235-7 Sparse-Flowering Orchardgrass Is Stable Across Temperate North America.



Tuesday, October 18, 2011: 2:45 PM
Hilton Palacio del Rio, El Mirador, Concourse Level

Michael Casler, U.S. Dairy Forage Research Center, USDA-ARS, Madison, WI, Yousef Papadopoulos, Agriculture and Agri-Food Canada, Truro, NS, Canada, Daniel Undersander, 1575 Linden Dr, University of Wisconsin-Madison, Madison, WI, Shabtai Bittman, Agriculture and Agri-Food Canada, Agassiz, BC, CANADA, Russell Mathison, University of Minnesota, Grand Rapids, MN, Doo-hong Min, E 3774 University Drive, Michigan State University, Chatham, MI, Joseph Robins, Forage and Range Research Lab, USDA-ARS, Logan, UT, Jerome Cherney, 503 Bradfield Hall, Cornell University, Ithaca, NY, Surya Acharya, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada, David Belesky, USDA-ARS, Beaver, WV, Stephen Bowley, University of Guelph, Guelph, ON, CANADA, Bruce Coulman, University of Sasketchewan, Saskatoon, SK, Canada, Raynald Drapeau, Agriculture and Agri-Food Canada, Normandin, QC, Canada, Nancy Ehlke, University of Minnesota, Department of Agronomy and Plant Genetics, St. Paul, MN, Marvin Hall, 116 AG Sciences & Industry Bldg., Pennsylvania State University, University Park, PA, Richard Leep, Michigan State University, Hickory Corners, MI, Real Michaud, Agriculture & Agri-Food Canada, Quebec, QC, Canada, John Rowsell, University of Guelph, New Liskeard, ON, Canada, Glenn Shewmaker, University of Idaho, Twin Falls, ID, Christopher Teutsch, Virginia Tech, Blackstone, VA and Wayne Coblentz, 2615 E 29th Street, USDA-ARS, Marshfield, WI
Three sparse-flowering orchardgrass populations were developed by selective breeding as a mechanism to reduce stem production during the early spring season in management-intensive grazing systems.  These populations and three check cultivars were evaluated under frequent- and infrequent-harvest systems at 21 locations in the USA and Canada in 2008-2010. The sparse-flowering trait, including its impact on forage yield and quality, was stably expressed across temperate North America with relatively subtle variations associated with climate and geography.  Sparse-flowering populations had 61% fewer culms and panicles compared to cultivars, resulting in a 24% reduction in first-cut forage yield under a 3-cut system and a 31% reduction in first-cut yield under a 5-cut system.  The sparse-flowering trait had little impact on regrowth forage yield, resulting in total annual forage yield reductions of 14% under both harvest systems.  As partial compensation for the forage-yield reductions, sparse-flowering populations were 2% lower in neutral detergent fiber (NDF), 3% higher in NDF digestibility, and 2% higher in in vitro dry matter digestibility compared to normal populations at first harvest.  These sparse flowering populations have significant potential to improve flexibility in grazing management of orchardgrass-based pastures, provided that the management advantages have sufficienit value to offset the reductions in forage yield and carrying capacity.
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