Leaf photosynthesis and yield response of winter green gram (Vigna radiata) to high temperature and elevated CO2 in the soil plant atmosphere research (SPAR)

Abstract

Legumes play an important role in India’s food security, inflation rate and export values. Climate variability might significantly affect the growth, development and yield of legume crops in various regions of the globe. The present study investigated the long episodes effect of high temperature and CO2 and ambient conditions on leaf photosynthesis and yield attributes of green gram (Vigna radiata) using soil plant atmospheric research (SPAR). Green gram was grown under high day temperature (HDT) (day maximum temperature + 3oC) and elevated CO2 (600ppm) (HDT and eCO2), high day and night temperature (HDNT) (day maximum temperature + 3oC) and elevated CO2 (600ppm) (HDNT and eCO2) and ambient conditions. Leaf photosynthesis, stomatal conductance, transpiration rate and chlorophyll index were significantly (p=0.05) increased by 25%, 24.1%, 23% and 4.6%, respectively, under HDT and eCO2 from 30 to 45 DAS (days after sowing) in comparison with ambient and HDNT and eCO2. The significant increase in number of flowers shed per plant increased under HDNT and eCO2 by 13% during 45 to 60 DAS. The increase in the number of pods per plant and grain yield per plant under HDT and eCO2 during 45 to 60 DAS by 26.9% and 25.7%, respectively. However, the biomass of the green gram was increased under HDNT and eCO2 during 30 to 45 DAS. These studies indicated a significant increase in leaf photosynthesis and yield of green gram under HDT and eCO2 at flower initiation to pod development stage (30 to 60 DAS) followed by HDNT and eCO2 and ambient condition. Overall study indicated that increasing temperature and CO2 would increase the biomass and yield of the green gram.