Endophyte Status in Summer-Dormant Tall Fescue in the Southern Great Plains of USA

Non-toxic fungal endophytes provide persistence-related benefits to summer-active, continental-type tall fescue (Festuca arundinacea Schreb.), as well as reduced animal toxicosis compared to toxic endophytes. However, the benefits of fungal endophytes to summer-dormant, Mediterranean-type tall fescue persistence or production are unclear. Summer-dormant tall fescue has potential to replace traditional, annual small grain graze-out systems in the Southern Great Plains region of the USA. This region is characterized by severe water deficits accompanied by extreme heat in summer, and by relatively mild, rainy winters (Malinowski et al. 2009). Summer-active tall fescues are better suited to high rainfall areas (\u3e 900 mm annual average rainfall (AAR)) east of the 97° longitudinal meridian, while summer-dormant tall fescues are best adapted to lower rainfall areas (600 to 900 mm AAR) between the 97° and 99° longitudinal meridian (Butler et al. 2011). The objective of this field study was to determine the effects of the ‘novel’ endophyte strain AR542 on persistence of summer-dormant tall fescue ‘Flecha’ in the Southern Great Plains of the USA. Two field experiments were conducted to evaluate the effect of the novel endophyte AR542 on the survival of Flecha