ESTIMATION OF GENERAL AND SPECIFIC COMBINING ABILITIES IN POTATO

Abstract

Seven quantitative traits of the cultivated potato (Solanum tuberosum L.) were studied in a partial diallel cross experiment. Large specific combining ability effects were observed for total and marketable yields, total number of tubers, and number of marketable tubers. Large general combining ability effects were obtained for average weight per tuber, average weight per marketable tuber, and specific gravity. The SCA effect for specific gravity was also significant. It is suggested that the difference of combining ability performance noted above for the two yield components was due to a long history of directional selection for high yield and stabilizing selection for tubers within the marketable size range. There were low frequencies of both GCA and SCA effects showing significant difference from the population mean. This is interpreted as an affirmation of the narrow genetic base which exists in the present gene pool in Solanum tuberosum. Heritability estimates based on GCA effects indicated that parents can be efficiently selected for average tuber weight and specific gravity.