Growth and yield response of winter blackgram (Vigna mungo) under high temperature and elevated CO2 conditions

Abstract

Blackgram is the most important legume crop grown throughout India. It is mostly cultivated during the rainy and winter seasons in central and southern India. An investigation was carried out during winter 2021 to evaluate the effect of High Day Temperature (ambient+3oC) and Elevated CO2 (600ppm) (HDT and eCO2) and High Day and Night Temperature (ambient+3oC) and Elevated CO2 (600ppm) (HDNT and eCO2) on growth and yield of blackgram (Vigna mungo) under soil plant atmospheric research (SPAR) and ambient conditions with eleven treatments (T1 to T11). The results revealed that significant (P=0.05) increase in photosynthetic rate, stomatal conductance, transpiration rate, number of pods per plant and grain yield by 22.3%, 80.6%, 29.2%, 28% and 41.3%, respectively, under HDT and eCO2 conditions from 46 to 60 DAS (days after sowing) in comparison with HDNT and eCO2 and ambient conditions. The increase in chlorophyll index under HDT and eCO2 during 16 to 30 DAS by 12.9%. The significant increase in the number of flowers per plant and biomass of the blackgram was increased under HDT and eCO2 during 31 to 45 DAS by 7% and 38.1%, respectively. However, the plant height and leaf area index of the blackgram were found to have significantly increased under HDT and eCO2 during the early stage (1 to 15 DAS) by 29.3% and 44.5%, respectively. This experiment indicated a significant increase in crop growth, leaf photosynthesis and yield of blackgram under HDT and eCO2 at flowering stage to pod development stage (31 to 60 DAS) followed by HDNT and eCO2 and ambient condition. The overall findings of the study showed that increased temperature and CO2 levels would result in greater biomass production and increased yield for the black gram.