Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2025
Abstract
presentation Sludge network meeting, 2025
Authors
Payel Bhattacharjee YeonKyeong Lee Marcos Viejo Gareth Benjamin Gillard Simen Rød Sandve Torgeir Rhoden Hvidsten Brit Salbu Dag Anders Brede Jorunn Elisabeth OlsenAbstract
Conifers are among the most radiosensitive plant species. Elevated, sublethal levels of ionising radiation result in reduced apical dominance in conifers, indicating a negative effect on shoot apical meristems (SAMs). The SAMs, harbouring the pluripotent stem cells, generate all the cells of the shoot, enabling growth and reproduction. However, knowledge on the effects of ionising radiation on such stem cells is scarce, but important for risk assessment and radioprotection of plants in contaminated ecosystems. Here, we assessed the sensitivity of in vitro-grown stem cells of Norway spruce to 144 h of gamma irradiation at 1–100 mGy h −1 , using such cells as a model for molecular toxicity of gamma radiation in conifers. Although there were no visible effects of the gamma irradiation on cell proliferation and subsequent embryo formation, dose rate-dependent DNA damage was observed at ≥ 10 mGy h −1 , and comprehensive organelle damage at all dose rates. Massive dose rate-dependent transcriptome changes occurred, with downregulation of a range of genes related to cell division, DNA repair and protein folding but upregulation of stress-related hormonal pathways and several antioxidant-related genes. The upregulation of such genes, survival and continued proliferation of at least a subset of cells and the post-irradiation normalisation of expression of DNA repair and protein-folding genes together with somatic embryo formation suggest that stem cells are able to recover from gamma-irradiation-induced stress. Collectively, regardless of cellular abnormalities after gamma irradiation, and huge transcriptomic shifts towards stress management pathways, the pluripotent stem cell cultures were able to retain their stemness.
Authors
Hannah Rivedal Todd Temple Robert Starchvick Joseph Gallagher Dustin Herb Jason Crisp Nicole Anderson Tatiana Benedetti Amy PeetzAbstract
Oregon’s grass seed industry specialises in producing forage grasses including annual ryegrass (ARG, Lolium multiflorum), a host for the seed gall nematode (SGN, Anguina funesta). SGN causes yield- limiting seed galls and are strictly regulated in international trade. From 2019 to 2020, over 500 metric tons of Oregon ARG seed were rejected from international ports due to SGN detection. A 2022 field survey of 22 ARG fields in the Willamette Valley of Oregon resulted in SGN detection in 50% of the fields throughout the growing season. Several approaches managing SGN are under evaluation. Previous reports indicate that there may be genetic resistance to SGN in other Lolium species. Therefore, a breeding population of 240 public accessions of L. multiflorum have been seeded with two seed galls and planted in the field. Seed were harvested to evaluate for galls in July 2025 and to identify potential resistant families for future study. To date, no nematicides are labelled for the control of SGN. Varied fluopyram timings and rates, as well as an untreated control, are being evaluated in the field with and without growth regulation for SGN control. Seed yield and galled seed data was collected showing limited differences between treatments. Cultural control methods are also being considered, including seed cleaning and utilizing high energy pulses on seed galls. Preliminary data suggests that these could be viable treatments to reduce SGN inoculum. Successful control options for the SGN in ARG seed production are important to reduce the spread of this nematode globally and maintain healthy forage production.
Authors
Seth Dorman Darrin Walenta Navneet Kaur Hannah Rivedal Nicole AndersonAbstract
Successful mitigation of agricultural insect pests depends on integrated pest management practices incorporating multiple techniques for effective population management below economically damaging levels. Pest surveillance remains the cornerstone of IPM programs, enabling appropriately timed management action. Phenological models using weather data are commonly used as decision support tools to predict the timing of ‘when’ economically important life stages are expected to occur. Furthermore, geostatistical models that consider landscape-level variation in environmental drivers of pest densities may inform ‘where’ outbreaks are expected to occur along spatial gradients of abiotic and biotic risk factors. Thus, predictors of pest populations can be leveraged to generate spatiotemporal risk assessments. Migratory and overwintering moth species in the family Noctuidae (order Lepidoptera) comprise a complex of serious pests that threaten the profitability of grasses grown for seed in the Willamette Valley, Oregon, USA, as well as seed production globally. Noctuid pests, including black cutworm, true armyworm, and winter cutworm, inflict crop damage by direct feeding on plant crowns and roots in the larval developmental stage. Management action with foliar insecticides is most effective when larvae are immature (early instar stage) due to insecticide susceptibility and pest behaviour. For noctuid pests (and other priority pests) in grass seed systems, real-time phenological models can provide field practitioners with information to better allocate pest monitoring and management resources to reduce input costs.
Authors
Jing Zhou Nicole Anderson Marshall Garrett Logan Snell Thomas ChastainAbstract
Seed moisture content (SMC) is the most reliable indicator of optimal harvest timing in many seed crops, including grass seed. Measuring SMC as grass seed crops approach maturity is recommended to determine optimal harvest timing. Currently, to measure SMC, seeds need to be stripped from heads by hand, weighed, dried until all the moisture has been lost, then re-weighed, and SMC manually calculated. Collecting SMC information in this manner is arduous, time consuming, and prone to error. Consequently, this procedure has resulted in inadequate SMC testing or failure to test in a timely fashion. In addition, SMC is an important factor in the storage of harvested seed, which typically needs to be stored under 12% SMC, to ensure high seed quality. The goal of this project is to develop a portable sensing device - The Grady Sensor - that allows for rapid and accurate SMC measurement of grass seed. The sensor employs near-infrared (NIR) spectroscopy principles that water molecules absorb specific NIR wavelengths. By analysing the light reflected from the seed surface, the sensor predicts SMC based on the intensity of the reflected light at moisture-sensitive wavelengths. Over two years, multiple sensor prototypes have been developed, and their performance has been validated through field tests in Oregon and New Zealand. Sensor readings were compared to laboratory oven gravimetric SMC values of samples collected from major grass seed species, including tall fescue, annual ryegrass, perennial ryegrass, orchardgrass, creeping red fescue, creeping bentgrass, Chewings fescue, and Kentucky bluegrass. The sensor readings demonstrated a significant linear relationship with the oven SMC. Mean absolute errors of sensor SMC predictions were within 1.2 to 4.6% across all grass species. The results indicate that the prototype is a reliable replacement for the traditional oven drying method.
Authors
Alison Wilette Pete Berry Andy Branka Nicole Anderson Navneet KaurAbstract
No abstract has been registered
Authors
Navneet Kaur Seth Dorman Christy Tanner Nicole AndersonAbstract
Tychius picirostris Fabricius (Coleoptera: Curculionidae), the clover seed weevil (CSW), is a major pest of white clover (Trifolium repens L.) seed crops in Oregon, USA, where larval feeding during seed development reduces yield and quality, causing substantial economic losses. For decades, CSW management has relied on bifenthrin (IRAC Group 3A), but since 2017 growers have reported reduced efficacy, prompting concern of resistance. Laboratory bioassays in 2022-2023 confirmed very high resistance to bifenthrin (RR50 = 178-726) and moderate resistance to malathion (Group 1B; RR50 = 7.8-32.8), underscoring the need for alternative chemistries and insecticide resistance management (IRM) guidelines. From 2022 to 2024, on-farm insecticide efficacy trials were conducted in commercial white clover seed fields in western Oregon. Early-season (pre-bloom or PB) application using contact insecticides (malathion, isocycloseram [Group 30], indoxacarb [Group 22]) targeted adults, either alone or in sequence with mid-season (full bloom or FB) application of systemic insecticides (chlorantraniliprole and cyantraniliprole [Group 28]) targeting larvae. Adult abundance was monitored with 20-sweep net samples, and larval densities were estimated from 30 inflorescences per plot extracted with Berlese funnels. Across sites and years, isocycloseram consistently suppressed adult populations, cyantraniliprole reduced larval densities, while indoxacarb showed variable performance. Although seed yields did not differ significantly among treatments, yet efficacy data supported product registration in Oregon and highlighted the value of chemical rotation plans for resistance management. Based on these findings, we recommend discontinuing bifenthrin and adopting an integrated resistance management (IRM) program that applies contact insecticides during spring adult migration when ≥2 weevils per sweep are detected and systemic insecticides during full bloom when ≥3 per 30 inflorescences are observed.
Authors
Mohammed Morad Nicole Anderson Thomas ChastainAbstract
Orchardgrass (Dactylis glomerata L.) is an important forage seed crop, but unlike other cool-season grass seed crops such as perennial ryegrass and tall fescue , seed yields have not increased over time. Research from the literature suggests that plant growth regulators (PGRs), such as trinexapac-ethyl (TE), and spring nitrogen (N) application increase seed yield in orchardgrass by increasing seed number. However, no research has investigated the effects of PGRs and spring N on orchardgrass seed development. Field trials were conducted in 2018 and 2019 to investigate orchardgrass seed development and the effects of PGR and spring N treatments on this process. Treatments included an untreated control, TE (210 g ai ha-1), spring N (112 kg ha-1), and TE + N. Regression analyses were used to elucidate seed development in three spikelet positions: distal, central, and proximal. In 2018, seed weight increased over growing degree days (GDD) in a bi-phasic segmented pattern from distal and central spikelets, but increases were linear from proximal spikelets. In 2019, seed weight increased in proximal spikelets following a bi-phasic segmented function, and in central spikelets, the seed weight increase was also bi-phasic, except for the TE treatment. Seed growth rate varied among spikelet positions, ranging from 0.22 to 0.34 mg GDD-1 per 100 seeds. The seed growth rate varied among TE and N treatments, ranging from 0.31 to 0.47 mg GDD-1 per 100 seed. The TE + N treatment had the shortest seed filling duration and one of the smallest seed growth rate values, producing low seed weight. The TE + N treatment produced high seed number and seed yield, indicating a reduction in seed abortion or shattering. Seed carbon (C) and N content increased during seed development and peak deposition preceded physiological maturity. There was no effect of TE on deposition of C or N in orchardgrass seed.
Authors
Nicole Anderson Hannah Rivedal Seth DormanAbstract
Epidemiology and management of aphid-transmitted yellow dwarf viruses (YDVs) have received international attention in small grains, but research regarding YDVs in grass seed production is limited. An integrated pest management program is needed to reduce the impact of YDVs in grass seed crops that are grown for more than one year. The objectives of this work were to: 1) survey commercial grass seed production fields to determine spatiotemporal virus composition, 2) evaluate the effects of nitrogen (N) fertiliser rate, and the timing and frequency of foliar insecticide applications on aphid abundance, YDV disease incidence, and seed yield in two perennial ryegrass cultivars, and 3) develop high-throughput phenotyping methods to screen cultivars for host plant resistance. To determine the incidence and diversity of YDVs, perennial ryegrass (n=20) and tall fescue (n=30) seed fields in Oregon were surveyed in 2021-2022. In 82% of fields, a Luteovirus-type YDV was detected, and 65% had detection of a Polerovirus-type YDV. In small-plot field trials conducted from 2021 to 2024, high N rates increased YDV incidence in perennial ryegrass. Seed yield was greatest for the less susceptible cultivar when protected with one insecticide treatment per season. A higher-than-recommended N rate did not increase seed yield across treatment combinations in first-year stands but did increase seed yields in second and third-year stands when YDV infection was >50%. Phenotyping methods were evaluated to assess potential host-plant resistance to YDVs using perennial ryegrass cultivars (n=27) with high- throughput automated video tracking for aphid behaviours that may confer resistance, and compared to traditional phenotyping methods. Several cultivars showed potential tolerance to YDVs. This research provides new knowledge of the spatial composition of aphid-transmitted YDVs, integrated pest management guidelines, and high-throughput methods for breeding programs to develop cultivars that are resistant to YDVs.
Authors
Willy Blaise Ineza Emelyne Clarisse Izere Roland Sonnenschein Collins B. Kukunda Fred Tumwebaze Richard Shumbusho Khamarrul Azahari RazakAbstract
No abstract has been registered