Breeding fine fescues for low maintenance; understanding dollar spot resistance and increasing tolerance to mesotrione

Fine fescues are group of cool-season grasses that are utilized as low maintenance grasses. The three main species most commonly utilized are Chewings fescue (Festuca rubra L. subsp. commutata Markgr.-Dann.), hard fescue (Festuca trachyphylla (Hack.) Hack.), and strong creeping red fescue (Festuca rubra L. subsp. rubra). The objectives of this research were to (i) determine the maternal and reciprocals effects of dollar spot resistance in hard fescue by performing a diallel cross between three resistant endophyte containing and three susceptible endophyte free parents, (ii) determine the physiological behavior of mesotrione associated with differential tolerance levels of three fine fescue species and (iii) to utilize a recurrent selection method to breed for increased tolerance to mesotrione in fine fescues and test the selections in field trials. Maternal and reciprocal effects were significant in the diallel cross of three E+ resistant parents and three E- susceptible parents. All progeny from E+ resistant mothers that got more than 40% dollar spot averaged over the 2 year study did not contain the endophyte. The high maternal inheritance of dollar spot resistance and the maternal inheritance of the Epichlöe festucae fungal endophyte along with demonstration of susceptibility in progeny from an E+ resistant maternal parent that did not get the endophyte suggest the endophyte presence is a major factor in the resistance to dollar spot in hard fescue. In the dose response study, mesotrione tolerance from highest to lowest was: hard > Chewings > strong creeping red fescue. For the absorption study foliar uptake from highest to lowest was: Chewings > strong creeping red > hard fescue, while root absorption was comparable among species. Overall, less foliar uptake and acropetal translocation may be associated with enhanced tolerance of hard fescue to broadcast mesotrione applications compared to Chewings and strong creeping red fescues. A total of 29 fine fescue selections were developed with mesotrione tolerance and evaluated over three generations. The hard fescues were consistently the most tolerant in each generation. The Chewings fescue were the second most tolerant group in the first and second generations and the strong creeping red fescues were the least tolerant in the first and second generations. In the third generation one strong creeping red fescue selection was ranked 5th overall for mesotrione injury behind two third generation hard fescue selections.Ph.D.Includes bibliographical reference