ABSTRACT

The majority of past studies of abiotic stress tolerance have compared the physiological status of a stressed plant with that of an unstressed control plant in order to deduce underlying mechanisms. In general, these studies have not included the molecular and genetic bases of stress tolerance to support the physiological ndings. However, recent developments in the eld of genetics and molecular biology have opened up exciting new possibilities in understanding the physiology of abiotic stresses (Bennett and Khush, 2003; Eynard et al., 2005; Ismail et al., 2007). Almost all the abiotic stresses-drought, submergence, salinity, alkalinity, toxicities of Fe and Al, and deciencies of P and Zn-limit rice production especially in the rainfed environments that contribute about half of the global rice area (Gregorio et al., 2002; Latte et al., 2004). Among these stresses, salinity has a particularly long-lasting effect on plant productivity as, unlike the situation with drought that can be relieved by irrigation, it is extremely difcult to remove salts from agricultural soils. In this chapter, we summarize some of the recent advances in understanding the molecular biology underlying the response of rice to salinity and sodicity and provide updated information particularly on quantitative trait loci associated with salt tolerance in rice.