Breeding And Evaluation Of Fine Fescues For Increased Tolerance To Mesotrione Herbicide

Fine fescues (Festuca sp.) are a group of species that require fewer inputs, such as fertilizer, than other cool-season species managed for turf. They are adapted to infertile, acidic soils; shade; and drought. One area that poses additional challenges is the lack of weed control options for fine fescues during establishment from seed. Mesotrione is a herbicide that provides preemergence control of many broadleaf and grassy weeds, such as annual bluegrass (Poa annua), but is currently not labeled for use in fine fescues at seeding. The objectives of this research were 1) to use a recurrent selection technique to develop mesotrione-tolerant chewings fescue (Festuca rubra ssp. commutata), hard fescue (Festuca brevipila), and strong creeping red fescue (F. rubra spp. rubra); and 2) to conduct field trials to compare the new selections to commercially available cultivars and experimental lines not selected for tolerance to mesotrione. Progress was made after each of the three generations of recurrent selection. The top statistical grouping of entries for injury following application of mesotrione at the 8-oz/acre rate included all the third-generation (G3) hard fescues, all the G3 chewings fescues, and the G3 strong creeping red fescue STB1 Composite. After three generations, selections of hard, chewings, and strong creeping red fescues had equivalent or better tolerance to mesotrione than tall fescue (Festuca arundinacea) and kentucky bluegrass (Poa pratensis) cultivars, which are on the label for safe use at seeding. These new selections would provide turf managers an option to control weeds using mesotrione during seedling establishment of fine fescues.