Abstract
Fifty-seven F1C2 genotypes of potato (Solanum tuberosum L.) were evaluated together with eight commercial varieties for stability of tuber yield and its component characters in four environments. For tuber yield, the average tuber weight and harvest index and the magnitude of non-linear [environment + (genotype x environment)] component was higher in comparison with genotype x environment (linear) component of genotype x environment, however, for number of tubers per plant, the linear component was higher compared to the non-linear. In general, the behaviour of genotypes over environments was likely to affect selection of highyielding and stable genotypes from the breeding materials. On the basis of three stability parameters, viz., ?i (genotypic mean expressed as phenotypic index = Pi), b1 (phenotypic stability), and S2di (deviation from regression), genotypes such as G-8, G-44, G-15, G-28, and G-33 were stable and suitable under favourable environments for tuber yield, while genotypes G-57, G-22, and V-65 were stable with high sensitivity to rich environments for tubers per plant. Genotype G-23 was stable under better environments for average tuber weight. Genotypes G-57 (bi > 1) and G-49 (bi = 1) had stability for harvest index under favourable and average environments, respectively. It was observed that genotypes G-8, G-44, G-15, G-28, and G-33 were the most desirable genotypes for tuber yield. Among the cultivars, Kufri Bahar (V-62) and Kufri Lauvkar (P-58) showed high performance (Pi > 0), average response (bi = 1), and instability (S2di > 0). Jalandhar-I was the best environment for tuber yield and its components.
