Abstract: In order to quickly evaluate the salt tolerance of diploid potato germplasm resources, five morphological indices and eight physiological and biochemical indices of plantlets in vitro of 17 diploid potato clones were measured using principal component analysis, subordinate function analysis, clustering analysis, and stepwise regression. The five morphological indices were simplified into one independent comprehensive index, while the eight physiological and biochemical indices were simplified into four independent comprehensive indices using principal component analysis. Those seventeen clones were classified into three clusters with different salt tolerance using cluster analysis, with A038, A002, and A024 being classified into the salt tolerance cluster. A regression equation of salt tolerance evaluation was established by morphological index. Shoot length, shoot dry weight, root fresh weight, root dry weight, relative water content, MDA content, and proline content could be used to quantify salt tolerance of potato in vitro. This study provides reference for evaluating salt tolerance of potato in vitro, and provides germplasm resources for breeding salt tolerant potato varieties.

Key words: potato, diploid, salt stress, principal component analysis, subordinate function, stepwise regression.