Estimation of combining ability and superiority percentage of half diallel crosses between yellow maize inbred lines for growth characters and some diseases resistance

Abstract

Half diallel cross among ten yellow maize inbred lines was made at Sakha Agriculture Research Station during the growing season 2015. The resultant 45 crosses along with two commercial hybrids as yellow checks (single crosses 162 and 168) were evaluated at two field experiments in two years 2016 and 2017. The results indicated that, years (Y) mean squares had significant effects for all traits, except resistance to downy mildew disease. Genotypes (G) and crosses (Cr) mean squares had high significant effects for all traits in the two years and its combined data. However, G x Y and Cr x Y interaction were significant or highly significant for all traits. Mean squares due to general combining ability (GCA) and specific combining ability (SCA) were highly significant for all traits in the two years and their combined analysis. On the other side, the interactions between GCA and SCA with years were highly significant for all traits. For GCA / SCA and GCA x Y / SCA x Y mean squares ratio, the data pointed out that, this ratio exceeded the unity for all studied traits in two years and their combined. The inbred line P4 had desirable significant of (g^i) for earliness, good plant type, resistance to downy mildew and late wilt diseases, also the inbred line P8 had desirable significant of (g^i) for earliness and good plant type. The single crosses; P1 x P3, P6 x P7 and P4 x P5 had negative and significant values of (s^ij) for good plant type and earliness. The single crosses P1 x P2,

Line × Tester Analysis for Estimation Combining ability of some New Yellow Maize Inbred Lines for Grain Yield and Downy Mildew Resistance

“…This finding is agreement with those of, Turgut et al (1995); Amer et al (2002) and Mosa et al (2017) who reported the preponderance of non-additive gene effects in controlling the inheritance of downy mildew and grain yield. Whereas, El-Shenawy and Mosa (2005); Mosa et al (2009) and El-Refaey et al (2018) who found that grain yield and downy mildew resistance were mainly controlled by additive gene effects Table 7. Estimates of additive gene effects (K 2 GCA) and non-additive gene effects (K 2 SCA) for six traits and downy mildew resistance.…”

“…A variety of DM strains have been reported, and the resistance to them is polygenically controlled. El-Shenawy and Mosa (2005), Mosa et al (2009) and El-Refaey et al (2018) reported that additive gene effects played a major role in the expression of the inheritance of downy mildew disease. While, Turgut et al (1995), Amer et al (2002) and Mosa et al (2017) stated that non-additive gene effects played an effective role in the inheritance of downy mildew resistance.…”