Feasibility of seed production from nonflowering orchardgrass
Nonflowering or sparse flowering orchardgrass (Dactylis glomerata L.) would greatly simplify management of intensive rotational grazing systems. Our objective was to quantify seed production on nonflowering 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. Most plants (92%) flowered at the three northern locations, but only 38% flowered at Parlier, which may have a winter insufficiently cold for adequate floral induction and vernalization. Mean panicle number was lowest (11%) for plants selected at the location with the warmest winter conditions, and highest (37%) for plants selected at the location with the coldest winter conditions. These results confirm our expectations that the most desirable plants (nonflowering under cold winters and normal flowering under mild winters) should arise from selection under more severe winters. Selection for nonflowering under mild winter conditions simply leads to nonflowering plants under all conditions. These results demonstrate that individual orchardgrass genotypes are capable of dual phenotypic expression, flowering in mild-winter climates or expressing the nonflowering trait in cold-winter climates and that the expression of this trait depends on both the selection and evaluation location.