Genetic Study of Traits Related to Forage Yield in Half Sib Families of Orachard Grass (Dactylis glomerata) under Drought Conditions

This research was conducted to evaluate genetic variation and estimate genetic parameters of forage yield and related traits in Dactylis glomerata. Twenty five 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 in Research Farm of Isfahan University of Technology. Results indicated that there are significant statistical differences and high genetic variation among the families for most of the studied traits. Drought stress significantly affected all forage related traits (except for leaf to stem ratio), leading to decreases in a majority of them. Mean of forage yield was decreased by 53.48 percent due to drought stress. Genotypic coefficient of variation under non-stress condition ranged from 1.78 to 45.1 and under drought condition ranged from 1.7 to 30.4, indicating a high genetic variation in this germplasm. The highest narrow sense heritability was related to crown diameter in both moisture environments. Narrow sense heritability for dry forage yield was 52% at non-stress and 45% at stress conditions. Based on dry forage yield, genotypes 2, 5, 8, 13 and 15 showed a higher general combining ability in both moisture conditions and, therefore, are potent to be used for developing synthetic varieties.