Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/28/2004
Publication Date: 1/4/2005
Citation: Wang, Z., Casler, M.D., Stier, J.C., Gregos, J.G., Maxwell, D.P., Millett, S.M. 2005. Genotypic variation for snow mold reaction among creeping bentgrass clones. Crop Science. 45:399-406. Interpretive Summary: Creeping bentgrass is an excellent grass for use on golf courses, but current cultivars suffer from a high level of susceptibility to fungi that cause snow mold disease. We evaluated a population of creeping bentgrass clones for reaction to snow mold fungi and found a large amount of genotypic variation within this population. The most resistant clones came from old golf course fairways on which there had been many years of natural selection for tolerance to snow mold fungi. Reactions to several isolates of snow mold fungi were positively correlated, indicating that resistance can be developed to a range of snow mold fungi that infect bentgrass. The information and germplasm derived from this study will be of great value to bentgrass breeders and, with the development of snow-mold resistant cultivars, to golf course superintendents by reducing their dependence on pesticides. This, in turn, will benefit the environment and the general public.
Technical Abstract: Creeping bentgrass (Agrostis stolonifera L.) is currently the most desirable grass for golf courses in temperate climates. In temperate climates, creeping bentgrass is highly susceptible to snow mold fungi that can cause significant injury and mortality on golf courses. The objectives of this study were to survey a collection of creeping bentgrass clones for reaction to snow mold fungi (Typhula spp.), to identify clones with potential resistance to snow mold fungi, and to identify ecological factors related to necrotic reactions of creeping bentgrass clones to snow mold fungi. Three hundred sixty creeping bentgrass clones, selected from old golf courses in Wisconsin, were evaluated for necrosis reaction during incubation and recovery periods following inoculation with Typhula ishikariensis or as non-inoculated controls. Genotypic variation was observed for tolerance to snow mold and cold, dark (non-inoculated) conditions but the two tolerances were uncorrelated with each other. Clones from fairways were more tolerant of snow mold, most likely due to long-term natural selection in the absense of fungicide applications. In a second experiment involving 72 selected clones, selection was successful identifying divergent groups of clones, although some lack of repeatability between experiments indicated that future selection and breeding should make use of multiple inoculation runs. Resistance to snow mold in creeping bentgrass appears to be non-specific with respect to race and species of snow mold isolates.