Selection indices in the improvement of wheat grain yield on drought stress conditions

Abstract

Drought is considered as one of the most important factors limiting crop yields around the world. Drought often causes serious problems in wheat production areas. In this regard, a field study of thirty bread wheat cultivars was conducted at the Agricultural Research Station of Islamic Azad University in Tabriz, Iran during 2009 to 2010 growing season to determine the most effective traits in the improvement of grain yield on drought stress conditions. Based on the results of combined analysis of variance, grain yield and 1000-grain weight had the greatest influence of drought stress. Moreover, there were highly significant diversities among the studied genotypes and genotype × environment interaction for the entire traits. According to the correlation analysis, the highest association between grain yield and biological yield revealed that grain yield could be efficiently increased by obtaining maximum expression of biological yield under drought stress conditions. Path analysis of grain yield indicated, straw yield and plant height had positive and significant role in accretion of grain yield on drought stress conditions. With respect to the achieved results, we can exploit biological yield, straw yield and plant height as suitable selection criteria for evolving high yielding genotypes in the wheat breeding programs under drought conditions. Key words: Bread wheat, drought stress, genotype × environment interaction, path analysis.