In this study, 24 wheat varieties (lines) grown in the Huanghuaihai region were chosen as experimental materials. The wheat plants were grown in pots outdoors, and they were moved into an artificial climate chamber to receive a cold treatment at booting stage. Seven physiological indicies in leaves were measured after cold treatment to understand the physiological cold resistance of different wheat varieties. The results showed that the relative electrical conductivity, soluble sugar content, MDA content and SOD activity showed higher values in the low-temperature treated plants than those in the control plants (P<0.01), and POD activiey was lower than that of CK, while soluble protein and free proline content showed fluctuations among different vatieties. Among the 7 indicies, the relative value of relative electrical conductance was the highest, and the relative value of POD activity was the lowest. For each wheat variety, the relative character values were used to calculate the average subordinative function value by the subordinative function method, and the comprehensive score by the polar ordination method. The average subordinative function values ranged from 0.17 to 0.64 and the comprehensive scores ranged from 1.93 to 4.02. Correlation analyses showed that the average subordinative function value and comprehensive score were significantly and positively correlated with soluble sugars content, soluble protein content and SOD activity (P<0.05), meanwhile they were significantly and negatively correlated with MDA content and relative electrical conductivity (P<0.05). Using K-means clustering analysis, the 24 winter wheat cultivars were divided into five groups named as strong, high, medium, low, and weak according to their cold resistance. The strong cold resistance group contained Jimai 585 and Shi B05-7388, and Shannong 055843 and C-44 were in the weak cold resistance group. |