Genetic variation in wheat germplasm for salinity tolerance at seedling stage: improved statistical inference

Salinity is the major threat to global wheat production, particularly in arid and semiarid areas. Breeding salt-tolerant cultivars is one feasible solution, while the presence of genetic variation is a prerequisite for genetic improvement. To detect genetic variation for salt tolerance in wheat, a total of 150 wheat genotypes were tested for seedling-stage tolerance response at 300 mM NaCl in hydroponic culture. Significant differences (P <= 0.001) were identified in wheat for seedling traits, and 20 salt-tolerant and 5 susceptible genotypes were selected on the basis of root and shoot weights. These 25 genotypes were tested for salt-tolerance response at the early developmental stage in hydroponic culture at 0, 70, 140, 210, 280, and 350 mM NaCl salinity levels. GGEbiplot analysis was used for measuring salt tolerance for relative growth rates of root length, shoot length, and plant weight. Genotypes DH-3, 9436, DH-14, Chenab-2000, DH-13, WN-174, WN-150, STW-135, 066284, and DH-2 were the most salt-tolerant and 4072, WN-64, WN-60, WN-165, and WN-140 were the most susceptible. Biplot analysis appeared advantageous over salt-tolerance indices due to its graphical nature and ability to demonstrate genotype x environment interactions.