SELECTION CRITERIA FOR IMPROVED GRAIN YIELD IN DURUM WHEAT

An experiment was conducted during 2007-2008 period, with the objective of estimating the associations between yield and yield-related traits and to identify direct effects of characters for durum wheat grain yield improvement. The experimental material consisted of 20 durum wheat genotypes, which are randomly taken from the germoplasm collection. Significant genotypic differences (P 0.01) were observed for all the traits studied, indicating considerable amount of variation among genotypes for each character. Grain yield had strong positive correlations (P 0.01) with plant height, number of kernels spike-1, grain yield plant-1, biological yield and thousand-kernel weight. On the other hand, grain yield had strong negative correlation (p 0.01) with days to heading, suggesting the usefulness of selecting early heading genotypes with long grain filling period in improving grain yield. The remaining traits recorded moderate to low phenotypic and genotypic estimates. The maximum positive direct effect on grain yield was exerted by biological yield (0.99) followed by days to maturity (0.89) and harvest index (0.73). While, maximum negative direct effects were exerted by days to heading (-0.81) and grain filling period (-0.68). Therefore, days to heading, biological yield and harvest index could be used as an indirect selection criterion for better grain yield. Thus, selecting early heading genotypes having high biological yield and harvest index could improve grain yield