Character associations and path analysis in bambara groundnut grown in mid-altitude highland of Jos-plateau, Nigeria

Bambara groundnut is an indigenous African legume, which is the third most important after peanut and cowpea in terms of consumption and socio-economic impact in semi-arid Africa. There is, therefore, the need for adequate research attention, especially with regard to yield improvement. In this study, nine genotypes of the Bambara groundnut (Cream with white eye, Black with white eye, Cream with brown eye, Cream with black eye, Cream with black eye and brown stripes, Cream with brown stripes, Deep-brown with white eye, Cream with black stripes and Brown white eye) were evaluated at Kuru, Nigeria (Lat. 090 44'N, Long. 080 47'E, altitude 1, 217 m above sea level) in 2018 in order to determine character associations and to analyse the pathways to grain yield. Results showed that emergence rate, plant height, number of leaves per plant, leaf area index, relative growth rate, harvest index, number of pods per plant and shelling percentage were positively correlated with total grain yield. The Results of the path coefficient analysis showed that the number of days to onset of flowering exerted the highest direct influence on total grain yield. Then followed by harvest index, emergence rate, 100-seed weight, net assimilation rate, shelling%, days to 50% flowering, relative growth rate, number of seeds per pod, and number of pods per plant. The highest total effect (0.988) was observed in 100-seed weight, followed by days to first flowering (0.837), days to 50% flowering (0.701), shelling % (0.658), emergence rate (0.574), number of pods per plant (0.557), relative growth rate (-0.375), net assimilation rate (0.226), harvest index (0.183) and number of seeds per pod (- 0.126) in that order. The study demonstrated that combining correlation and path coefficient analyses is important in determining reliable trait associations that can be used for developing superior genotypes. Therefore, days to first flower, days to 50% flowering, harvest index, emergence rate and 100-seed weight should be considered as major selection indices for the improvement of the Bambara groundnut in the Jos-Plateau environment in Nigeria. Key words: Correlation, direct effect, indirect effect, grain yield, Vigna subterranea (L.) Verdc.