Received: 03-01-2018 / Accepted: 18-04-2018
Seven genotypes of groundnut (DM1, DM2, DM3, DM4, HL11, HL22 and LDDL) provided by the Agricultural Genetics Institute were evaluated for growth and physiological characteristics under drought conditions at seedling stage. A pot-experiment in nethouse was arranged according to a completely randomized design. Drought stress was imposed on three true leaf seedlings (15 days after sowing) by withholdingt irrigation untill the soil osmotic pressure reached -80 KPa. Meanwhile, regular irrigation schedules were perfomed for maintaining the soil moisture at 70% saturation in the control and in non-drought periods. Drought stress inhibited growth and photosynthesis, transpiration and significantly reduced dry matter of groundnut at seedling stage and the inhibition varied with genotype. Three indexes showing close correlations with dry weight included drought susceptibility index (DSI); drought tolerance efficiency (DTE) and drought tolerant index (DTI) with correlation coefficients of r = -0.55 and -0.602, r = 0.55 and 0.83, and r = 0.53 and 0.98 at drought and recovery periods, respectively. The chlorophyll stability index (CSI) showed no correlation with dry weight and did not reflect drought tolerance. The results also showed that the genotypes HL22 and DM4 possessed higher drought tolerance comparing to the others.
