Screening of salt-tolerant wheat (Triticum aestivum L.) through morphological and molecular markers

Screening of wheat genotypes containing suitable candidate genes for salt tolerance is an essential step in stress-breeding. This study aimed to determine genetic variation, and screen salt-tolerant genotypes using morphological and molecular markers as selection criteria. In this study, 44 genotypes of wheat were screened at the seedling stage by hydroponic culture. The treatments included a control (1 dSm−1), and low (9 dSm−1), moderate (12 dSm−1) and high (15 dSm−1) salinity stresses. Moreover, these genotypes were subjected to marker-assisted selection using 15 salt tolerance related gene-linked simple sequence repeats (SSRs). The total salt stress response indices (TSSRI) categorized wheat genotypes into four groups; tolerant, moderately tolerant, moderately susceptible, and susceptible. TSSRI and principal component analysis (PCA) revealed that Akbar was the most salt-tolerant wheat genotype, followed by Barigom-20, Barigom-22, BW-1284, BW-1262, BW-1237, and Barigom-24. It was evident that the growth of most of the genotypes was significantly inhibited by salt treatment. The tolerant genotypes, however, had to face a lower reduction in morphological parameters. The highest value (0.7127) of polymorphism information content (PIC) was shown by the marker Xwmc17. UPGMA dendrogram showed a clear differentiation of 43 wheat genotypes into seven major clusters considering genetic similarity. Cluster-I consisted of twelve genotypes, seven of which were found salt-tolerant, cluster-VI was composed of seven genotypes, of which four emerged as salt-tolerant, and Cluster-VII accommodated three genotypes all of which were tolerant based on TSSRI. On the contrary, seven genotypes in Cluster-II, and five in Cluster-III were found salt-susceptible according to phenotypic assessment at the seedling stage. In conclusion, considering the morphological characterization and molecular markers response, Akbar, Barigom-20, Barigom-22, BW-1284, and BW-1262 are identified as tolerant genotypes. Therefore, these screened genotypes could be utilized as valuable genetic resources in wheat breeding for salinity tolerance research.