Heritability of cooking time and water absorption traits in dry beans (Phaseolus vulgaris L.) using a North Carolina design II mating scheme

  • FM Elia University of Dar es Salaam, Department of Botany, P.O. Box 35060, Dar es salaam, Tanzania


Estimation of genetic variances, heritabilities and estimations of response to selection of the cooking time and water absorption traits of Andean gene pool of dry bean seed Phaseolus vulgaris L. were done. General combining ability (GCA) i.e. GCA males and GCA females, and Specific combining ability (SCA) were estimated. The parents were crossed in a North Carolina mating design II and genetic analysis was made on the F3 and F4. Both male and female effectations within sets for the cooking trait in F3 and F4 were highly significant for the traits studied. Variances due to General combining ability (GCA) and Specific combining ability (SCA) were significant for the traits. It was observed that quick cooking parental genotypes produced progenies that were rapid cooking. This suggests that it is possible to select superior cooking progenies from crosses involving quick cooking parents due to the preponderance of the additive genetic variance in both F3 and F4. The high heritability and large magnitude in the range of the means of the cooking time trait indicates that population improvement is possible through recurrent selection. Estimation of response to selection indicated that genetic gain in selection was achievable.

Partitioning among the entry source of variance for the water absorption into male and female effects within sets, their interactions, and the environment main effect indicated that the values were highly significant in both F3 and F4. The GCA male and GCA female effects had a much larger component of variance than the SCA. This indicates that additive genetic variances were important. The large magnitude in the heritability and the range in the mean of water absorption, and the estimated high response to selection indicate that the population can be improved through selection as shown by the presence of genetic gain in selection for the trait. It appears from the results obtained in this study that soaking dry beans before cooking is indicative of the amount of time required to render them eating soft. Hence water absorption can be used as a secondary selection index or indirect selection criteria for cooking time in a crop improvement program. In both traits studied, narrow sense heritability estimates were high (76% to 85 %).

Tanz. J. Sci. Vol.29(1) 2003: 25-34

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