Plant Pathology Commons^™

Kentucky Alfalfa Conference: A Team Approach To Alfalfa Education And Technology Transfer, Garry D. Lacefield, Monroe Rasnake, Christi L. Forsythe, Jimmy C. Henning, Bill Talley

IGC Proceedings (1977-2023)

Alfalfa has played an important role in providing farmers of Kentucky with a high yielding, high quality, persistent forage legume for many years. In 1980, a group of individuals under the leadership of University of Kentucky Forage Extension Specialists organized and implemented the first statewide educational event on alfalfa. This initial meeting gave rise to the Kentucky Alfalfa Conference that celebrated it’s twentieth anniversary in February 2000. This annual event has been co-sponsored by the University of Kentucky, Kentucky Forage and Grassland Council, along with other state and national groups including Certified Alfalfa Seed Council, Kentucky Department of Agriculture, Kentucky …

Developing A National Alfalfa Information System, David B. Hannaway, K. J. Hannaway, P. Sohn, S. Griffith, B. E. Avery, E. Nowick, W. F. Wedin, L. R. Vough, S. C. Bosworth, Garry D. Lacefield, Gary E. Bates, D. Undersander, N. P. Martin, J. Caddel, G. L. Kilgore, S. B. Orloff, A. M. Gray, R. Ditterline, T. Griggs, D. H. Putnam, M. J. Ottman

IGC Proceedings (1977-2023)

Using state-of-the-art telecommunication technologies, this project is developing a comprehensive knowledge resource for alfalfa (Medicago sativa L.); the National Alfalfa Information System (NAIS). This project will serve as an improved model for Extension educational programs. Alfalfa is the most important forage crop in the USA and grown worldwide for feeding millions of livestock and in many cropping systems. As a legume, it is important in sustaining the environment and the productivity of agriculture. Information needs are present in every state and internationally. The NAIS is being developed through national and international cooperation, putting the best science-based alfalfa information and …

Map Based Www Tool For Recommending Forage Species, M. H. Hall, D. A. Miller, J. H. Cherney

IGC Proceedings (1977-2023)

Selecting the “best” forage species or species mixture requires a knowledge and understanding of the consuming animal, soil characteristics, and forage species. The multivariate nature of the problem presents challenges to those interested in solving the practical problem of maximizing available resources. Earlier work at Cornell University resulted in a WWW-based interface that allowed the user to provide a soil type or zip code and additional management factors to initiate the species selection. This approach relies on either user knowledge of soil series or an implied relationship between zip code and soil series that may often be wrong. To improve …

Remote Sensing Application To Grassland Monitoring, Z. B. Nan

IGC Proceedings (1977-2023)

Application of remote sensing to the management of grassland resources, the role this plays in developing sustainable grassland farming systems and opportunities for further development are outlined. Use of remote sensing technologies in grassland monitoring has a history of more than 30 years. Both fine- and coarse-grained remote sensing techniques are used to monitor and study grasslands. Fine-grained techniques are used to study landscape scale processes through the use of sensors providing spatial resolution of a few meters, whereas coarse-grained techniques are used to study catchment scale areas, and even entire biomes, using satellite-based sensors with a spatial resolution of …

Modelling Grassland Ecosystems, J. H. M. Thornley

IGC Proceedings (1977-2023)

In this contribution a view of the promise and difficulties of modelling grassland is given. This is largely centred around work with a grassland ecosystem simulator known as the Hurley Pasture Model.

A brief introduction sets forth possible reasons for building a large ecosystem model, and stresses the importance of modelling objectives. It is suggested that a model is de rigeur for any research programme which aims to take a firm grasp of the complex responses of grassland. Mechanistic models are required to provide the understanding needed for intelligent and flexible management of grassland, whatever the prevailing environmental or economic …

Estimating Herbage Mass In Stargrass (Cynodon Nlenfuensis Var Nlenfuensis) Using Sward Surface Height And The Rising Plate Meter, D. E. Oliveira, S. R. Medeiros, L. J. M. Aroeira, L. G. Barioni, D. P. D. Lanna

IGC Proceedings (1977-2023)

Estimation of herbage mass is necessary both in research and farm management. Methods for such estimations should be inexpensive, rapid and reliable. Since estimations through hand clipping are time consuming, a range of indirect methods have been developed and tested in the literature. This study had the aim of comparing precision of two indirect methods, sward surface height (SSH) and the rising plate meter (RPM), to estimate herbage mass in stargrass pastures (Cynodon nlenfuensis var. nlenfuensis). Pre-grazing measurements of SSH and RPM readings were taken and compared with the paddock herbage mass. RPM readings were converted into centimeters. Average …

The Analysis Of Results From Paired Paddock Comparisons, David R. Kemp, P. M. Dowling, D. L. Michalk, G. Millar

IGC Proceedings (1977-2023)

Paired-paddock comparisons are a common way of evaluating new grassland practices at a scale more relevant to farmers. They are also being used to replace or augment designed experiments and can be the only source of information available on a practice. However, it is often uncertain if the differences between paddocks are significant. Importantly, a current trend among funding organisations is to support paddock comparisons. The need for valid procedures to compare unreplicated treatments is increasingly urgent. It is suggested that a range of tools be used to infer statistical significance from using typical error values from related studies or …

Length And Width To Estimate Dry Mass Of Panicum Maximum Cv. Tanzânia Leaves, L. G. Barioni, P. M. Santos, A. Coldebella, M. Corsi

IGC Proceedings (1977-2023)

An analysis of the relationship of leaf length (LL) and leaf width (LW) with leaf dry weight (LDW) in Panicum maximum was carried out with the objective of improving estimations of tissue flow in that plant. Data was collected in a mob grazing experiment with 28 days grazing interval sampled the day before grazing in 9 grazing cycles. Regression analysis revealed highly significant effect (P < 0.001) of both LL and LW on LDW. A lack of fit test gave strong evidence of non-linear relationship of LDW with LL (p < 0.05), fitting the model 1 0 LDW = β₀LL^β₁ , while LW presented a linear relation with LDW. LL was a better predictor of LDW than LW. LL solely or in combination with LW produced equations with …

Bioeconomic Model For Decision-Making On Fattening Beef-Cattle, G. Ferreira, O. Cardozo, J. M. Soares De Lima

IGC Proceedings (1977-2023)

Profitability and competitiveness of agricultural systems it is closely related with the technology used. Economic and financial appraisal of investments on pasture improvements, facilities, feed and management plans, etc. are often required in order to make decisions. A bio-economic simulation model was developed in order to support decision making on beef-cattle grazing fattening. The aim of the model is to show the relationship between the technological alternative analysed in physical terms as well as financial and economic. By this way it is possible to asset and relate the bio-economic impact of the different animal and pasture management alternative technologies. Results …

Sequential Injection Analysis: A Powerful Tool For Routine Soil And Plant Laboratories, A. R. A. Nogueira, F. V. Silva, M. Y. Kamogawa, G. B. Souza, L. F. M. Ferraz

IGC Proceedings (1977-2023)

Sequential injection analysis (SIA) present attractive characteristics for analyses in large scale. In SIA the analytical determination can be performed automatically reducing the number of steps usually involved in a chemical analysis. In order to demonstrate the advantages found in the implementation of a SIA procedure in a laboratory dedicated to routine analyze, the determination of volatile nitrogen in silage and soil samples has been performed. The nitrogen content was determined after NH₃ on-line separation in alkaline conditions by using a gaseous diffusion or a pervaporation unit for liquid-liquid separation. An ammonium tubular selective electrode detector was used for …

A Chance-Constrained Linear Model For Beef Policy Analysis, Claudio F. Machado, S. T. Morris, C. Dake, A. Macdonald, I. M. Brookes, F. Di Croce, F. Gonzalez, N. J. Auza

IGC Proceedings (1977-2023)

A simple linear model to evaluate different bull beef policies (BBP) by incorporating the stochastic nature of pasture yield from a database with separate chance constraints (ChC) was developed. A 100 ha farm was used, and the model was run with five different BBP and set to different levels of pasture yield risk to maximise production.ha^-1.year^-1. Summer was the most risky season, and the optimum mix of policies changed at different levels of risk. Chance constraint represents an interesting and simple alternative to include pasture variation into a linear model.

Mapping Nitrogen Fixing Shrubs In Dry Unimproved Tussock Grassland, C. C. Boswell, W. L. Lowther, P. D. Espie

IGC Proceedings (1977-2023)

Global Positioning System (GPS) was used to both map the positions of individual nitrogen-fixing shrub plants and record individual plant height and breadth dimensions, within a small catchment of dry sub-humid unimproved short tussock grassland. The distributions of different species of shrubs varied with different landscape units within the catchment. The information will provide the base data for a first approximation of the role of the shrubs in the nitrogen balance of the ecosystem, which is pivotal to the sustainability of pastoral farming in the tussock grasslands.

Repeated Measurement Analyses Of Forages In Cropping Systems, A. R. De Freitas, O. Primavesi, L. De A. Corrêa, A. C. Primavesi, E. B. Pott, A. Dos S. Mascioli

IGC Proceedings (1977-2023)

Repeated measurements (RM) are common in forage experiments. The data used in this study were accumulated ammonia losses by volatilization (N) and dry matter production (DM) of Cynodon dactylon cv. Coastcross pasture from an experiment in blocks with five levels of urea: 0, 25, 50, 100 and 200 kg of N ha^-1, applied in five periods (cuttings). For N, RM were the averages of cuttings and nine days of observation. The F test for the hypothesis of no effect for Period and Level x Period interaction (DM) and for Days and Level x Days interaction was not affected …

Farmwi$E: A Flexible Decision Support Tool For Grazing Systems Management, A. D. Moore

IGC Proceedings (1977-2023)

CSIRO's new FarmWi$e decision support tool provides a framework that permits pasture-livestock systems and management policies of any level of complexity to be simulated. An underlying "modelling protocol" permits other simulation models to be added, further extending its domain of applicability. Management policies are specified in FarmWi$e by means of rules that govern when, whether and how management events take place. An example of the use of FarmWi$e to study lamb production is given.

Sward Height; Visual Estimate Compared With Plate Meter Height, W. B. Bryan, E. C. Prigge, E. L. Nestor, O. J. Gekara, M. A. Schettini

IGC Proceedings (1977-2023)

Sward height (SH) is widely used in pasture research and farm practice to evaluate pasture conditions. Visual estimates can take less time than actual measurements. This study compared visually estimated SH, of continuously grazed cool-season permanent pasture with plate meter height. Weekly estimates, by five people, were made on 12, 0.75 to 1 ha fields, grazed at two intensities. Paired data (visual estimate and plate meter height) were subjected to variance and covariance analyses and prediction equations were developed. Average visual height accounted for 86% of the variability in plate meter height. Inclusion of other sources of variability in the …

Sources Of Error For Ultrasonic Measurements Of Steer Compositional Traits In Grazing Studies, Glen E. Aiken, F. M. Rouquette Jr., A. H. Brown Jr.

IGC Proceedings (1977-2023)

Real-time ultrasound technology has potential use for measuring compositional traits in grazing studies. Sources of error with this application must be identified for designing experiments with adequate precision to determine treatment effects. A study was conducted to evaluate breed type (Angus x Brahman, AB; Simmental x [Angus x Brahman], SAB; Simmental x [Brahman x Hereford], SBH), initial body weight, and initial ultrasonic measures as sources of experimental error in the analyses of external fat (EF) depths and longissimus dorsi (ribeye) areas (LDA). Steers were ultrasonically scanned at the initiation and conclusion of a grazing study that examined stocking rate effects …

Grassland Management And Animal Product Quality, G. W. Sheath, J. B. Coulon, Q. A. Young

IGC Proceedings (1977-2023)

The expectations of consumers ultimately determine the specification of product quality; and grassland systems produce a wide range of animal-based products. Therefore, to provide focus, this paper deals only with food products that are destined for markets that exhibit strong discretionary choice. Quality expectations of consumers have traditionally been based on product attributes such as taste, freshness, nutritional value and appearance, but customer expectations are expanding to encompass food safety, environmental care, animal welfare and biotechnologies.

Grassland forages and their management influence the intrinsic sensory properties of food. A dairy products case study is presented, indicating that pasture species and …

Priority Setting And Funding Of Agricultural Research, M. Petit

IGC Proceedings (1977-2023)

Agricultural research funding amounts and modalities have been profoundly transformed in recent years in many countries. For instance, competitive funding has become the norm rather than the exception in most countries and funding sources have been greatly diversified. In addition, in some major countries, the private sector has become a major actor In agricultural research, both as a funder of research and as a provider research results. This poses a major challenge to public research institutions, which remain the major agricultural research actors and employers of researchers in most countries. With these changes in funding, formal procedures for research priority-setting …

Dilemma: Increase In Human Food Production Or Use Of Grasslands For Environmental And / Or Social Purposes, A. D. Meister

IGC Proceedings (1977-2023)

In the title for this paper we find three major objectives: to feed the world, sustain the environment and provide resources for social purposes, and a dilemma. Even though the word ‘dilemma’ usually implies choice between undesirable alternatives, it is obvious that the alternatives here are not undesirable. Is the dilemma then, that we can only do one at the time, or that the consequences of favouring one over the other can lead to undesirable outcomes? It is my opinion that we are talking about the latter interpretation. It is the foreclosing of options by allowing one objective to dominate …

The Development And Prospect Of Chinese Grassland Economic System, Fuzeng H.

IGC Proceedings (1977-2023)

China is a country with an old agriculture civilization of the world. The arrangement of the crop and pasture area had developed from Han and Tang dynasty. (From A.C 206.to AD 907). Chinese livestock economic had undergone the winding development for a thousand years of feudal society, however, It still belong to a phase of the loose private ownership. From 1949 when The People's Republic of China was founded, the pasture was nationalized and collective management. Since 1980s, the planned economic changed into the market economic gradually. The pasture was public ownership, but management by contract, paid utilization and unchanged …

Contextual Factors In The Management Of Common Grazing Lands: Lessons From Mongolia And Northwestern China, R. Mearns

IGC Proceedings (1977-2023)

Seen in a global perspective, pastoral development is now increasingly motivated by social and environmental objectives rather than by production- or output-orientated objectives. Attention is shifting towards a broader concern with sustainability, both of grasslands, and of the livelihoods of those who rely on them (de Haan et al, 1997, Fratkin and Mearns forthcoming). Quite how these twin sustainability objectives may be achieved in particular contexts, however, is an empirical question. Drawing on examples from a diverse range of natural grassland-based livestock production systems under economic transition in Mongolia and northwestern China, this summary paper aims to show how an …

De-Intensification Of Grasslands: Understanding The Processes To Find The Balance, K. C. Hodgkinson

IGC Proceedings (1977-2023)

There is a growing trend in Australia and other developed countries for deintensification of animal production from grasslands and for grasslands to be used for purposes other than livestock grazing. These shifts are occurring for a variety of reasons including unsustainable land management practices, environmental pollution, loss of conservation value, poor commodity prices and declining rural infra-structure and communities. In Australia, the shifts are under way in agricultural grasslands, where sown pastures occur in a matrix of semi-natural woodlands, but less so in the other three major natural grasslands that forms the arid and semi-arid rangelands.

The conversion of natural …

De-Intensification Of Grasslands: Current State And Trends, Michael Duru, Bernard Hubert

IGC Proceedings (1977-2023)

De-intensified use of grasslands, and more generally of the livestock systems they support, has been triggered by a growing sensitivity of citizens to environmental quality (nitrogen) and quality of animal products, and by the warnings addressed to political authorities by scientists about the environmental consequences of economic imbalances (decreasing biodiversity, drop in soil fertility, greenhouse effect), and in particular of food overproduction in Europe.

From an ecological standpoint, grassland de-intensification must be envisaged whenever the techniques implemented disrupt resource sustainability. The grassland resource itself may be at risk when a rate of vegetation offtake by herbivores that is incompatible with …

Fddm1 And Fddm2, Two Sgs3-Like Proteins, Function As A Complex To Affect Dna Methylation In Arabidopsis, Shengjun Li, Weilong Yang, Yunfeng Liu, Guangyong Li, Xiang Liu, Yaling Liu, James R. Alfano, Chi Zhang, Bin Yu

Center for Plant Science Innovation: Faculty Publications

DNA methylation is an important epigenetic modification required for the specific regulation of gene expression and the maintenance of genome stability in plants and animals. However, the mechanism of DNA demethylation remains largely unknown. Here, we show that two SGS3-like proteins, FACTOR OF DNA DEMETHYLATION 1 (FDDM1) and FDDM2, negatively affect the DNA methylation levels at ROS1-dependend DNA loci in Arabidopsis. FDDM1 binds dsRNAs with 50 overhangs through its XS (rice gene X and SGS3) domain and forms a heterodimer with FDDM2 through its XH (rice gene X Homology) domain. A lack of FDDM1 or FDDM2 increased DNA methylation levels …

Qteller: A Tool For Comparative Multi-Genomic Gene Expression Analysis, Margaret R. Woodhouse, Shatabdi Sen, David Schott, John L. Portwood Ii, Michael Freeling, Justin W. Walley, Carson M. Andorf, James Schnable

Center for Plant Science Innovation: Faculty Publications

Motivation: Over the last decade, RNA-Seq whole-genome sequencing has become a widely used method for measuring and understanding transcriptome-level changes in gene expression. Since RNA-Seq is relatively inexpensive, it can be used on multiple genomes to evaluate gene expression across many different conditions, tissues and cell types. Although many tools exist to map and compare RNA-Seq at the genomics level, few web-based tools are dedicated to making data generated for individual genomic analysis accessible and reusable at a gene-level scale for comparative analysis between genes, across different genomes and meta-analyses. Results: To address this challenge, we revamped the comparative gene …

Root Phenotyping Of Peptide-Treated Glycine Max, Salem Jackson, Fiona Goggin

Inquiry: The University of Arkansas Undergraduate Research Journal

Plant elicitor peptides (Peps) – endogenous chains of amino acids involved in natural plant defense – have been shown to decrease damage from herbivores and pathogens by inducing an immune response, increasing the emission of volatile organic compounds (VOCS), transcripts, and metabolites. Exogenous treatment of soybean seeds with plant elicitor peptide GmPep3 has been shown to induce these broad-spectrum defenses and offers a new method for increasing crop yield. However, the effects of GmPep3 on indicators of soybean health – root characteristics, growth stages, etc. – have not been fully realized. Using the root-phenotyping platform RhizoVision Explorer, several root traits …

The Quest To Identify A New Virus Disease Of Sunflower From Nebraska, Robert M. Harveson, Maher Al Rwahnih, California Department Of Food And Agriculture, Alex Karasev, Tom J. Gulya, Jeff Bradshaw

Panhandle Research and Extension Center

Between 2010 and 2018, sunflower plants exhibiting virus-like symptoms, including stunting, mottling, and chlorotic ringspots on leaves, were observed from commercial fields and research plots from four sites within three distinct counties of western Nebraska (Box Butte, Kimball, and Scotts Bluff). Near identical symptoms from field samples were reproduced on seedlings mechanically in the greenhouse on multiple occasions, confirming the presence of a sap-transmissible virus from each site. Symptomatic greenhouse-inoculated plants from the 2010 and 2011 Box Butte samples tested negative for sunflower mosaic virus (SuMV), sunflower chlorotic mottle virus (SuCMoV), and all potyviruses in general by ELISA and RT-PCR. …

Proceedings Of The 2022 Passion Fruit Conference: Growing The U.S. Passion Fruit Industry A Strategic Conference For: Growers, Marketers, Researchers, And Stakeholders, Eric T. Stafne

CREC Publications

We are pleased to deliver these proceedings of the passion fruit conference that was held in Homestead, Florida on June 14 and 15, 2022. It was a culmination of a lot of hard work by many people, most of them listed in the previous page. However, it would not have been a success without the attendees who came from various parts of the country to share their experiences growing passion fruit. What follows in these proceedings are the slides of the presentations with by notes taken by attendees along with notes taken of discussion regarding the five priority topic areas: …

Epidemiology And Management Of Frogeye Leaf Spot Of Soybean: Damage Thresholds, Efficacy And Profitability Of Foliar Fungicides, Jhonatan Paulo Barro

Theses and Dissertations--Plant Pathology

Frogeye leaf spot (FLS), caused by Cercospora sojina, is an economically important disease of soybean in many parts of the world where soybean is grown, including the United States. A meta-analytic approach was used to summarize a data set of 66 uniform field research trials conducted to evaluate fungicide efficacy against FLS on soybean. The dataset spanned 10 years (2012 to 2021) of experiments conducted across eight states in the U.S., including Alabama, Arkansas, Illinois, Iowa, Kentucky, Louisiana, Mississippi and Tennessee. First, the relationship between FLS severity and soybean yield was investigated. A significant negative slope obtained through random …

An Improved Understanding Of Diplodia Ear Rot In Kentucky Corn, Nolan Ryan Anderson

Theses and Dissertations--Plant Pathology

Stenocarpella maydis and Stenocarpella macrospora are both causal agents of Diplodia ear rot (DER) of corn in the U.S. The current prevalence and distribution of each is unknown worldwide. Signs and symptoms of DER include white mold on and between kernels, bleached husks, and pycnidia visible in the cob pith. The term hidden Diplodia describes when no mycelia or bleached husk is present, but pycnidia are still visible inside the cob. This phenomenon is reported to be caused by late infections of Stenocarpella spp. New fungicide nozzle technology has been promoted to increase spray coverage in the lower canopy, which …