الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 166 |  |  |
| | | from | 166 | | |
Abstract
This investigation aimed to study the variation in mean performance, heterosis, phenotypic and genotypic variances, magnitude and types of gene action, heritability, predicted genetic advance and correlation coefficient analysis for earliness characters, flag leaf area and spike characteristics, yield, its components and grain protein content in six bread wheat cross populations grown under normal and late sowing dates. The results indicated that, the mean squares of parental wheat genotypes and their crosses in F1, F2 and back crosses were significant for all studied characters in all crosses under both normal and late sowing dates.The values of heterosis and heterobeltiosis varied according to the parental wheat genotypes involved in the crosses and sowing dates. The first and second crosses (Sakha 93 x Gemmeiza 7 and Sakha 93 x Sids 1) are considered as desirable early mature crosses, while the crosses 3 (Gemmeiza 7 x Sids 1) and 6 (Sids 4 x Cham 6) exhibited highly significant positive heterosis and heterobeltiosis for both grain yield and grain protein content in normal and late sowing, suggesting that these crosses could be used for commercial exploitation of heterosis or selection of transgressive segregants for earliness, grain yield and grain protein content.Scaling test showed that most studied characters in the six crosses under normal and late sowing were significant, indicating the presence of non-allelic interactions. Otherwise, the insignificant scaling test estimates obtained for days to heading in 1st, 2nd, 3rd and 6th crosses under normal sowing and 1st and 4th crosses under late sowing; days to maturity in 2nd and 6th crosses in normal sowing as well as flag leaf area in 4th cross in normal sowing, indicating that the simple additive-dominance genetic model proved to be satisfactory in explaining the inheritance of the foregoing characters.The results indicated positive and significant phenotypic and genotypic correlations between grain yield per plant and each of spike length in 3rd cross under normal sowing; number of spikes per plant in 1st, 4th and 5th crosses in normal sowing and 6th cross in late sowing; number of grains per spike in 3rd cross in normal sowing and 2nd cross in late sowing as well as 1000-grain weight in 1st cross under normal sowing. The genotypic and phenotypic correlation among grain yield per plant and days to heading were negative and significant in 2nd cross in late sowing. This investigation aimed to study the variation in mean performance, heterosis, phenotypic and genotypic variances, magnitude and types of gene action, heritability, predicted genetic advance and correlation coefficient analysis for earliness characters, flag leaf area and spike characteristics, yield, its components and grain protein content in six bread wheat cross populations grown under normal and late sowing dates. The results indicated that, the mean squares of parental wheat genotypes and their crosses in F1, F2 and back crosses were significant for all studied characters in all crosses under both normal and late sowing dates.The values of heterosis and heterobeltiosis varied according to the parental wheat genotypes involved in the crosses and sowing dates. The first and second crosses (Sakha 93 x Gemmeiza 7 and Sakha 93 x Sids 1) are considered as desirable early mature crosses, while the crosses 3 (Gemmeiza 7 x Sids 1) and 6 (Sids 4 x Cham 6) exhibited highly significant positive heterosis and heterobeltiosis for both grain yield and grain protein content in normal and late sowing, suggesting that these crosses could be used for commercial exploitation of heterosis or selection of transgressive segregants for earliness, grain yield and grain protein content.Scaling test showed that most studied characters in the six crosses under normal and late sowing were significant, indicating the presence of non-allelic interactions. Otherwise, the insignificant scaling test estimates obtained for days to heading in 1st, 2nd, 3rd and 6th crosses under normal sowing and 1st and 4th crosses under late sowing; days to maturity in 2nd and 6th crosses in normal sowing as well as flag leaf area in 4th cross in normal sowing, indicating that the simple additive-dominance genetic model proved to be satisfactory in explaining the inheritance of the foregoing characters.The results indicated positive and significant phenotypic and genotypic correlations between grain yield per plant and each of spike length in 3rd cross under normal sowing; number of spikes per plant in 1st, 4th and 5th crosses in normal sowing and 6th cross in late sowing; number of grains per spike in 3rd cross in normal sowing and 2nd cross in late sowing as well as 1000-grain weight in 1st cross under normal sowing. The genotypic and phenotypic correlation among grain yield per plant and days to heading were negative and significant in 2nd cross in late sowing. This investigation aimed to study the variation in mean performance, heterosis, phenotypic and genotypic variances, magnitude and types of gene action, heritability, predicted genetic advance and correlation coefficient analysis for earliness characters, flag leaf area and spike characteristics, yield, its components and grain protein content in six bread wheat cross populations grown under normal and late sowing dates. The results indicated that, the mean squares of parental wheat genotypes and their crosses in F1, F2 and back crosses were significant for all studied characters in all crosses under both normal and late sowing dates.The values of heterosis and heterobeltiosis varied according to the parental wheat genotypes involved in the crosses and sowing dates. The first and second crosses (Sakha 93 x Gemmeiza 7 and Sakha 93 x Sids 1) are considered as desirable early mature crosses, while the crosses 3 (Gemmeiza 7 x Sids 1) and 6 (Sids 4 x Cham 6) exhibited highly significant positive heterosis and heterobeltiosis for both grain yield and grain protein content in normal and late sowing, suggesting that these crosses could be used for commercial exploitation of heterosis or selection of transgressive segregants for earliness, grain yield and grain protein content.Scaling test showed that most studied characters in the six crosses under normal and late sowing were significant, indicating the presence of non-allelic interactions. Otherwise, the insignificant scaling test estimates obtained for days to heading in 1st, 2nd, 3rd and 6th crosses under normal sowing and 1st and 4th crosses under late sowing; days to maturity in 2nd and 6th crosses in normal sowing as well as flag leaf area in 4th cross in normal sowing, indicating that the simple additive-dominance genetic model proved to be satisfactory in explaining the inheritance of the foregoing characters.The results indicated positive and significant phenotypic and genotypic correlations between grain yield per plant and each of spike length in 3rd cross under normal sowing; number of spikes per plant in 1st, 4th and 5th crosses in normal sowing and 6th cross in late sowing; number of grains per spike in 3rd cross in normal sowing and 2nd cross in late sowing as well as 1000-grain weight in 1st cross under normal sowing. The genotypic and phenotypic correlation among grain yield per plant and days to heading were negative and significant in 2nd cross in late sowing.