VARIATION, HERITABILITY AND SELECTION RESPONSE OF SEVERAL CHARACTERS IN WHITE YAM (dioscorea rotundata poir)

Abstract

Phenotypic and genotypic coefficients of variation, heritability, expected genetic gain and selection response were estimated for several agronomic characters among 40 selected clones of white yam. Three hybrid varieties (89-02565, H-2665, 89-2677) were included in the study as checks. Significant mean squares were observed in days to emergence, vine length, spininess, number of vines, and number of tubers, tuber length, tuber girth, tuber yield per hill, fresh tuber yield, and dry tuber yield among the selected 40 clones. Among the selected clones, fresh tuber yield varied from a minimum of 1.5 t/ha to a maximum of 25.5 t/ha. On the contrary, the fresh tuber yield of hybrid checks varied from a minimum of 6.0 t/ha to a maximum of 13.5 t/ha. The magnitude of phenotypic variance and phenotypic coefficient of variation were higher than genetic variance and genotypic coefficient of variation for all characters respectively. High heritability along with high genetic gain and high response to selection were observed for days to emergence, vine length, number of leaves, leaf area, number of vines, number of tubers, tuber per vine, tuber yield per hill, fresh tuber yield, and dry tuber yield. The study revealed that under more suitable environment, single plant selections followed by vegetative propagation should improve selection progress for higher tuber yield.