VARIABILITY STUDIES OF YIELD RELATED CHARACTERS IN SWEETPOTATO (Ipomoea Batatas (L.) Lam) GROWN IN OSUN STATE, NIGERIA

Abstract

The study was conducted at the Teaching and Research Farms of Osun State University, Osogbo (Ejigbo campus), and University of Ilesa, Osun State, over two years to assess variation among cultivars of sweet potato. Forty-five accessions were evaluated using a randomized complete block design with three replications, and data were collected on yield and related agronomic traits. Significant effects of genotype, environment, and year were observed for most traits. Genotype × environment interaction was significant for petiole colour (8.78), internode length (1.12), vine length (3.12), petiole length (0.006), and fresh root yield (1.06), indicating differential cultivar responses across environments. The phenotypic coefficient of variation (PCV) exceeded the genotypic coefficient of variation (GCV) for all traits, suggesting environmental influence on trait expression. PCV ranged from 5.44% for mature leaf length to 148.96% for dry matter, while GCV ranged from 5.44% for mature leaf shape to 86.39% for petiole colour. Heritability was highest (100%) for mature leaf length, leaf shape, and abaxial leaf vein pigmentation, with corresponding genetic advance values of 20.15, 11.21, and 29.59, respectively. Fresh root yield and vine length exhibited moderate heritability coupled with high genetic advance. Significant genotypic and phenotypic correlations were observed among key traits. Path analysis indicated that mature leaf length had the highest direct effect on dry matter, suggesting its importance as a selection criterion for improvement. Overall, the results demonstrates substantial genetic variability and highlight key traits that can be effectively targeted to enhance sweet potato performance and quality in the study environments.