Yield and harvest index of short and long duration grain legume crops under twice the ambient CO2 levels.

Abstract

Foodgrain requirements of India (both human and cattle) are estimated at 300 million tonnes in 2020 (Sinha et al. 1998). With the alarming increase in GHG concentration and its expected impact on climate, the issue emerging would be to achieve the targeted production. To address the above issue from the agricultural point of view, it is desirable to select the crops and their cultivars thereof, that can better utilize the increased concentration of CO2 for both biomass and grain yield. In case of food legumes where grain is harvested for human consumption, the translation of increased biomass more towards grain or improved harvest index need to be achieved for breaking the yield barriers of these very important C3 grain legumes predominantly grown in the marginalized rainfed areas. India is the largest producer and consumer of pulses in the world. India grows pulses in about 22.5 million ha and 80% is in dry areas. However, pulses production has been stagnant at between 11 and 14 million tonnes over the last two decades. Per capita pulses consumption over the years has come down from 61 g/day in 1951 to 30 g/day in 2008 (Amarender Reddy 2009). Elevated CO2 condition appears to improve the overall growth of plants in general and may result in changes in partitioning of photo assimilates to various plant organs over time. An attempt was made to quantify the response of two major rainfed grain legume crops, viz pigeonpea and blackgram to increased atmospheric CO2 level in terms of