Abstract:

A total of 159 wheat samples imported from the International Center for Agricultural Research in the Arid Areas (ICARDA) were used as the research subjects. To simulate drought conditions during the seedling stage, 20% PEG-6000 was applied, while a normal nutrient solution served as the control. The effects of drought on 7 physiological traits related to the seedling stage (malondialdehyde content, superoxide dismutase activity, relative conductivity, peroxidase activity, soluble sugar content, proline content, and chlorophyll content) were analyzed. Correlation analysis of drought resistance-related physiological traits in the 159 wheat samples was conducted using a 55K SNP chip. The results indicated that, following drought treatment, the levels of proline and soluble sugars increased, whereas other traits did not show consistent trends. Under normal conditions, malondialdehyde content was significantly positively correlated with peroxidase activity and highly significantly negatively correlated with proline content; peroxidase activity was highly significantly negatively correlated with soluble sugar content. Under drought stress, soluble sugar content was significantly positively correlated with malondialdehyde content and relative conductivity, while chlorophyll content was highly significantly positively correlated with soluble sugar content and significantly negatively correlated with proline content. Association analysis identified 311 drought resistance-related markers (P ≤ 0.001) across 24,151 SNP loci, distributed on all 21 wheat chromosomes, with contribution rates of 7.13%–21.11%. Eight stable loci were detected under both treatments, located on chromosomes 1B, 2B, and 6A, with contribution rates of 7.85%–14.58%. Additionally, a multiple effector locus associated with both superoxide dismutase activity and soluble sugar content was found on chromosome 3D, with a contribution rate of 7.95%–8.69%. Four significant loci associated with the drought resistance coefficient of relative conductivity, peroxidase activity, chlorophyll content, and traits such as relative conductivity, peroxidase activity, proline content, and superoxide dismutase activity under drought treatment were detected on chromosomes 2D, 3A, and 4A, with a contribution rate of 7.61%–14.74%.

Key words: wheat, seedling stage, physiological indicators, SNP, correlation analysis