High Temperature Stress in Chickpea: Effects on Physiological Processes, Nitrogen Fixation, Pollination and Reproductive Growth

Plants face various abiotic stresses such as drought, salinity, chilling, freezing, and high temperatures etc. during their lifespan. Chickpea (Cicer arietinum L.) is an important food legume crop and heat stress affects chickpea ontogeny over a range of environments. The crop often experiences abnormally high temperature (>35℃) during the reproductive stage. Heat stress at the reproductive stage is thus increasingly becoming a serious constraint to chickpea production in northern India due to climate change. Heat stress (≥ 35℃) during flowering and pod development results in severe yield losses due to the impact of high temperatures on different physiological processes. The most significant effects on the reproductive phase that affect pod set, seed set and yield are (1) flowering time (2) asynchrony of male and female floral organ development and (3) impairment of male and female floral organs. This review describes the recent status of chickpea production, the effects of high temperature on chickpea, and the scopes for genetic improvement of chickpea to high-temperature tolerance. Recent field screening at ICRISAT has identified several heat tolerant germplasm, which can be used in successful breeding programs for improved heat tolerance in chickpea. It is observed that the detrimental effects of high temperature on membrane integrity, chlorophyll content, nitrogen-fixing ability, pollen and stigma function etc. are comparatively less in the tolerant genotypes than the sensitive ones. Therefore, identification and development of heat tolerant genotypes is an important aspect of chickpea breeding, especially in the aspect of the continuously changing global climate scenario.