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

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, P1 x P8, P2 x P8, P4 x P8, P5 x P8, P6 x P8, P7 x P8, P8 x P9 and P8 x P10 had superiority percentage in
desired direction over both check cultivars i.e., SC 162 and SC 168 for earliness and good plant type.