Analyzing genetic variation for important yield-contributing attributes in genotypes of orange-fleshed sweet potatoes

Abstract

An experiment was conducted to estimate genetic variability of 47 orange-fleshed sweetpotato(OFSP) genotypes. It was established in two locations(Umudike and Igbariam) in a RCBD fashion with three replications. Data collected were subjected to ANOVA using the software; AGD-R. The results showed that all the characters studied were highly significant (p<0.01) for genotypes. All the traits were significant for location except the vine length, days to 50% flowering and root yield. Most of the characters were also significant for genotypes-location interaction. Significant differences observed among genotypes for most traits indicated the presence of genetic variation among the materials. The genotypic coefficient of variation(GCV) was very high for beta carotene(73.8%) and vitamin A(70.0%). Phenotypic coefficient of variation(PCV) was very high for beta carotene(183.5%), root yield per hectare(151.6%), total root weight per plant(150.6%) and total number of roots per plant(113.5%). The PCV was higher than their corresponding GCV for all the characters studies, indicating that the expression of these characters was influenced by environment. The GCV was consistently higher than PCV in all the traits. The genotypic variance was high for days to 50% flowering(373.16), dry matter(220.30), root girth (140.73), root length (68.10) and root yield per hectar (349.66). The magnitude of VA was consistently larger than that of VD for all the traits suggesting that the additive genetic variance was more important than the dominance genetic variance in the inheritance of most studied traits. All the characters studies had high heritability (>60%). High heritability estimates for those traits indicated a high response to selection