Identification of drought resistance and screening of evaluation indexes of 80 potato germplasm resources introduced by CIP

<bold>Objective</bold> The primary constraints that restricted the development and innovation of potato germplasm includes the relative scarcity of germplasm resources，the homozygous genetic background，and the close genetic relationships.In addition，drought poses a major threat to potato（<italic>Solanum tuberosum</italic> L.）production.Therefore，the selection of superior and drought-resistant germplasm resources can not only effectively deal with the challenges of potato production brought by drought，but also provide an important solution for alleviating the narrow genetic background and germplasm resource shortage of Chinese potato. <bold>Method</bold> In this study，80 tetraploid germplasm resources with good performance were selected from about 300 high-generation germplasm resources of TON panel evaluated by International Potato Center （CIP）phenotypic observation as experimental materials，and field experiments were conducted in Dingxi Potato Research Institute，Gansu Province.15 main traits including agronomic，yield and quality were measured under normal irrigation （CK）and drought treatment （D）condition in this study.The drought response levels of the 80 potato germplasm resources were evaluated by correlation analysis，principal component analysis，membership function analysis，cluster analysis and step regression analysis. <bold>Result</bold> 12 representative indexes were selected by calculating the drought resistance coefficient（<italic>P_I</italic> ）and coefficient of variation（CV）of each index.The drought resistance coefficients of 12 separate variables were converted into 6 independent comprehensive indicators using principal component analysi （the cumulative contribution rate was 80.45%）.Based on the comprehensive assessment value（<italic>D</italic> value）and cluster analysis，the 80 potato accessions were classified into 3 categories，with 9 accessions including B20，B40，B55 etc.clustered in Class I which were highly drought resistant，Class Ⅱ contains 62 accessions including B32，B77 and B28，which was identified as moderate drought resistant，whiles Class Ⅲ consisted of 9 accessions including B73，B42 and B19 belonging to drought sensitive types.Furthermore，a regression model for drought resistance evaluation was established by stepwise regression analysis，<italic>Y</italic>=-0.138+0.198PH +0.080RL+0.109LAI+0.144RFW+0.162TDW+0.079RSC（<italic>R</italic>²=0.917，<italic>P</italic>=0），and the estimated accuracy was above 86.6%.The results showed that the model could be used for the screening of drought-resistant potato germplasm resources. <bold>Conclusion</bold> Nine strains，including B20，B40 and B55，were highly resistant to drought and can be selected as hybrid parents to breed drought-resistant varieties of potato.Plant height，total root length，leaf area index，total fresh root weight，dry weight of potato block per plant and reducing sugar content can be used as predictive indexes for rapid selection of drought-resistant potato germplasm resources，making it easier to evaluate and identify potato drought resistance.