Evaluation of Thermo Tolerant Cowpea Genotypes by Field Conditions

Cowpea is mainly grown in the arid and semiarid regions at the global level. The temperature above 35oC affects the morpho-physiological processes and decreases the biomass. Hence, identification of thermotolerant genotypes is necessary to ensure food security in the face of climate change, allowing farmers to cultivate resilient varieties. In this regard, one hundred ninety-one genotypes were screened for yield attributes under field conditions at Raichur, Karnataka. The crop was exposed to a higher temperature up to 41oC during the entire crop growth period. The plants experienced high levels of heat stress which led to increase in mean leaf temperature, decreased mean SPAD chlorophyll meter reading (SCMR), total dry matter (TDM) and other yield attributing traits. Tolerant cowpea genotypes which showed minimum reduction in total dry matter compared to susceptible genotypes where identified. The tolerant genotypes IC-402172, EC-458453, EC- 458470, NBC-21, NBC-14, EC-394708, CB-10, IC-458430, IC-249588 and EC-458490 can sustain the temperature up to 35oC without compromising the total dry matter. This can be used for further crop improvement programme to develop themotolerance.