GENERAL COMBINING ABILITY AND ITS REPEATABILITY IN EARLY GENERATIONS OF POTATO BREEDING PROGRAMS

General combining ability and its repeatability in the early generatio ns of a potato breeding programme was studied by evaluating 72 progeni es (18x4) of 22 parents in a factorial mating design for three success ive generations. The mean squares for combining ability due to females , males and females x males were significant for eight out of the ten characters studied. Variance estimates due to specific combining abili ty were more important than those due to general combining ability for most of the characters in all the generations. General combining abil ity effects varied from generation to generation. Most of the correlat ion coefficients between generations for general combining ability eff ects were significant, but of moderate magnitude (0.5-0.8). Parents wi th consistent performance over generations and those specifically suit able for a TPS crop were identified.