Selection for Persistence in Endophyte‐Free Kentucky 31 Tall Fescue

Abstract

‘Kentucky 31’, released in 1943, remains the most widely used tall fescue cultivar (Festuca arundinacea Schreb.). The fungal endophyte, Neotyphodium coenophialum (Morgan‐Jones & Gams.) Glenn, Bacon & Hanlin comb. nov., which naturally infects Kentucky 31, enhances survival and competitiveness of the grass. However, cattle grazing forage from endophyte‐infected (E+) Kentucky 31 suffer from fescue toxicity because of alkaloids in the forage. A possible strategy to reduce fescue toxicity is cultivar improvement to develop more persistent endophyte‐free (E−) cultivars. The objective of our research was to assess the results of selection with different levels of stress (grazing and competition with bermudagrass, Cynodon dactylon L.) to increase persistence and competitiveness within E− Kentucky 31. Populations were selected in the following environments: (i) seeded into bermudagrass and grazed with continuously stocked beef cattle, (ii) seeded into bermudagrass and clipped intermittently with a mower, (iii) seeded into tilled soil and grazed with continuously stocked beef cattle, and (iv) seeded into tilled soil and clipped intermittently with a mower. Populations were developed from the best surviving plants in each selection condition and tested for grazing persistence and competitiveness with bermudagrass. Grazing, especially when combined with bermudagrass competition, created the greatest reduction of persistence. No selected population was found to survive better than E− Kentucky 31 even when tested in the same conditions used during its selection. The E+ checks were the most persistent entries in all testing conditions. These experiments indicate that selection within E− Kentucky 31 for improved persistence will be difficult and may need to be explored on other E− tall fescue germplasm sources, but another strategy may be reinfection with non‐toxic endophyte strains.

Fungal endophyte infection increases tall fescue's survival, growth, and flowering in a reconstructed prairie

“…These results are consistent with previous work demonstrating the benefits of endophyte infection for tall fescue in diverse plant communities (e.g. Clay & Holah ; Bouton et al ; Rudgers et al ; Rudgers & Clay ; Slaughter et al ). However, our observed lack of endophyte infection effects on the species diversity or richness of the surrounding, developing plant community contradicts our second hypothesis and prior findings (Clay & Holah ; Rudgers et al ; Rudgers & Clay ).…”

Agronomic Performance and Lamb Health among Several Tall Fescue Novel Endophyte Combinations in the South‐Central USA

“…In general, entries did not persist well under heavy grazing pressure except at Haskell, OK (Table 3). Although Booneville, AR, is within the traditional area of tall fescue use in the United States, stands fell from 9 plants m −2 at establishment to 6 or fewer plants m −2 within 21 mo, most likely because of competition from bermudagrass coupled with grazing, as has been reported by others (Bouton et al, 2001). Incidentally, no entries persisted well at Overton, regardless of whether plots were grazed or not during the establishment year.…”

Comparison of Conventional and Minimal Tillage for Low-Input Pasture Improvement

“…This difference in response of legumes may arise from instances of self‐seeding and consequent increase in legume stand (31,37) or from management practices that allow legume to become a dominant component in pasture (89). Management subsequent to pasture establishment is likely to play a major role in sustaining pasture productivity over time (3,11,53). Thom et al (85) observed that improvements in forage production following overseeding of cool season grass into warm season grass were small and limited to the first six months after sowing because of a lack of persistence of the oversown crop.…”

“…Thom et al (85) observed that improvements in forage production following overseeding of cool season grass into warm season grass were small and limited to the first six months after sowing because of a lack of persistence of the oversown crop. These authors, however, subjected their pastures to intensive grazing post‐renovation, and this may have contributed to the early disappearance of sown species (11,86). Decline in yield of cool‐season pastures over time is not unique to establishment by minimal tillage (34,43,69) and data available do not show that grass pastures deteriorate more quickly when sown following minimal tillage than following conventional cultivation.…”