Ikufīziyuluzhī-i Giyāhān-i Zirā̒ī (Jun 2016)
Evaluation of Genetic Variation of Bread Wheat Genotypes for Some Morphological and Physiological Characteristics under Drought Stress Condition
Abstract
The present study was conducted in the agricultural research farm of Islamic Azad University, Ardabil Branch, to investigate genetic variation of some bread wheat genotypes for some morpho-physiological traits under separate environmental conditions (drought stress and without drought stress). Results from analysis of variance showed that the interaction of “irrigation levels × genotypes” on traits like plant height, infertile tillers number, spike length, peduncle to plant height ratio, spike number per m2 and grain yield were significant. Genotype No. 35 (4057) produced the highest (6.3 ton/ha) grain yield. Linear multivariable regression revealed that traits such as grain numbers per spike, node number and spike weight accounted for about 58% of overall mean yield among the genotypes under terminal drought stress condition. Node number had the highest direct effect (0.438) on grain yield. The results, also, showed that the direct effect of grain number per spike on yield was positive (0.135) while spike weight on yield was negative (-0.345). Direct effect of node number on yield by spike weight was higher than indirect effect of spike weight by node number. Based on the factor analysis, 75.80% of total variations were explained by 6 factors. The first up to the sixth factors accounted for 21.32, 18.13, 9.72, 9.62, 9.4 and 7.6% of the total variations respectively. Furthermore, cluster analysis, based on Ward method and by using Euclidian squared distance, classified the genotypes into five groups. Results from this study suggest that traits such as grain number per spike, node number and spike weight can be used as a selection criteria in breeding programs for higher grain yield of bread wheat in the regions where plants may be subject to terminal drought stress.
