The research was conducted at the Maize Researches Department, General
Commission for Scientific Agriculture Researches (G.C.S.A.R.) Damascus,
Syria during the summer growing seasons of 2010, 2011 and 2012. Treatments
were arranged in a Randomized
Complete Blocks Design with three
replications. The research aimed to evaluate genetic parameters for some traits
like days to 50% silking, plant and ear height, ear length, ear diameter, number
of rows per ear, number of kernels per row, 100 kernel weight and grain yield
per plant using generations means analysis of two maize hybrids (IL.292-06 ×
IL.565-06, IL.459-06 × IL.362-06) to detect epistasis and estimates of mean
effect [m], additive [d], dominance [h], additive × additive [i], additive ×
dominance [j] and dominance × dominance [l] parameters. Results showed that
the additive - dominance model was adequate to demonstrate the genetic
variation and its importance in the inheritance of most studied traits. Nonallelic
gene interaction was operating in the control of genetic variation in most
studied traits. The signs of [h] and [l] were opposite in most studied traits for
the two crosses. Also, the inheritance of all studied traits was controlled by
additive and non-additive genetic effects, but dominance gene effects play the
major role in controlling the genetic variation of the most studied traits,
suggesting that the improvement of those characters need intensive selection
through later generations. The phenotypic variations were greater than
genotypic variations for all studied traits in the two crosses, indicating greater
influence of environment in the expression of these traits. Highly significant
heterosis relative to mid and better parents, respectively was found for all
characters, and this accompanied with inbreeding depression for all traits.
Narrow sense heritability and genetic advance were low in most of the traits
due to the dominance of non-additive gene action in controlling the genetic
variation of the most studied traits and this predict low to medium values of
genetic advance through selection process.
