Genetical Studies on Yield and its Components of Four Bread Wheat Cultivers

Abstract

The present investigation used four bread wheat cultivars to study some earliness, yield and its components characters. The parental cultivars produced six F 1 hybrids following 4 x 4 half Diallel crossing without reciprocal. F 1 hybrids and their parents were evaluated via combined analysis to study mean squares due to the parents and their hybrids which showed significant values for all studied traits. The parental variety P 1 was the best for earliness. However, P 4 was the best for yield and its components. The crosses P 1 x P 4 and P 2 x P 4 were the best for earliness. However, four crosses were the best for yield components. The mean squares associated with general and specific combining ability appeared significant values for all studied traits in the both seasons. Gemmeiza 9 was the good parent for earliness traits; however, Gemmeiza 10 was the best parent for yield and its components in the two seasons. The graphical analysis Wr/Vr showed significance of over dominance gene effects, as well as, significance of additive and dominance genetic variance in controlling all traits. The additive components (A) were lower than dominance for all traits in both seasons. Heritability in narrow sense was low for all traits in both seasons. The magnitude of dominance (H 1 and H 2) was significant than additive for most traits in both seasons which reflected the presences of over dominance. The environmental variance (E) showed that all traits have been greatly affected by environmental factors.