The present study was conducted at the First of May Station belongs to the
General Commission For Scientific Agricultural Research (GCSAR) at
Damascus during 2011 and 2012 growing seasons to estimate gene action,
heritability, genotypic and phenot
ypic coefficient variations (GCV, PCV) and
genetic advance for two crosses of soybean. The five population (P1, P2, F1, F2,
F3) of each cross were grown in a randomized complete block design (RCBD)
with three replications in order to evaluate oil and protein contents and seed
yield traits. Results of mean square analysis showed significant differences
(p<0.05) among mean values of the five populations for all studied traits
between the populations of each cross. The second cross achieved high broad
and narrow sense heritability (66%, 44%) for protein content, high value of
phenotypic and genotypic variations in seed yield in the second cross achieved
(18.03,17.30) and high value of expected genetic advance was obtained 11.09%.
In most traits, epistasis of the dominance × dominance type of gene action
occupied the first rank in order of importance in controlling inheritance of the
evaluate traits in both crosses indicating the importance of selection in late
segregating generations to improve these traits. These findings are supported
by high values of heritability, which was related with low to moderate expected
genetic advance in two crosses.
