• Germination and seedling establishment of spiny hopsage in response to planting date and seedbed environment

      Shaw, N. L.; Haferkamp, M. R.; Hurd, E. G. (Society for Range Management, 1994-03-01)
      Reestablishment of spiny hopsage (Grayia spinosa [Hook.] Moq.) in the shrub steppe requires development of appropriate seeding technology. We examined the effect of planting date and seedbed environment on germination and seedling establishment of 2 seed sources at 2 southwestern Idaho sites. Seedbeds were prepared by rototilling. In 1987-88, seeds collected in 1986 were drilled at 66 viable seeds m-1 of row at Birds of Prey in late fall, winter, and early spring and at Reynolds Creek in late fall, early spring, and late spring. Seeds collected in 1986 and 1988 were broadcast at 400 viable seeds m-2 at both sites in late fall, early spring, and late spring 1988-89. Seeds in nylon bags were also planted at each site in late fall, winter, and early spring in 1987-88 and in late fall, winter, early spring, and late spring in 1988-89. On each succeeding planting date and in early summer, 5 bags of each seed source from each of the earlier planting dates were recovered. Water content, viability, and germination were compared among seeds from previous plantings and control seeds stored in the laboratory. Each year, first-year seedling establishment at both sites was favored by late fall compared to other planting dates. In 1988, seedlings established only from late fall plantings at a density of 1 m(-2) st each site. In 1989, late fall planting at the 2 sites increased seedling establishment 6 (51 vs 8 m-2) and 20 (41 vs 2 m-2) times compared to early spring planting. Germination was generally greater for seeds incubated at field sites compared to controls. Germination total and rate increased 6-11 times and 13 days from late fall 1987 to early spring 1988, 1-6 times and 4 and 9 days from winter 1988 to early spring 1988, 17 times and 10-11 days from late fall 1988 to winter 1989, and 4-7 times and 11 days from winter 1989 to early spring 1989. Late fall or early winter planting is essential to permit early spring germination when surface soils are moist.
    • Influence of storage, temperature, and light on germination of Japanese brome seed

      Haferkamp, M. R.; Karl, M. G.; MacNeil, M. D. (Society for Range Management, 1994-03-01)
      Japanese brome (Bromus japonicus Thunb.), an alien annual grass, is an important component of some northern mixed-prairie communities. Understanding the relationship between environment and population dynamics for this species is critical for efficient management of infested ranges. Our objective was to determine the germination pattern of seed harvested in the Great Plains with varying collection dates, storage conditions, incubation temperatures, and light regimes. Seeds were collected from inflorescences (nondisseminated seed) during July in Oklahoma a Montana and during November and December in Montana. July collections were stored in paper sacks in a laboratory, and November and December collections were divided into thirds and stored in an unheated warehouse, oven-dried at 46 degrees C, or frozen at -18 degrees C. Seeds were germinated in 2 regimes, where temperatures alternated every 12 hours and light was provided during the hours of high temperature. One regime provided 10 days of prechilling (0 and 10 degrees C) followed by 18 days of a warm temperature (8 and 23 degrees C) (chilling). Another regime consisted of 28 days of the warm temperature (warm). Samples of seeds were also imbibed in the warm regime with 12-hour or intermittent periods of light. July collections germinated rapidly to > 90% regardless of temperature. November and December collections stored in the warehouse germinated > 70% in the warm regime, but germination was reduced to < 20% with chilling, suggesting secondary dormancy was induced by imbibition at 0 degrees C. Oven drying was the only treatment that consistently reduced maximum germination. Darkness enhanced 7-day germination, but light improved 28-day germination, and more recently collected seeds were more sensitive to light than older ones. These and earlier findings from Kentucky suggest Japanese brome seeds grown in different locations respond similarly to changing environmental conditions.