COMBINING ABILI'IY AND FACIDR ANALYSIS IN F2 DIALLEL CROSSES OF RAPESEED VARIETIES

v. Rameeh

Abstrakt

Fifteen F 2 progenies derived from a 6x6 half diallel crosses along with their parents of rapeseed (Brassica MpUS L.) varietie5 were evaluated for pods per main axis, pods per plant, length of pod, seeds per pod, 1000- seed weight , grain yield and oil content The Analysis of variance based on Griffing's method two, with mixed-B model on F 2 progenies and their parents revealed significant mean squares for general combining ability (GCA), specific combining ability (SCA) indicating that both additive and non-additive genetic effects were involved in controlling these traits. High narrow-sense heritability estimates and degree of dominance less than one were observed for length of pod and 1000-seed weight indicated the prime importance of additive genetic effects for controlling these two traits. Narrow-sense heritability estimates for pods per main axis, pods per plant, seeds per pod, grain yield and oil content were estimated 0.22, 0.14, 0.30, 0.15 and 0.08, respectively concluded that the importance role of non-additive genetic effects for controlling these traits. Among yield components, pods per main axis and pods per plant had significant positive correlation with grain yield (0.54* and 0.60**), so any changing of these traits would have significant effects on grain yield. Based on the results of factor analysis on GCA effects revealed that pods per main axis, pods per plant and grain yield had high coefficients of factor loading in the factor one, but on SCA effects pods per main axis, pods per plant and 1000- seed weight had high coefficients of factor loading and the same direction of variation.