Reza TALEBI, Farzad FAYYAZ

Estimation of Heritability and Genetic Parameters Associated with Agronomic Traits of Bread Wheat (Triticum aestivum L.) Under Two Constructing Water Regimes

A 2-years field investigation was carried out to estimate genetic parameters and relationship among morpho-agronomic traits studied on 24Iranian bread wheat cultivars under two constructing water regimes. There was a positive and significant correlation between harvest index, number of grains per spike and number of seeds per m2 with yield at both genotypic and phenotypic level in both environments. The highest environmental variances were found for plant height, number of seeds per m2 and yield in both environments. Across the traits studied, in irrigated condition the PCV ranged from 0.359% for harvest index to 35.9% for number of seeds per spike and in drought stress condition this value ranged from 0.113% for harvest index to 21.57 for plant grain yield. The GCV values were the lowest (<2%) for harvest index and highest (12%) for plant height, number of seeds per spike and plant grain yield. 1000-seeds weight and plant biomass as well as number of seeds per m2, also showed relatively low GCV values (3.8-8.8%).Broad sense heritability estimates was very high under both control and water stress conditions, for plant height and number of seeds per spike, while broad sense heritability significantly decreased under water stress conditions for harvest index, 1000 grain weight and number of seeds per plant. In irrigated condition number of seeds per spike, 1000 grain weight and plant biomass showed more direct positive effects on yield, while, in drought stress condition number of seeds per spike showed negative direct effect on yield and harvest index and number of seeds per m2 showed more direct positive effects on yield. In conclusion, this study indicates that the improvement of the Iranian wheat cultivars may be possible either through indirect selection for yield components or direct selection for grain yield

Keywords: