Analysis of thermotolerance behaviour of five chickpea genotypes at early growth stages

Abstract

Global warming has negative effects on agriculture which affect different crop species around the world. In different geographical conditions, temperature is an important factor for crop growth. Chickpea is a heat-sensitive crop, and heat stress affects chickpea production across the globe. In the present study, effects of heat stress on different chickpea genotypes have been studied. Five different chickpea genotypes viz. C-235, CSJD-884, RSG-888, GNG-1581, and RSG-895 have been used to analyse the heat stress effect and thermotolerance behaviour of these genotypes at early growth stages under three different temperature regimes, i.e. 30, 35 and 40 °C. Different growth parameters were analysed at different time intervals after heat stress followed by 10 days of recovery period at 25 °C. Seedling length in control versus stressed plant was estimated after 48 h and 72 h, while branching, cotyledon colour and shoot colour were observed after 96 h. Root length, shoot length, relative water content (RWC) and photosynthetic pigments (chl a, chl b and carotenoids) were examined after recovery period. A comparative analysis among all the selected genotypes was carried out to predict the thermotolerance behaviour. Heat stress under 40 °C showed the lethal effect on growth of the plant after 96 h. Seedling length and branching of roots were increased under heat stress as compared to control. Photosynthetic pigments as well as RWC were negatively affected under heat stress as compared to control. In conclusion, genotypes CSJD-884 and RSG-895 showed thermotolerance behaviour with the highest growth rate, RWC and photosynthetic pigments and C-235 variety was the most sensitive genotype under heat stress.