http://hdl.handle.net/1957/14728 Thu, 16 May 2013 10:24:47 GMT 2013-05-16T10:24:47Z http://hdl.handle.net/1957/38588 Seed quality and plant establishment studies of seashore paspalum (Paspalum vaginatum Sw.) Baker, Stanley D. (Stanley David) Seashore paspalum (Paspalum vaginatum Sw.) is an important warm-season perennial turfgrass, known for its tolerance to salinity. Turfgrass is used for homes, municipalities, sod farms, resorts, and sports fields. Seashore paspalum has historically been planted in sub-tropical and tropical climates because of its heat tolerance. Seashore paspalum could become an alternative turfgrass and seed crop in Oregon's Willamette Valley (OWV) if summer temperatures increase because of climate change. Typically, seashore paspalum has been propagated vegetatively through rhizomes and stolons, but transporting this vegetative material has been problematic as much of the material either does not survive or does not transplant well. Ideally, it would be commercially beneficial to grow seashore paspalum from seed. However, planting seed has been restricted due to low seed germination rate, slow germination, and variable establishment in the field. Thus, the purpose of this research was 1) to establish the optimum blowing point (OBP) to separate pure seashore paspalum seeds from light inert matter in order to allow for more accurate seed testing and possibly improved seed cleaning, 2) to determine the extent of dormancy in newly harvested seeds and germination requirements for laboratory germination test, and 3) to identify the optimum time for planting seashore paspalum under OWV environmental conditions. The results for the OBP study showed that an air velocity of 2.2 m/s was the OBP for seashore paspalum. The results of germination studies indicated that there is significant dormancy in seashore paspalum and that given this dormancy, an alternating temperature regime of 20/30⁰C (16 h dark/8 h light) provided best germination test results. The results for the establishment study showed that there were no significant differences in establishment among cultivars of seashore paspalum. Furthermore, seashore paspalum established at a range of 480 to 549 GDD (GDD = [(Max. Temp ⁰ C + Min. Temp ⁰C)/2] - 5⁰ C) based on air temperature and achieved ≥ 90% green within 90 days. July and August proved optimum for establishment due to lower Poa annua intrusion. Graduation date: 2013; Access restricted to the OSU Community at author's request from May 15, 2013 - May 15, 2015 Wed, 01 May 2013 00:00:00 GMT http://hdl.handle.net/1957/38588 2013-05-01T00:00:00Z http://hdl.handle.net/1957/38305 Cultivation and Irrigation of Fernleaf Biscuitroot (Lomatium dissectum) for Seed Production Shock, Myrtle P.; Shock, Clinton C.; Feibert, Erik B. G.; Shaw, Nancy L.; Saunders, Lamont D.; Sampangi, Ram K. Native grass, forb, and shrub seed is needed to restore rangelands of the U.S. Intermountain West. Fernleaf biscuitroot [Lomatium dissectum (Nutt.) Mathias & Constance] is a desirable component of rangelands. Commercial seed production is necessary to provide the quantity and quality of seed needed for rangeland restoration and reclamation efforts. Fernleaf biscuitroot has been used for hundreds if not thousands of years in the western United States as a source of food and medicine. Knowledge about fernleaf biscuitroot is confined to ethnobotanical reports, evaluation of some of its chemical constituents, and its role in rangelands. Products derived from fernleaf biscuitroot are sourced from wild plant populations. Little is known about fernleaf biscuitroot cultivation or its seed production. Variations in spring rainfall and soil moisture result in highly unpredictable water stress at flowering, seed set, and seed development of fernleaf biscuitroot. Water stress is known to compromise seed yield and quality for other seed crops. Irrigation trials were conducted at the Oregon State University Malheur Experiment Station at Ontario, OR, a location within the natural environmental range of fernleaf biscuitroot. It was anticipated that supplemental irrigation would be required to produce a seed crop in all years. Fernleaf biscuitroot was established through mechanical planting and cultivation on 26 Oct. 2005 in a randomized complete block design with four replicates; plot size was 9.1 m × 3.04 m wide. Irrigation treatments were 0 mm, 100 mm, and 200 mm/year applied in four equal treatments 2 weeks apart, timed to begin with flowering and continue through seed formation. First flowering occurred in the third year after planting. Seed production increased from the fourth through the sixth year. Optimal irrigation for seed production was calculated as 140 mm/year. This is a scanned version of a published article. The original can be found at: http://hortsci.ashspublications.org/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Mon, 01 Oct 2012 00:00:00 GMT http://hdl.handle.net/1957/38305 2012-10-01T00:00:00Z http://hdl.handle.net/1957/38170 Effects of elevated CO2 and temperature on seed quality Hampton, J. G.; Boelt, B.; Rolston, M. P.; Chastain, T. G. Successful crop production depends initially on the availability of high-quality seed. By 2050 global climate change will have influenced crop yields, but will these changes affect seed quality? The present review examines the effects of elevated carbon dioxide (CO₂) and temperature during seed production on three seed quality components: seed mass, germination and seed vigour. In response to elevated CO₂, seed mass has been reported to both increase and decrease in C₃ plants, but not change in C₄ plants. Increases are greater in legumes than non-legumes, and there is considerable variation among species. Seed mass increases may result in a decrease of seed nitrogen (N) concentration in non-legumes. Increasing temperature may decrease seed mass because of an accelerated growth rate and reduced seed filling duration, but lower seed mass does not necessarily reduce seed germination or vigour. Like seed mass, reported seed germination responses to elevated CO₂ have been variable. The reported changes in seed C/N ratio can decrease seed protein content which may eventually lead to reduced viability. Conversely, increased ethylene production may stimulate germination in some species. High-temperature stress before developing seeds reach physiological maturity (PM) can reduce germination by inhibiting the ability of the plant to supply the assimilates necessary to synthesize the storage compounds required for germination. Nothing is known concerning the effects of elevated CO₂ on seed vigour. However, seed vigour can be reduced by high-temperature stress both before and after PM. High temperatures induce or increase the physiological deterioration of seeds. Limited evidence suggests that only short periods of high-temperature stress at critical seed development stages are required to reduce seed vigour, but further research is required. The predicted environmental changes will lead to losses of seed quality, particularly for seed vigour and possibly germination. The seed industry will need to consider management changes to minimize the risk of this occurring. This is the publisher’s final pdf. The published article is copyrighted by Cambridge University Press and can be found at: http://www.cambridge.org/. Fri, 30 Mar 2012 00:00:00 GMT http://hdl.handle.net/1957/38170 2012-03-30T00:00:00Z http://hdl.handle.net/1957/38098 Weed management for giant reed (Arindo donax) biomass production in Oregon Attarian, Amir Giant reed (Arundo donax L.) is a candidate to provide feedstock for the Portland General Electric power plant in Boardman, Oregon. Giant reed is a fast perennial grass, producing 23-27 metric tons ha⁻¹ of biomass and has the ability to adapt to diverse environments making it a good candidate for biomass production. This study tested postemergence and preemergence herbicides for controlling weeds in giant reed during the establishment year in which giant reed plants are more sensitive to weed competition. The greenhouse study demonstrated that among the tested herbicides, bromoxynil plus MCPA at 0.841 kg ai ha⁻¹, nicosulforun at 0.035 kg ha⁻¹, and dimethenamid-p at 0.735 kg ha⁻¹ did not injure giant reed. In a field study, preemergence application of dimethenamid-p at 0.735 kg ha⁻¹ followed by a postemergence application of 2,4-D amine at 0.560 kg ha⁻¹ and a postemergence application of bromoxynil plus MCPA at 0.841 kg ha⁻¹ did not injure giant reed. The presence of weeds in a field does not always mean that crop yield will be reduced and there are some periods during the growing season when weeds will not cause considerable yield loss. Therefore, predicting a critical period of weed control (CPWC) that includes the best time for weed control in giant reed could improve weed management in the field. The length of the CPWC could be different depending on the level of acceptable yield loss (AYL). Our results are reported for AYL of 5 and 10%. The CPWC started at 290 accumulated growing degree days (GDD) and ended at 820 for a 5% AYL, while for a 10% AYL, it started at 333 GDD and ended at 727 GDD. Based on the results, there are some herbicides which could be selected for further study for weed control in the giant reed and the estimated CPWC which could be used to inform weed management practices in giant reed production. Graduation date: 2013 Wed, 06 Mar 2013 00:00:00 GMT http://hdl.handle.net/1957/38098 2013-03-06T00:00:00Z