Mung bean (vigna radiata) is one of the most popular pulse crop in Asia. It is cultivated biannually in large areas of Pakistan during warm seasons and is a good source of protein. Optimum temperature for all four mung bean genotypes (NM 19-19, NM 20-21, NM121-123 and NCM 89) was found to be 30°C. Lethal temperature was 50°C (2 hours) as severe growth retardation was seen but better growth performance was found when a pretreatment of 40°C (1 hour) prior to 50°C (2 hours) was given as visualized by improvement in seedling length and heat stress tolerance index (HST). Mean seedling length and heat stress tolerance index was reduced under heat stress however more reduction was seen in NM 20-21 while less in NM 19-19.
