Agronomy and Crop Sciences Commons^™

Water Quality, Carrier Volume And Droplet Size Effects On Herbicide Efficacy And Drift Potential, Barbara Houston

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Herbicide performance is directly related to the amount of active ingredient that has been deposited on the plant. Hence, spray solution characteristics and application parameters are crucial in determining the efficacy of an herbicide application. To maximize the effectiveness of chemical control, methods to deliver full chemical dose must be utilized: allowing the active ingredient to be readily absorbed once added to the carrier and mitigating off-target movement and low herbicide doses. Water is the most frequently used carrier in herbicide applications. Chemical parameters, such as water hardness and pH, can have a critical role in herbicide performance. It is …

Recombination Hotspots In Soybean [Glycine Max (L.) Merr.], Samantha J. Mcconaughy

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Recombination allows for the exchange of genetic material between two parents which plant breeders exploit to make new and improved varieties. This recombination is not distributed evenly across the chromosome. In crops, it mostly occurs in the euchromatic regions of the genome and even then, recombination is focused into recombination hotspots flanked by recombination cold spots. Understanding the distribution of these hotspots along with the sequence motifs associated with them may lead to methods that enable breeders to better exploit recombination in breeding.

In chapter 1 background information on recombination, recombination hotspots detection methods, landscape of recombination (describe recombination patterns …

Pestfacts Wa Issue 06 - June 2022, Cindy L. Webster, Svetlana Micic, Alan Lord, Benjamin S. Congdon, Steve Collins

PestFacts WA

PestFacts WA Issue 06 - June 2022 contents:

• African black beetle
• Aphid and turnip yellows virus update
• Cutworm caterpillars
• European earwigs are damaging canola
• Other recent insect activity
• New PestFacts WA Reporter app available for apple devices

Targeting Tor And Snrk1 Genes In Rice With Crispr/Cas9, Bhuvan Pathak, Chandan Maurya, Maria C. Faria, Zahra Alizada, Soumen Nandy, Shan Zhao, Muhammed Jamsheer K, Vibha Srivastava

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Genome targeting with CRISPR/Cas9 is a popular method for introducing mutations and creating knock-out effects. However, limited information is currently available on the mutagenesis of essential genes. This study investigated the efficiency of CRISPR/Cas9 in targeting rice essential genes: the singleton TARGET OF RAPAMYCIN (OsTOR) and the three paralogs of the Sucrose non-fermenting-1 (SNF1)-related kinase 1 (OsSnRK1α), OsSnRK1αA, OsSnRK1αB and OsSnRK1αC. Strong activity of constitutively expressed CRISPR/Cas9 was effective in creating mutations in OsTOR and OsSnRK1α genes, but inducible CRISPR/Cas9 failed to generate detectable mutations. The rate of OsTOR mutagenesis was relatively lower and only the …

Wastewater-Recycled Struvite As A Phosphorus Source In A Wheat-Soybean Double-Crop Production System In Eastern Arkansas, Niyi Sunday Omidire, Kristofor R. Brye

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Fertilizer-phosphorus (P) sources are mainly derived from rock phosphate (RP), which is a finite, actively mined resource. With growing human populations globally, alternative P sources are vitally important to ensure future food security. Precipitation of the mineral struvite (MgNH₄PO₄·6H₂O) from wastewater could be a potential alternative fertilizer-P option from crop production. The objective of this study was to evaluate the effects of chemically precipitated struvite (CPST), compared with triple superphosphate (TSP) and an unamended control (UC) treatment, and irrigation (irrigated and non-irrigated/dryland) on above- (dry matter, yield, and tissue-N, -P, and -Mg concentrations and …

Field-Evolved Δg210-Ppo2 From Palmer Amaranth Confers Pre-Emergence Tolerance To Ppo-Inhibitors In Rice And Arabidopsis, Pamela Carvalho-Moore, Gulab Rangani, Ana Claudia Langaro, Vibha Srivastava, Aimone Porri, Steven J. Bowe, Jens Lerchl, Nilda R. Burgos

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Resistance to protoporphyrinogen IX oxidase (PPO)-inhibitors in Amaranthus palmeri and Amaranthus tuberculatus is mainly contributed by mutations in the PPO enzyme, which renders herbicide molecules ineffective. The deletion of glycine210 (ΔG210) is the most predominant PPO mutation. ΔG210-ppo2 is overexpressed in rice (Oryza sativa c. ‘Nipponbare’) and Arabidopsis thaliana (Col-0). A foliar assay was conducted on transgenic T1 rice plants with 2× dose of fomesafen (780 g ha−1), showing less injury than the non-transgenic (WT) plants. A soil-based assay conducted with T2 rice seeds confirmed tolerance to fomesafen applied pre-emergence. In agar medium, root growth of WT …

Utility Of Roller Wiper Applications Of Dicamba For Palmer Amaranth Control In Soybean, Rodger Bruce Farr, Jason K. Norsworthy, L. Tom Barber, Thomas R. Butts, Trenton Roberts

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

BACKGROUND

The commercialization of dicamba-resistant soybean has resulted in increased concern for off-target movement of dicamba onto sensitive vegetation. To mitigate the off-target movement through physical drift, one might consider use of rope wicks and other wiper applicators. Although wiper-type application methods have been efficacious in pasture settings, the utility of dicamba using wiper applicators in agronomic crops is not available in scientific literature. To determine the utility of roller wipers for dicamba applications in dicamba-resistant soybean, two separate experiments were conducted in the summer of 2020 and replicated in both Keiser and Fayetteville, AR, USA.

RESULTS

Utilizing opposing application …

Can Double Ppo Mutations Exist In The Same Allele And Are Such Mutants Functional?, Aimone Porri, Matheus M. Noguera, Michael Betz, Daniel Salinger, Frank Brandle, Steven J. Bowe, Jens Lerchl, Lucie Meyer, Michael Knapp, Nilda Roma-Burgos

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

BACKGROUND

Resistance to protoporphyrinogen oxidase (PPO)-inhibiting herbicides is endowed primarily by target-site mutations at the PPX2 gene that compromise binding of the herbicide to the catalytic domain. In Amaranthus spp. PPX2, the most prevalent target mutations are deletion of the G210 codon, and the R128G and G339A substitutions. These mutations strongly affect the dynamic of the PPO2 binding pocket, resulting in reduced affinity with the ligand. Here we investigated the likelihood of co-occurrence of the most widespread target site mutations in the same PPX2 allele.

RESULTS

Plants carrying R128G+/+ ΔG210+/−, where + indicates presence of the mutation, were crossed …

Transcriptional Analysis Of Maize Under Drought Stress And The Impact Of Plant Maturity, Oliver J. Oviedo

Biology ETDs

Climate change related drought is projected to harm maize production. Water use strategies can help mitigate the impact of drought on crop yield. However, little is known about maize metabolic response to drought at different developmental stages. To shed light on this, drought conditions were applied to maize at the six-leaf stage (V6), twelve leaf stage (V12), and tassel stage (VT). V6 and VT took eight days to achieve a low stomatal conductance threshold, but V12 took 16 days. Differential gene expression analysis of the transcriptome indicates that V6 showed the most response with 53 impacted metabolic pathways, many of …

Herbicide Tolerance Options For Weed Control In Lanza® Tedera, Daniel Real, Harmohinder S. Dhammu, John H. Moore, David Clegg, Andrew Van Burgel

Grain and Other Field Crops Research Articles

Tedera is a drought-tolerant perennial forage legume introduced in Australia in 2006. In October 2018, T15-1218 Lanza®, the world’s first tedera variety, was released by the Department of Primary Industries and Regional Development and Meat & Livestock Australia for commercial use. A key agronomic practise for the successful establishment and adoption of tedera is to have a robust herbicide package to control a range of grass and broadleaf weeds well tolerated by tedera. A total of 9 pre-emergent and 44 post-emergent herbicide treatments were evaluated in eight experiments from 2017 to 2021. To control grasses such as annual ryegrass ( …

Grain-Filling Rate Improves Physical Grain Quality In Barley Under Heat Stress Conditions During The Grain-Filling Period, Hamid Shirdelmoghanloo, Kefei Chen, Blakely Paynter, Tefera Angessa, Sharon Westcott, Hammad Aziz Khan, Camilla Beate Hill, Chengdao Li

Grain and Other Field Crops Research Articles

Heat stress is a primary constraint to Australia's barley production. In addition to impacting grain yield, it adversely affects physical grain quality (weight and plumpness) and market value. The incidence of heat stress during grain filling is rising with global warming. However, breeding for new superior heat-tolerant genotypes has been challenging due to the narrow window of sensitivity, the unpredictable nature of heat stress, and its frequent co-occurrence with drought stress. Greater scientific knowledge regarding traits and mechanisms associated with heat tolerance would help develop more efficient selection methods. Our objective was to assess 157 barley varieties of contrasting genetic …

Cover Crops And Irrigation Impacts On Corn And Soybean Production In The Mid-Southern Usa, Dillon Aaron Russell

Theses and Dissertations

Reducing groundwater withdrawals from the Mississippi River Valley Alluvial Aquifer is imperative to sustain future irrigated cropping systems in the mid-southern USA. This research was conducted to determine the impacts of cover crops and irrigation sensor thresholds on corn (Zea mays L.) and soybean (Glycine max L.) production, water productivity, irrigation water use efficiency, and soil physical properties in the Mississippi Delta. The cover crop treatments included cereal rye (Secale cereale L.), hairy vetch (Vicia villosa R.), wheat (Triticum aestivum L.)-radish (Raphanus sativus L.)-turnip (Brassica rapa L.) mix, and no cover crop. The irrigation thresholds included -40 kPa, -90 kPa, …

Quantifying The Effects Of Abiotic Stress On Early Season Growth, Development, And Physiological Characteristics In Corn, Charles Hunt Walne

Theses and Dissertations

Corn is one of American agriculture's greatest success stories, where we have witnessed incredible increases in yield potential over the last half-century. However, abiotic stress is still the primary limiting factor preventing plants from reaching their true yield potential. In addition, agriculture is not exempt from the deleterious effects of changing weather patterns and the altered climate our world will face as time progresses. Thus, increasing our understanding of how crops interact with their environment both above and below the soil will be crucial to increasing production on a global scale while maximizing profitability at a local level. Five studies …

Evaluating The Effect Of Coated Urea And Urea-Ammonium-Nitrate Solution On Cane Tonnage, Sugar Yield, And Leaf-Soil Nitrogen Content Under Louisiana Sugarcane Production System, Hector J. Mendoza Lagos

LSU Master's Theses

Nitrogen (N) is a crucial nutrient for proper plant growth and development. N deficiency results in poor tillering and thin, short internode stem production for sugarcane production, thus resulting in low cane tonnage. Therefore, proper N fertilizer management is essential for a sustainable sugarcane production system. This research was conducted at the LSU AgCenter Sugar Research Station in St. Gabriel, LA, from 2019 to 2020 at three Sites (Site 1, 2, and 3). The treatments consisted of different N rates (0, 45, 90, and 135 kg N ha^-1) and sources (urea-ammonium-nitrate solution [UAN]-32%, 30-day [Coated Urea 1], 45-day …

Are You Paid For Your Hard Red Winter Wheat Quality? Yes, But Indirectly, Shane Roberts, Kathleen Brooks, Lia Nogueira, Cory Walters

Cornhusker Economics

Hard red winter wheat (HRWW) is the largest wheat class grown in the United States, with approximately 660 million bushels produced in 2020, representing about 36% of total U.S. wheat production (USDA ERS 2021). The world market is an important destination for U.S. HRWW. In 2020, exports of U.S. HRWW represented 52% of U.S. production and total U.S. wheat exports represented 13% of total world exports (USDA ERS 2021). U.S. HRWW differs from other wheat classes based on physical characteristics such as color, kernel hardness and planting season as well as consistency in producing end uses such as pan and …

Water Use Efficiency In Western Australian Cropping Systems, Martin Harries, Ken C. Flower, Michael Renton, Geoffrey C. Anderson

Grain and Other Field Crops Research Articles

Rotations and associated management practices in rainfed farming systems of southwest Australia have shifted towards intensified cropping. Survey data from 184 fields spanning 14 Mha of southwest Australia were used to document water use efficiency (WUE) and water-limited yield potential (WLYP) of commercial crops and crop sequences and identify biophysical variables influencing WUE. WUE achieved in commercial wheat crops was 10.7 kg grain/ha.mm. Using a boundary function Ywl = 25 × (WU − 45), farmers achieved 54% of WLYP. Climate variables affected WUE more than management and biotic variates, the highest latitude region having WUE of 9.0 kg grain/ha.mm, compared …

Investigating The Mechanics And Chemistry Of Sickle Polish Development, Justin Jared Dubois

Graduate Theses and Dissertations

This series of experiments is designed to understand the development and chemistry of sickle gloss. Sickles are common in the archaeological record and have long been studied for their eponymous “sickle gloss”. There is debate as to how this gloss is formed. Five experimental sickles containing flint and novaculite blades were used to harvest high and low moisture content rye and common fescue and associated field weeds. The differences in the development of sickle gloss were examined. High moisture content plants create thick, smooth fields of polish with undulating, billowing margins at a higher developmental speed. Low moisture content plants …

Pestfacts Wa Issue 05 - May 2022, Jean Galloway, Cindy L. Webster, Steve Collins

PestFacts WA

PestFacts WA Issue 05 - May 2022 contents:

• Blackleg and the risk of sowing canola on canola
• Meet PestFacts WA team member – Steve Collins

Pestfacts Wa Issue 04 - May 2022, Svetlana Micic, Benjamin S. Congdon, Cindy L. Webster, Andrea Hills, Ravjit Khangura

PestFacts WA

PestFacts WA Issue 04 - May 2022 contents:

• Grasshoppers are hatching
• Aphid activity and turnip yellows virus detections
• Downy mildew and damping off in canola
• Nodorum blotch in wheat
• Plant disease webinar recording can now be viewed online

An Investigation Of Factors Affecting The Rooting Ability Of Hardwood Muscadine Cuttings And Genetic Diversity Of Wild And Cultivated Muscadine Grapes (Vitis Rotundifolia Michx.), Kenneth Buck

Graduate Theses and Dissertations

The muscadine (Vitis rotundifolia syn. Muscadinia rotundifolia) is a grape species native to the southeastern United States. Muscadines are one of three grape species in subgenus Muscadinia with a chromosome number of 2n=40 (V. rotundifolia, V. munsoniana, and V. popenoei), making them genetically distinct from the European wine and table grape (Vitis vinifera) and other species in subgenus Euvitis. Rooting hardwood cuttings from muscadine vines has traditionally been considered an exceptionally difficult task. Many previous studies observed almost no root formation, leading to a general consensus that muscadines should either be propagated by softwood cuttings or vegetative layering. However, the …

Economic Viability Of Weed Management Strategies In High-Tunnel Tomato, Gracie Morrison

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Cost-effective weed suppression is an important consideration for tomato growers. Growers often choose methods which minimize hand labor, as hand weeding can be prohibitively expensive. This project determined economic viability of high tunnel tomatoes treated with several methods of weed control, both organic and chemical. These methods included: 2-week hand weeding, 1-week hand weeding, preemergent, straw, landscape fabric, and untreated weedy control plots. These treatments were applied to randomized blocks in a high-tunnel. Weeding, planting, and harvest were all timed to determine labor and material costs of weed management strategy implementation. After harvest, marketable yield was weighed to determine revenue. …

Effects Of One-Pass Microwave Drying On Rice’S Utilization In The Brewing Process., Christopher Stuckey

Food Science Undergraduate Honors Theses

Rice is utilized as an adjunct grain by the beer manufacturing industry. Before utilization, the rice has to be dried to a desired moisture content. The drying process employed may have an impact on the rice’s physicochemical properties which influence the rice’s performance in the brewing process. This study focused on investigating the impact of microwave drying on rice’s physicochemical properties and utilization in the brewing process. Rough rice samples at an initial moisture content of 19.7% wet basis were exposed to microwave dryer set to deliver 525 kJ/kg of energy in a single drying pass. The effects of the …

Dicamba Tank Mixtures And Formulations And Their Effects On Sensitive Crops During Cleanout Procedures, Vinicius Velho

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The introduction of dicamba-tolerant (DT) soybeans (Glycine max L. Merr) and cotton (Gossypium hirsutum L) in 2017 provided an additional tool for herbicide resistant weeds management. In the subsequent years, off-target movement of dicamba allegedly caused damage to sensitive crops and vegetation.

Possible causes of off-target movement include tank contamination, physical drift, and volatility. Additional products, such as herbicides to control grass, are often added to tank with dicamba, which is used to control broadleaf weeds, to increase the spectrum of control and application efficiency. Dicamba products registered for DT crops require the use of drift reducing …

Winter Cover Crop Impacts On Weed Dynamics In Eastern And Central Nebraska, Elizabeth Ann Oys

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Reducing tillage in cropping systems causes weed management to be dependent on chemical and cultural methods for weed control. Over time, herbicide-resistant weeds have developed due to the continuous selection pressures from herbicides, particularly in the Midwest Corn Belt. Integrated weed management strategies, such as cover crops, can be used to mitigate some of these issues. Cover crops are primarily known for their soil health benefits, but there is evidence that cover crops can suppress weeds. However, less research has been done at the field-scale level to address cover crop impacts on the weed seedbank and aboveground weeds during the …

Regional Plant Community Differences In The Nebraska Sandhills, Travis Millikan

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The Nebraska Sandhills is very valuable to the state of Nebraska, representing one of the most in-tact and largest grassland ecosystems in temperate regions in the world. Rangeland managers must understand plant community dynamics across the Sandhills to better inform management decisions. The first objective of this study was to evaluate plant community variability on upland Sands ecological sites across different precipitation zones in the Nebraska Sandhills. The second objective of our study was to utilize the Rangeland Analysis Platform (RAP) to examine spatial and temporal variability in biomass production and cover on pastures of ranches analyzed in the first …

Exploration Of Genes Controlling Grain Yield Heterosis In Hybrid Wheat (Triticum Aestivum L.) Utilizing 3ʹ Rna Sequencing, Nichole Lynn Miller

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The implementation and future success of hybrid wheat (Triticum aestivum L.) is impacted by breeders’ inability to create consistent high yielding, high heterosis hybrids. This research addresses this problem by conducting an exploration of transcriptomes from hybrids and parent lines to determine what genes are active in heterotic or non-heterotic hybrids and how their level of expression can explain the phenotype of grain yield heterosis. Using hybrids that showed positive mid-parent heterosis (MPH), classified as heterotic in our study, and negative or no difference MPH hybrids, classified as non-heterotic, differentially expressed genes (DEGs) potentially related to heterosis and hybrid …

Pestfacts Wa Issue 03 - May 2022, Svetlana Micic, Dustin Severtson, Jean Galloway, Cindy L. Webster

PestFacts WA

PestFacts WA Issue 03 - May 2022 contents:

• Seeing chewing damage in sprayed canola crops but can’t find the culprit?
• Mites and lucerne flea are active
• Slaters
• Meet PestFacts WA team member – Svetlana Micic
• Field pea blackspot forecasts for WA are available online
• PestFacts WA podcast

Wayne E. Sabbe Arkansas Soil Fertility Studies 2021, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.

Oestrogenic Subterranean Clover Guide. Identification And Remediation, Kevin J. Foster, Megan H. Ryan, Daniel R. Kidd

Bulletins 4000 -

Subterranean clover (subclover, Trifolium subterraneum L.) is an annual pasture legume that provides high quality feed for livestock. It is estimated to be sown over 30 million hectares across southern Australia, with cultivars developed for the low, medium and high rainfall zones. Unfortunately, some older cultivars contain high levels of phytoestrogen which can affect the reproductive system of sheep and cause other health issues. This became a significant issue for sheep producers from the 1940s as new land was cleared and sheep grazed subclover-dominant pastures. There was a collection of livestock issues observed and these were grouped together under the …

Evaluation Of Benzobicyclon In Midsouth Rice (Oryza Sativa) Production Systems, Jake Patterson

Graduate Theses and Dissertations

Controlling weedy rice postemergence is challenging for rice producers in the United States because of the lack of herbicide options. Weedy rice is genetically similar to cultivated rice, thus making it difficult to control with mid-season postemergence herbicide applications without also damaging the crop. Hence, there is a need for a new effective postemergence weedy rice control herbicide. Findings from this research indicate that the use of benzobicyclon in current standard quizalofop- and imidazolinone-resistant rice herbicide programs provides tremendous utility for Midsouth rice producers. In both of these production systems, the addition of benzobicyclon to the respective standard herbicide programs …