Selection parameters for improving grain yield of bread wheat under terminal heat stress

Abstract

Improving terminal heat tolerance is an issue of top priority in wheat breeding in the present era of climate change. Present study was carried out to identify the association among traits of economic importance under terminal heat stress environment. The grain yield/sq. meter under terminal heat stress environment recorded highly significant positive correlation both at genotypic and phenotypic level with grain weight/spike, number of spike/sq. meter, harvest index and 1000-grain weight in both the crop seasons. Path coefficient analysis carried out using genotypic correlation coefficients revealed that days to heading contributing maximum positive direct effect towards grain yield under terminal heat stress environment followed by grain filling duration. Other characters contributing positive direct effects towards grain yield were grain weight/spike, number of spike/sq. meter, harvest index and biological yield/sq. meter under both the crop season. Thus, for improving the wheat grain yield under terminal heat stresses conditions, breeder should aim for selecting genotypes with bold grains or high grain weight /spike, more number of tillers/sq. meter, higher harvest index and longer grain filling duration.