Institute of Vegetables and Flowers，Chinese Academy of Agricultural Sciences，Key Laboratory of Biology and Genetic Improvement of Tuber and Root Crops，Ministry of Agriculture and Rural Affairs，Beijing 100081，China
Abstract：Potato is an important grain-vegetable-forage crop．In China it is mainly distributed in arid and semi-arid areas．Drought severely affects potato production．Therefore，it is of great importance to screen drought-resistant germplasm and foster varieties with drought resistance and high-yielding potential．This study firstly evaluated the drought resistance of diploid populations containing 121 genotypes，and divided them into 5 categories according to the drought resistance coefficient．Among them，16 were extremely drought-resistant and 14 were highly drought-sensitive．One genotype was further selected from each category for further studies，namely conducting different water treatments，measuring plant height，photosynthesis and chlorophyll fluorescence related indicators and yield，etc. and calculating each indicator’s correlation with yield and drought resistance coefficient．The results showed that under different water conditions，along with potato growth and development and aggravation of drought stress，the correlation of each indicator with yield and drought resistance coefficient was changed．Therefore，when screening high-yield droughtresistant materials，certain indicators need to be determined during a specific period．Under pot culture conditions，substrate relative water content was 35%-45%，the drought resistance coefficient of each genotype had the highest correlation with that in the fields．And there were maximum indicators having the significant relationship with the drought resistance coefficient under this water treatment．Plant height and Chl at budding stage and P_WUE and Tr at full blossom stage were significantly correlated with yield，which could be used preliminarily to determine the yield of each genotype．At full blossom stage，P_WUE and drought resistance coefficient was significantly positively correlated in the condition that substrate relative water content was 75%-85%，which could be used to distinguish the drought resistance of selected genotype．
