton cannot be effective in India because the major cotton pest here, the bollworm, is not susceptible to the Cry 1 Ac toxin of Bt cotton.
Cry 1 Ac works against the tobacco budworm, Heliothis virescens, which is the major pest of cotton in USA. Bt cotton varieties in USA cause 99-100 % mortality in Heliothis, hence they are successful in providing protection. The Cry 1 Ac based technology cannot ever really succeed in India.
Further, unbundling the scientific basis for the failure of India’s Bt cotton, the CICR study suggests that poor Bt cotton performance in India is possibly due to the fact that in India, Bt cotton is produced as a hemizygous hybrid (gene expression in only one parent), compared to the homozygous form of the composite varieties which are produced in other countries like China, Australia and South Africa.
Global analysis of Bt cotton performance shows that performance is better in true breeding varieties as compared to the hybrids that are being produced in India. This explains to some extent the positive reports from China.
The primary question that Indian regulators must answer is, why is Bt cotton hybrids being promoted, when they will force the fanner to buy seeds for every new planting? Why did the GEAC not take the decision that only true breeding varieties of Bt cotton would be permitted in India, not only because they perform better but also because they would be a cheaper option for farmers who could save seeds for the next harvest? The future of Bt cotton in India appears to depends on scientists skills, political will and farmers acceptance.