不同基因型春小麦种质苗期抗旱性评价OA

To explore the drought resistance of different genotypes of spring wheat germplasm at the seedling stage under drought stress,15 spring wheat germplasm resources from different sources were used as materials.Under different degrees of drought stress,the indicators including root length,root volume,root surface area,seedling fresh weight,seedling length,and superoxide dismutase(SOD)were determined.Multiple methods such as cluster analysis,membership function analysis,correlation analysis,and principal component analysis(PCA)were comprehensively applied to conduct a comprehensive and systematic evaluation of the drought resistance of spring wheat germplasm.There were significant differences in drought resistance among the 15 spring wheat germplasm resources.Under mild drought stress,the coefficient of variation(CV)of each indicator ranged from 7.60％to 39.05％.Under severe drought stress,the CV ranged from 8.51％to 37.89％,and under control conditions,the CV ranged from 7.96％to 47.84％.Compared with the control,seedling length,chlorophyll content,and seedling fresh weight of all spring wheat germplasm decreased to varying degrees under drought stress(both mild and severe),while the activities of peroxidase(POD),catalase(CAT),and SOD as well as the content of malondialdehyde(MDA)increased to varying degrees.Through PCA,13 seedling-stage indicators were divided into 4 principal components.The contribution rates of the 4 principal components under mild drought stress were 45.98％,16.18％,11.71％,and 8.69％respectively,while those under severe drought stress were 47.88％,14.30％,12.74％and 8.72％respectively.Based on the drought resistance coefficients of each physiological indicator and combined with the principal component eigenvectors determined in the PCA process,the comprehensive drought resistance coefficient(D value)was finally obtained through systematic calculations.The drought resistance of the 15 spring wheat germplasm was ranked according to the D value,and cluster analysis based on the D value divided the tested germplasm into 4 groups respectively under mild and severe drought stress.One highly drought-resistant germplasm(Ganchun 0058)and two drought-sensitive germplasm(Ganchun No.33,IBWSN 93)were screened out.Seedling fresh weight,seedling dry weight,root fresh weight,root dry weight,root length,and root surface area were identified as effective indicators for evaluating the drought resistance of spring wheat germplasm at the seedling stage.