Articles
Heterosis and nature of gene action in okra (Abelmoschus esculentus (L.) Moench)
Article number
1187_30
Pages
291 – 298
Language
English
Abstract
The presence of variations among four lines of okra and their hybrids for various traits was investigated in this study.
The mean squares of the genotypes were highly significant except plant height (cm) and pod length (cm). General combining ability (GCA) was highly significant for all traits.
Therefore, additive genetic variance was more important in the inheritance of these traits.
The values of GCA were higher than those of specific combining ability (SCA) for plant height (cm), number of nodes to first flower and pod diameter (cm) indicating that additive genetic variance was more important for these traits.
The values of SCA were larger than those of GCA for other tested traits indicating the importance of non-additive effects.
The magnitudes of GCA and SCA values were close for the pod diameter, thus illustrating the importance of both values for this trait.
The crosses P1×P2 and P4×P2 were promising and showed highly significant estimates of SCA effects.
Genetic variances including dominance (σ2D) were positive and highly significant for most traits except for pod length.
The reciprocal variances were smaller than the additive genetic variances for average pod weight and number of seeds pod-1. The results showed that the reciprocal effect (σ2rec) or maternal effect was present and should not be neglected.
The heritability in broad sense was larger than the corresponding values in narrow sense for all traits.
In general, the F1 hybrid P2×P3 and P2×P4 gave desirable value for early yield trait where the mean number of nodes of first flower was -38.51 and 31.03 g for Average weight of pod plant-1, respectively.
However, the F1 hybrids P1×P2 gave the highest values of hybrid vigor with a mean of 57.1 for number of pods plant-1, 32.14 kg for weight of pods plot-1 and 38.59 for number of seeds pod-1. Whereas, the F1 hybrids P1×P2 and P2×P3 were outstanding for most traits.
This result indicated that choice of parents is an important factor.
These hybrids can be utilized in breeding programs to produce improved okra lines and new cultivars.
The mean squares of the genotypes were highly significant except plant height (cm) and pod length (cm). General combining ability (GCA) was highly significant for all traits.
Therefore, additive genetic variance was more important in the inheritance of these traits.
The values of GCA were higher than those of specific combining ability (SCA) for plant height (cm), number of nodes to first flower and pod diameter (cm) indicating that additive genetic variance was more important for these traits.
The values of SCA were larger than those of GCA for other tested traits indicating the importance of non-additive effects.
The magnitudes of GCA and SCA values were close for the pod diameter, thus illustrating the importance of both values for this trait.
The crosses P1×P2 and P4×P2 were promising and showed highly significant estimates of SCA effects.
Genetic variances including dominance (σ2D) were positive and highly significant for most traits except for pod length.
The reciprocal variances were smaller than the additive genetic variances for average pod weight and number of seeds pod-1. The results showed that the reciprocal effect (σ2rec) or maternal effect was present and should not be neglected.
The heritability in broad sense was larger than the corresponding values in narrow sense for all traits.
In general, the F1 hybrid P2×P3 and P2×P4 gave desirable value for early yield trait where the mean number of nodes of first flower was -38.51 and 31.03 g for Average weight of pod plant-1, respectively.
However, the F1 hybrids P1×P2 gave the highest values of hybrid vigor with a mean of 57.1 for number of pods plant-1, 32.14 kg for weight of pods plot-1 and 38.59 for number of seeds pod-1. Whereas, the F1 hybrids P1×P2 and P2×P3 were outstanding for most traits.
This result indicated that choice of parents is an important factor.
These hybrids can be utilized in breeding programs to produce improved okra lines and new cultivars.
Authors
G.M. Shamloul, A.M. Moghazy
Keywords
okra, diallel crosses, heritability, combining ability
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