Oilseed bonanza

HYBRID rapeseed and mustard seeds -- the Holy Grail of agricultural researchers worldwide -- that could substantially increase the yield of these crops, may soon be available to the Indian farmers. Scientists at the Delhi-based Tata Energy Research Institute (TERI) claim to have already developed rapeseed hybrid seeds that are undergoing trials.

Although the production of oilseeds in India has increased by 58 per cent since 1986, the country is still not self-sufficient in oilseeds. The leader of the TERI group, Akshay Pradhan, says that crop yields "are very low in India compared to many other countries".

But the hybrids, the scientists hope, will increase mustard crop yields by as much as 30 per cent and rapeseed produce by 50 per cent. TERI scientists are also trying to develop varieties with enhanced nutritional qualities.

Hybrids are produced by crossing 2 disparate plant varieties to combine the favourable traits of both the parents in one plant. To ensure that the 2 different varieties actually form the parents, it is necessary to make the receptive female plant male sterile -- to protect it from the pollen or male cells of its own flowers.

Pradhan's team has identified some wild rapeseed varieties that produce naturally male sterile flowers. This sterility, explains Pradhan, is a result of a gene present in the cytoplasm or cell fluid, as opposed to the nuclear DNA where most genes lie.

Besides the cytoplasmic male sterile varieties, TERI scientists have also identified fertility restorer lines -- those varieties that can restore male fertility in rapeseed. Says Pradhan, "Thanks to our research, hybrid seed production in rapeseed now seems feasible."

Through classical breeding techniques, the male sterility trait has been introduced into commonly cultivated rapeseed species. Using these male sterile lines, the scientists have successfully produced hybrid seeds which are being tested in the field. But in the case of mustard, TERI scientists are trying to identify male sterile wild species but have had little success so far, admits Pradhan.

TERI scientists are also trying to develop varieties of mustard and rapeseed that can be used to produce oil and meal which are free of 2 toxic compounds -- erucic acid and glucosinolates. Erucic acid forms in mustard and rapeseed oil when they are stored. Deoiled cakes, produced from varieties of mustard and rapeseed grown in India, suffer from high contents of glucosinolates. Pradhan and his colleagues have already produced hybrid rapeseed varieties with erucic acid content between 2.4 and 8 per cent, compared to 30 per cent in traditional varieties.