Variability in Growth and Yield Response of Maize Genotypes at Elevated CO2 Concentration

Abstract

Three contrasting maize (Zea mays L.) genotypes- DHM-117 (single cross hybrid), Varun (synthetic) and Harsha (composite) with different yield potentials were selected to assess their growth and yield performance at ambient (390ppm) and elevated (550ppm) CO2 condition in Open Top Chamber (OTC) facility. The phenology, biomass accumulation, grain yield and HI was quantified of these three maize genotypes at both CO 2 levels. The phenology of flowering was early by 1.5 to 2 days, while the anthesis silking interval (ASI) was not influenced by elevated CO 2 in DHM-117 and Varun, where as it was reduced by two days in Harsha. Response of selected three maize genotypes was different to elevated CO 2 (550ppm) condition in terms of biomass, grain yield and HI. The improvement in biomass ranged from 32% to 47%, grain yield 46% to 127% with 550ppm CO2 as compared with ambient control. The improvement in grain yield was due to increased grain number (25-72%) as well as improved test weight (8-60%). The overall response of less efficient maize genotype Harsha with elevated CO 2 concentration was found to be significantly high especially the grain yield and its components. Elevated CO 2 also improved the maize HI (11% to 68%) indicating that influence of elevated CO2 was there on partitioning of biomass of this C 4 crop.