Screening the salinity tolerance of the wheat cultivars at germination and seedling stages

One of the most significant objectives of plant breeding experts is enhancing the salinity tolerance of crops and screening the tolerant ones. The present study was carried out in an attempt to evaluate and screen the salinity tolerance of the wheat cultivars at germination and seedling stages. The experiment followed a split plot, randomized complete block design and was conducted in three replications. The main and sub plots respectively included: the wheat cultivars and the salinity levels (i.e. 0, 50, 100, and 150 mM NaCl). The traits under analysis at germination stage included: germination percentage, radicle length, hypocotile length, coleoptile length, radicle fresh and dry weight, and hypocotile fresh and dry weight. In addition, shoot fresh and dry weight, relative water content (RWC), sodium and potassium contents, potassium to sodium ratio, chlorophyll content, prolin, and the total leaf area were investigated at the seedling stage. The results indicated that there was significant difference at P<0.01 among the wheat cultivars, considering all of the traits and salinity levels. Salinity significantly increased sodium and prolin, while it significantly decreased all of the other traits. The regression analysis revealed that there was a linear relation between all of the traits except for the coleoptile length, potassium content, potassium to sodium ratio, prolin, and the total leaf area. Finally, on the basis of the most significant salinity tolerance indices, i.e. dry weight, sodium content, potassium to sodium ratio, RWC, prolin, and the total leaf area, Hamoon and Hirmand cultivars might be introduced as tolerant cultivars. Alvand cultivar demonstrated moderate tolerance. The cluster analysis also placed Hamoon and Hirmand cultivars in one group, which confirms the aforementioned results.