ABSTRACT
Current world agricultural production is largely limited by environmental stresses (Boyer 1982). It is estimated that only 10% of the world’s arable land may be free of stress (Dudal 1976). Extreme temperatures, drought, soil salinity, and nutrient imbalances (including mineral toxicities and deficiencies) are among the major environmental constraints to crop production worldwide. Most plant breeding programs have focused on the development of cultivars with high yield potential in favorable (i.e., nonstress) environments. Such efforts have been extremely successful in improving the efficiency of crop production per unit area thus resulting in significant increase in total agricultural production (Duvick 1986). However, with the rapid increase in human population there is a greater need for food production, and with the increasing diminution in natural resources, and arable lands, greater efforts must be made to increasing crop productivity under stressful agricultural environments and bringing marginal lands under cultivation. Marginal agricultural environments could be enriched by growing stress tolerant plants to increase yields, which is an important step toward solving the problem of feeding the world’s growing population.
