Estimation of genetic architecture for agro-morphological characters in common wheat

Abstract

In order to estimate genetic parameters and variability of agro-morphological characters in bread wheat an experiment was conductetd in the frame of randomized complete block design with three replications under water stress conditions in the experimental greenhouse of the College of Agriculture, Razi University, Kermanshah, Iran. The analysis of variance showed highly significant differences among the genotypes for stress yield (Ys), biomass (BI), harvest index (HI), thousand seed weight (TSW), number of seed per spike (NSPS), spike length (SL), awn length (AL), plant height (PH), spike weight (SW) and peduncle length (PL) suggesting the presence of considerable amount of variability among the genotypes of wheat according to the characters evaluated in the present study. Mean comparisons classified the genotypes in different groups for all the characters under study indicating the presence of genetic variability found in the analysis of variance. The phenotypic coefficient of variation (PCV) was generally higher than the genotypic coefficient of variati (GCV) for all the characters. The highest values were shown by AL, Ys and TSW. GCV was higher than environmental coefficient of variation (ECV) for all the characters except for SL indicating that the traits studied are more genetic. High heritability estimates (> 0.5) were observed for all the characters investigated except SL. High heritability estimates associated with high genetic gain for Ys, TSW and AL reflecting the involvement of additive gene action.According to the results, the highest genotypic and phenotypic covariance observed between Ys and SW indicating significant contribution of these traits to increase grain yield in wheat under raifed condition (correlated response). High co-heritability was observed between BI and AL (4.195) and SL and PH (4.097). Positive coheritability estimate was observed between Ys and all the agro-morphological traits. This suggests that selection of either of the characters would simultaneously affect the Ys positively.