ESTABLISHMENT OF TESTS FOR FACILITATING SCREENING OF DROUGHT TOLERANCE IN SOYBEAN

Abiotic stress due to environmental changes causing water deficit, extreme temperatures and low atmospheric humidity decreases plant productivity. One of the elements of overcoming the stress is to develop new varieties. However, drought tolerance has a complex nature which makes this problem difficult to solve and involves different approaches and methods. The process of creating new varieties could be facilitated by screening of genotypes with higher resistance. In this respect laboratory tests in in vitro and ex vitro conditions could complement in vivo experiments. To make stress models availability of a factor causing or imitating the stress is required. In addition, choosing appropriate criteria of correspondence between responses in field and in laboratory conditions is crucial. The high molecular weight substance polyethylene glycol (PEG) causes osmotic shock which is one of the components of the drought. Different concentrations (2-10 %) of PEG were used in our experiments. PEG was added into the media for germination of seeds and its effect on water absorption and seed development was followed. Soybean lines obtained previously and varieties (used as standard) were studied. Positive correlation between the level of drought tolerance of the genotypes in the field and in laboratory experiments was identified. The results are interesting for establishment of quick screening tests for identification of lines appropriate for breeding programs of soybean, commonly used grain legume with multiple product application.