Methods of screeningAcer platanoidesL. seedlings for resistance to wilt (Verticillium dahliaeKleb.)

Abstract

SummarySeveral methods of challenging young seedlings of Norway maple (Acer platanoides) with Verticillium dahliae were investigated to develop a method for screening seed provenances for wilt resistance. Seedlings were inoculated by pouring conidial suspension (106 conidia ml−1) over roots wounded in situ, or by dipping roots in the same conidial suspension at transplanting, or by transplanting germinated seed or seedlings into compost infested with a beet-seed or straw-cultured inoculum. On the basis of foliar symptoms during the growing season, and on seedling height, and vascular staining and the presence of V. dahliae in the wood at the end of the season, root-dipping was the most severe test; planting seeds or seedlings into straw-based inoculum was less severe than root-dipping but gave similar levels of infection. Beet seed was a less effective form of inoculum than straw, and inoculation of roots damaged in situ resulted in disease escape. A comparison of the root-dip technique using three, five-...