Evaluation of Yield Potentiality for Some Rapeseed (Brassica Napus L.) Genotypes

Six parental genotypes and their fifteen F1 crosses of rapeseed resulted from half diallel were employed to estimate mean performance, combining ability, genetic variance components and heterosis. Meantime, phenotypic stability parameters were estimated for seed yield/fed and seed oil content (%).The results indicate a high degree of genetic variability existed among parental rapeseed genotypes and their F1 crosses for yield, yield components and seed oil content. General and specific combining ability, were highly significant for most studied characters with great importance of general combining ability in the genetics of the studied characters. Additive and dominance genetic variances were highly significant for all studied characters. Additive component played the major role in the inheritance of plant height, number of secondary branches/plant, number of silliquaes/plant, number of seeds/silliquae, seed yield/plant and seed oil content. The dominance genetic variance was the main component controlling the inheritance of number of primary branches/plant and 1000-seed weight. Narrow sense heritability was high (> 50%) for all yield contributing characters, except 1000-seed weight which was moderate (42.1%).Positive and highly significant better- parents heterosis for seed oil content was registered by the cross combinations (Pactol x Serw 4), (Pactol x M10) and (M 36 x M39), as well as seed yield/ plant by the cross combinations (Pactol x Serw 4), (Serw8 x M 39), (Serw 8 x M 39), (M10 x M 36) and (M10 x M39).Phenotypic stability indicated that the most stable genotypes were pactol, M 36 and M 39 but these genotypes exhibited mean values less than grand mean with the lowest and insignificant S2d for seed yield/plant. Serw 4 appeard to be more stable for seed oil content.