GENETICAL STUDY ON SOME BREAD WHEAT CROSSES UNDER TWO NITROGEN LEVELS

Abstract

Heterosis and nature of genetic effects on plant growth and yield characters were studied in a 6x6 diallel crosses, without reciprocals, in the F1 and their F2 generations in wheat to define and select efficient and prospective materials to be used in hybridization programs in order to improve grain yield of wheat in Egypt. Parents, F1 and F2 were evaluated using a randomized complete block design (RCBD) with three replications for quantitative characters in 2018/2019 season. Significant genotype mean squares of parents and crosses were obtained for all characters. Significant heterosis in F1 generation was obtained for all studied characters. The useful heterosis of grain yield/ plant relative to better parent varied from 6.22 to 38.91% in F1 crosses. Two crosses, viz. P1xP2 and P3xP6 had the best values of heterosis for grain yield. General (GCA) and specific (SCA) combining ability mean squares were significant for all characters. Besides, MSe (GCA)/ MSe (SCA) ratios indicated the relative importance of additive gene action in their inheritance for all the characters. The two parents P1, P4 and P5 gave the highest positive significant iĝ effects for grain yield plant-1 in both generations. The three crosses P1xP5, P3xP6 and P4xP5 showed significantly desirable heterotic effects for most studied traits. Generally