A Rapid Screening Method for Testing the Resistance of Cotyledons to Downy Mildew inBrassica napusandB. campestris

摘要

AbstractSeveral hundred breeding lines of summer and winter forms of turnip rape as well as winter rape, were sown on greenhouse tables filled with soil. A week later the cotyledons were artificially inoculated and covered with a plastic tunnel. Approximately two weeks later the average percentage of the wilted leaf area was estimated.The method is rapid and demands little labour. It is therefore suitable for testing large numbers of breeding lines. The response toPeronospora parasitica(Pers. ex Pers.) Fr. in the rape material varied from being highly susceptible to highly resistant. Only minor differences were detected between lines with high and low glucosinolate contents. All the turnip rape material had very high resistance toP. parasiticaat the cotyledonous stage.