Abstract:In order to study the effects of physiological, morphological indexes and the physiological mechanism on drought stress for Fagopyrum tataricum cultivars, we took the pot experiment of artificial water control and three water treatments included normal irrigation, moderate water stress, and heavy water stress. The experimental materials included ‘Diqing’, ‘Xinong9909’, ‘Heifeng1’ and ‘Xiqiao1’. Three results were drawn from this experiment. (1) Compared to the normal water treatment, the main root length of ‘Diqing’ and ‘Xinong9909’ increased under the heavy water stress; The plant height, stem diameter, leaf area, shoot dry weight, root dry weight, root volume, root area of ‘Heifeng1’ and ‘Xiqiao1’ decreased, and the decrease of drought tolerant cultivars were less than those of nondrought tolerant cultivars. Besides, the drought stress made root/shoot ratio increased of ‘Diqing’ and declined of other cultivars. (2) Drought stress could make chlorophyll content, leaf relative water content, Fm, Fv/Fm, root activity and soluble protein content significantly decreased, but superoxide dismutase (SOD) activity, peroxidase (POD) activity, malonaldehyde (MDA) content, soluble sugar content and free proline content increased. Also, there were differences of up or down for different varieties. (3) Subordination function method and principal component analysis were used to synthetically evaluate the drought resistance of different F. tataricum genotypes. We found out that the resistance ranking (‘Diqing’> ‘Xinong9909’> ‘Heifeng1’> ‘Xiqiao1’). The results of correlation analysis showed that plant height, root dry weight, dismutase (SOD) activity, soluble protein content were significantly correlated with D value and the proline content and soluble sugar content were very significantly correlated with D value. The study has shown that ‘Diqing’ and ‘Xinong9909’ had the best performance for the indexes of various aspects under two kinds of drought conditions, thus we could conclude that these cultivars had better adaptability under drought environment. ‘Heifeng1’ and ‘Xiqiao1’ had the poor performance, which showed low drought resistance. At the same time, plant height, root dry weight, dismutase (SOD) activity, soluble protein content, proline content and soluble sugar content can be used as indicators for the rapid determination of drought resistance.