Heritability of Dollar Spot Resistance in Hard Fescue.

Hard fescue, Festuca brevipila, is a cool-season bunch type turfgrass that has a low fertility requirement, high density, and good heat and drought tolerance. Hard fescue often contains the fungal endophyte Epichlӧe festucae which has been shown to suppress diseases such as dollar spot (Sclerotinia homoeocarpa) and red thread (Laetisaria fuciformis) as well as to enhance drought tolerance and resistance to above ground feeding insects. These traits and its endophyte association make hard fescue an excellent choice in low maintenance areas. Diseases such as dollar spot can be especially devastating under low input management. To develop cultivars resistant to this disease, breeders must first understand the heritability of this trait in hard fescue. In this study, the heritability of dollar spot disease resistance was determined by performing reciprocal crosses utilizing six parental lines; three resistant lines and three susceptible lines of hard fescues. Progeny of each cross were planted in tiller plots along with clonal replicates of the parental lines in a randomized complete block. Tiller plots were then inoculated with multiple strains of the S. homoeocarpa at a rate of 1 g/m² of sterilized Kentucky bluegrass seeds.  Disease severity was evaluated in each plant visually (percent of foliage infested with dollar spot) and by using digital image analysis. Narrow-sense heritability of the dollar spot disease response was estimated by progeny parent regression. Analysis of reciprocal crosses showed a strong maternal effect indicating that the endophyte (only inherited maternal) could be providing the enhanced resistance observed.