Malinowski, D.P., Zuo, H., Kramp, B.A., Muir, J.P., and W. E. Pinchak. 2005. Obligatory Summer-Dormant Cool-Season Perennial Grasses for Semiarid Environments of the Southern Great Plains. Agron. J. 97:147-154.

Introduced cool-season perennial grasses may become an important complementary winter forage to dual-use wheat (Triticum aestivum L.) in high-risk semiarid environments of the southern Great Plains. Currently recommended cultivars are summer semi-dormant, not adapted to prolonged and severe summer drought, and not productive in the fall grazing season (October-December). In an experiment planted in Vernon, TX on a Miles fine sandy loam (fine-loamy, mixed, thermic Udic Paleustalfs) in October 2000, we evaluated productivity and plant survival of an obligatory summer-dormant ‘Grasslands Flecha’ and summer semi-dormant ‘Georgia 5’, ‘Jesup’, and ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.), a highly summer semi-dormant ‘Grasslands Maru’ hardinggrass (Phalaris aquatica L.), summer semi-dormant ‘Grasslands Matua’ and ‘Grasslands Tango’ prairiegrass (Bromus wildenowii Kunth) under two defoliation intensities of 7.5 and 15 cm. Tall fescue cultivars Georgia 5, Jesup, and Grasslands Flecha were either infected with the novel Neotyphodium coenophialum Glenn, Bacon and Hanlin endophyte strain AR542, with their endemic (WT) endophytes (except for Grasslands Flecha) or noninfected (E–). Only Grasslands Flecha and Grasslands Maru survived summer droughts during 2001-2004 and successfully recovered each autumn. Prairiegrass behaved as an annual but was not able to reseed in 2003. Aboveground biomass was greater at 15- vs. 7.5-cm defoliation height except for 2004 growing season. In Grasslands Flecha tall fescue, the novel endophyte increased tiller survival after summer drought by 150% in 2001 and 121% in 2002 when compared with E– plants. Results indicate that obligatory and highly summer semi-dormant cultivars of perennial cool-season grasses may be productive and persistent in semiarid environments of the southern Great Plains and have the potential to complement forage from dual-use wheat pastures.