Prospects of success of biotechnological approaches for improving tolerance to drought stress in crop plants

Abiotic stresses such as drought, temperature, salinity and others generally reduce crop productivity. The abiotic stresses are location-specific, exhibiting internal variation in occurrence, intensity and duration. These could occur at any stage of plant growth and development which represent the dynamic nature of crop plants and their yield. A few transgenics in tobacco and rice overproducing osmolytes and stress proteins have been produced and tested jor tolerance to salt and drought stress in the vegetative stage. The genes being manipulated are not mechanistically linked with the process of yield formation. Using biotechnological approach it is difficult to foresee abiotic stress-resistant transgenics growing in the farmer's field in the near future. It is suggested that breeding for drought tolerance requires the identification of traits for phenology and those contributing to yield so that these can be pyramided using conventional means