Agricultural Science Commons^™

Adding A Late Fall Application Of Proxy (Ethephon) Before Two Traditional Spring Applications Improves Seedhead Control Of Annual Bluegrass, Zachary Reicher, Matthew Sousek, Aaron J. Patton, Adam Van Dyke, William C. Kreuser, John C. Inguagiato, Kevin M. Miele, John Brewer, Shawn D. Askew, Aaron Hathaway, Thomas A. Nikolai, Alec Kowalewski, Brian Mcdonald

Department of Agronomy and Horticulture: Faculty Publications

Annual bluegrass (ABG) (Poa annua L.) is a prolific seed producer in the spring on golf courses that in turn decreases aesthetic quality and trueness of ball roll on coolseason putting greens. Proxy (ethephon) applied twice in the spring after green-up is the current industry standard after the loss of Embark (mefluidide) from the turf and ornamental market. However, plant growth regulators including Proxy have been used for years to help suppressABGseedheads with inconsistent success. The primary objective of this study was to determine if ABG seedhead suppression is improved by adding a late fall application of Proxy to …

Allelic Variation In Rice Fertilization Independent Endosperm 1 Contributes To Grain Width Under High Night Temperature Stress, Balpreet K. Dhatt, Puneet Paul, Jaspreet Sandhu, Waseem Hussain, Larissa Irvin, Feiyu Zhu, Maria Arlene Adviento-Borbe, Argelia Lorence, Paul Staswick, Hongfeng Yu, Gota Morota, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

A higher minimum (night-time) temperature is considered a greater limiting factor for reduced rice yield than a similar increase in maximum (daytime) temperature. While the physiological impact of high night temperature (HNT) has been studied, the genetic and molecular basis of HNT stress response remains unexplored.

We examined the phenotypic variation for mature grain size (length and width) in a diverse set of rice accessions under HNT stress. Genome-wide association analysis identified several HNT-specific loci regulating grain size as well as loci that are common for optimal and HNT stress conditions.

A novel locus contributing to grain width under HNT …

Leveraging Genome-Enabled Growth Models To Study Shoot Growth Responses To Water Deficit In Rice, Malachy T. Campbell, Alexandre Grondin, Harkamal Walia, Gota Morota

Department of Agronomy and Horticulture: Faculty Publications

lucidating genotype-by-environment interactions and partitioning its contribution to phenotypic variation remains a challenge for plant scientists. We propose a framework that utilizes genome-wide markers to model genotype-specific shoot growth trajectories as a function of time and soil water availability. A rice diversity panel was phenotyped daily for 21 d using an automated, high-throughput image-based, phenotyping platform that enabled estimation of daily shoot biomass and soil water content. Using these data, we modeled shoot growth as a function of time and soil water content, and were able to determine the time point where an inflection in the growth trajectory occurred. We …

Voxel Carving-Based 3d Reconstruction Of Sorghum Identifies Genetic Determinants Of Light Interception Efficiency, Mathieu Gaillard, Chenyong Miao, James Schnable, Bedrich Benes

Department of Agronomy and Horticulture: Faculty Publications

Changes in canopy architecture traits have been shown to contribute to yield increases. Optimizing both light interception and light interception efficiency of agricultural crop canopies will be essential to meeting the growing food needs. Canopy architecture is inherently three-dimensional (3D), but many approaches to measuring canopy architecture component traits treat the canopy as a two-dimensional (2D) structure to make large scale measurement, selective breeding, and gene identification logistically feasible. We develop a high throughput voxel carving strategy to reconstruct 3D representations of sorghum from a small number of RGB photos. Our approach builds on the voxel carving algorithm to allow …

Genome-Wide Identification And Analysis Of Heterotic Loci In Three Maize Hybrids, Hongjun Liu, Qin Wang, Mengjiao Chen, Yahui Ding, Xuerong Yang, Jie Liu, Xiaohan Li, Congcong Zhou, Qilin Tian, Yiqi Lu, Danlin Fan, Junpeng Shi, Lin Zhang, Congbin Kang, Mingfei Mingfei Sun, Fangyuan Li, Yujian Wu, Yongzhong Zhang, Baoshen Liu, Xiang Yu Zhao, Qi Feng, Jinliang Yang, Bin Han, Jinsheng Lai, Xian Sheng Zhang, Xuehui Huang

Department of Agronomy and Horticulture: Faculty Publications

Heterosis, or hybrid vigour, is a predominant phenomenon in plant genetics, serving as the basis of crop hybrid breeding, but the causative loci and genes underlying heterosis remain unclear in many crops. Here, we present a large-scale genetic analysis using 5360 offsprings from three elite maize hybrids, which identifies 628 loci underlying 19 yield-related traits with relatively high mapping resolutions. Heterotic pattern investigations of the 628 loci show that numerous loci, mostly with complete–incomplete dominance (the major one) or overdominance effects (the secondary one) for heterozygous genotypes and nearly equal proportion of advantageous alleles from both parental lines, are the …

Cover Crops And Cover Crop Mixes: Stratification Of Biological Effects, Landon M. Gibbs

Theses and Dissertations--Plant and Soil Sciences

The potential nutrient cycling benefits from legumes (e.g. N₂-fixation) and the high biomass potential of cereal rye are well known. Further studies are warranted to evaluate bi-culture mixtures and their effects on soil nutrient stratification and microbial enzyme activity because these two properties may be differently expressed (enhanced) by legume/grass mixes. The objectives of this study were: (1) show different cover crops and cover crop mixes containing grasses and legumes differentially stratify carbon and N; (2) show the change in microbial enzyme activity in soils planted with individual cover crops relative to cover crop mixes; 3) determine the …

The Balancing Act Of Cytokinin In Environmental Stress Tolerance, Sumudu Sandeepani Karunadasa

Theses and Dissertations--Plant and Soil Sciences

Cytokinin, long known as a phytohormone that regulates plant growth and development, has been recently recognized as an important regulator of stress responses. However, our current knowledge about the mechanisms by which cytokinin regulates stress responses is fragmentary, as many of the studies in this field yielded conflicting results. Most of the work described here has focused on analyses of the molecular mechanisms of cytokinin-dependent regulation of growth and development under stress conditions, with an emphasis on the role of cytokinin-dependent regulation of protein synthesis in development and stress tolerance.

One of the important contributions of this study is the …

Toward A Holistic Agricultural Student Recruitment Model: A National Analysis Of The Factors Affecting Students’ Decision To Pursue An Agricultural Related Degree, Antoine J. Alston, Richie Roberts, Chastity W. English

Journal of Research in Technical Careers

Currently, the agricultural industry struggles to fill positions with qualified agricultural workers. Therefore, it is critical to attract high caliber individuals to agricultural degree programs that are prepared to enter the workforce with the skills needed to navigate complex issues and problems. The purpose of this national study was to identify key factors that influence the recruitment of agriculture students at land-grant and non-land-grant universities. Using Chapman’s model of student success as our conceptual lens, we tested 66 factors identified in the literature as successful recruitment strategies for colleges of agriculture based on students’ personal characteristics as well as key …

Comparing And Linking Organic Carbon And Iron In Soil And Headwater Stream In A Pasture And A Forest Catchment In A Central Appalachian Region, West Virginia, Lili Lei

Graduate Theses, Dissertations, and Problem Reports (ETD)

Continued global warming and surface water brownification are two main environmental issues which have attracted attention and are related to soil organic carbon (SOC) cycling. Iron oxides differ in reducibility and thus have essential roles in regulating SOC preservation and remineralization in soil and transport of dissolved organic carbon (DOC) from soil to surface water. In the central Appalachian region, anthropogenic disturbances are increasing, which leads to major issues of soil degradation and depletion of SOC concentrations. Cropland and pasture soils are subject to intense disturbances compared to the forest soil, which may lead to differences in SOC fractions and …

Comparing Water Quality For Aquaponics Systems With Different Solids Removal Methods And Biofilter Media, And Effluent Output To Grow Beds, John W. Cutt, Heather M. Joesting, Brigette A. Brinton

Honors College Theses

Aquaponics is a closed-loop, sustainable method of food production that combines fish and plant production. This method of agriculture has the potential to bring fresh, local food to food-insecure areas, but challenges remain due to high operating costs. In order to develop a strong aquaponics industry, the creation of the most efficient system designs will be critical in optimizing production. This study’s purpose was to compare water quality between two aquaponics system designs that differ in filtration and solid removal methods. System 1 used a sock filter for solid removal and Kaldnes media for biofiltration while System 2 used a …

Effect Of Organic Soil Amendment On Hemp, Mounica Talasila

Murray State Theses and Dissertations

The research study is about the impact of different levels of organic soil amendment on the levels of psychoactive compounds produced in industrial hemp. Inorganic or chemical pesticides or fertilizers are not as extensively used in hemp as in other crops. Apart from this, using an organic soil amendment would be an environmentally sustainable way. A randomized block design (RBD) model was used to study the impacts of the soil amendment. The soil amendment used is called “Rehab” a product of Organilock created from the remnants of animals like fish and chicken. This research design has 3 different soil amendment …

Occurrence Of Plant-Parasitic Nematodes On Enset (Ensete Ventricosum) In Ethiopia With Focus On Pratylenchus Goodeyi As A Key Species Of The Crop, Selamawit A. Kidane, Beira H. Meressa, Solveig Haukeland, Trine Hvoslef-Eide, Christer Magnusson, Marjolein Couvreur, Wim Bert, Danny L. Coyne

All Peer-Reviewed Publications

Summary - Enset (Ensete ventricosum) is an important starch staple crop, cultivated primarily in south and southwestern Ethiopia. Enset is the main crop of a sustainable indigenous African system that ensures food security in a country that is food deficient. Related to the banana family, enset is similarly affected by plant-parasitic nematodes. Plant-parasitic nematodes impose a huge constraint on agriculture. The distribution, population density and incidence of plant-parasitic nematodes of enset was determined during August 2018. A total of 308 fields were sampled from major enset-growing zones of Ethiopia. Eleven plant-parasitic nematode taxa were identified, with Pratylenchus (lesion nematode) being …

Unlocking Maize Crop Productivity Through Improved Management Practices In Northern Tanzania, Kihara J, Kizito F, Jumbo M, Kinyua M, M. Bekunda

All Peer-Reviewed Publications

Addressing the problem of low crop productivity and food insecurity can be accelerated through community-centered implementation of good agricultural management practices. This study was conducted in Babati, Northern Tanzania. The objective of the study was to determine nitrogen (N) and phosphorus (P) application requirements for maize, and demonstrate economically viable best bet yield-improving management technologies under three ecozones namely; ‘low elevation low rainfall', ‘medium elevation high rainfall' and ‘medium elevation low rainfall' ecozone. Two sets of trials were conducted: N (0, 45, 90, 120 and 150 kg ha-1) and P (0, 15, 30, 40 kg ha-1) response trials in 16 …

Seed Quality And Mycoflora Associated With Chickpea (Cicer Arientinum L.) Seed In Ethiopia, G. Getaneh, T. Tefera, F. Lemmessa, S. Ahmed, A. Zewudie

All Peer-Reviewed Publications

The study was conducted at Ethiopian Institute of Agricultural Research, Haramaya University and Jimma University, Ethiopia. Crop yield is directly associated with the physical and biological quality of planting material or seed. Ninety-nine (99) chickpea seed lot samples were collected for physical purity, seed health and germination tests from major chickpea growing areas in Ethiopia in the 2016/17 cropping season to assess the status of chickpea seed health and quality among subsistence farmers, research stations and seed growers. The seed lots were grouped as researcher saved, farmers saved and seed growers’ saved seed. The maximum physical purity of 97.5% was …

Mineral Fertilizer Use In Land-Scarce Conditions: Case Of Rwanda, Josaphat Rusisiro Mugabo, Eric Tollens, Jonas Nwankwo Chianu, Bernard Vanlauwe

All Peer-Reviewed Publications

This study was undertaken to investigate the use of mineral fertilizer by smallholder farmers in order to understand the set of factors influencing the decisions of smallholder farmers to use fertilizers in land-scarce conditions. Using descriptive analysis and the Cragg's double-hurdle model, the study identified and analyzed factors that determine smallholder farmer adoption of mineral fertilizers and those that affect the intensity of household mineral fertilizer use. From factors that only influence the decision of smallholder farmers to use mineral fertilizers, distance to fertilizer market and livestock affects it negatively; while farmer association membership, landholding per capita, access to extension …

Diversity Of Fall Armyworm, Spodoptera Frugiperda And Their Gut Bacterial Community In Kenya, Joseph Gichuhi, Subramanian Sevgan, Fathiya Khamis, Johnnie Van Den Berg, Hannalene Du Plessis, Sunday Ekesi, Jeremy K. Herren

All Peer-Reviewed Publications

Background: The invasive fall armyworm, Spodoptera frugiperda (J.E. Smith) is a polyphagous pest that causes widespread damage particularly to maize and sorghum in Africa. The microbiome associated with S. frugiperda could play a role in the insects' success and adaptability. However, bacterial communities in S. frugiperda remain poorly studied. Methods: We investigated the composition, abundance and diversity of microbiomes associated with larval and adult specimens of S. frugiperda collected from four maize growing regions in Kenya through high throughput sequencing of the bacterial 16S rRNA gene. The population structure of S. frugiperda in Kenya was assessed through amplification of the …

Impact Of Integrated Fruit Fly Management Strategy On Food Security Among Smallholder Mango Farmers In Kenya, P. N. Nyang'au, B. W. Muriithi, J. M. Nzuma, P. Irungu, H. M. Gichungi, G. Diiro

All Peer-Reviewed Publications

Adoption of agricultural innovations is perceived as a key avenue for poverty reduction and improved food and nutritional security in developing countries. The International Centre for Insect Physiology and Ecology (icipe) has developed and implemented a set of Integrated Pest Management (IPM) strategies in several sub-Saharan African countries aimed at controlling mango infesting fruit flies (Bactrocera dorsalis). Although positive returns from the use of fruit fly IPM have already been documented, the impact of these technologies on food security is not well understood. This study evaluated the impact of the IPM strategy on food security with the help of a …

Application Of Advanced Algorithms And Statistical Techniques For Weed-Plant Discrimination, Saman Akbar Zadeh

Theses: Doctorates and Masters

Precision agriculture requires automated systems for weed detection as weeds compete with the crop for water, nutrients, and light. The purpose of this study is to investigate the use of machine learning methods to classify weeds/crops in agriculture. Statistical methods, support vector machines, convolutional neural networks (CNNs) are introduced, investigated and optimized as classifiers to provide high accuracy at high vehicular speed for weed detection.

Initially, Support Vector Machine (SVM) algorithms are developed for weed-crop discrimination and their accuracies are compared with a conventional data-aggregation method based on the evaluation of discrete Normalised Difference Vegetation Indices (NDVIs) at two different …

Can Precision Farming Technologies Be Applied To Grazing Management?, S. Mark Rutter

IGC Proceedings (1977-2023)

In arable farming, precision is used to monitor and manage crop variability. The same precision approach can be used to manage grassland, by using crop sensing, targeted fertilizer/herbicide/pesticide application and forage yield measurement when it is harvested mechanically. An additional challenge in grassland agriculture is developing precision approaches to manage the grazing process. This requires technologies to determine where an animal is, when, what and how much it is grazing which the system then needs to use in conjunction with other sources of information to control where the animal grazes next. This paper reviews the existing technologies in these …

Manipulation Of The Spatial Grazing Behaviour Of Livestock In Extensive Grassland Systems, Derek W. Bailey, Mitch B. Stephenson, Milton G. Thomas, Juan F. Medrano, Gonzalo Rincon

IGC Proceedings (1977-2023)

Spatial behaviour of livestock is a critical factor in grassland management. Recent and ongoing research suggests that new approaches can be used to manipulate where cattle graze. The combination of strategic supplement placement and low-stress herding can be used to target cattle grazing and potentially may be useful for managing fine fuels. A phenotype to genotype association study of cattle spatial behavior suggests that use of rugged terrain and areas far from water is inherited. Although more research is needed, selection for animals specifically adapted for mountainous terrain or extensive paddocks may be an alternative for managing grasslands in the …