This research has been carried out at the experimental Station of
Agriculture Faculty, Damascus University during the period of 1998-2000. Five
parents were selected from the Cotton Office Germplasm (Aleppo40, Raqua5,
Dir22, Daltabain50, 88G6104)
to examine the inheritance of some
morphophysiological, yield, and quality related traits. In1998, the five parents
were hand-crossed in all combinations (with no reciprocals) generating ten F1
hybrids. During 1999, the ten crosses and their parents were planted to produce
F2 seeds. In 2000 the F1s, F2s, and their parents were grown in a randomized
complete block design with two replications.
Heritability estimates in broad sense showed that the earliness traits possess
the highest values, followed by total and actual bolls number, indicating the
importance of additive gene action in the inheritance of these traits. Whereas,
heritability values for other traits were markedly different, revealing the
genetic diversity of these hybrids parents.
High estimates of expected genetic advance were found to be associated with
high heritability estimates for total and actual bolls number, indicating that
direct selection should be effective for these traits. On the other hand,
improvement of traits, possessing intermediate estimates of genetic advance
and high heritability estimates, such as total bolls number, harvest index,
flowering earliness and fiber elongation in some studied hybrids, through direct
selection might be less effective. The results suggest that traits with high
heritability estimates associated with low estimates of genetic advance; and
those possess intermediate estimates of heritability and genetic advance or low
estimates of both parameters are most likely controlled by non-additive genes,
therefor, direct selection might not be effective for improving these traits.
