Abstract:In order to explore the cold resistance of Hedychium species and select the cold-tolerance species, the changes in relative conductivity, contents of soluble protein and malondialdehyde (MDA), activities of superoxide dismutase (SOD) and peroxidase (POD) of 3 species and 11 cultivars of Hedychium were studied under natural overwintering condition and then their cold resistance were comprehensively evaluated by principal component analysis combined with subordinate function method. The results showed that the five physiological indexes increased at first and then decreased along the winter, and most of them reached the maximum value in the coldest month (February). In the same period, the species or varieties with strong cold resistance had low relative conductivity and MDA content, and high activities of SOD and POD, as well as soluble protein content. The correlation analysis showed that SOD activity was significantly negatively correlated with MDA content, and soluble protein content was extremely significantly positively correlated. MDA content and soluble protein were significantly negatively correlated. Principal component analysis showed that the five indicators could be converted into two principal components, with a cumulative contribution rate of 81.29%. The decreased order of cold resistance of Hedychium germplasm and cultivars by comprehensive evaluation was H. ‘Orange Crush’, H. coccineum var. aurantiacum ‘Orange Brush’, H. ‘Clown Suit’, H. chrysoleucum, H. coronarium, H. gardnerianum ‘Kahili’, H. coronarium ‘Elizabeth’, H. ‘Pink V’, H. flavescens, H. gardnerianum ‘Tara’, H. ‘Tarissima’, H. ‘Fireflies’, H. stenopetalum ‘White Stars’, and H. coronarium ‘White Starburst’. Therefore, these would provide theoretical and practical basis for the selection of excellent cold-resistant species of Hedychium and the promotion and application of variety resources.