The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Z. Y. Wang - One of the best experts on this subject based on the ideXlab platform.
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Tall Fescue (Festuca arundinacea Schreb.).
Methods in molecular biology (Clifton N.J.), 2006Co-Authors: Z. Y. WangAbstract:Tall Fescue (Festuca arundinacea Schreb.) is the predominant cool-season perennial grass in the United States. It is widely used for both forage and turf purposes. This chapter describes a protocol that allows for the generation of large number of transgenic Tall Fescue plants by Agrobacterium-mediated transformation. Embryogenic calli induced from caryopsis are used as explants for inoculation with A. tumefaciens. The Agrobacterium strain used is EHA105. Hygromycin phosphotransferase gene (hph) is used as the selectable marker and hygromycin is used as the selection agent. Calli resistant to hygromycin are obtained after 4-6 wk of selection. Soil-grown Tall Fescue plants can be regenerated 4-5 mo after Agrobacterium-mediated transformation.
B Clark - One of the best experts on this subject based on the ideXlab platform.
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improving Tall Fescue festuca arundinacea for cool season vigour
Animal Production Science, 2004Co-Authors: K F M Reed, S L Clement, W F Feely, B ClarkAbstract:A highly winter-active cultivar of Tall Fescue, Melik, was compared with 3 commercial cultivars in a field experiment in South West Victoria. Winter production of Melik was superior to the widely used commercial cultivars (P 0.05). It was concluded that, while increased cool season production from Tall Fescue may be obtained by the use of highly winter-active cultivars sown alone, blends of the contrasting types of Tall Fescue may provide a more even distribution of growth throughout the year. To significantly increase winter growth in the Hamilton climate, however, the highly winter-active component may have to represent >66% of the blend. Options for using Mediterranean type Tall Fescue for their autumn–winter growth potential are discussed for districts with a shorter growing season. Melik Select was compared against 5 check cultivars, in a 3-year field experiment at Hamilton, to characterise the seasonal growth of 36 Neotyphodium endophyte infected accessions of Tall Fescue collected from the Mediterranean basin. These accessions contained endophyte variants differing from N. coenophialum, as found in continental winter-dormant types of Tall Fescue. Ratings confirmed the importance of Mediterranean material as a source of vigorous growth during the cool season. Melik Select was superior to other cultivars and accessions in both the cool and warm seasons. The use of Melik Select to develop and evaluate a new type of highly winter-active Tall Fescue for temperate Australia, since released as cultivar Fraydo, is discussed.
N S Hill - One of the best experts on this subject based on the ideXlab platform.
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ergot alkaloid concentrations in high and low moisture Tall Fescue silage
Crop Science, 2014Co-Authors: C A Roberts, Robert L Kallenbach, David Davis, George E Rottinghaus, M L Looper, N S HillAbstract:Ergot alkaloids are mycotoxins found in foods and forage crops, including common Tall Fescue [Lolium arundinaceum (Schreb.) Darbysh. = Schedonorus arundinaceus (Schreb.) Dumort.], which hosts a fungal endophyte. The objective of this study was to determine changes in ergovaline and total ergot alkaloid concentrations in Tall Fescue silage produced at high moisture (650 to 680 g H₂O kg⁻¹) and low moisture (340 to 400 g H₂O kg⁻¹). The study was conducted on endophyte-infected pastures of Tall Fescue in northern and southern Missouri. Tall Fescue was clipped after seedhead emergence but before anthesis, wilted to high or low moisture, baled, and wrapped. After >100 d of ensiling, bales were cored and samples analyzed for ergovaline and total ergot alkaloid concentrations. Ergovaline concentration decreased (P < 0.05) during ensiling at both locations and moisture levels, and the decrease ranged from 24 to 58%. In contrast, total ergot alkaloid concentrations increased during ensiling in high moisture silage in northern (P < 0.10) and southern (P < 0.05) Missouri but did not change in low moisture silage. The opposing responses of ergovaline and total ergot alkaloids offer partial explanations for differences reported in studies involving Tall Fescue silage. These responses also caution against recommendations to ensile Tall Fescue to reduce toxins because one analyte indicates detoxification is possible, while the other analyte does not.
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Infection of Somatic Embroys of Tall Fescue with Acremonium coenophialum
Crop Science, 1991Co-Authors: J. F. Kearney, W. A. Parrott, N S HillAbstract:The aviability of a Tall Fescue (Festuca arundinacea Schreb.) clone whose members are infected with different strains of its endophytic fungus, Acremonium coenophialum Morgan-Jones & Gams, would help identify the individual contributions of the endophyte and Tall Fescue toward traits normally associated with endophyte-infected Tall Fescue plants
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Ergopeptine Alkaloid Production by Endophytes in a Common Tall Fescue Genotype
Crop Science, 1991Co-Authors: N S Hill, W. A. Parrott, D. D. PopeAbstract:The fungal endophyte, Acremonium coenophialum Morgan-Jones & Gams, is present in many Tall Fescue (Festuca arundinacea Shreb.) pastures. It imparts fitness-related traits to the Tall Fescue plant but produces ergopetine alkaloids, which may be the cause of Fescue toxicosis in grazing livestock. Inasmuch as the endophyte-infected Tall Fescue populations that are incapable of producing ergopeptine alkaloids may be a solution to providing a sustainable nontoxic grass base for livestock producers
K F M Reed - One of the best experts on this subject based on the ideXlab platform.
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improving Tall Fescue festuca arundinacea for cool season vigour
Animal Production Science, 2004Co-Authors: K F M Reed, S L Clement, W F Feely, B ClarkAbstract:A highly winter-active cultivar of Tall Fescue, Melik, was compared with 3 commercial cultivars in a field experiment in South West Victoria. Winter production of Melik was superior to the widely used commercial cultivars (P 0.05). It was concluded that, while increased cool season production from Tall Fescue may be obtained by the use of highly winter-active cultivars sown alone, blends of the contrasting types of Tall Fescue may provide a more even distribution of growth throughout the year. To significantly increase winter growth in the Hamilton climate, however, the highly winter-active component may have to represent >66% of the blend. Options for using Mediterranean type Tall Fescue for their autumn–winter growth potential are discussed for districts with a shorter growing season. Melik Select was compared against 5 check cultivars, in a 3-year field experiment at Hamilton, to characterise the seasonal growth of 36 Neotyphodium endophyte infected accessions of Tall Fescue collected from the Mediterranean basin. These accessions contained endophyte variants differing from N. coenophialum, as found in continental winter-dormant types of Tall Fescue. Ratings confirmed the importance of Mediterranean material as a source of vigorous growth during the cool season. Melik Select was superior to other cultivars and accessions in both the cool and warm seasons. The use of Melik Select to develop and evaluate a new type of highly winter-active Tall Fescue for temperate Australia, since released as cultivar Fraydo, is discussed.
G C M Latch - One of the best experts on this subject based on the ideXlab platform.
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Infection of Tall Fescue Cultivars with Non-toxic Endophytes
2000Co-Authors: Frederick N. Thompson, Larry L. Hawkins, G C M LatchAbstract:For Tall Fescue in the southeastern USA, long term persistence, competitiveness, yield, and summer survival are directly related to the presence of a fungal endophyte (Neotyphodium coenophialum; formerly called Acremonium coenophialum) living in the Fescue plant. However, cattle grazing forage from the predominant USA Tall Fescue cultivars infected with their naturally occurring endophyte strains (E+) suffer from a condition called "Fescue Toxicosis". Occurrence of Fescue toxicosis is associated with the presence of this endophytic fungus. Endophyte Effects on Summer Survival Summer drought results in the greatest loss of Tall Fescue stands in the southeast. Table 1 dramatically shows the value of infection with the N. coenophialum endophyte for survival in a very hot, dry summer in Georgia (Bouton et al. 1993a). Literally, the endophyte-free (E-) versions of all cultivars in this particular experiment died completely while the E+ versions maintained good stands. Another stress factor for Tall Fescue pastures is encroachment by bermudagrass. This aggressive, warm season grass has been observed to reduce the stands of both E+ and E- Tall Fescue especially when combined with grazing in hot, dry summers. To better assess the effect of both bermudagrass competition and grazing, E+ and E- Tall Fescue cultivars were tested under grazing or hay clipping management after their establishment in tilled soil or bermudagrass sod seeded conditions (Table 2). The positive effect of endophyte infection on plant survival was seen by the better survival of E+ ‘Georgia 5' compared to E- ‘AU Triumph’ in all testing conditions. Grazing, when combined with bermudagrass competition, created the greatest stress for Tall Fescue survival. For future studies to rapidly assess stand persistence of either E+ or ETall Fescue cultivars, plots can be established in bermudagrass sods and grazed. Besides defining a worse-case but real-world scenario in the southeast region, this type of screening procedure allows cultivars to be assessed more quickly and efficiently.
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evolutionary diversification of fungal endophytes of Tall Fescue grass by hybridization with epichloe species
Proceedings of the National Academy of Sciences of the United States of America, 1994Co-Authors: Hueifung Tsai, Chuck Staben, M. R. Siegel, G C M Latch, Michael J. Christensen, Christopher L SchardlAbstract:Abstract The mutualistic associations of Tall Fescue (Festuca arundinacea) with seed-borne fungal symbionts (endophytes) are important for fitness of the grass host and its survival under biotic and abiotic stress. The Tall Fescue endophytes are asexual relatives of biological species (mating populations) of genus Epichloe (Clavicipitaceae), sexual fungi that cause grass choke disease. Isozyme studies have suggested considerable genetic diversity among endophytes of Tall Fescue. Phylogenetic relationships among seven isolates from Tall Fescue, three from meadow Fescue (a probable ancestor of Tall Fescue), and nine Epichloe isolates from other host species were investigated by comparing sequences of noncoding segments of the beta-tubulin (tub2) and rRNA (rrn) genes. Whereas each Epichloe isolate and meadow Fescue endophyte had only a single tub2 gene, most Tall Fescue endophytes had two or three distinct tub2 copies. Phylogenetic analysis of tub2 sequences indicated that the presence of multiple copies in the Tall Fescue endophytes was a consequence of hybridization with Epichloe species. At least three hybridization events account for the distribution and relationships of tub2 genes. These results suggest that interspecific hybridization is the major cause of genetic diversification of the Tall Fescue endophytes.
