Evaluation location: Oklahoma, United States
Seedlings were started in the greenhouse in summer and transplanted to the field in October1999. Plots consisted of a row of ten spaced plants representing an accession; where a sufficient number of seedlings were available, a given accession was duplicated twice in a separate area of the field. The field was located on The Noble Foundation Headquarters Farm in Ardmore, OK (34 10 N, 97 04 W); soil type was a Konsil loamy fine sand (fine-loamy, siliceous, thermic Ultic Paleustalfs). Prior to planting, a subset of seeds of several Festuca and Lolium accessions 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 endophyte free, although endophyte status of plants at transplanting was not verified. The initial number of live plants per plot was recorded in spring, 2000 prior to grazing, to account for plant loss due to transplant failure. Plots were grazed by beef cattle (Bos taurus), at a stocking rate of approximately 4200 kg live weight hectare -1, from 30 March to 31 May, 2000; plots were grazed again from 30 June to 19 July, 2000 at a rate of about 1000 kg live weight hectare -1. Plots were grazed to maintain a stubble height of approximately 5 cm or less, and very little or no summer re-growth occurred following grazing because of onset of summer dormancy. Approximate stocking rates in 2001, in kg live weight hectare -1, were as follows: 2500 (16 March to 2 April), 850 (3 April to 29 April), 1245 (30 April to 1 July), 2150 (2 July to 25 July). In December, 2001 to February, 2002, plants were assigned a vigor rating, with 0 being dead, 9 being maximum vigor. Vigor ratings were based on visual estimates of the amount of fall growth, density of tillering, and plant diameter, or for rhizomatous species, plant spread.