ESTIMATION OF GENETIC VARIATIONS AND CONTRIBUTION OF YIELD COMPONENTS IN GRAIN YIELD OF SOME BREAD WHEAT GENOTYPES

: This study was conducted to determine the genetic variations, correlation and factor analysis for grain yield and its components in eight wheat genotypes. The wheat genotypes showed significant differences for all the studied traits. Genotypes Sakha 95, Misr 1, Giza 171, Misr 1, and Misr 2 performed well in both seasons for grain yield and its components. Maximum phenotypic and genotypic variances were detected for number of spikes/m 2 and plant height in both seasons. The phenotypic coefficient of variation and genotypic one ranged from 48.72and 28.78% to 132.67and 74.73% and from 34.85and 21.42% to 182.98 and 117.17% for 1000 grains weight and the number of spikes/ m 2 in the 1 st season and the 2 nd one, respectively. The highest heritability was detected for plant height and flag leaf area in both seasons. Moderate heritability was observed for number of grains/ spikes in both seasons. Low heritability was detected for the remaining traits during both seasons. A high genetic advance was observed for number of spikes/m 2 (29.61) in the 2 nd season. A significant positive correlation was registered between grain yield (ard./fed.) and each of flag leaf area, the number of spikes/plant and 1000 grains weight in both the 1 st season and the 2 nd one. The factor analysis method grouped the studied variants into two factors. These factors represented 79.424% in the 1 st season and 84.255% in the 2 nd one of the total variations of grain yield. The results of this study could be used to develop breeding programs for bread wheat improvement.