Epichlöe festucae endophyte mediated maternal inheritance of dollar spot disease resistance in hard fescue

Hard fescue (Festuca brevipila) is a fine-leaved cool-season turfgrass and is well adapted for low-maintenance areas, such as home lawns, parks, and roadsides. Breeding for improved disease resistance is a major objective in utilizing hard fescue under low-input management. The Epichlöe festucae endophyte-mediated dollar spot (Clarireedia jacksonii) resistance and its mechanism have been well-documented in strong creeping red fescue (F. rubra subsp. rubra). However, little is known about dollar spot resistance in hard fescue. The objectives of this research were to (1) understand the inheritance of dollar spot resistance in hard fescue and determine the reciprocal effects by performing a diallel cross between three resistant endophyte-containing and three susceptible endophyte-free parents and (2) confirm the role of E. festucae endophyte in dollar spot resistance by artificially inoculating hard fescue with the endophyte (ME+) and comparing ME+ plants to their genetically identical counterparts without the endophyte (E‒) under dollar spot pressure. The highly significant maternal effect from the diallel cross experiment demonstrated that the dollar disease resistance is maternally inherited in hard fescue and linked with the maternal inheritance of the E. festucae endophyte. The greenhouse study further confirmed that the presence of E. festucae endophyte significantly reduced dollar spot in hard fescue. Understanding this endophyte effect on maternal inheritance of dollar spot resistance will enable more efficient breeding and selection of plant materials to use in the development of improved dollar spot resistant cultivars in hard fescue.