IMPROVEMENT OF SNOW MOLD RESISTANCE BY CONVENTIONAL AND IN-VITRO TECHNIQUES

Under our climatical conditions Microdochium nivale is the main pathog en which causes snow mould in grasses. Like many Fusarium species, M. nivale is able to produce toxins like Deoxynivalenol (DON). In vitro s election with callus cultures from two populations of perennial ryegra ss and DON as selective agent was carried out in a one step (subcultur e) or two step procedure (induction plus subculture). The regenerants from in vitro selection and a seed derived control from the two popula tions were artificially inoculated with M. nivale. Significant improve ment of snow mould tolerance in the high DON variant could be found. A dditionally, a toxin test was established which allows to screen large numbers of mature embryos without laborious callus culture. The sexua l progenies (R1) of the regenerants were subjected to both the snow mo uld and the toxin test. Toxin and pathogen resistance were not always in good accordance. The application of both tests in practical plant b reeding is discussed.