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 se edling growth, and to identify characters that can be used for screening ge notypes. Cultivars known to be differently tolerant to drought were used. G ermination and seedling growth tests were conducted at 0, 0.5, -1.0, -1.5 a nd -2.0 MPa. Tolerant cultivars had higher percentage germination and germi nation speed under moisture stress than susceptible cultivars, but germinat ion speed was more sensitive to changes in osmotic potential than percentag e germination. Root and shoot weights of all cultivars were reduced when os motic potential was decreased, but the extent of reduction in root growth w as less than that for shoots. Shoot to root ratio measurements were not alw ays consistent with tolerance ratings. Root leakage ratio increased with de creasing osmotic potential, but no cultivar differences were observed. Tole rance, at least up to the seedling stage, could not be ascribed to one or t wo traits but was due to a number of traits, only some of which were presen t in a single cultivar.