Vegetos

Abstract

Late sowing of wheat results in exposure to high temperature during reproductive phase (seed filling). The present paper studies the effects of late sown condition on various morphophysiological parameters at different stages of growth, in two wheat genotypes i.e., HUW-510 (high temperature resistant) and HUW-468 (high temperature sensitive). The three dates of sowing were 20^th November (DOS I), 10^th December (DOS II) and 30^th December (DOS I). Leaf area (LA), number of leaves, net assimilation rate (NAR), crop growth rate (CGR), relative growth rate (RGR) and leaf area index (LAI) were higher in the early sown plants compared to late sown plants. The declining trend was found in LA and number of leaves at DOS III in HUW-468. NAR in both the genotypes increased slowly at the early stages of growth while it increased sharply at the later stages with fluctuations in most cases. Higher values of CGR were found in the early sown condition in HUW-468. LAI was highest in DOS I while higher reduction was observed under DOS III in both the genotypes. The number of ear per 20 cm row length, number of grains per ear, grain yield per plant, 1000 grain weight and harvest index were significantly higher in HUW-510 followed by HUW-468 under DOS I as compared to DOS III. Late sown condition significantly decreased various morpho-physiological responses and yield attributes in wheat, particularly, in case of high temperature sensitive genotype, HUW-468.