Abstract: In this study, four potato cultivars (lines) were treated with two simulated drought conditions, namely, artificial water control in pot culture and PEG6000 stress in tissue culture. The differences of their drought tolerance were evaluated by morphological and physiological indices, aiming to provide the basis for potato resistant cultivation and breeding of drought-tolerant cultivars. Normal irrigation (CK) and two drought stress treatments were set up in potted planting including moderate drought (T1, relative soil moisture index 45%±5%) and mild drought (T2, relative soil moisture index 55%±5%). Four PEG-6000 levels (5%, 10%, 15%, 20%) were set up for the tissue culture seedlings. We measured the average yield per plant, nine morphological indicators, and six physiological indicators of the potted planting potatoes. Three methods were used to analyze the experimental data. The drought tolerance of the tested materials was preliminarily evaluated and verified by tissue culture seedlings. The results showed that the drought-tolerant germplasms screened by two different simulated drought treatments were consistent. Drought-tolerant cultivars (lines) were the advanced strain D1520 and “Dianshu 97”, and drought-sensitive cultivars were “Qingshu 9” and “Dianshu 1418”. Seven indicators that were more sensitive to drought stress were identified from fifteen indicators, including abscisic acid content, peroxidase activity, number of leaves, plant height, number of nodes, number of branches, and leaf angle. Among them, number of leaves of each cultivar (line) could be used as an important index for drought-tolerant evaluation after being verified by the tissue culture experiment.

Key words: potato, drought stress, tissue culture seedling, PEG-6000, principal component analysis, membership function