Epichloid endophytes provide protection from a variety of biotic and abiotic stresses for cool-season grasses, including tall fescue. A collection of 85 tall fescue lines from 15 locations in Greece, including both Continental and Mediterranean germplasm, was screened for the presence of native endophytes. A total of 37 endophyte-infected lines from 10 locations were identified, and the endophytes were classified into five distinct groups (G1 to G5) based on physical characteristics such as colony morphology, growth rate, and conidial morphology. These classifications were supported by phylogenetic analyses of housekeeping genes tefA and tubB, and the endophytes were further categorized as Neotyphodium coenophialum isolates (G1, G4, and G5) or Neotyphodium sp. FaTG-2 (Festuca arundinacea taxonomic group 2 isolates (G2 and G3). Analyses of the tall fescue matK chloroplast genes indicated a population-wide, host-specific association between N. coenophialum and Continental tall fescue and between FaTG-2 and Mediterranean tall fescue that was also reflected by differences in colonization of host tillers by the native endophytes. Genotypic analyses of alkaloid gene loci combined with chemotypic (chemical phenotype) profiles provided insight into the genetic basis of chemotype diversity. Variation in alkaloid gene content, specifically the presence and absence of genes, and copy number of gene clusters explained the alkaloid diversity observed in the endophyte-infected tall fescue, with one exception. The results from this study provide insight into endophyte germplasm diversity present in living tall fescue populations.

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Tall fescue (Lolium arundinaceum) is a valuable and broadly adapted forage grass that occupies approximately 14 million hectares across the United States. A native to Europe, tall fescue was likely introduced into the US around the late 1800's. Much of the success of tall fescue can be attributed to Epichloë coenophiala (formerly Neotyphodium coenophialum) a seed borne symbiont that aids in host persistence. Epichloë species are capable of producing a range of alkaloids (ergot alkaloids, indole-diterpenes, lolines, and peramine) that provide protection to the plant host from herbivory. Unfortunately, most tall fescue within the US, commonly referred to as “Kentucky-31” (KY31), harbors the endophyte E. coenophiala that causes toxicity to grazing livestock due to the production of ergot alkaloids. Molecular analyses of tall fescue endophytes have identified four independent associations, representing tall fescue with E. coenophiala, Epichloë sp. FaTG-2, Epichloë sp. FaTG-3, or Epichloë sp. FaTG-4. Each of these Epichloë species can be further distinguished based on genetic variation that equates to differences in the alkaloid gene loci. Tall fescue samples were evaluated using markers to simple sequence repeats (SSRs) and alkaloid biosynthesis genes to determine endophyte strain variation present within continental US. Samples represented seed and tillers from the Suiter farm (Menifee County, KY), which is considered the originating site of KY31, as well as plant samples collected from 14 states, breeder's seed and plant introduction lines (National Plant Germplasm System, NPGS). This study revealed two prominent E. coenophiala genotypes based on presence of alkaloid biosynthesis genes and SSR markers and provides insight into endophyte variation within continental US across historical and current tall fescue samples.

Impact (Reg. No. CV-283, PI 687328) crabgrass [Digitaria ciliaris (Retz.) Koeler] was developed by the Noble Research Institute, LLC, and released in 2016. Selections were made from 'Red River' by recurrent phenotypic selection for late lowering and high individual plant yield. In Ardmore, OK, trials in 2014 and 2015, Impact headed signiicantly later than Red River and the early-maturing cultivar Quick-n-Big. This later maturity produced in vitro true dry matter digestibility numerically greater than Red River and signiicantly greater than Quickn-Big (697 g kg −1 vs. 685 and 665 g kg −1 , respectively, across 11 harvests) and lower neutral detergent iber (635 g kg −1 vs. 654 g kg −1 ) than Quick-n-Big. In Oklahoma, there were no consistent diferences in monthly or total dry matter yields in Impact compared with Red River (Impact ranged from 9160 to 19,764 kg ha −1 , depending on year and location), but Impact yielded higher during most late-season harvest dates (mid-August-early October) compared with Quick-n-Big. At Vashti, TX, during 2014, Impact produced more monthly forage and total dry matter yield than both Red River and Quick-n-Big. In Mississippi and Tennessee, cultivar diferences were similar to Oklahoma results. Impact demonstrated summer animal gains of 0.78 kg d −1 and total season gains of 230 kg ha −1 . It is high yielding and should be broadly adapted as annual summer pasture throughout the south-central and southeastern United States.

NFTW6001 (Reg. No. GP‐99; PI 676025) tall wheatgrass [Thinopyrum ponticum (Podp.) Barkworth & D.R. Dewey] germplasm, also tested under the designation Jose HDMD C2, was developed by the Samuel Roberts Noble Foundation and released in 2014. Selections were made from ‘Jose’ in north Texas for persistence and digestibility, followed by a second cycle of selection in southern Oklahoma emphasizing digestibility. The heading date of NFTW6001 in Ardmore, OK, is on average 7 d earlier than Jose. Persistence was improved by selection, based on greater stands of NFTW6001 (72%) compared with Jose (17%) at Vernon, TX. Total forage yield of NFTW6001 has equaled or exceeded (up to 607 kg ha− 1) the yield of Jose in Oklahoma. Despite its earlier maturity, digestibility and crude protein concentration of NFTW6001 in summer is equal to Jose. The digestibility and crude protein of NFTW6001 and Jose are similar in fall. NFTW6001 was released by the Noble Foundation's plant materials release committee due to its earlier maturity, improved forage yield, and persistence relative to Jose.

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Tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.] is a perennial cool‐season grass in which improved freeze tolerance could result in greater winterhardiness and persistence. Our objective was to evaluate survival and freeze‐tolerance thresholds of ‘Flecha’ summer‐dormant (SD) and ‘Texoma Max QII’ summer‐active (SA) tall fescue at seedling (1–2 leaves) and tillered (5–6 leaves) growth stages using controlled environment freezing chambers. Target temperatures ranged from 0 to −9 °C (seedlings) and 0 to −12 °C (tillered plants). Predicted lethal temperature at which 50% mortality occurs (LT50) was −5.7 and −5.5 °C for SA and SD seedlings, respectively, and −6.0 and −5.7 °C for SA and SD tillered plants, respectively. Based on these results, a controlled temperature chamber appears to be a useful tool for plant breeders when evaluating survival and freeze tolerance of SA and SD tall fescue germplasm at seedling and tillered growth stages.

Chisholm' (Reg. No. CV-102, PI 686938) summer-dormant (SD) tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] is a forage-type, synthetic cultivar developed from phenotypic selections for persistence in southern Oklahoma and north Texas from the cultivar Flecha. Chisholm was jointly developed, tested, and released in 2016 by the Noble Research Institute, LLC, Ardmore, OK, USA, GENTOS, Buenos Aires, Argentina, and Grasslanz Technology, Ltd., Palmerston North, New Zealand. Chisholm tall fescue is a mediterranean or SD ecotype characterized by productive growth in mild winters and dormancy during hot and dry summers. Chisholm difers (p < 0.05) from the SD cultivar Flecha by possessing a later heading date (4 d) and a more erect growth habit. Plants of Chisholm have wider (p < 0.05) lag and tiller leaf widths of 0.4 and 0.8 mm, respectively when compared to plants of Flecha. When tested in small plot grazing trials for persistence in southern Oklahoma and north Texas from 2011 to 2016, inal stands of Chisholm were 23% greater (p < 0.05) than Flecha and the mediterranean cultivar Prosper when averaged across all locations, which is the justiication for Chisholm's release. Chisholm is capable of producing high-quality pasture from autumn through spring, thereby providing a perennial forage option for livestock producers to complement or replace the planting of winter annuals such as dual-purpose wheat (Triticum aestivum L.). Chisholm is licensed to Warner Brothers Seed Company, Lawton, OK. Abbreviations: NIRS, near-infrared spectrometer; PLS, pure live seed; RCBD, randomized complete block design; SA, summer active; SD, summer dormant.