Repeatabilty of general and specific combining ability effects of seedling and clonal generations in potato

The relative magnitude of general combining ability (gca) and specific combining ability (sca) effects in three generations (years), viz. Seedling (SG), first clonal generation (FCG) and second clonal generation (SCG) for tuber yield, tuber number, average tuber weight and tuber dry matter of potato in a line x tester mating design (10 4) was studied. There were marked differences in the gca effects of 14 parents. GCA and SCA for various characters varied from generation to generation. In general the correlation between various generations was varied and general conclusion could be arrived except in case of gca effects of males for dry matter. Considering the consistent performance over various generations for general combining ability, genotypes viz., MP/92-136, MP/91-65 and MP/90-95 for tuber yield and MP/92-136 for tuber number, Kufri Jyoti, for average tuber weight and MP/91-65 and QB/A-9-120 for dry matter were good general combiners, both in seedling and clonal generation. Similarly the crosses with consistent performance of specific combining ability over generations are cross MP/92-136 x Kufri Chipsona-1 for tuber yield and average tuber weight and QB/A-9-120 x MP/90-94 for tuber number and dry matter, were consistently good specific combiners in all generations. The variation in general combining ability effects over generation observed in the present study for tuber dry matter can be attributed to genotype environment interaction. Hence, combining ability to select suitable parents for potato breeding has to be done based over years/generations. Parents and crosses with consistent performance over generations and those specifically suitable for breeding for processing quality were identified.