Rapid Evaluation of Buffalograss Germplasm for Leaf Spot Resistance.

Buffalograss (Buchloe dactyloides) is a North American native turfgrass species, ideally suited for low input sustainable turf applications.  The fungal pathogen Curvularia lunata causes leaf spot disease of buffalograss.  Resistance to leaf spot would improve buffalograss performance and reduce fungicide applications further contributing to the reduced input requirements of buffalograss management.   As a prelude to a field study, 87 distinct buffalograss genotypes, including seven named varieties and 80 experimental lines, were grown in the greenhouse in a randomized complete block design with three replications.  On March 20^th, 2012, each genotype was inoculated by spraying with 15 ml of a C. lunata spore solution.  The spore solution contained 3.9 x 10⁵ conidiospores/ml.  Each inoculated genotype was placed inside a clear plastic bag and sprayed every other day with water prior to the final rating date to promote environmental conditions conducive to disease development.  Occurrence of disease was visually estimated on a zero (no disease) to ten (100% diseased) scale on March 30th and April 3rd, 2012.  Ratings ranged from one to nine, with an average rating of 3.95 across all samples and rating dates.  Cultivar Prestige performed the worst with a mean rating of 6.33 and the experimental line NE-BFG-11-3625 performed the best with a mean rating of 1.33.  Some individuals also exhibited delayed onset of disease.  This data was used for selecting 15 leaf spot resistant buffalograss genotypes that will be tested for resistance in a field study.  The combined data will allow us to determine the efficacy of greenhouse screening for leaf spot resistance in buffalograss.