SELECTION ON THE BASIS OF PROGENY TEST WITH LOW-HERITABILITY TRAITS

Methods of selection based on progeny evaluation with that based on ow n performance were compared. Twelve generations of mice were selected by these methods for a low-heritable trait, i.e. body weight at weanin g (21st day of life). No significant differences were found in respons e to selection and cumulative selection differentials between these tw o methods. The realized heritabilities were 0.24 for the progeny test line but above 1 for the mass selected line. Significant differences w ere found between correlated responses to selection in the group of ma les at 42 days of age and in weight gains. Realized genetic correlatio ns estimated for the growth traits were high in the performance test g roup (0.83 with 6-week weight and 0.78 with body gains) and overestima ted in the progeny test group. Results demonstrated a larger correlate d response for the progeny test group relative to the performance test group.