AGB 211: Livestock and Poultry Breeding (2+1)

SELECTION FOR GENERAL AND SPECIFIC COMBINING ABILITY

• The specific combining ability of a cross cannot be measured without making and testing that particular cross. To get SCA, two lines should be developed which differ in gene frequencies. Two methods of selection are available viz., recurrent selection and reciprocal recurrent selection.
• Both these systems involve progeny testing. Due to the increased generation intervals, this would be expected to result in slower progress than other breeding systems for characters moderate to high in heritability. They would be expected to be more useful than other breeding systems only if overdominance or other non-additive types of inter- or intra-allelic gene action are important in heterosis.