Estimating Heritability and Genetic Advance in Bambara Groundnut

Abstract

Aim: Bambara groundnut compares favourably with cowpea in terms of nutritional and economic values. The crop is, however, characterised by variable and unpredictable yields. Recently, there has been growing interest in the potential of the crop to contribute to food security in the sub-Sahara Africa. Therefore, there is the need for increased research attention, especially in the aspect of yield improvement. The selection of a superior genotype in a breeding programme depends on the amount of genetic variability present and the extent to which the characters are inherited and advanced. This study was aimed to estimate heritability and genetic advance in the Bambara groundnut.
 Place and Duration of the Study: The experiment was carried out in Kuru, Plateau State, Nigeria, during the rainy season between June and October 2018.
 Methodology: Nine genotypes of Bambara groundnut were laid out in the field using the randomised complete block design in five replicates. Genotypic variance, phenotypic variance, environmental variance, genotypic and phenotypic coefficients of variation, broad sense heritability, genetic advance and genetic advance as percent of population mean were computed from analysis of variance tables using the respective mean squares for each of the parameters studied.
 Results: Results of the study showed significant differences amongst genotypes for emergence rate, plant height, number of leaves and dry matter content. The coefficient of variability ranged from 7.56 % for plant height to 45.95 % for total grain yield. The phenotypic coefficient of variability was generally higher than the genotypic and environmental coefficients of variability for all the traits studied. Low heritability estimates were observed for number of days to onset of flowering, number of days to 50 % flowering, leaf area index, harvest index, stand count, pods per plant, shelling %, seeds per pod, dry matter content and total grain yield. Moderate heritability estimates were observed for plant height, leaf number per plant and net assimilation rate. High estimates of heritability were observed for emergence rate and relative growth rate. The genetic advance as percent of population mean ( GAM) was low for plant height, days to onset of flowering and 50 % flowering, harvest index, pods per plant, shelling %, 100-seed weight and dry matter content. GAM was high for emergence rate, leaf number per plant, leaf area index, relative growth rate, net assimilation rate, seed number per pod and total grain yield.
 Conclusion: The coefficient of variability was generally high for many of the attributes studied. Similarly, the phenotypic coefficient of variability was higher than the environmental and genotypic coefficients of variability for all the attributes studied. Heritability estimates were high for emergence rate and relative growth rate but moderate for plant height, number of leaves per plant and net assimilation rate. Genetic advance as percent of population mean was high for emergence rate, number of leaves per plant, leaf area index, relative growth rate, net assimilation rate, number of seeds per pod and total grain yield, suggesting the involvement of both additive and non-additive genes in the expression of these characters. Therefore, these traits can be considered as major selection indices in the improvement of the Bambara groundnut in the Jos-Plateau environment.