A Review on Molecular Approaches in Breeding for Abiotic Stress Tolerance

Abiotic stresses such as drought, high temperature, salinity, cold and frost reduce crop productivity. It has been estimated that crops attain only about 25% of their potential yield because of the detrimental effects of environmental stress (Boyer, 1982). The abiotic stresses are location specific, exhibiting variation in frequency, intensity and duration. Stresses can occur at any stage of plant growth and development, thus illustrating the dynamic nature of crop plants and their productivity. Because of the large impact that stresses have on crop yields, many plant breeders also target increased resistance to stress as a major route to crop improvement. One difficulty in breeding for stress tolerance per se is that genetic advancement is often evaluated in terms of yield performance.