Abstract

                                Pulses are one of the important food crops due to higher protein content. Among the pulses, greengram (Vigna radiataL.) is popular and major grain legume used for consumption since ancient days. Elevated temperature stress during critical crop growth stages affects yield in greengram and lead to very low productivity Worldwide. Hence, it is essential to study the responses of critical growth stages of greengram under elevated temperature stress. With this background, the present investigation was carried out in CO 8 variety of greengram to study the physiological characters and yield responses of greengram under different elevated temperature stress conditions. The experiment was conducted in the open top chambers located in the Department of Crop Physiology, Tamil Nadu Agriculture University, Coimbatore during 2016-2017. Elevated temperature stress was given two levels, by raising the temperature up to 2ºC and 4ºC from the ambient temperature. Plants subjected to an elevated temperature at various stages viz., vegetative, flowering and pod development. Observations on various physiological parameters viz., leaf area, gas exchange parameters like photosynthetic rate, stomatal conductance, transpiration rate, leaf temperature were recorded. Also, osmotic potential and osmotic adjustments were studied under stress period. The response of yield was also recorded under different elevated temperature stress. Among the growth stages, the flowering stage was more critical to the elevated temperature and the impact of 4ºC raise from ambient temperature was higher when compared with the elevated temperature of 2ºC.

Key words : Leaf area, gas exchange parameters, osmotic adjustment and yield traits..