Molecular characterization of salt tolerance of wheat genotypes using microsatellite markers and stress tolerance index

Salinity affects wheat ( Triticum aestivum L) plants growth by the osmotic stress of the salt around the roots, as well as by toxicity caused by excessive accumulation of salt in leaves. Therefore, salinity has a limiting factor for wheat crop in Saudi Arabia. In this study, twenty wheat genotypes (5 genotypes from ICARDA, 7 genotypes from Pakistan, 5 Australian genotypes, one American genotype (YocoraRojo), one Egyptian genotype (Sakha 93) and one local genotype (Sama)) were subject to different salinity levels of Irrigated water ( control, 4000, 8000 ppm NaCl). The trial was conducted under green house environmental condition at Qassim University Agricultural Research and Experimental Station to observe stress susceptibility index (SSI) based on grain yield plant-1. The genetic variation and relationships among different wheat genotypes with different responses to salt stress were also investigated by SSR markers. The results showed that Auqab 2000, Bhan 2000 and Shaka 93 scored the lowest SSI value. These genotypes can be considered as salinity resistant varieties In addition, the result of genetic variation reveled that there are two main groups at genetic similarity at (0.69), the first group divided into four subgroups where genotype IC1 in the first subgroup and the second subgroup divided into two sub-sub-group at similarity (0.80). The first sub-sub-group included genotypes Sakha93, YocaraRojo, IC16, P7, P8, IC17, Bhan2000, Pasban90, and Auqab2000 and the second sub-sub-group included Sis27, Sis32, Inq91, and P6 and with similarity (0.85), and the third sub-group included IC96. While, the fourth sub-group included the least salt tolerance genotypes (local and IC15, P2, P9). Thus, the three wheat genotypes that show salt tolerance (Sakha93, Bhan2000 and Auqab2000) are in one group after using SSR markers that linked to salt tolerance. These genotypes can be used in wheat breeding programs for salt affected areas.