Genetic parameters of some economically significant characteristics of Thryonomys swinderianus

Heritability of weight at 4 months of age (P4), weight at 8 months of age ( P8), docility (DOC) and litter size (TAIL-P) in grass-cutter (Thryonomys sw inderianus) as well as the genetic and phenotypic correlations between each two traits were estimated using two basic approaches: offspring-parent reg ression and analysis of variance in hierarchical half- and full sib groups. The data used consisted of five generations of unselected animals. Analyse s of variance yielded noticeably higher estimates of heritability coefficie nts in comparison with regression methods. Analysis of variance estimates.. of heritability coefficients were 0.52 +/- 0.14, 0.58 +/- 0.16, 0.19 +/- 0 .06 and 0.12 +/- 0.04 respectively for weight at 4 months of age, weight at 8 months of age, docility and litter size. Estimates of heritability coeff icients from regression analyses were 0.42 +/- 0.08, 0.42 +/- 0.03, 0.16 +/ - 0.06 and 0.10 +/- 0.04 respectively for each trait mentioned above. Estim ates of 0.44 and 0.67 were found, respectively for genetic and phenotypic c orrelations between weight at 4 months of age and weight at 8 months of age . Estimates of genetic and phenotypic correlations between weight at 8 mont hs of age and docility were -0.34 and -0.10 respectively. Genetic and pheno typic correlations of 0.32 and 0.30 were obtained between weight at 8 month s of age and litter size.