Heterosis And Combining Ability For Some Important Characters In Half Diallel Crosses Of Bread Wheat (Triticum Aestivum L.)

Abstract

A half diallel mating crosses was carried out amongst six diversed Bread wheat cultivars (Triticum aestivum L.). the six parents  and its fifteen F₁ crosses were grown in a field experiment at the agricultural research center of Idlib, to estimate Heterosis over mid parents (HMP) and better parents (HBP), general combining ability (GCA) and specific combining ability (SCA) for the characters of (number of days to heading (DH), plant height( PH), Main spike length (MSL), number of productive tellers (PT), main spike Kernel number (SKN), main spike Kernel weight (SKW), thousand kernel weight (TKW), and grain yield of the individual plant (PGY). Comparing Means performance, reflects that parent had sufficient variation for most investigated characters , which makes these parents eligible to enter breeding programs for achieving the desired genetic advance; and that was evident in the resulting F₁ crosses for most studied characters. The analysis of variance for combining ability showed that mean square due to general combining ability (GCA) were significant for the characters of plant height, number of productive tellers, and individual plant grain yield. While, mean square due to specific combining ability (SCA) were significant for the rest characters, reflecting the importance and participation of both additive and non- additive gene effects in the inheritance of these characters.  General Combining ability were higher than [1]those of specific combining ability, consequently the GCA/SCA ratios were more than unity for the characters; number of days to heading, plant height, spike length, number of productive tellers, and grain yield of the individual plant, indicating the prevailing of additive gene effect which have considerable roles in the inheritance of these characters. specific Combining ability were higher than those of General combining ability, consequently the SCA / GCA ratios were more than unity for the characters of main spike Kernel number, main spike Kernel weight and thousand kernel weight, indicating the prevailing of non-additive gene effect which have considerable roles in the inheritance of these characters. The cultivars Doma ₄ and Doma ₂ were good combiners for early heading, Sham ₁₂ for plant height, Doma ₂ and Sham ₁₂ for spike length, Wafea for number of productive tellers and doma₄These results seem to be useful for wheat breeding program in making the proper decision when initiating a crossing Program.