Abstract: 【Objective】 In recent years, the low light stress has become an important limiting factor for the development of winter-cropping, protected cultivation and intercropping potato production. The objective of this study is to screen the identification indices of potato low light tolerance, and to evaluate the low light tolerance of different potato varieties, so as to provide a scientific basis for the low light tolerance potato breeding, winter-cropping and intercropping potato production. 【Method】 In a field experiment, 10 potato cultivars were used as the test materials and planted. The plants were shaded with black nets which had 70% shading rate of natural light from emergence to harvest. The natural light plants were used as the control. The plant heights, internode elongations, leaf areas and other morphological indexes, pigment contents including chlorophyll a, chlorophyll b and carotenoid and net photosynthetic rates, stomatal conductance, transpiration rates and other photosynthetic physiological indexes were measured at bud flowering stage. Yields were tested after harvest. In order to make it can be comparable among these indexes, the low-light tolerance coefficient, low-light tolerance index and each shade stress index were calculated by varies of yields and other traits, then the low-light tolerance coefficients and low-light tolerance indexes expansion values were used to evaluate low-light tolerance types of different potato varieties. After that, correlation analysis were performed according to the indexes of stress index respectively with low-light tolerance coefficients and low-light tolerance indexes, screening significant related indicators. 【Result】 The potato varieties were changed in morphology, physiology, and yield after shading treatment. Compared with the control, plant heights, internode elongations and the leaf areas were increased; the chlorophyll a, chlorophyll b and total chlorophyll contents were increased, the chlorophyll a/b values were decreased, and the carotenoid contents showed an increasing trend; the net photosynthetic rates, instantaneous water use efficiencies, and stomatal conductance were decreased, the transpiration rates were increased and intercellular CO2 concentrations showed an increased trend; tuber weights were decreased significantly by 62.14%-90.74%. The assessment results showed a similar trend in tolerance by low-light tolerance coefficients method and low-light tolerance index method. Low-light tolerance index not only reflects the potato yield sensitivity to shading stress, but also reflects the influences of different genotype differences on the yield, the evaluation results of the low-light tolerance index was more strict than the method by low-light tolerance coefficient. There are 6 stress indexes including leaf area, per plant tuber weight, chlorophyll a, chlorophyll b, total chlorophyll and carotenoid content were significantly or extremely significantly correlated with the low-light tolerance coefficient or low-light tolerance index, which can be used as the effective indicators to identify the low-light tolerance of potato.【Conclusion】 After comprehensive evaluation, it was concluded that the ‘Zhongshu20’ has a high low light tolerance, ‘Woff’ has a moderate low light tolerance, ‘Favorita’ and ‘Hui-2’ have a poor low light tolerance, and other potato varieties have a bad low light tolerance. The way to use the low-light tolerance coefficient and low-light tolerance index as the main index, and combined with the related morphological, physiological and yield indexes for evaluation of the low-light tolerance of potato varieties is a more objective, reliable and convenient method. Key words:

Key words: potato (Solanum tuberosum L.), low-light tolerance, low-light tolerance coefficient, low-light tolerance index, evaluating indicator