Tuesday, November 6, 2007
175-1
Seed Production from Non-flowering Orchardgrass: Proof of Concept.
Michael Casler, USDA-ARS, USDA/ARS U.S. Dairy Forage Res.Ctr., 1925 Linden Drive West, Madison, WI 53706-1108, Richard Johnson, PO Box 646402, USDA-ARS, USDA ARS, Washington State Univ., 59 Johnson Hall, Pullman, WA 99164-6402, Reed Barker, Oregon State University, Grass Genomic Testing, Inc, Corvallis, OR 97331-7102, Maria Jenderek, USDA-ARS-NPA-SPNRU, USDA, ARS, NCGRP, 1111 South Mason St., Fort Collins, CO 80521, Yousef A. Papadopolous, Agriculture and Agri-Food Canada, Truro, NS B2N 5Z3, Canada, and Jerome Cherney, 503 Bradfield Hall, Cornell University, Dept.of Crop & Soil Sciences, Cornell University, Ithaca, NY 14853.
Non-flowering or sparse flowering orchardgrass (Dactylis glomerata L.) would greatly simplify management of intensive rotational grazing systems in which flowering stems are an impediment to efficient pasture utilization. Our objective was to quantify seed production on non-flowering orchardgrass clones selected in cold-winter climates, but grown for seed in mild-winter climates. We evaluated 98 orchardgrass clones for seed production traits at four locations: Pullman and Central Ferry, WA; Corvallis, OR; and Parlier, CA. Most plants (~92%) flowered at the three northern locations, but only 38% flowered at Parlier. The latter location may have a winter that is insufficiently cold for adequate floral induction and vernalization. Among non-flowering plants that flowered at the three northern locations, number of panicles and plant seed yield were reduced by 64% relative to that of two check cultivars. Mean panicle number was lowest (11%) for plants selected at Ithaca, NY, the selection location with the warmest winter conditions, and highest (37%) for plants selected at Charlottetown, PEI, the selection location with the coldest winter conditions. Because flowering in these plants appears to be regulated by winter temperatures, these results confirm our expectations that the most desirable plants (non-flowering under cold winters and normal flowering under mild winters) should arise from selection under more severe winter conditions. Intensive selection among the 86 clones originating from non-flowering germplasm identified five clones with high and stable seed production at all three northern locations, averaging only 12% fewer panicles, but 54% higher panicle seed yield and 24% higher plant seed yield compared to check cultivars. These results provide proof-of-concept that orchardgrass plants selected for stable expression of the non-flowering trait are capable of producing adequate seed yields in typical orchardgrass seed production environments, provided some relatively intensive selection pressure for seed production traits.