Integrated evaluation and screening of salt-tolerant wheat germplasm and indices

Successful evaluation and screening of salt-tolerant wheat germplasm at different stages are of great importance for breeding resilient crops. In the present study, we tested 30 wheat entries out of 417 American accessions screened in a previous study. Fifteen physiological and biochemical indices were investigated at the seedling stage, and eight agronomic indices at the adult stage. Principal component analysis and correlation analysis found superoxide dismutase activity, soluble protein, and potassium levels to be related to high salt tolerance at the seedling stage. Hierarchical clustering analysis identified seven accessions exhibiting high salt tolerance at both the seedling and adult stages. A Random Forest model was constructed to predict salt-resilient entries at the seedling stage. Transcriptome and quantitative reverse-transcription PCR analyses comparing salt tolerant and sensitive accessions revealed that genes and signaling pathways related to the redox system, MAPK, and plant pathogen interactions contributed to salt resistance. Our results provide basic materials for the breeding of new salt-tolerant wheat varieties, indices to screen for salt-resilient cultivars, and insights into salt-tolerance mechanisms.