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United States Department of Agriculture (USDA) 2002


Weed Management Dryland Crops

United States Department of Agriculture (USDA) Research, Education & Economics Information System (REEIS)


Identification : ORE00242A

Pays : Etats Unis

Durée : Jul 1, 2002 à Sep 30, 2007

Mots clés : winter wheat herbicide resistance grass seed integrated control (weeds) management systems dryland farming bromus tectorum aegilops cylindrica phenology lolium grasses production efficiency peas barley weed control climate seed set predictive models seed development ecosystems resistance management herbicide resistant plants seed dormancy vernalization longevity niches


Identify and characterize climatic, and phenological factors that control timing of seed set in downy brome, jointed goatgrass, and feral rye and develop models to predict seed development of these species in dryland agroecosystems. Develop herbicide resistance management strategies to slow the spread of ALS inhibitor resistance in winter annual grass weeds in dryland wheat. Investigate new herbicides to improve weed management and environmental suitability for inland Pacific Northwest dryland cropping systems and in Columbia Basin and Grande Ronde Valley grass seed production. Investigate biological and ecological characteristics of Vulpia myrous and Puccinellia spp. Research will focus on characteristics such as seed dormancy, longevity, vernalization requirements, and ecological niche preferences

Locally collected seed of jointed goatgrass and feral rye will be planted at field sites near Pendleton in the fall and repeated over several years. Growing degree-days will be calculated during the growing season through the period of seed production. Climatalogical data will be collected at the site. At various times from early boot through maturity, seed spike samples will be taken to evaluate the presence of viable seed embryos using a combination of visual evaluation, tetrazolium chloride (TZ) assay, and germination tests. Seed development will be related to growing degree-days from 50% emergence and from January 1, a hypothetical starting date after vernalization. Feral rye and jointed goatgrass plants grown under field conditions will be treated at various intervals with glyphosate or paraquat to determine the influence of these non-selective herbicides on seed production. Changes in downy brome population susceptibility to sulfosulfuron due to herbicide use patterns are being evaluated in continuous, direct-seeded winter wheat. This type of cropping system will necessarily rely on high herbicide inputs to maintain downy brome densities below economically damaging levels. Field plots were established in a commercial winter wheat field that receives average annual precipitation of approximately 10 inches. Weather recording instruments were installed at the site. Sulfosulfuron treatments were applied postemergence for a one, two, or three year period on plots of direct-seeded winter wheat plots naturally infested with downy brome. An untreated control was included to observe downy brome population density and differences in sulfosulfuron susceptibility compared to treated plots over the three year study period. In each plot, mature downy brome seed panicles are collected at the time of downy brome panicle maturity. Plants grown from collected seed are treated with a series of sulfosulfuron rates and assessments made of GR50 values. Calculated GR50 values between sulfosulfuron treated and untreated downy brome populations will be compared to assess the development of herbicide resistance in treated downy brome populations. Optimum seed germination temperatures will be determined for dry stored seed of Vulpia myrous, Puccinellia sp. using a thermogradient plate germinator. If seed germination is limited in preliminary germination tests, this will suggest that primary dormancy may exist. Dormant seeds will be subjected to germination promoting treatments to characterize the type of dormancy existing in these species. Germination promoting treatments will include, at a minimum, gibberillic acid, and scarification. Seed longevity studies will be determined by buring seeds of V. myrous, Puccinellia sp. at 10, 20, 30, and 60 cm depths in the soil. Packets will be recovered at six month intervals for a period of 5 years, seeds separated from soil, and tested for viability by germination testing.

Présentation : USDA

Page publiée le 30 novembre 2015, mise à jour le 30 octobre 2017