This study was carried out through three successive growing seasons (2003,
2004 and 2005). Thirty triallel crosses were combined among five parental lines
belong to Gossyp < /em>ium barbadense L. were evaluated at Sids Agricultural Research
Station to estimate general and specific combining abilities for yield, yield
components and some fiber properties. The nature of gene action that controlling
the inheritance of the studied characters were also estimated. .
The results showed that the performances of most triallel crosses were as
good as or better than their both grand parents orland their third parent. The mean
squares of genotypes were highly significant for all studied characters which were
mainly due to the variances among the parents as well as the variances among the
triallel crosses. The mean squares of general and specific combining abilities were
significant for first and second kind for most traits. Significant positive general effects
of hi and gi revealed that the selection of P3 or P5 as a grand parent and P1 or P2 as
a third parent would be more benefit to improve SCY and L Y characters in the
breeding programs. The triallel crosses (15 x 2), (34 x 2), (35 x 2) and (45 x 2) were
positive and significant for yield and its components, (25 x ~) for MIC, PI, UHM and
UI, (12 x 4) specific effects of the triallel crosses (tijk) were predominately cffe::ted by the specific
effects of second kind effects (sij) (third parent) rather than the first kind (dij) (single
hybrids) and partially by the general effects of first and second kind. The magnitudes
of dominance variances were larger than those of the additive variances for all
studied traits except for MIC and UHM traits. Concerning the epistatic variances, the
results indicated that the additive x dominance type of epistasis played the major role
in controlling the inheritance of the stucied characters of the triallel crosses.
Therefore, recurrent selection might be useful in improving the studied characters of
the triallel crosses in the breeding programs.