October 29, 2001	Monday	Shaba'an 11, 1422

COTTON is one of the most important crops of Pakistan which accounts for 60 per cent of total foreign exchange earnings through the export of raw cotton and cotton products.

It also provides raw material to local domestic cotton industry. It has 85 per cent share in the total vegetable oil produced in the country. Cottonseed cake, an important by-product, is a valuable source of protein for ruminant cattle. About 40 per cent labour force of the country is employed in cotton growing and cotton processing. Cotton is, therefore, rightly called the back-bone of Pakistan’s economy.

Pakistan ranks fourth in area and production of cotton in the world. Pakistan has 9.36 per cent of total world cotton area, 10.18 per cent of production 8.06 per cent of consumption and 4.55 per cent of total world export of raw cotton. Pakistan produced record cotton production in 1991 but since then the production has been facing ups and downs. The yield per hectare has gone down due to manifold reasons including failure of insect control due to insecticides resistance development in insects especially bolloworm and whitefly against commonly used insecticides, cotton leaf and virus disease, etc. The year 1992-93 was disastrous for cotton crop because of severity of the cotton leaf curl virus disease causing large-scale damage to the crop. In Punjab, over an area of 2.4 million hectares, the lint cotton yield dropped from 849 to 493 kg/ha in 1991-92. In the following three years the total consequent losses up to 1994-95 were estimated around 3 million bales valued at about Rs 30 billion. It is still a major threat to our economy.

Now a strategy has to be established to cope with these problems and to enhance the per hectare yield which may ultimately uplift the cotton production of the country. Presently, cotton production of the country faces three threats which are; low yield, pest pressure and dclcv menace. These threats can be overcome in one stroke that is “production of hybrid cotton resistant to CLCV and bolloworm complex”; this is the only tool by which we can face these threats.

Hybrid vigour (heterosis) in cotton was first identified by Mell in 1894 who reported an increase in some agronomic and fiber properties in hybrids compared with their parents. Heterosis was commercially exploited for the first time in 1970 in India with the release of an intrahirsutum hybrid. H4, which gave increase of 138 per cent over a commercial variety; as such India is the first country in the world to exploit commercially the phenomenon of heterosis in cotton. At present, 27 per cent of the total area under cotton in India is grown under hybrids but their share of total cotton production is more than 40 per cent. Exploitation of hybrid vigour (heterosis) necessitates isolation of best parents manifesting highest degree of heterosis in desire characters in F1 combination for ultimately developing highest degree of heterosis in desired characters in F1 combination for ultimately developing commercial cotton hybrids. The heterosis or hybrid vigour in cotton has only been useful when the hybrids have excelled their parents or commercial variety at least by 50 to 80 per cent with respect to yield of seedcotton coupled with other desirable fiber characteristics.

From the breeding point of view it is utmost important to make use of better genotypes for increased per hectare yield. Again, to make hybrids a commercial possibility, it is also very necessary first to identify parents with best combining ability and to estimate the extent of superiority of hybrids over commercial variety.

The Central Cotton Research Institute, Sakrand, initiated the work to produce cotton hybrids with Bt-gene. As such seven F1 hybrids with Bt-gene (induced conventionally) were developed and sown in the field along with two commercial varieties to monitor lepidopteran insect activity in an unsprayed block. the results demonstrated that the hybrids with Bt-gene were almost free from bollworm attack in total, eight bolls of different six combinations were attacked by spotted bollworm with the result that the larvae died in the holes.

The combination Reshmi x Bt-cotton though visited by lepidopterans as observed from the scars on the bolls but remained without any damage. Further, fresh young bolls and flowers of these seven F1 hybrids and two commercial checks were taken to laboratory and kept in separate cages. Fifteen lepidopteran larvae collected from field were released in each cage for monitoring their activity. The bolls / fruiting bodies with Bt-gene were almost remained un-attacked, and if attacked, the larvae got died. the bolls / fruting bodies of two commercial checks, CRIS-134 and NIAB-78 were damaged and larvae remained safe except one larva which died due to un-known reason.

the studies further revealed that NIAB-78 x Bt-cotton combination proved to be high yielding and early maturing and can be used in commercial hybrid cotton production without spraying the crop against lepidopteran insects thus reducing the pesticide use to a greater extent and increasing the seedcotton yield to a respectable level. The studies further revealed that combining one parent with Bt-gene and CLCV resistance would always yield F1 hybrids resistant to bollworm complex and CLCV disease respectively. It is therefore high time now to provide funds to CCRI Sakran in the shape of a three years project to take up further studies for screening out the combinations with specific coining ability with one of the parents as CLCV resistant and with Bt-gene to explore the best F1 hybrids having high yield potential, CLCV and lepidopteran insects resistance and better fibre quality traits for commercial hybrid cotton production with minimum use of pesticides.

It is further proposed/suggested that after identification of F1 hybrid combinations with high yield potential, resistant to bollworm complex and CLCV disease with better fiber characters, another project on training of progressive growers to produce their own hybrid cottonseed of identified combinations on their farms may be initiated on high priority basis, this will definitely enhance the cotton production of the country with reduced cost and pesticides use and would provide friendly atmosphere for cotton production.