Abstract: 【Objective】This paper aims to probe the relationship between agronomical characters and physi-biochemical indexes of wheat cultivar with its drought tolerance. 【Method】 12 indexes, including 5 agronomical characters and 7 physi-biochemical indexes that measured in 65 wheat cultivars grown at drought shelf and no-irrigation conditions, were analyzed using gray relational grade analysis method. 【Result】 Gray correlation degrees facilitating to identify the drought tolerance of wheat were calculated between each index and its drought resistance index, they were ranked as follows by their contribution to drought tolerance: stomata conductance (γ=0.7995), photosynthetic rate (γ=0.7909), transpiration rate (γ=0.7556), soluble sugar content (γ=0.7467), MDA content (γ=0.7336), dissociative proline content (γ=0.7267), spike length (γ=0.7102), number of kernel per spike (γ=0.7095), 1000-kernel weight (γ=0.7005), water potential (γ=0.6959), tiller (γ=0.6951), plant height (γ=0.6866). And the clustering analysis based on the weighted drought index of cultivars could finely represent their breeding and application areas. Species that have the best drought resistance among the 65 species are: Luohan 6, Xiaoyan 6, Jinmai 47, Shanmai 168 etc. 【Conclusion】 The result indicates that the physi-biochemical indexes related to leaf stomata have the closest relationship with the drought resistance of wheat, and these indexes are significantly influenced under water stress, thus have the greatest relation degree with drought resistance index, so the physi-biochemical indexes including stomata conductance, photosynthetic rate and transpiration rate should be used for the assistant selection of drought tolerance to improve the selection efficiency.

Key words: Wheat, Drought tolerance, Agronomic characters, Physi-biochemical indexes, Gray correlation analysis