ABSTRACT
An experiment was conducted with blackgram (Vigna mungo L. Hepper) cv T-9 in Open top chambers (OTCs) to assess the impact of moisture deficit and its interaction with two levels of CO2 (550ppm and 700ppm) on biomass and seed yield. At flowering stage moisture deficit was imposed by withholding irrigation. Both elevated CO2 levels improved the total biomass and the extent of improvement was 2.7% and 23.5% under irrigated conditions, while 9.0% and 26.1% under moisture stress conditions at 550ppm and 700ppm of CO2 respectively. Higher improvement in seed yield than biomass at both elevated CO2 levels was recorded and under irrigated condition the seed yield improved by 26.3% and 58.9% while under moisture deficit conditions by 9.0% and 34.7% at 550ppm and 700ppm respectively. Though moisture deficit reduced the total biomass, seed yield and HI at all CO2 levels, however the magnitude of reduction was less at elevated CO2 levels. The ameliorative effect of enhanced CO2 concentrations under moisture deficit condition was observed through better pod number in blackgram as compared with ambient control which reflected as higher seed yield.