Abstract
High temperature is one the major abiotic stress that are principal cause of reduced crop yield world wide. Four mung bean genotypes
(NM 19-19,NM 20-21, NM121-123 and NCM 89) were tested against high temperature treatments with and without GA3.
When mung bean seedlings were exposed to 50°C for 2 hours (C) lethality occurred within 72 hours. The effect of lethal temperature
was reduced by the mild temperature treatment of 40°C for 1 hour prior to 50°C for 2 hours (B) and most of the seedlings improved in
their length and fresh weight. This effect is further improved by the exogenous application of 100 uM GA3 either as treatment B1or
treatment B2 . The effect of GA3 showed positive effect on seedling length, fresh weight and heat stress tolerance index (HST),
however treatment B2 was better than treatment B1. Mean seedling length, fresh weight and heat stress tolerance index was increased
during GA3 application. More improvement was seen in NM 19-19 than in NM 20-21.
