Genetic Analysis for Yield and its Components in Bread Wheat

Abstract

Eight bread wheat cultivars were used to study some earliness and yield and its component traits. The parental cultivars were employed to produce 28 F 1 hybrids following 8 x 8 half Diallel crossing without reciprocals. The seeds of 28 F 1 hybrids and their parents were planted to estimate mean squares due to parents and their crosses which were significant for all studied traits. The parental variety P 3 was the best parent for earliness. However, P 8 was the best for remained traits. The crosses (P 1 x P 4) and (P 2 x P 4) were the best combinations for earliness traits, while the six crosses were the best for remained traits. Highly significant negative desirable heterotic effects were detected for earliness, on the contrary for remained traits relative to mid and better parent. The mean squares associated with general and specific combining abilities detected significant and highly significant estimates for all studied traits. Results indicated that P 4 (Sids12) was good combiner for earliness traits and most of yield and its component traits. The best cross combinations displayed fair amount of SCA effect were obtained from (P 2 x P 4) and (P 4 x P 5) for earliness traits, the six crosses for remained traits. The graphical analysis Wr/Vr indicated the importance of over dominance gene effects in controlling all traits. The results indicated the importance of additive and dominance genetic variances in controlling these traits. The "a" item was significant for most studied traits and more than "b" item. Narrow sense heritability was less than (0.50) for all traits except plant height trait (0.80). Positive alleles were not equally distributed among parents (H 2 /4H 1 ≠ 0.25) for all studied traits. The magnitude of dominance (H 1 /H 2) was significant or highly significant higher than additive components (D) for all traits, expect plant height trait. All estimates of environmental variance (E) were positive significant and highly significant for all studied traits indicating that all studied traits have greatly affected by environmental factors.

Heterosis, Correlations and Path Analysis of Grain Yield Components in Bread Wheat (Triticum aestivum L.)

“…The analysis of variance table (1) shows that the parental genotypes differed significantly at the level of probability (1%) for all studied traits except for the number active tillers plant -1 , which differed significantly from the level of probability (5%), while the first-generation crosses (Table 2) differed significant in all the studied traits at the level of probability (1%) except for the characteristic of the number of spikelet's, spike -1 , which differed significantly at the level of probability (5%). This result agreed with [12], [13].…”

Combining Ability and Gene Action of Half Diallel Crosses in Bread Wheat (Triticum aestivum L.)

“…It is noted from the tables of the analysis of variance (1) that the parental genotypes differed significantly at the level of probability (1%) in all the studied traits except for the number of active tillers plant -1 differed significantly from the level of probability (5%), and from the table of the analysis of variance (2) It was found that the first-generation hybrids were significant in all the studied traits at the level of probability (1%) except for the number of spikelet's spike -1 differed significantly from the level of probability (5%), This is evidence of the genetically different parental genotypes, as well as the difference in crosses resulting from half-diallel crosses. This result agreed with [12,13].…”