GAS-EXCHANGE AND LEAF WATER RELATIONS IN 2 PEANUT CULTIVARS OF DIFFERENT DROUGHT TOLERANCE

In summer seasons of 1991 and 1992 the gas exchange and leaf water relations were analysed in two peanut cultivars: drought tolerant cv. GG 2 (DT) and drought sensitive cv. JL 24 (DS). Soil moisture stress was imposed by withholding irrigation at pod development phase. The decrease in photosynthesis (P-N) under stress was associated with a decrease in stomatal conductance (g(s)) and relative water content (RWC). The P-N and RWC were significantly higher under stress in DT than DS. On relief of stress the g(s) and RWC recovered more quickly in DT than DS. The maintenance of higher RWC (>80 %), g(s) and P-N under stress appears to be imparting drought tolerance in peanut.