Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/26/2004
Publication Date: 9/1/2004
Citation: Bonos, S.A., Casler, M.D., Meyer, W.A. 2004. Genotype responses and plant characteristics associated with dollar spot resistance in creeping bentgrass (agrostis palustris huds.). Crop Science. 44:1763-1769. Interpretive Summary: Dollar spot is one of the most serious diseases of bentgrasses used on golf courses throughout the USA. A study was undertaken to survey selected creeping bentgrass germplasm from several parts of the USA for stability and reaction to the dollar spot organism. Five hundred clones were evaluated for 2 years at two locations in New Jersey. The study identified several clones with high and stable levels of apparent resistance to dollar spot. This germplasm will form the basis of dollar-spot germplasm for use on golf courses throughout the USA. This information is of interest to golf course superintendents and turfgrass researchers.
Technical Abstract: Dollar spot, incited by Sclerotinia homoeocarpa F.T. Bennet, is one of the principle diseases affecting creeping bentgrass (Agrostis palustris Huds.) greens, fairways, and tees. Genetic resistance is the most promising of the disease control strategies. A study was initiated to: 1) evaluate dollar spot resistance of 500 genotypes of creeping bentgrass in two locations through disease resistance ratings; 2) determine genotype stability of dollar spot resistance; and 3) evaluate ten resistant and susceptible genotypes disease, turf, and leaf traits. The field study was arranged in a randomized complete block design with 6 replications in each of two locations established in North Brunswick, NJ. Five isolates of S. homoeocarpa were used to inoculate the field studies and applied at a rate of 1.75 g m-2 of prepared inoculum. Twelve of the original 500 genotypes (2%) maintained significant dollar spot resistance over both years and both locations. New Jersey fairway collections had the highest percentage of stable dollar spot resistant genotypes compared to Illinois fairway and New Jersey and New York green collections in this particular study. This suggests that old golf course fairways in New Jersey may be a worthwhile place to collect more stable dollar spot resistant germplasm to more efficiently develop dollar spot resistant cultivars. Resistant genotypes maintained a significantly higher turf density and green turf cover and smaller dollar spot diameter sizes compared to susceptible genotypes.