Response of seed yield and its components of red gram (Cajanus cajan L. Millsp.) to elevated CO2.

Pigeon pea (Cajanus cajan L. Millsp.) is an important grain legume crop of the semi arid tropics and is a major dietary protein source. The extra short duration cultivar of pigeon pea ICPL 88039 was evaluated at ambient (370 μmol/mol) and twice the ambient (700 μmol/mol) concentrations of CO 2 in open top chambers (OTCs). The results showed that the crop recorded a significant positive enhanced response for total biomass, fodder yield, grain yield, number of pods and seeds per plant, test weight and HI at elevated CO 2 . The ANOVA revealed significant dif ferences in response of the characteristics to CO 2 concentrations. Under elevated CO 2 the total biomass recorded an improvement of 91.3%, grain yield 150.1%, fodder yield 67.1%. The major contributing components for improved grain yield under elevated CO 2 were number of pods, number of seeds and test weight which recorded an increase of 97.9%, 119.5% and 7.2%, respectively. The crop maintained a significant positive increase of harvest index (HI) at elevated CO 2 with an increment of 30.7% over ambient values. This increase in HI was due to its improved pod set and seed yield under enhanced CO 2 concentration thereby emphasizes this crop for sustained food with nutritional security under climate change scenario.