General combining ability and its repeatability in early generations of potato breeding programmes

General combining ability and its repeatability in the early generations of a potato breeding programme was studied by evaluating 72 progenies (18x4) of 22 parents in a factorial mating design for three successive 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 ability were more important than those due to general combining ability for most of the characters in all the generations. General combining ability effects varied from generation to generation. Most of the correlation coefficients between generations for general combining ability effects were significant, but of moderate magnitude (0.5-0.8). Parents with consistent performance over generations and those specifically suitable for a TPS crop were identified.