Assessment of Relationship between Seed Yield and its Components in Half Sib Populations of Orchard Grass (Dactylis Glomerata) under Normal and Drought Conditions

This research was conducted to study relationships among yield and yield components in Orchard grass (Dactylis glomerata). For this purpose 25 half sib families derived from poly cross of 25 parental genotypes were evaluated under two moisture environments (normal and drought conditions) according to a randomized complete block design at the research farm of Isfahan University of Technology. The results indicated that seed yield had positive correlation with most of the studied traits. The highest correlations were observed between seed yield and seed weight in panicle (0.96**) and seed number in plant (0.89**) in non-stress and drought stress conditions, respectively. The correlations of seed yield with flag leaf width and flag leaf length were 0.41 and 0.39 in non-stress conditions. The results of factor analysis indicated that flag leaf is an important trait for improving seed yield. According to regression analysis seed weight in panicle, seed number in panicle and seed number in plant accounted for 98 and 96% of seed yield variation under normal and drought conditions, respectively. Path analysis for seed yield showed that under normal condition, seed weight per panicle and seed number per plant and under drought stress condition, seed number and thousand seed weight had the highest direct effect on seed yield. Genetic information on association among seed related traits can be used for increasing efficiency of indirect selection of seed yield in this crop.