Diallel crosses analysis of F2 generation in soybean [Glycia Max (L.) merril] [electronic resource].

Includes references.

A half diallel of F z generation crosses involving six parental varieties of soybean was evaluated to estimate the heterosis and combining ability for earliness, resistance to cotton leaf worm, yield and yield components. Significant genotypes, parents, F1 hybrids and P.V.S. F1 hybrids mean squares were detected for all characters except number of days to maturity and number of pods per plant in parent vs F1 hybrids, p4. behaved as earliest one, P1 was the top of the tested parental variety for yield and yield components. The crosses (P1 x P3) and (P5 x P6) gave the highest mean value for yield. Variances with general and specific combining ability (GCA) were significant for all studies characters except for number of seeds per pod in (SCA). The magnitudes of the ratio of GCA/SCA revealed that additive and additive types of gene action were the more important expression for all characters except plant height. p. and P, had significant negative (g^i) effects for flowering date, maturity date, and maturity period and prDved to be good combiners for earliness. p. and PJ had significant positive (g^i) effects for seed yield per plant, 100- seed weight and number of seeds per plant. For infection ratio of the cotton leaf worm defoltion P3 and p. considerable significant negative (g^i) effects. For plant height and number of seeds per plant (PI and P5) had considerable significant positive (g^i) effects. The highest desirable SCA effects were in cross (5 x 6) for earliness, yield and most component, the cross (1 x 4) gave the highly significant positive SCA effects for seed yield per plant and number of seeds per plant, the cross (4 x 5) gave significant positive (SCA) effects for seed yield per plant. Also, it gave negative number of days to maturity, and the crosses (I x 3), (2 x 3) and (2 x 4) were the best natural tolarance to cotton leaf worm. Heterotic effects for better parent were the two crosses (4 x 5) and (S x 6) showed the significant positive effects for seed yield per plant and must component and significant negative for number of days to maturity. also, the crosses (P1 x P3), (P2 X P3) and (P2 x P4) showed the heterotic effects for tolarance to cotton leaf worm.

Summary in Arabic.

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