Germination and seedling development of drought tolerant and susceptible wheat under moisture stress

The aim of this study was to investigate the responses of drought tolerant and susceptible wheat cultivars to osmotic stress during germination and seedling growth, and to identify characters that can be used for screening genotypes. Cultivars known to be differently tolerant to drought were used. Germination and seedling growth tests were conducted at 0, 0.5, -1.0, -1.5 and -2.0 MPa. Tolerant cultivars had higher percentage germination and germination speed under moisture stress than susceptible cultivars, but germination speed was more sensitive to changes in osmotic potential than percentage germination. Root and shoot weights of all cultivars were reduced when osmotic potential was decreased, but the extent of reduction in root growth was less than that for shoots. Shoot to root ratio measurements were not always consistent with tolerance ratings. Root leakage ratio increased with decreasing osmotic potential, but no cultivar differences were observed. Tolerance, at least up to the seedling stage, could not be ascribed to one or two traits but was due to a number of traits, only some of which were present in a single cultivar.