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Evaluation Of Spray Pattern Uniformity Using Three Unique Analyses As Impacted By Nozzle, Pressure, And Pulse-Widthmodulation Duty Cycle, Thomas R. Butts, Joe D. Luck, Bradley K. Fritz, W. Clint Hoffmann, Greg R. Kruger

Department of Agronomy and Horticulture: Faculty Publications

BACKGROUND: The increasing popularity of pulse-width modulation (PWM) sprayers requires that application interaction effects on spray pattern uniformity be completely understood to maintain a uniform overlap of spray, thereby reducing crop injury potential andmaximizing coverage on target pests. The objective of this researchwas to determine the impacts of nozzle type (venturi vs. non-venturi), boom pressure, and PWMduty cycle on spray pattern uniformity. Research was conducted using an indoor spray patternator located at the University of Nebraska-Lincoln in Lincoln, NE, USA. Coefficient of variation (CV), root mean square error (RMSE), and average percent error (APE) were used to characterize spray pattern …

Waste Management Of Highway Right Of Way Areas In Southeast Georgia, David M. Penn Ii

College of Graduate Studies: Theses & Dissertations

Maintenance of highway right of way (ROW) areas has become problematic during the last several years due to the high cost, and little to no economic return associated with disposing vegetation waste that is continuously generated on all highways and interstates across the state of Georgia. The Georgia Department of Transportation (GDOT) was interested in evaluating the feasibility of replacing ROW vegetation of highways throughout the state with high-value alternatives such as switchgrass (Panicum virgatum L. ‘Alamo’), big bluestem (Andropogon gerardii) and woodland sunflower (Helianthus divaricatus). Preliminary objective involved measuring and mapping SOC and soil N concentrations in the highway …

Investigation Of Mechanisms Involved In Germination Enhancement Of Wheat (Triticum Aestivum) By Cold Plasma: Effects On Seed Surface Chemistry And Characteristics, Agata Los, Dana Ziuzina, Daniela Boehm, Patrick J. Cullen, Paula Bourke

Articles

Recent reports indicate that atmospheric cold plasma (ACP) treatment of seeds can enhance their germination, however, the mechanisms of action are not yet entirely clear. In the present work, we report on the effects of plasma treatment on wheat seed germination and seedling growth. Additionally, changes in the surface chemistry and characteristics of the wheat seeds exposed to plasma were investigated. Treatments of 30–60 s significantly enhanced the germination rate and showed positive effects on seedling growth. ACP resulted in changes of seed surface and chemical characteristics including water uptake and contact angle values. Changes in seed pH and total …

Profit Efficiency And Smallholder Sugarcane Out-Growers Under Contract Farming In Tanzania: Does Location Matter?, Thobias Nsindagi, Jennifer K. Sesabo

Journal of Humanities and Social Sciences

Tanzania is among countries that value the sugarcane sector as one of the potential crops for poverty alleviation. The sector provides direct employment to about 14,000 people, and it is an outlet for the produce of over 30,000 farming households (Nkonya & Barreiro Hurle, 2012). Likewise, it provides direct earnings and savings amounting to about US$28m annually (Sugar Board of Tanzania (SBT), 2007). However, sugarcane out-growers in Tanzania have been getting low prices relative to unit costs (Matango, 2006). This has generated substantial debate about the need and level of government support. Like other developing countries, contract farming (CF) has …

Pengaruh Pupuk Hayati Majemuk Dan Pupuk Fosfor Terhadap Pertumbuhan Dan Hasil Kedelai Di Inceptisol Jatinangor, Aep Wawan Irwan, Tati Nurmala

Jurnal Kultivasi

Kedelai merupakan salah satu tanaman yang membutuhkan fosfor dalam jumlah besar. Ketersediaan P merupakan faktor pembatas utama pada pertumbuhan dan produksinya. Fosfor tidak banyak tersedia untuk tanaman, sehingga dibutuhkan pupuk hayati yang mengandung mikroorganisme untuk dapat melarutkan fosfor. Penelitian ini bertujuan untuk memperoleh dosis pupuk hayati majemuk dan pupuk P yang efektif dan dapat memberikan pengaruh terbaik terhadap pertumbuhan, komponen hasil, dan hasil tanaman kedelai kultivar Anjasmoro. Penelitian dilakukan pada bulan Maret sampai Juni 2017 di Kebun Percobaan Ciparanje, Fakultas Pertanian Universitas Padjadjaran, dengan ketinggian tempat yaitu ± 780 mdpl. Percobaan dilakukan dengan menggunakan Rancangan Acak Kelompok terdiri dari 9 …

Pengaruh Cara Pemberian Pupuk Organik Cair Vinasse Terhadap Pertumbuhan Awal Bawang Dayak (Eleutherine Palmifolia), Rina Ekawati, Lestari Hetalesi Saputri

Jurnal Kultivasi

Pupuk organik bermanfaat untuk meningkatkan kandungan hara, bahan organik tanah, serta memperbaiki sifat fisik, kimia, dan biologi tanah. Vinasse merupakan limbah dari proses pembuatan bioetanol pada industri pengolahan gula, jika telah mengalami proses pengomposan dapat digunakan sebagai pupuk organik cair (POC) vinasse yang dapat meningkatkan pertumbuhan tanaman. Bawang dayak merupakan salah satu tanaman hortikultura yang dapat dijadikan sebagai tanaman berkhasiat obat. Penelitian ini bertujuan untuk mempelajari pengaruh cara pemberian pupuk organik cair vinasse terhadap pertumbuhan awal tanaman bawang dayak. Percobaan ini dilakukan di Politeknik Lembaga Pendidikan Perkebunan (LPP) Yogyakarta, dari bulan Juli hingga November 2018. Penelitian ini menggunakan rancangan acak …

Respon Pertumbuhan Dan Hasil Tanaman Hanjeli Pada Panen Awal Akibat Pemberian Dosis Pupuk Biosilika Dan Paklobutrazol Di Lahan Kering Jatinangor, Ruminta, Tati Nurmala, Yuyun Yuwariah, Nita Yuliani Pratiwi

Jurnal Kultivasi

Hanjeli (Coix lacryma-jobiL) merupakan salah satu tanaman pangan alternatif dan tanaman fungsional. Hanjeli belum sepenuhnya dimanfaatkan petani salah satunya karena tanaman yang cukup tinggi dan memiliki umur cukup lama. Penelitian ini bertujuan untuk mengetahui dosis pupuk biosilika dan konsentrasi paklobutrazol yang dapat memberikan pengaruh terbaik terhadap pertumbuhan dan hasil tanaman hanjeli pulut dipanen awal (matang kuning). Penelitian dilaksanakan bulan Agustus 2017-Januari 2018 di Ciparanje, Universitas Padjadjaran, Jatinangor, Sumedang. Rancangan percobaan yang digunakan adalah rancangan petak terbagi yang terdiri dari petak utama pupuk biosilika dengan dosis 0 kg/ha; 100 kg/ha; 200 kg/ha dan anak petak paklobutrazol dengan konsentrasi 0 ppm; 1250 …

Peningkatan Produktivitas Tanaman Kedelai Kultivar Anjasmoro Asal Benih Terdeteriorasi Dengan Kompos Trichoderma Dan Bokashi, Sumadi, Denny Sobardini Sobarna, Pujawati Suryatmana, Meddy Rachmadi, Erni Suminar

Jurnal Kultivasi

Trichoderma spp merupakan golongan fungi yang bersifat antipatogen, khususnya layu kecambah, sedangkan bokashi merupakan kompos yang diperkaya dengan beberapa mikroba yang bermanfaat bagi pertumbuhan tanaman.Tulisan ini merupakan rangkuman penelitian pot menggunakan kompos Trichoderma spp sebagai pelapis benih terdeteriorasi disertai bokashi kotoran hewan yang dilakukan pada tanah lahan kering dan tanah sawah pada tahun 2014 dan 2017. Percobaan pertama membandingkan efektivitas beberapa agen hayati sebagai pelapis benih pengaruhnya terhadap vigor benih dan hasil tanaman. Hasil percobaan menunjukkan penggunaan kompos Trichoderma hasilnya lebih baik dibandingkan agen hayati lainnya. Hasil percobaan selanjutnya menunjukkan bahwa pelapisan benih dengan 1 sampai 3 g kompos Trichoderma …

Recoupling Fire And Grazing Reduces Wildland Fuel Loads On Rangelands, Heath D. Starns, Samuel D. Fuhlendore, R. Dwayne Elmore, Dirac L. Twidwell Jr, Eric T. Thacker, Torre J. Hovick, Barney Luttbeg

Department of Agronomy and Horticulture: Faculty Publications

Fire suppression and exclusion, the historically dominant paradigm of fire management, has resulted in major modifications of fire-dependent ecosystems worldwide. These changes are partially credited with a recent increase in wildfire number and extent, as well as more extreme fire behavior. Fire and herbivory historically interacted, and research has shown that the interaction creates a unique mosaic of vegetation heterogeneity that each disturbance alone does not create. Because fire and grazing have largely been decoupled in modern times, the degree to which the interaction affects fuels and fire regimes has not yet been quantified. We evaluated effects of fire-only and …

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 …

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 …

Arkansas Soybean Research Studies 2017, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

Understanding Spatial Dynamics Of Tallgrass Prairie Dominated By Tall Fescue, Callie Griffith

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

This study was conducted on restored tallgrass prairie and invaded tallgrass prairie located in the Grand River Grasslands of southern Iowa to determine differences in heterogeneity of plant structure and functional group composition at different scales. Restored tallgrass prairies were seeded with a species-rich seeding mixture and managed by burning the entire prairie, every three years. Data were collected in August 2014 and 2015 to compare heterogeneity of restoration of native plant structure and functional group composition to the heterogeneity of invaded tallgrass prairies that were managed with patch burning and conventionally grazed. Invaded tallgrass prairies were managed with patch-burning …

Generation And Evaluation Of Modified Opaque-2 (O2) Popcorn Suggests A Route To Quality Protein Popcorn (Qpp), Ying Ren

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

I have been working on a Quality Protein Popcorn breeding project where QPM conversion is carried out simultaneously for several elite popcorn germplasms. During my study in the graduate program, I led the following aspects of the Quality Protein Popcorn Breeding Project:

1. Identified suitable QPMs as opaque-2 allele donors.

2.Examined the feasibility of quick introgression of the opaque-2 allele into popcorn lines via marker-assisted selection.

3. Monitored modification by SDS-PAGE zein profiling and light box phenotypic selection to make sure multiple modifier loci for opaque-2 were incorporated each time generation advancement was carried out.

4. Carried out high throughput …

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 …

Grazing Strategy Effects On Utilization, Animal Performance, Aboveground Production, Species Composition, And Soil Properties On Nebraska Sandhills Meadow, Aaron Shropshire

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

Ultrahigh stocking density (a.k.a., mob grazing) is proposed as a management tool that results in greater harvest efficiency, animal performance, aboveground plant production, species richness, and soil carbon content. The study objective was to determine grazing treatment, haying, or non-defoliated control effects on forage utilization, aboveground production, animal performance, and soil properties. In 2010, 25 ha of Sandhills meadow were divided into 2 replications of 3 grazing, a hay, and control treatment. Grazing treatments were a 120-pasture rotation with one grazing cycle (mob), a 4-pasture rotation with one cycle (4PR1), and a 4-pasture rotation with two cycles (4PR2) at stocking …

Impacts Of Cover Crop Mixtures On Productivity Of Cropping Systems, Brionna Lee West

Graduate Theses/Dissertations

A field study and a meta-analysis were conducted to compare the impact of cover crops on carbon and nitrogen dynamics and cash crop yield. The field study included six treatments: winter cereal rye, winter cereal rye-Austrian winter pea at two seeding rates, cereal rye-Austrian winter pea-radish at two seeding rates, and a no cover control. Meta-analysis data sets were compiled from studies published between 1994 and 2017. Treatments were grouped into the following classifications: monoculture, binary mix, polyculture, or control. In both the field study and meta-analysis, cover crops did not affect cash crop yield. However, plant biomass and plant …

Relative Contribution Of Physical Interference And Allelopathy To Weed Suppression By Winter Annual Cover Crop Mixtures, Alyssa D. Travlos

Graduate Theses/Dissertations

Cover cropping systems are widely used in crop production systems to prevent erosion, improve soil health, and suppress weeds. Common cover cropping systems include combinations of cereal rye (Secale cereale L.), Brassica species, legumes, and other winter annual species. Three cover crop mixtures (cereal rye alone, cereal rye plus winter pea, and cereal rye plus winter pea plus radish) were applied using three methods (fresh residue, dried leached residue, and leachate) to common waterhemp (Amaranthus tuberculatus var. rudis) and large crabgrass [Digitaria sanguinalis (L.) Scop.]. The experiment was conducted once in a greenhouse and once in a …

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 …

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 …

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 …

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. …

A Simple Metabolic Switch May Activate Apomixis In Arabidopsis Thaliana, David Alan Sherwood

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Apomixis, asexual or clonal seed production in plants, can decrease the cost of producing hybrid seed and enable currently open pollinated crops to be converted to more vigorous and higher yielding hybrids that can reproduce themselves through their own seed. Sexual reproduction may be triggered by a programmed stress signaling event that occurs in both the meiocyte, just prior to meiosis, and later in the egg just prior to embryo sac maturation. The prevention of stress signaling and the activation of a pro-growth signal prior to meiosis triggered apomeiosis, the first half of apomixis. The same approach was used prior …

Soybean Androgenesis, Martina Garda

Student Theses and Dissertations

Food is a constant world demand, and soybeans are among the most complete food crops which have fed people since its domestication. Unfortunately, soybean is a difficult crop to work within the biotechnology laboratory. Soybean androgenesis has been a challenging process yet to be advanced significantly after years of attempts. There have been some minor advances, for instance, reports of a 2% induction rate in anther culture, formation of roots, rare shoots, but only a handful of plantlets that did not survive to maturity. This dissertation compiles these efforts in the context of developing a pyramidal stressors model for androgenesis …

Hybridisation-Based Target Enrichment Of Phenology Genes To Dissect The Genetic Basis Of Yield And Adaptation In Barley, Camilla Beate Hill, Tefera Angessa, Lee-Anne Mcfawn, Debbie Wong, Josquin Tibbits, Xiao-Qi Zhang, Kerrie Forrest, David Moody, Paul Telfer, Sharon Westcott, Dean A. Diepeveen, Yanhao Xu, Cong Tan, Matthew Hayden, Chengdao Li

Grain and Other Field Crops Research Articles

Barley (Hordeum vulgare L.) is a major cereal grain widely used for livestock feed, brewing malts and human food. Grain yield is the most important breeding target for genetic improvement and largely depends on optimal timing of flowering. Little is known about the allelic diversity of genes that underlie flowering time in domesticated barley, the genetic changes that have occurred during breeding, and their impact on yield and adaptation. Here, we report a comprehensive genomic assessment of a worldwide collection of 895 barley accessions based on the targeted resequencing of phenology genes. A versatile target-capture method was used to …

Investigation Of Alternative Hosts And Agronomic Factors Affecting Xanthomonas Vasicola Pv. Vasculorum, Causal Agent Of Bacterial Leaf Streak Of Corn, Terra Marie Hartman

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

Xanthomonas vasicola pv. vasculorum, causal agent of bacterial leaf streak of corn, was first reported in the U.S. in 2016 on Nebraska corn leaf samples. Prior to this report, the pathogen had only been reported on corn in South Africa. After the Nebraska report, the pathogen was reported on corn in Argentina, Brazil, and several U.S. states. This pathogen has an extensive host range, which includes sugarcane (Saccharum officinarum), grain sorghum (Sorghum bicolor), palm species (Dictyosperma album, Roystonea regia, and Areca catechu) and broom bamboo (Thysanolaena maxima). Plants commonly found in …

Biological Activity Of A Tertiary Amine Plant Growth Regulator, Bmve, In Arabidopsis Thaliana And Wheat (Triticum Aestivum), Jaspinder Singh

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

Plant growth regulators are synthetic compounds that influence plant growth and development and can increase growth, yield, and nutritive value of food crops. Research in the past has shown that a class of plant growth regulators known collectively as substituted tertiary amines have the potential to increase crop productivity, photosynthetic efficiency, and overall plant vigor. However, earlier efficacy studies that involved spraying plants were sometimes inconsistent or showed only minimal benefits. A new delivery method involving seed application of tertiary amines before sowing has shown promise in field trials for multiple crop species (US patent 9464283) (Yokoyama, Chan, Oyama, & …

Identification Of Genes/Genomic Regions Controlling Resistance To Biotic And Abiotic Stresses In Synthetic Hexaploid Wheat, Madhav Bhatta

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

Synthetic hexaploid wheat (SHW; 2n=6x=42, AABBDD, Triticum aestivumL.) is produced from an interspecific cross between durum wheat (2n=4x=28, AABB, T. turgidumL.) and goat grass (2n=2x=14, DD, AegilopstauschiiCoss.). It is reported to have a considerable amount of genetic diversity and is a potential source of novel alleles controlling abiotic and biotic stresses resistance and improving wheat quality. Therefore, the first study was to understand the genetic diversity and population structure of SHWs and compare the genetic diversity of SHWs with elite bread wheat (BW) cultivars. The result of this study identified a wide range of genetic diversity within …