GENETIC VARIANCE COMPONENT AND HERITABILITY ESTIMATES OF FREEDOM FROMWEEVIL INJURY TO SWEET-POTATO

Abstract. Narrow-sense heritability for component traits of freedom fr om weevil injury and yield of sweetpotato were estimated by parent-off spring regression and variance component analysis. Heritability estima tes by variance component analysis based on half-sib families for perc ent and number of uninjured roots were 0.25 and 0.83, respectively. In dividual plant heritability estimates for uninjured root percent and n umber were 0.03 and 0.13, respectively. Heritability estimates by pare nt-offspring regression for uninjured root percent and number were 0.3 5 and 0.52, respectively. Genetic variance was mostly additive for all traits except stem diameter. Genetic correlations between total root number, uninjured root number, and percent uninjured roots ranged from 0.66 to 0.87, indicating that selection for uninjured root number sho uld most effectively increase uninjured root number and percent, as we ll as total root numbers. Predicted gains in uninjured root percent an d number were 8.8% and 0.87 in the progeny derived from intermating th e highest four out of 19 families for uninjured root number. The 0.87 gain in uninjured root number equals a 24% increase in one breeding cy cle.