Agricultural Science Commons^™

A High-Throughput Gene Silencing Approach For Studying The Interaction Between Perennial Ryegrass (Lolium Perenne) And The Fungal Endophyte Neotyphodium Lolii, S. Felitti, P. Tian, D. Edwards, G. C. Spangenberg

IGC Proceedings (1977-2023)

Perennial ryegrass (Lolium perenne L.) and its fungal endophyte (Neotyphodium lolii) are known to establish a mutualistic association that impacts on the agronomic productivity of endophyte-infected ryegrass pastures. To study this interaction at the molecular level, a genomic resource consisting of 13,964 endophyte ESTs has been generated. However, the functions of a large proportion of these genes remain to be elucidated. Recent work has demonstrated the potential for RNA-mediated gene silencing to suppress gene expression in a sequence specific manner thus allowing for the subsequent analysis of gene function.

Isolation And Characterization Of Novel Btb Domain Protein Encoding Genes From Fungal Grass Endophytes, M. Ramsperger, S. A. Felitti, D. Edwards, G. C. Spangenberg

IGC Proceedings (1977-2023)

Pasture grasses belonging to the Pooideae sub-family of the Poaceae family frequently host symbiotic fungal endophytes. These include the sexual Epichloë species and the anamorphic asexual Neotyphodium species, which are thought to have evolved from Epichloë species either by the direct loss of sexual reproduction or by interspecific hybridisation. The two key temperate pasture grasses, tall fescue (Festuca arundinacea Schreb) and perennial ryegrass (Lolium perenne L.) interact with the fungal endophytes N. coenophialum and N. lolii, respectively. Large insert genomic DNA libraries are valuable resources for the discovery and isolation of genes and their regulatory sequences, for …

Genetic Variation In The Perennial Ryegrass Fungal Endophyte Neotyphodium Lolii, E. Van Zijll De Jong, N. R. Bannan, A. V. Stewart, K. F. M. Reed, M. P. Dobrowolski, K. F. Smith, G. C. Spangenberg, J. W. Forster

IGC Proceedings (1977-2023)

The common fungal endophytes (Neotyphodium species) of temperate pasture grasses are associated with improved tolerance to water and nutrient stress and resistance to insect pests, but are also the causal agents of animal toxicoses. Considerable variation exists among grass-endophyte associations for these beneficial and detrimental agronomic traits. The extent to which this variation may be attributed to the endophyte genotype, the host genotype or environmental interactions is currently unknown. The development of molecular genetic markers for endophytes based on simple sequence repeat (SSR) loci and the demonstration of the specific detection of endophytes in planta with these markers (van …

Metabolome Analysis Of The Interaction Between Perennial Ryegrass (Lolium Perenne) And The Fungal Endophyte Neotyphodium Lolii, P. Tian, S. Felitti, M. P. Dobrowolski, K. F. Smith, D. Edwards, R. Hall, J. Kopka, G. C. Spangenberg

IGC Proceedings (1977-2023)

Perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinacea Schreb.) frequently contain endophytic fungi (Neotyphodium lolii in perennial ryegrass and N. coenophialum in tall fescue). The presence of the endophyte has been shown to improve seedling vigour, persistence and drought tolerance in marginal environments as well as provide protection against some insect pests. Endophyte-infected grasses also produce a wide range of metabolites, including ergopeptine alkaloids, indole-isoprenoid lolitrems, pyrrolizidine alkaloids, and pyrrolopyrazine alkaloids. In contrast to information on alkaloids and animal toxicosis, the beneficial physiological aspects of the endophyte/grass interactions have not been well characterised. The physiological …

Endophyte Effects On Antioxidants And Membrane Leakage In Tall Fescue During Drought, C. P. West, R. D. Carson, C. A. Guerber, B. De Los Reyes

IGC Proceedings (1977-2023)

Tall fescue [Festuca arundinacea (Schreb.)=Lolium arundinaceum (Schreb.) S.J. Darbyshire] infected (E+) by its fungal endophyte [(Neotyphodium coenphialum Morgan-Jones & Gams.) Glenn, Bacon & Hanlin] often shows greater persistence during summer drought than endophyte-free (E-) plants (Malinowski et al., 2005). Survival of the apical meristem and growing zone of vegetative tillers likely involves biochemical adaptations whose benefits to the host are enhanced by endophyte presence. Antioxidant enzymes may scavenge free radicals during heat and drought, and thereby reduce membrane damage. Their roles in endophyte-mediated drought tolerance in tall fescue have not been tested. Our objective was to …

Nutritive Value Of Alopecurus Pratensis, Festuca Rubra, Arrhenatherum Elatius And Lolium Perenne Grown In The South Of Belgium, A. Nivyobizi, A. G. Deswysen, D. Dehareng, A. Peeters, Y. Larondelle

IGC Proceedings (1977-2023)

In Europe, recent strategies have aimed at encouraging farmers to use production techniques more efficient in preserving the environment and maintaining natural areas. Those strategies have encouraged the use of secondary grass species in forage production systems. However, the nutritive value of those grasses is not well known. Therefore, the aim of the present study was to evaluate the energy and nitrogen values of Alopecurus pratensis (ALPR), Festuca rubra (FERU) and Arrhenatherum elatius (AREL) under moderate rates of nitrogen (N) application (60 kg N/ha per cut) and a hay-cutting regime (2 cuts/year: 25 May and 9 July). Lolium perenne cv. …

The Influence Of Management On Health Status Of Festuca Rubra In Mountain Meadows, B. Voženílková, F. Klimeš, J. Květ, Z. Mašková, B. Čermák, K. Suchý

IGC Proceedings (1977-2023)

Snijders & Winkelhorst (1996) investigated swards in West Europe and showed that it was not the snow mould (Microdochium nivale) but other species of the genus Fusarium (F. cerealis (Cooke) Sacc., F. graminearum Schwabe, F. culmorum (Wm. G. Sm.) Sacc. and F. acuminatum Ellis & Everh.) that caused serious damage to grasslands where Lolium perenne L. and Festuca rubra L. were dominant components. In this study the spread and harmfulness of pathogeneous fungi involved in damage to and death of some species (Festuca rubra L., Holcus mollis L.) in grass swards was examined.

Increasing The Productive Potential Of Permanent Grasslands From The Forest Steppe Area Of Romania, V. Vintu, C. Samuil, T. Iacob, St. Postolache

IGC Proceedings (1977-2023)

In Romania permanent grasslands represent 32 % of the total agricultural area, stretching over 4,872 million hectares, out of which 340,000 ha are located in the forest steppe area, on less productive soils, which explains their inadequate botanical composition and low quality and yields (Vintu, 2003). One of the main measures taken to increase the productivity of grasslands is through fertilisation (Birch, 1999). This paper presents the results obtained during 2000-2004 on the effect of organic fertiliser on degraded grasslands made up of Festuca valesiaca L.

Productivity Of Sahiwal And Friesian–Sahiwal Crossbreds In Marginal Grasslands Of Kenya, W. B. Muhuyi, F. B. Lukibisi, S. N. Ole Sinkeet

IGC Proceedings (1977-2023)

Dual-purpose cattle can be used to exploit the production potential of semi-arid grasslands of Kenya for milk and meat production. Although the Sahiwal is adapted to these grasslands, its productivity is low. In order to increase milk and meat productivity, the Sahiwal has been crossed with the Friesian to produce Friesian-Sahiwal crossbreds (McDowell et al., 1996) adapted to the tropical environment. The objective of this study was to evaluate the productivity of Sahiwal and Friesian-Sahiwal crossbreds.

The Influence Of Harvest Period And Fertilisation On The Yield Of Some Mixed Grass And Leguminous Species Under The Forest Steppe Conditions Of North-East Romania, V. Vintu, C. Samuil, T. Iacob, St. Postolache

IGC Proceedings (1977-2023)

In the forest steppe area of North-east Romania, temporary grasslands represent an important source of high quality fodder but they have a short period of exploitation, associated with some changes in the floristic composition (Vintu, 2003). Fertiliser application and harvest period have an important role in maintaining high productivity (Hopkins, 1991). The aim of this paper is to determine the influence of harvest period and fertilization on the yield of some grass and leguminous species in the forest steppe conditions of North-east Romania.

Yield And Mineral Concentration Changes In Maize And Italian Ryegrass Cropping Systems, Sachiko Idota, Yasuyuki Ishii

IGC Proceedings (1977-2023)

Mineral balance between plants and soil to which fertilizer has been applied is important in sustainable agriculture. Cropping systems are chosen based on considerations of crop yield, soil physical and chemical properties and climatic conditions. Thus, the sustainability of a forage cropping system should only be assessed after continuous cultivation has been practiced for several years. Forage crop production is employed in the rice paddies of Japan during summer. Thus, the objective of this study was to evaluate the yield and mineral concentration of forage crops cultivated in hard-textured soils for 4 years.

Predicting Site‑Specific Economic Optimal Nitrogen Rate Using Machine Learning Methods And On‑Farm Precision Experimentation, Alfonso De Lara, Taro Mieno, Joe D. Luck, Laila A. Puntel

Department of Agronomy and Horticulture: Faculty Publications

Applying at the economic optimal nitrogen rate (EONR) has the potential to increase nitrogen (N) fertilization efficiency and profits while reducing negative environmental impacts. On-farm precision experimentation (OFPE) provides the opportunity to collect large amounts of data to estimate the EONR. Machine learning (ML) methods such as generalized additive models (GAM) and random forest (RF) are promising methods for estimating yields and EONR. Twenty OFPE N trials in wheat and barley were conducted and analyzed with soil, terrain and remote-sensed variables to address the following objectives: (1) to quantify the spatial variability of winter crops yield and the yield response …

A Plea For Scale, And Why It Matters For Invasive Species Management, Biodiversity And Conservation, Nicholas A. Mcmillan, Samuel D. Fuhlendorf, Craig A. Davis, Robert G. Hamilton, Landon. K. Neumann, Samantha M. Cady

Department of Agronomy and Horticulture: Faculty Publications

1. Invasive species are suspected to be major contributors to biodiversity declines worldwide. Counterintuitively, however, invasive species effects are likely scale dependent and are hypothesized to be positively related to biodiversity at large spatial scales. Past studies investigating the effect of invasion on biodiversity have been mostly conducted at small scales (<100 m²) that cannot represent large dynamic landscapes by design. Therefore, replicated experimental evidence supporting a negative effect of invasive plants on biodiversity is lacking across many landscape types, including large grasslands.

2. We collected data across eight large (333–809 ha) grassland landscapes managed with pyric herbivory—that is the recoupling …

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Soil Depth And Geographic Distance Modulate Bacterial Β-Diversity In Deep Soil Profiles Throughout The U.S. Corn Belt, Lucas Dantas Lopes, Stephanie L. Futrell, Emily E. Wright, Gerasimos J. Danalatos, Michael J. Castellano, Tony J. Vyn, Sotirios V. Archontoulis, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Understanding how microbial communities are shaped across spatial dimensions is of fundamental importance in microbial ecology. However, most studies on soil biogeography have focused on the topsoil microbiome, while the factors driving the subsoil microbiome distribution are largely unknown. Here we used 16S rRNA amplicon sequencing to analyse the factors underlying the bacterial β-diversity along vertical (0–240 cm of soil depth) and horizontal spatial dimensions (~500,000 km²) in the U.S. Corn Belt. With these data we tested whether the horizontal or vertical spatial variation had stronger impacts on the taxonomic (Bray-Curtis) and phylogenetic (weighted Unifrac) β-diversity. Additionally, we …

Graph Convolutional Network Using Adaptive Neighborhood Laplacian Matrix For Hyperspectral Images With Application To Rice Seed Image Classification, Jairo Orozco, Vidya Manian, Estefania Alfaro, Harkamal Walia, Balpreet K. Dhatt

Department of Agronomy and Horticulture: Faculty Publications

Graph convolutional neural network architectures combine feature extraction and convolutional layers for hyperspectral image classification. An adaptive neighborhood aggregation method based on statistical variance integrating the spatial information along with the spectral signature of the pixels is proposed for improving graph convolutional network classification of hyperspectral images. The spatial-spectral information is integrated into the adjacency matrix and processed by a single-layer graph convolutional network. The algorithm employs an adaptive neighborhood selection criteria conditioned by the class it belongs to. Compared to fixed window-based feature extraction, this method proves effective in capturing the spectral and spatial features with variable pixel neighborhood …

Harvest Aids Did Not Advance Maturity Of Non-Shatter Pennycress, Julija A. Cubins, Samantha Wells, Russ W. Gesch, Gregg A. Johnson, Maninder K. Walia, Ratan Chopra, M. David Marks, Rebecca D. Swenson, Katherine Anna Frels

Department of Agronomy and Horticulture: Faculty Publications

Reliance on summer annual crops in the Upper Midwest results in fallow land from late fall through early spring, providing opportunities to integrate winter crops, such as pennycress (Thlapsi arvense L.), onto the landscape. Pennycress agronomics have primarily been studied using unimproved wild-type lines prone to seed shatter, resulting in significant yield loss if not harvested early. However, high plant and seed moisture complicates harvest and seed storage. A new breeding line with a reducedshatter mutation made it possible to use harvest aids to reduce plant moisture without the risk of seed loss. The objectives of this study were …

Pollen-Mediated Gene Flow From Genetically Modified Herbicide Resistant Creeping Bentgrass, L. S. Watrud, E. H. Lee, A. Fairbrother, C. Burdick, J. R. Reichman, M. Bollman, M. Storm, G. King, P. K. Van De Water

IGC Proceedings (1977-2023)

Approximately 162 ha of multiple experimental fields of creeping bentgrass (Agrostis stolonifera L.) genetically modified for resistance to Roundup ®herbicide, were planted in central Oregon in 2002. When the fields flowered for the first time in the summer of 2003, a unique opportunity was presented to evaluate methods to monitor potential pollen-mediated gene flow from the experimental GM crop fields to compatible sentinel and resident plants that were located in surrounding, primarily non-agronomic areas.

Assessing The Risk Posed By Transgenic Virus-Resistant Trifolium Repens To Native Grasslands In Southeast Australia, R. C. Godfree, P. W. G. Chu, A. G. Young

IGC Proceedings (1977-2023)

In Australia, comprehensive environmental risk assessments must be performed on transgenic plants (GMOs) prior to their commercial release. A key element is the determination of whether the release of a particular GMO poses any weediness threat to the environment or other agricultural systems, which can occur by means of direct invasion or by introgression of transgenes into wild populations of the same or closely related species. For transgenic pasture plants this question could be of added importance because many of these species have been selected for traits encouraging long-term persistence and competitiveness in complex plant communities (Godfree et al., …

Belowground Meristem Populations As Regulators Of Grassland Dynamics, Harmony J. Dalgleish, D. C. Hartnett

IGC Proceedings (1977-2023)

Studies of plant populations are critical for linking organism to ecosystem-level phenomena and for understanding mechanisms driving responses to global change. In perennial grasslands, the below-ground population of meristems (the bud bank) plays a fundamental role in local plant population recruitment, persistence and dynamics. We explore two aspects of the bud bank in North American grasslands. It has been hypothesized that low variability in arid biomes is explained by meristem limitation, which constrains responses to pulses of high resource availability. Our research tests this hypothesis by comparing bud-bank populations across six sites in the United States that vary 3-fold in …