Ardmore 1997
Seedlings were started in the greenhouse in summer and transplanted to the field in October 1997. 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). Plots were grazed by beef cattle (Bos taurus), at a stocking rate of approximately 4052 kg live weight hectare -1, from 9 April to 23 April, and 29 May to 5 June, 1998. 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.

In November, 1998, 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. Fall re-growth had essentially ceased when vigor ratings were taken. Two heifers (216 kg live weight hectare -1) grazed the approximately 2.35 hectare field from December, 1998 to 23 March, 1999, after which time they were confined to the approximately 0.4 hectare tall fescue planting, resulting in an estimated stocking rate of 1350 kg live weight hectare -1.

Heifers were removed on 14 June, 1999; one heifer grazed the area (730 kg live weight hectare -1) from 23 June - 13 July. Vigor ratings for the tall fescue planting were taken in November, 1999 following the same procedures as for 1998. Vigor ratings were used to assign accessions an Average Grazed Recovery (AGR) score. AGR is an estimate of the average vigor rating, following heavy grazing, for an accession. A score of 0 indicates plant death whereas 9 indicates maximum recovery from grazing. AGR is calculated as the sum of plot grazed recovery scores divided by the number of plots evaluated for a given accession. Plot grazed recovery = sum of ratings/initial numbers of live plants.

Iowa Park 1997
Seedlings were started in the greenhouse in summer and transplanted to the field in October 1997. 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, or more as noted, in a separate area of the field. The evaluation trial was located near Iowa Park, in the Wichita Falls area of north central Texas (33 59 N, 98 47 W); soil type was a Frankirk loam (fine, mixed, thermic, Udic Argiustolls).

The planting consisted of approximately 0.5 hectares and was part of an approximately 2.9 hectare field. One or two plots were planted for all accessions except for the following, which were duplicated three or more times: PI 578687 (intermediate wheatgrass); 97TXB8 (Texas bluegrass); and 97WW2, 97WW3, 97WW4, 97WW5, 97WW9, 97WW18, 97WW20, 97WW22, 97WW26, 97WW27 (western wheatgrass). Plots were grazed only lightly (6 - 17 April and 25 -28 May) by beef cattle in 1998 to allow for establishment and yet prevent seed production; stubble height was greater than 10 cm.

Plots were grazed in 1999 from12 - 30 March (545 kg live weight hectare -1), mowed to a height of 10 cm on 9 April, and grazed again from 13 April - 2 June (940 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.

Vigor ratings were assigned in early November, 1999. 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. Fall re-growth had essentially ceased when vigor ratings were taken. Vigor ratings were used to assign accessions an Average Grazed Recovery (AGR) score. AGR is an estimate of the average vigor rating, following heavy grazing, for an accession.

A score of 0 indicates plant death whereas 9 indicates maximum recovery from grazing. AGR is calculated as the sum of plot grazed recovery scores divided by the number of plots evaluated for a given accession. Plot grazed recovery = sum of ratings/initial numbers of live plants.

Burneyville 1998
Seedlings were started in the greenhouse in summer and transplanted to the field in October 1998. 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 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. 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. 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. 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. Fall re-growth had essentially ceased when vigor ratings were taken. Vigor ratings were used to assign accessions an Average Grazed Recovery (AGR) score. AGR is an estimate of the average vigor rating, following heavy grazing, for an accession. A score of 0 indicates plant death whereas 9 indicates maximum recovery from grazing. AGR is calculated as the sum of plot grazed recovery scores divided by the number of plots evaluated for a given accession. Plot grazed recovery = sum of ratings/initial numbers of live plants.

Iowa Park 1998
Seedlings were started in the greenhouse in summer and transplanted to the field in October 1998. 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 plot area used was immediately adjacent to that of the 1997 Iowa Park evaluation. Check entries included 'Luna' and 'Manska' pubescent wheatgrass, 'Slate' and 'Oahe' (PI574517) intermediate wheatgrass, as well as 'Ariba' and 'Barton' western wheatgrass. The accession PI 531721, which was evaluated in the Iowa Park 1997 trial, was also included in the Iowa Park 1998 trial.

Plots were grazed in 1999 the same as for the Iowa Park, 1997 trial. Two steers (1250 kg live weight hectare -1) grazed the approximately 0.4 hectare area to a stubble height of 1 -2 cm in 2000; grazing dates were 28 March to 20 April. Vigor ratings were assigned in early December, 2000. 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. Fall re-growth had essentially ceased when vigor ratings were taken.

Vigor ratings were used to assign accessions an Average Grazed Recovery (AGR) score. AGR is an estimate of the average vigor rating, following heavy grazing, for an accession. A score of 0 indicates plant death whereas 9 indicates maximum recovery from grazing. AGR is calculated as the sum of plot grazed recovery scores divided by the number of plots evaluated for a given accession. Plot grazed recovery = sum of ratings/initial numbers of live plants.

See: Germplasm Database