Variability in Phenology, Physiology and Yield Response of Different Maturity Duration Pigeon Pea Genotypes at Elevated CO_2

摘要

Three pigeon pea (Cajanus cajan L. Millsp.) genotypes - ICPL-88039, GT-1, and AKP-1 - with varying crop duration, growth habit and flowering pattern were grown at ambient (390 ppm) and elevated (550 ppm) CO_2 levels in Open Top Chambers (OTCs) to assess the variability in their responses for phenology, physiology, biomass and seed yield parameters. It was observed that elevated CO_2 significantly increased the photosynthetic rate (Anct), decreased the transpiration rate and increased water use efficiency (WUE). Higher impact of elevated CO_2 on the earliness of flowering was observed as the duration of the genotype was increased. 50% flowering at 550 ppm was early by 1.3 days in ICPL-88039 and 12 days in GT-1 and 20 days in AKP-1 as compared with ambient. All the selected genotypes improved their biomass and seed yield with elevated CO_2; however, the response of individual component and magnitude of the response was genotype specific. As the duration of the pigeon pea genotypes was increasing fromextra-short to short and short-medium, the response of vegetative biomass was increasing under elevated CO_2 as compared with reproductive biomass and influencing the harvest Index (HI).