Physio-genetic approches for increasing wheat (Triticum aestivum) productivity under rice (Oryza sativa)-wheat cropping system

Abstract

A field experiment was conducted during the season of 2 2-2005 at the Indian Agricultural Research Institute. New Delhi, to study the traits which could be used for screening of large number of wheat (Triricunz aesriv~r?rLt emend. Fiori & Paol.) genotypes under late-sown conditions. The observations were taken on membrane injury index, relative water content and rate of photosynthesis under normal and late planting conditions on various stages of ontogeny. Correlation between plant height, grain yield, pedunclelength, graindspike, tiller/m2, splkele/spike, flag leaf areaand spike length with biomass weight was worked out under late-sown rainfed and irrigated conditions. Maintenance of low leaf temperature ( 2 9 17OC) was found to be essential trait for atolerant genotypes. The low membraneinjury index ( 14.&25.5%) and high relative water content (86.34) was also essential trait for tolerant type genotype. At low leaf temperature the pace of metabolic activities are relatively high under stress conditions. The low membrane injury index and high relative waler content also essential for tolerant genotypes. The close association (0.76) of membrane injury index with per cent reduction in biomass has clearly indicated that this trait could be used for screening large number of genotypes under late sown conditions.