SCREENING FOR DROUGHT TOLERANCE - EVALUATION OF SEED-GERMINATION AND SEEDLING GROWTH FOR DROUGHT RESISTANCE IN LEGUME PLANTS

Experiments were performed to evaluate seed germination and seedling g rowth in simulated drought as screening techniques for drought toleran ce rating. Several laboratory screening tests were evaluated for abili ty to estimate drought resistance in 18 cultivars of legume plants (fi eld bean, soybean, field pea, lupine). Drought was simulated by a wate r solution of mannitol of chemical water potential psi = -0.3 and -0.6 MPa. Both solutions significantly affected seed germination (final ge rmination and promptness index) and seedling growth parameters (seedli ng height, dry matter of shoot and root as well as leaf injury by drou ght and high temperature). The tested cultivars could be grouped as dr ought resistant and drought susceptible plants. Drought tolerance rati ngs of legume plants in the laboratory tests were, on the whole, consi stent with the ratings based on estimation of direct effects of soil d rought on seed yield in field experiments. Measurements of electrocond uctivity of leaf diffusate to evaluate invisible injury caused by drou ght or high temperature were found to be an adequate criterion for dro ught tolerance rating. It is concluded that tolerance to drought stres s in growing seedlings can be screened for by using mannitol containin g nutrient solution. According to the results collected in this resear ch, varieties differences in seed germination, seedling growth and lea f injury affected by drought or heat temperature were evident, however , not all treatments appeared to be equally useful for screening of le gume species cultivars.