Agronomy and Crop Sciences Commons^™

Determination Of Optimum Harvest Date For Winter Malting Quality Barley In Northwest Arkansas, Paul Wolf, David Moon, Richard Esten Mason

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Due to the strict quality requirements, only 10% of worldwide barley is used for malting, though malting quality barley comes with a price increase of up to 50% or greater. With the craft brewery industry growing in Northwest Arkansas there is a growing demand for locally sourced malt quality barley. However, data are lacking regarding production practices for barley in Arkansas. The optimal harvest date for malting quality barley is at physiological maturity. This is because many of the malting traits (such as germination energy) decline as harvest is delayed, which make it difficult to meet the criteria for malting …

Instructions For Authors, Discovery Editors

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

Contents, Discovery Editors

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

Impact Of Selected Infrared Wavelengths On Inactivation Of Microbes On Rough Rice, Rebecca L. Bowie, Griffiths Atungulu, Abass Oduola, Shantae Wilson, Zeinab Mohammadi-Shad

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Formation of harmful microbes and their associated mycotoxins on rough rice during storage presents negative socioeconomic impacts to producers and consumers. The objective for this study was to investigate the impact of treating rough rice with selected infrared (IR) wavelengths at different IR intensities and heating durations, followed by a tempering step for further inactivation of microbes (mold and bacteria) on the grain. Freshly-harvested long-grain, hybrid, rough rice (XL 745) with initial moisture content (IMC) of 18.4% wet basis (w.b.) was used. Two-hundred grams (200 g) samples of rice were treated at different IR wavelengths (λ), 3.2, 4.5, and 5.8 …

Evaluating Rice Straw As A Substitute For Barley Straw In Inhibiting Algal Growth In Farm Ponds, Jacob O. Maris, Mary Savin, Lisa S. Wood

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Algal blooms disrupt aquatic ecosystems and are more common in lakes, ponds, and rivers during the summer months due to nutrient pollution. Livestock production can contribute increased quantities of nutrients to water bodies from runoff of manure. Commonly used mechanical and chemical control methods may have limited success because algae are small and propagate quickly. Barley (Hordeum vulgare) straw has been shown to inhibit the growth of algae as the straw decomposes aerobically in ponds. Therefore, barley represents a natural option for algal biomass control. However, the small amount of barley production in Arkansas limits the availability of …

Defining The Genetic Regulation Of Appressorium Formation In Cercospora Zeae-Maydis, Hazel Apiyo Buyu

Graduate Theses and Dissertations

Cercospora zeae-maydis is one of the primary pathogens associated with gray leaf spot, one of the most damaging foliar diseases of maize in the world. Gray leaf spot can be managed to some extent by cultural practices and fungicide applications. To infect maize, C. zeae-maydis grows towards stomata and forms infectious structures, termed appressoria, over stomatal pores. Prior research on the pathogen revealed that appressorium formation is crucial for foliar infection. Although several genes involved in pathogenesis have been identified in C. zeae-maydis, the molecular regulation of appressorium formation in this pathogen is poorly understood. Specifically, how the fungus senses …

Molecular Basis Of Pathogenesis And Host Determination In Cercospora Sojina: From Phenotypic To Genotypic Patterns, Wagner Calegari Fagundes

Graduate Theses and Dissertations

Frogeye leaf spot (FLS), caused by Cercospora sojina, is an important and recurrent disease of soybean in many production regions. Genetic resistance is potentially one of the most cost-effective and sustainable strategies to control FLS. However, C. sojina has already demonstrated the ability to overcome resistance conveyed by single R-genes (resistance genes) of soybeans, followed by the emergence of new physiological races. Although understanding population genomics and the virulence gene inventories in fungal plant pathogens is extremely important to improve disease control measures, studies regarding host specificity and pathogenesis in C. sojina are very limited. Therefore, the overarching goal of …

Understanding And Predicting Nematode Damage On Soybean Using Spatially Weighted Analysis, Barry Boney

Graduate Theses and Dissertations

Aerial imagery offers great potential as a predictive scouting method and could allow growers to better understand crop performance over time. Evidence suggests that the seed treatments fluopyram and abamectin result in decreased reproduction and root galling by Meloidogyne incognita, but yield protection in fields with higher or different nematode pressure is unclear. The objective of this work was to determine the efficacy of these seed treatments compared to 1,3-dichloropropene (1,3-D) applied site-specifically and then predict where these might best be applied to other fields. In a soybean field infested with M. incognita, apparent electrical conductivity was highly correlated with …

Water Conservation Practices For Irrigation Of Turfgrass Lawns, Daniel Sandor

Graduate Theses and Dissertations

Turfgrass lawns are widely used in residential and commercial landscapes, providing many environmental, aesthetic, and recreational benefits. However, concerns and scrutiny arise with perceived maintenance requirements, particularly with regards to irrigation. It is important to manage irrigation in order to maximize water conservation without significantly reducing lawn quality. A series of field and greenhouse studies were conducted to investigate how water usage might be reduced in irrigation practices with the following proposed objectives: 1) evaluate the use of rain and soil moisture sensors in a humid transition zone environment; 2) evaluate the effects of chronic drought stress between drought-resistant and …

Linkage Mapping For Soybean (Glycine Max) Flood Tolerance, Wade Stiles Hummer

Graduate Theses and Dissertations

Flood tolerance in soybean (Glycine max) is not a well-characterized trait, yet flooding damage is second only to drought stress in terms of yield reduction. The objectives of this study were to determine genetic variation for flooding tolerance in two populations of soybean recombinant inbred lines (RILs) and to identify and confirm flood tolerant QTL. Population A (WHA) consisted of 111 RILs derived from the cross 5002T by 91210-350 and Population B (WHB) consisted of 79 RILs from the cross RA-452 by Osage. Experiments were conducted at the Rice Research and Extension Center (RREC) near Stuttgart, AR in 2015 and …

Mitigating The Risk For Glufosinate Resistance, Christopher John Meyer

Graduate Theses and Dissertations

While glufosinate-resistant weeds have not yet been identified in U.S. row crops, rapid evolution of glyphosate-resistance, and resulting cost to U.S. farmers, demonstrates the need to responsibly steward the limited number of herbicides available in agricultural systems. Field and laboratory experiments were conducted to: 1) Identify herbicide interactions that can occur in Enlist™ and Roundup Ready® Xtend® systems; 2) Identify herbicide interactions that occur when glufosinate is mixed with fomesafen, clethodim, and glyphosate; 3) Determine the optimum rate structure and application timings when multiple POST applications of glufosinate are applied to LibertyLink soybean; 4) Use 14C techniques to determine why …

Influence Of Loss Of Function Of The Fatty Acid Desaturase 7 Gene On Photosynthetic Activity And Foliar Redox Status, Janithri Savindya Wickramanayake

Graduate Theses and Dissertations

Fatty Acid Desaturase7 (FAD7) is a chloroplast-localized enzyme that converts 16 and 18 carbon dienoic fatty acids to trienoic fatty acids. The suppressor of prosystemin-mediated response2 (spr2) mutant in tomato (Solanum lycopersicum) and the fad7-1 mutant in Arabidopsis (Arabidopsis thaliana) result in the loss of function of FAD7, which alter the fatty acid profiles of chloroplast membranes and enhance resistance against aphids. This research contributes toward the long-term goal of identifying factors that determine aphid resistance in FAD7 mutants. Previous data suggested constitutive differences between spr2 and WT including increased expression of genes associated with photosynthesis and differences in redox …

Arkansas Soybean Research Studies 2017, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

Systems To Attract And Feed Pollinators In Warm-Season Lawns, Michelle Wisdom

Graduate Theses and Dissertations

Pollinating insects are responsible for the production of many agricultural crops and they require floral resources to fulfill their life-cycle. Ideally, pollinating insects will encounter a diversity of floral resources across their entire season of activity, and those floral resources can include both herbaceous and woody plant species. Managed turfgrass areas have been identified as potential locations for creating pollinator-friendly habitats. In the transition zone, where both warm- and cool-season turfgrass species are present, the persistence of herbaceous plants in warm-season turfgrasses such as bermudagrass (Cynodon spp.) and buffalograss (Buchloe dactyloides), may be affected not only by the competitive nature …

Arkansas Corn And Grain Sorghum Performance Tests 2018, R. D. Bond, J. A. Still, J. F. Carlin

Arkansas Agricultural Experiment Station Research Series

Corn and grain sorghum performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture. The tests provide information to companies marketing seed within the state, and aid the Arkansas Cooperative Extension Service in formulating recommendations for producers.

Physiological Characterization Of The Soynam Parental Lines Under Field Conditions, Akshita Mishra

Graduate Theses and Dissertations

The narrow genetic pool of soybean (Glycine max L. Merr.) in North America can limit its future yield gains. Among the worldwide germplasm collection of 45,000 unique landraces, only 80 contribute 99% to the collective parentage of North American soybean cultivars. Among these 80 landraces, just 17 contribute to 86% of the collective parentage of the modern cultivars. The Soybean Nested Association Mapping population (SoyNAM) was therefore developed with the objective of diversifying the soybean gene pool. Forty diverse soybean genotypes from maturity groups (MG) 1 through 5 were crossed with a common MG 3 parent to develop 40 recombinant …

Weed Control And Management For Vegetable Soybeans In Arkansas, Seth Bernard Abugho

Graduate Theses and Dissertations

Vegetable soybean [Glycine max (L.) Merr.], known as edamame, needs weed management tools. Releasing locally adapted edamame soybean varieties and registering herbicides are necessary for successful production and expanding the edamame industry. This research aimed to 1) identify herbicides labeled for grain soybean for potential use on edamame; 2) evaluate differential tolerance of edamame soybean varieties to selected grain soybean herbicides; and 3) identify a feasible edamame-based crop rotation system. For objective 1, 26 herbicide treatments were tested on AVS-4002 edamame including preplant (PPL), preemergence (PRE) and postemergence (POST) herbicides labeled for grain soybean. Preplant herbicides caused 9 to 28% …

Evaluation Of Rice Stink Bug, Oebalus Pugnax (F.), Damage And Monitoring Techniques In Rice, Oryza Sativa L., And Grain Sorghum, Sorghum Bicolor (L.), Aaron Joseph Cato

Graduate Theses and Dissertations

Rice stink bug, Oebalus pugnax (F.), is a serious pest of headed rice, Oryza sativa L. and an occasional pest of heading grain sorghum in the Mid-south. Work from this dissertation focuses on resolving gaps in and knowledge of rice stink bug sampling and management, and attempts to create a basis for rice stink bug damage assessment in future studies.

Field experiments were conducted from 2016-2018 to asses variation in sweep net sampling by observing producers, researchers, extension personnel, consultants and their workers. Large levels of variation were found in sweep lengths between observed sweepers and reliability of smaller sweep …

Evaluation And Characterization Of Fitness Costs In Multiple Herbicide Resistant Echinochloa In Arkansas, Teal Marie Penka

Graduate Theses and Dissertations

Echinochloa spp. are major weed problems for rice (Oryza sativa L.) on a global scale. In the southern rice belt of the U.S.A., Echinochloa colona (L.) Link (junglerice) and E. crus-galli (L.) P. Beauv (barnyardgrass) are the most troublesome weeds. These species are morphologically diverse, and its high ploidy level augurs high genetic diversity, which favors high adaptability to stress, including herbicide selection pressure. The objectives of these studies were to 1) isolate resistant (R) and sensitive (S) biotypes from eight accessions of E. colona with different resistance profiles; 2) determine the resistance levels of selected R and S biotypes …

Evaluation Of Soybean Maturity Group And Planting Date In A Soybean-Rice Rotation On Overall Crop Productivity, Carrie Ortel

Graduate Theses and Dissertations

Little is known about the effects of soybean (Glycine max L.) management techniques on soil-nitrogen (N) credit development and its impact on the subsequent rice (Oryza sativa L.) crop’s success. This study was conducted to determine how soybean maturity group (MG) and planting date effect overall soybean productivity and its influence on the following rice crop. Various soybean planting dates (optimum and late) and MGs (3.5, 4.7, 5.4, and 5.6) were grown and followed in rotation with a rice crop. Six rates of pre-flood fertilizer-N (0, 44, 89, 134, 179, 224 kg N ha-1) were applied to the rice crop. …

Summaries Of Arkansas Cotton Research 2017, Fred Bourland

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

Methane Emissions From Rice Production On A Silt-Loam Soil In Arkansas, Joshua Jeffry Humphreys

Graduate Theses and Dissertations

Methane (CH4) emissions from rice (Oryza sativa L.) production are a source of concern in the environmental and agricultural communities. New and/or revised agronomic methodologies will be needed to identify production practice combinations that reduce CH4 emissions without decreasing yields. The objective of this multi-year study was to evaluate the effects of water management (i.e., full-season flood and mid-season drain) (2015), cultivar (i.e., pure-line cultivar ‘LaKast’ and the RiceTec hybrid “XP753”) (2015), soil organic matter (SOM) concentration (2016), and tillage [conventional tillage (CT) and no-tillage (NT)] and urea-based fertilizers [N-(n-butyl) thiophosphoric triamide (NBPT)-coated urea and non-coated urea] (2017) on CH4 …

Arkansas Wheat Cultivar Performance Tests 2017-2018, R. E. Mason, R. G. Miller, D. E. Moon, J. P. Kelley

Arkansas Agricultural Experiment Station Research Series

Wheat cultivar performance tests are conducted each year in Arkansas by the University of Arkansas System Division of Agriculture’s Arkansas Agricultural Experiment Station, Department of Crop, Soil and Environmental Sciences. The tests provide information to companies developing cultivars and marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating cultivar recommendations for small-grain producers.

B. R. Wells Arkansas Rice Research Studies 2017, R. J. Norman, K. A. K. Moldenhauer

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

Association Mapping And Genomic Selection For Yield And Agronomic Traits In Soft Winter Wheat, Dennis Bulusan Lozada

Graduate Theses and Dissertations

Tools such as genome-wide association study (GWAS) and genomic selection (GS) have expedited the development of crops with improved genetic potential. While GWAS aims to identify significant markers associated with a trait of interest, the goal of GS is to utilize all marker effects to predict the performance of new breeding lines prior to testing. A GWAS for grain yield (GY), yield components, and agronomic traits was conducted using a diverse panel of 239 soft winter wheat (SWW) lines evaluated in eight site-years in Arkansas and Oklahoma. Broad sense heritability of GY (H2=0.48) was moderate compared to other traits including …

Evaluation Of Acetochlor And Other Very-Long-Chain Fatty Acid-Inhibiting Herbicides In Arkansas Rice, Michael E. Fogleman

Graduate Theses and Dissertations

The prevalence of herbicide resistance and lack of effective management options for controlling problematic weeds such as barnyardgrass and weedy rice in Arkansas rice production has led to exploration of alternative herbicide sites of action (SOA). Very-long-chain fatty acid (VLCFA)-inhibiting herbicides are not currently labeled for use in U.S. rice production but have been used with success in other row crops and in rice production in Asia. Based on preliminary research, rice tolerance and weed control were evaluated following various application timings and rates of acetochlor and pethoxamid, in addition to several other VLCFA-inhibiting herbicides. Rice tolerance to acetochlor was …

Effect Of Allelic Variation In Rht Loci On Plant Height And Grain Yield Of Soft Red Winter Wheat (Triticum Aestivum L.), Habib Hayat

Graduate Theses and Dissertations

Plant height in wheat (Triticum aestivum L.) is controlled in large part by two major Rht genes, Rht-B1 and Rht-D1, which pleiotropically impact lodging and grain yield. Prior to the Green Revolution, wheat varieties contained only ‘wild-type’ Rht alleles (Rht-B1a and Rht-D1a) and were tall and prone to lodging. Introgression of a semi-dominant mutation at either of these two loci (Rht-B1b or Rht-D1b) results in a semi-dwarf phenotype and reduced plant height. When combined (Rht-B1b and Rht-D1b) an extremely short double-dwarf phenotype is observed. The objective of this study was to determine the impact of allelic variation in Rht-B1 and …

Dissection Of Soil Waterlogging Tolerance In Soft Red Winter Wheat Using Genomic Approaches, Marlovi Andrea Acuna-Galindo

Graduate Theses and Dissertations

Genomic methods including genome wide association analysis (GWAS), genomic selection (GS) and RNA-seq allow for faster selection of superior breeding lines and for identification and resolution of candidate genes. A panel of 240 soft red winter wheat (Triticum aestivum L.) cultivars and breeding lines were subjected to soil waterlogging stress over two seasons at Stuttgart, AR and St. Joseph, LA, US. Total concentrations of P, K, Ca, Mg, Mn, Fe, Al, B, Cu, Na, S and Zn were determined in wheat shoots post-waterlogging using inductively coupled plasma spectroscopy. Yield components kernel number per spike (KNPS), kernel weight per spike (KWS) …

Sustainable Intensification Of Agriculture: Opportunities And Challenges For Food Security And Agrarian Adaptation To Environmental Change In Bangladesh, Aaron Michael Shew

Graduate Theses and Dissertations

This dissertation investigates three unique aspects of sustainable agricultural intensification (SAI) in the context of Bangladeshi rice production. The first article presents a qualitative analysis of SAI and farmer surveys in the embanked polder region of coastal Bangladesh. The second article investigates the global food security and environmental impacts of already adopted High Yielding Variety (HYV) rice and double-cropped rice systems in Bangladesh using a spatial partial equilibrium trade model and a Life Cycle Assessment (LCA). The final article demonstrates a remote sensing methodology for monitoring dry season rice production at 30 m resolution in Bangladesh using a harmonic time …

Arkansas Soybean Research Studies 2016, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

Arkansas is the leading soybean-producing state in the mid-southern United States. Arkansas ranked 11th in soybean production in 2016 when compared to the other soybean-producing states in the U.S. The state represents 3.4% of the total U.S. soybean production and 3.8% of the total acres planted to soybean in 2016. The 2016 state soybean average was 47 bushels per acre, 2.5 bushels per acre less than the state record soybean yield set in 2014. The top five soybean-producing counties in 2016 were Mississippi, Phillips, Poinsett, Crittenden, Arkansas Counties. These five counties accounted for 34.7% of soybean production in Arkansas in …