Salinity and drought are two very important abiotic stresses that dramatically affect the growth and yield of crop plants because most of the economically important crops are intolerant/sensitive to abitoic stress. There is enormous current interest in improving the salinity and drought tolerance of crops. Salinity/drought tolerance is a complex trait that involves numerous aspects of developmental, physiological, biochemical and molecular adjustments. The regulatory pathways leading to these adjustments are poorly understood and remain a focal point of our research. The "rational" approach is to elucidate the physiological and molecular basis of existing salt- and drought-tolerance mechanisms in different plant species or cultivars and to identify the superior genes/alleles involved so that they can be incorporated into improved cultivars.