Evaluation location: Oklahoma, United States
The trial was conducted at the Noble Foundation Red River Demonstration and Research Farm (33 53' N, 97 15' W) near Burneyville, in south central Oklahoma. The plot area consisted of approximately 0.60 hectares and was part of a 2.03 hectare field. Soil type was a Minco fine sandy loam (coarse-silty, mixed, thermic Udic Haplustoll). Tall fescue check entries consisted of 'Jesup', 'KY-31', 'Dovey', 'AU Triumph' and the experimental population PDF; 'Barton' western wheatgrass (PI 578778) was also included as a check. Prior to planting, a subset of seeds of Jesup, KY-31, and PDF were placed inside a forced draft oven set at 48 C for 4 - 5 weeks in an effort to remove any viable endophyte (Neotyphodium coenophialum Glenn, Bacon, Hanlin). A pan of water was also placed in the oven to provide moisture. These resulting entries are referred to in this report as 'Jesup E-', 'KY-31 E-', and PDF E-, although endophyte status of tall fescue plants at transplanting was not verified. Stocking rates, in kg live weight hectare -1, were approximately 980 for 2 to 23 June and 441 for 24 June to 20 July, 1999, and 934 for 10 to 27 April and 435 for 28 April to 7 June, 2000. It should also be noted that heavy infestations of grasshoppers (Melanoplus spp.) occurred at the Burneyville location in summer 1999 and 2000, with densities of 32 grasshoppers m-2 being observed in nearby fields (Jeff Ball, Noble Foundation, personal communication). Vigor ratings were taken December, 2000 to February, 2001. No additional fall re-growth occurred during this period.