Effectiveness of in vitro selection for agronomic characters in potato

Effectiveness of in vitro selection for agronomic characters was studied by finding correlation coefficients between in vitro and in vivo performance of 22 potato genotypes. Evaluation was performed under eight in vitro and two in vivo conditions. Genotypic differences were highly significant for various characters under all in vitro and in vivo conditions. Error mean squares were much lower in in vitro experiments than in in vivo experiments. In vitro selection was found to be highly effective for tuber colour, stem pigment and number of eyes, and moderately effective for average tuber weight, plant vigour and foliage senescence under specific conditions. The results also indicated the possibility of in vitro selection for heat tolerance. For tuber yield and number of tubers, effectiveness of in vitro selection was low to very low, because differences in phenotypic expressions of genotypes were much enlarged under in vitro conditions compared to under in vivo conditions. Correlation coefficients for certain characters were better when in vitro conditions were closer to in vivo conditions. To improve the efficiency of in vitro selection, there is perhaps a need to simulate and identify the in vitro conditions under which genotypic differences are reflected in phenotypes more realistically as they are expressed under in vivo conditions.