Horticulture Commons^™

Population Structure And Genetic Diversity Of Bromus Tectorum Within The Small Grain Production Region Of The Pacific Northwest, Nevin C. Lawrence, Amber L. Hauvermale, Amit Dhingra, Ian C. Burke

Department of Agronomy and Horticulture: Faculty Publications

Bromus tectorum L. is an invasive winter annual grass naturalized across the United States. Numerous studies have investigated B. tectorum population structure and genetics in the context of B. tectorum as an ecological invader of natural areas and rangeland. Despite the wealth of information regarding B. tectorum, previous studies have not focused on, or made comparisons to, B. tectorum as it persists in individual agroecosystems. The objectives of this study were to assess the genetic diversity and structure, the occurrence of generalist and specialist genotypes, and the influence of climate on distribution of B. tectorum sourced exclusively from within …

A Transcriptome‑Snp‑Derived Linkage Map Of Apios Americana (Potato Bean) Provides Insights About Genome Re‑Organization And Synteny Conservation In The Phaseoloid Legumes, Jugpreet Singh, Scott R. Kalberer, Vikas Belamkar, Teshale Assefa, Matthew N. Nelson, Andrew D. Farmer, William J. Blackmon, Steven B. Cannon

Department of Agronomy and Horticulture: Faculty Publications

Apios (Apios americana; “apios”), a tuberous perennial legume in the Phaseoleae tribe, was widely used as a food by Native Americans. Work in the last 40 years has led to several improved breeding lines. Aspects of the pollination biology (complex floral structure and tripping mechanism) have made controlled crosses difficult, and the previous reports indicated that the plant is likely primarily an outcrosser. We used a pseudo-testcross strategy to construct a genetic map specific to the maternal parent. The map was built using single-nucleotide polymorphism markers identified by comparing the expressed sequences of individuals in the mapping population …

The Trouble With Cover Crops: Farmers’ Experiences With Overcoming Barriers To Adoption, Gabrielle E. Roesch-Mcnally, Andrea D. Basche, J. G. Arbuckle, John C. Tyndall, Fernando E. Miguez, Troy Bowman, Rebecca Clay

Department of Agronomy and Horticulture: Faculty Publications

Cover crops are known to promote many aspects of soil and water quality, yet estimates find that in 2012 only 2.3% of the total agricultural lands in the Midwestern USA were using cover crops. Focus groups were conducted across the Corn Belt state of Iowa to better understand how farmers confront barriers to cover crop adoption in highly intensive agricultural production systems. Although much prior research has focused on analyzing factors that help predict cover crop use on farms, there is limited research on how farmers navigate and overcome field-level (e.g. proper planting of a cover crop) and structural barriers …

Genetic Diversity Of Danthonia Spicata (L.) Beauv. Based On Genomic Simple Sequence Repeat Markers, Chandra S. Thammina, Keenan Amundsen, Shaun B. Bushman, Matthew H. Kramer, Scott E. Warnke

Department of Agronomy and Horticulture: Faculty Publications

Danthonia spicata (L.) Beauv., commonly known as poverty oatgrass, is a perennial bunch-type grass native to North America. D. spicata is often found in low input turfgrass areas on the East Coast of the United States and has potential for development as a new native low input turfgrass species. Roche 454 sequenced randomly sheared genomic DNA reads of D. spicata were mined for SSR markers using the MIcroSAtellite identification tool. A total of 66,553 singlet sequences (approximately 37.5 Mbp) were examined, and 3454 SSR markers were identified. Trinucleotide motifs with greater than six repeats and possessing unique PCR priming sites …

Molecular And Phenotypic Characterization Of Transgenic Wheat And Sorghum Events Expressing The Barley Alanine Aminotransferase, Pamela A. Peña, Truyen Quach, Shirley Sato, Zhengxiang Ge, Natalya Nersesian, Ismail M. Dweikat, Madhavan Soundararajan, Tom Clemente

Department of Agronomy and Horticulture: Faculty Publications

Main conclusion — The expression of a barley alanine aminotransferase gene impacts agronomic outcomes in a C3 crop, wheat.

The use of nitrogen-based fertilizers has become one of the major agronomic inputs in crop production systems. Strategies to enhance nitrogen assimilation and flux in planta are being pursued through the introduction of novel genetic alleles. Here an Agrobacterium-mediated approach was employed to introduce the alanine aminotransferase from barley (Hordeum vulgare), HvAlaAT, into wheat (Triticum aestivum) and sorghum (Sorghum bicolor), regulated by either constitutive or root preferred promoter elements. Plants harboring the transgenic …

Metabolism Of 2,4-Dichlorophenoxyacetic Acid Contributes To Resistance In A Common Waterhemp (Amaranthus Tuberculatus) Population, Marcelo R. A. Figueiredo, Lacy J. Leibhart, Zachary J. Reicher, Patrick J. Tranel, Scott J. Nissen, Philip Westra, Mark L. Bernards, Greg R. Kruger, Todd A. Gaines, Mithila Jugulam

Department of Agronomy and Horticulture: Faculty Publications

BACKGROUND: Synthetic auxins such as 2,4-D have been widely used for selective control of broadleaf weeds since the mid-1940s. In 2009, an Amaranthus tuberculatus (common waterhemp) population with 10-fold resistance to 2,4-D was found in Nebraska, USA. The 2,4-D resistance mechanism was examined by conducting [¹⁴C] 2,4-D absorption, translocation and metabolism experiments.

RESULTS: No differences were found in 2,4-D absorption or translocation between the resistant and susceptible A. tuberculatus. Resistant plants metabolized [¹⁴C] 2,4-D more rapidly than did susceptible plants. The half-life of [¹⁴C] 2,4-D in susceptible plants was 105 h, compared to …

Multisite Evaluation Of Apex For Water Quality: Ii. Regional Parameterization, Nathan O. Nelson, Claire Baffaut, John A. Lory, G.M.M.M. Anomaa Senaviratne, Ammar B. Bhandari, Ranjith P. Udawatta, Daniel W. Sweeney, Matt J. Helmers, Mike W. Van Liew, Antonio P. Mallarino, Charles S. Wortmann

Department of Agronomy and Horticulture: Faculty Publications

Phosphorus (P) Index assessment requires independent estimates of long-term average annual P loss from fields, representing multiple climatic scenarios, management practices, and landscape positions. Because currently available measured data are insufficient to evaluate P Index performance, calibrated and validated process-based models have been proposed as tools to generate the required data. The objectives of this research were to develop a regional parameterization for the Agricultural Policy Environmental eXtender (APEX) model to estimate edgeof- field runoff, sediment, and P losses in restricted-layer soils of Missouri and Kansas and to assess the performance of this parameterization using monitoring data from multiple sites …

Araucaria In The Urban Landscape: A Novel Leaning Pattern And Evidence Of Cultivated Hybridization, Jason W. Johns

Master's Theses

Our understanding of the natural world is constantly evolving and strengthening as more observations are made and experiments are performed. For example, we understand that tree stems grow toward the light (positive phototropism; Darwin 1880, Loehle 1986, Christie et al. 2013) and against gravity (negative gravitropism; Knight 1806, Hashiguchi et al. 2013). We also know that plants respond to mechanical stimulus and perturbation (thigmotropism; Braam 2005). Genes and their resulting proteins have been described to uncover some of the mechanisms for these environmental responses, but relatively speaking, we have just scratched the surface (Wyatt et al. 2013). While the discovery …

A Survey Of Non-Crop Plants As Alternative Hosts To Raspberries For Drosophila Suzukii (Spotted Wing Drosophila), Bennur Agbaba

Electronic Theses and Dissertations

The spotted wing fruit fly (SWD), Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is a pest of small fruit crops. Unlike most other Drosophila species, this insect can oviposit into ripe fruits, rendering them unmarketable. Drosophila suzukii is spreading quickly throughout the continental United States including South Dakota, and causing serious damage to horticultural crops, particularly those within the fruit industry. This study determines the D. suzukii host plant both commercial crops and native plants, and defines non-crop host plants by season in South Dakota. Further, it confirms the occurrence of the fly in southeastern South Dakota and identifies high-risk infestation areas …

Perimeter Cropping As A Means Of Reducing Insect Injury And Increasing Crop Yield, Brett L. Owens

Electronic Theses and Dissertations

The squash vine borer, Melittia cucurbitae Harris, (Lepidoptera: Sesiidae) is a destructive insect known to injure a broad range of cucurbit crops. Many studies have focused on insecticide management of this insect in squash (Cucurbita) and pumpkin (Cucurbita pepo Linnaeus) production; however, little work has been documented on organic approaches to reduce or eliminate injury from this pest to these crops in the Midwest. This study used trap cropping and pollinator mixtures to test whether a reduction of squash vine borer could be achieved in a specific cultivar of pumpkins, Cucurbita pepo ‘Howden’. The study was …

Robust Spatial Frameworks For Leveraging Research On Sustainable Crop Intensification, Patricio Grassini, Cameron M. Pittelkow, Kenneth Cassman, Haishun S. Yang, Sotirios Archontoulis, Mark Licht, Kendall R. Lamkey, Ignacio A. Ciampitti, Jeffrey A. Coulter, Sylvie M. Brouder, Jeffrey J. Volenec, Noemi Guindin-Garcia

Department of Agronomy and Horticulture: Faculty Publications

Meeting demand for food, fiber, feed, and fuel in a world with 9.7 billion people by 2050 without negative environmental impact is the greatest scientific challenge facing humanity. We hypothesize that this challenge can only be met with current and emerging technologies if guided by proactive use of a broad array of relevant data and geospatial scaling approaches to ensure local to global relevance for setting research priorities and implementing agricultural systems responsive to real-time status of weather, soils, crops, and markets. Despite increasing availability of field-scale agricultural data, robust spatial frameworks are lacking to convert these data into actionable …

An Assessment Of Economic Considerations For Industrial Hemp Production, Luke Lane, Jennie S. Popp, Michael P. Popp, Harrison M. Pittman

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

United States farm policy and programs are governed by the Farm Bill. The 2014 Farm Bill allows for the legal production and research of industrial hemp as long as it meets the standards outlined in the Farm Bill. Although it has a wide range of uses (upwards of 25,000 products use hemp), there is a lack of recent information regarding the economic feasibility of hemp production for the private agricultural sector. Through an extensive search of existing literature, information was gathered to construct an enterprise budget for industrial hemp. Data from the enterprise budget were used in a constrained linear …

Instructions For Authors, Discovery Editors

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

No abstract provided.

The Effect Of Artificial Selection On Phenotypic Plasticity In Maize, Joseph L. Gage, Diego Jarquin, Cinta Romay, Aaron Lorenz, Edward S. Buckler, Shawn Kaeppler, Naser Alkhalifah, Martin Bohn, Darwin A. Campbell, Jode Edwards, David Ertl, Sherry Flint-Garcia, Jack Gardiner, Byron Good, Candice N. Hirsch, Jim Holland, David C. Hooker, Joseph Knoll, Judith Kolkman, Greg Kruger, Nick Lauter, Carolyn J. Lawrence-Dill, Elizabeth Lee, Jonathan Lynch, Seth C. Murray, Rebecca Nelson, Jane Petzoldt, Torbert Rocheford, James C. Schnable, Patrick S. Schnable, Brian Scully, Margaret Smith, Nathan M. Springer, Srikant Srinivasan, Renee Walton, Teclemariam Weldekidan, Randall J. Wisser, Wenwei Xu, Jianming Yu, Natalia De Leon

Department of Agronomy and Horticulture: Faculty Publications

Remarkable productivity has been achieved in crop species through artificial selection and adaptation to modern agronomic practices. Whether intensive selection has changed the ability of improved cultivars to maintain high productivity across variable environments is unknown. Understanding the genetic control of phenotypic plasticity and genotype by environment (G × E) interaction will enhance crop performance predictions across diverse environments. Here we use data generated from the Genomes to Fields (G2F) Maize G × E project to assess the effect of selection on G × E variation and characterize polymorphisms associated with plasticity. Genomic regions putatively selected during modern temperate maize …

Allelic Variants Of Oshkt1;1 Underlie The Divergence Between Indica And Japonica Subspecies Of Rice (Oryza Sativa) For Root Sodium Content, Malachy T. Campbell, Nonoy Bandillo, Fouad Razzaq A. Al Shiblawi, Sandeep Sharma, Kan Liu, Qian Du, Aaron J. Schmitz, Chi Zhang, Anne-Alienor Very, Aaron J. Lorenz, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

Salinity is a major factor limiting crop productivity. Rice (Oryza sativa), a staple crop for the majority of the world, is highly sensitive to salinity stress. To discover novel sources of genetic variation for salt tolerance-related traits in rice, we screened 390 diverse accessions under 14 days of moderate (9 dS m^-1) salinity. In this study, shoot growth responses to moderate levels of salinity were independent of tissue Na⁺ content. A significant difference in root Na+ content was observed between the major subpopulations of rice, with indica accessions displaying higher root Na⁺ and japonica …

Jasmonoyl-L-Tryptophan Disrupts Iaa Activity Through The Aux1 Auxin Permease, Paul E. Staswick, Martha Rowe, Edgar P. Spalding, Bessie L. Splitt

Department of Agronomy and Horticulture: Faculty Publications

Amide-linked conjugates between tryptophan (Trp) and jasmonic (JA) or indole-3- acetic (IAA) acids interfered with gravitropism and other auxin-dependent activities in Arabidopsis, but the mechanism was unclear. To identify structural features necessary for activity several additional Trp conjugates were synthesized. The phenylacetic acid (PAA) conjugate was active, while several others were not. Common features of active conjugates is that they have ring structures that are linked to Trp through an acetic acid side chain, while longer or shorter linkages are inactive or less active. A dominant mutant, called tryptophan conjugate response1-D that is insensitive to JA-Trp, but still sensitive …

Tgbs® Genotyping-By-Sequencing Enables Reliable Genotyping Of Heterozygous Loci, Alina Ott, Sanzhen Liu, James C. Schnable, Cheng-Ting 'Eddy' Yeh, Kai-Sin Wang, Patrick S. Schnable

Department of Agronomy and Horticulture: Faculty Publications

Conventional genotyping-by-sequencing (cGBS) strategies suffer from high rates of missing data and genotyping errors, particularly at heterozygous sites. tGBS® genotyping-by-sequencing is a novel method of genome reduction that employs two restriction enzymes to generate overhangs in opposite orientations to which (single-strand) oligos rather than (double-stranded) adaptors are ligated. This strategy ensures that only doubledigested fragments are amplified and sequenced. The use of oligos avoids the necessity of preparing adaptors and the problems associated with inter-adaptor annealing/ligation. Hence, the tGBS protocol simplifies the preparation of high-quality GBS sequencing libraries. During polymerase chain reaction (PCR) amplification, selective nucleotides included at the 3'-end …

Plantcv V2: Image Analysis Software For High-Throughput Plant Phenotyping, Malia A. Gehan, Noah Fahlgren, Arash Abbasi, Jeffrey C. Berry, Steven T. Callen, Leonardo Chavez, Andrew N. Doust, Max J. Feldman, Kerrigan B. Gilbert, John G. Hodge, J. Steen Hoyer, Andy Lin, Suxing Liu, César Lizárraga, Argelia Lorence, Michael Miller, Eric Platon, Monica Tessman, Tony Sax

Department of Agronomy and Horticulture: Faculty Publications

Systems for collecting image data in conjunction with computer vision techniques are a powerful tool for increasing the temporal resolution at which plant phenotypes can be measured non-destructively. Computational tools that are flexible and extendable are needed to address the diversity of plant phenotyping problems. We previously described the Plant Computer Vision (PlantCV) software package, which is an image processing toolkit for plant phenotyping analysis. The goal of the PlantCV project is to develop a set of modular, reusable, and repurposable tools for plant image analysis that are open-source and community-developed. Here we present the details and rationale for major …

Leveraging Agroecology For Solutions In Food, Energy, And Water, Marcia Delonge, Andrea D. Basche

Department of Agronomy and Horticulture: Faculty Publications

Global agriculture is facing growing challenges at the nexus of interconnected food, energy and water systems, including but not limited to persistent food insecurity and diet-related diseases; growing demands for energy and consequences for climate change; and declining water resources, water pollution, floods and droughts. Further, soil degradation and biodiversity loss are both triggers for and consequences of these problems. In this commentary, we argue that expanding agroecological principles, tools, and technologies and enhancing biological diversity can address these challenges and achieve better socioeconomic outcomes. Agroecology is often described as multi- or transdiscplinary, and applies ecological principles to the design …

Improving Water Resilience With More Perennially Based Agriculture, Andrea D. Basche, Oliver F. Edelson

Department of Agronomy and Horticulture: Faculty Publications

Land conversion from natural to managed ecosystems, while necessary for food production, continues to occur at high rates with significant water impacts. Further, increased rainfall variability exposes agricultural systems to impacts from flood and drought events. In many regions, water limitations are overcome through technological approaches such as irrigation and tile drainage, which may not be sustainable in the long term. A more sustainable approach to combat episodes of floods and droughts is to increase soil water storage and the overall green water efficiency of agroecosystems. Agricultural practices that promote “continuous living cover,” such as perennial grasses, agroforestry and cover …

Using An Active-Optical Sensor To Develop An Optimal Ndvi Dynamic Model For High-Yield Rice Production (Yangtze, China), Xiaojun Liu, Richard B. Ferguson, Hengbiao Zheng, Qiang Cao, Yongchao Tian, Weixing Cao, Yan Zhu

Department of Agronomy and Horticulture: Faculty Publications

The successful development of an optimal canopy vegetation index dynamic model for obtaining higher yield can offer a technical approach for real-time and nondestructive diagnosis of rice (Oryza sativa L) growth and nitrogen (N) nutrition status. In this study, multiple rice cultivars and N treatments of experimental plots were carried out to obtain: normalized difference vegetation index (NDVI), leaf area index (LAI), above-ground dry matter (DM), and grain yield (GY) data. The quantitative relationships between NDVI and these growth indices (e.g., LAI, DM and GY) were analyzed, showing positive correlations. Using the normalized modeling method, an appropriate NDVI simulation model …

Genomic Prediction With Pedigree And Genotype X Environment Interaction In Spring Wheat Grown In South And West Asia, North Africa, And Mexico, Sivakumar Sukumaran, José Crossa, Diego Jarquin, Marta Lopes, Matthew P. Reynolds

Department of Agronomy and Horticulture: Faculty Publications

Developing genomic selection (GS) models is an important step in applying GS to accelerate the rate of genetic gain in grain yield in plant breeding. In this study, seven genomic prediction models under two cross-validation (CV) scenarios were tested on 287 advanced elite spring wheat lines phenotyped for grain yield (GY), thousand-grain weight (GW), grain number (GN), and thermal time for flowering (TTF) in 18 international environments (year-location combinations) in major wheat-producing countries in 2010 and 2011. Prediction models with genomic and pedigree information included main effects and interaction with environments. Two random CV schemes were applied to predict a …

Validation Of Qtl Mapping And Transcriptome Profiling For Identification Of Candidate Genes Associated With Nitrogen Stress Tolerance In Sorghum, Malleswari Gelli, Anji Reddy Konda, Kan Liu, Chi Zhang, Thomas E. Clemente, David R. Holding, Ismail M. Dweikat

Department of Agronomy and Horticulture: Faculty Publications

Background: Quantitative trait loci (QTLs) detected in one mapping population may not be detected in other mapping populations at all the time. Therefore, before being used for marker assisted breeding, QTLs need to be validated in different environments and/or genetic backgrounds to rule out statistical anomalies. In this regard, we mapped the QTLs controlling various agronomic traits in a recombinant inbred line (RIL) population in response to Nitrogen (N) stress and validated these with the reported QTLs in our earlier study to find the stable and consistent QTLs across populations. Also, with Illumina RNA-sequencing we checked the differential expression of …

Pollen-Mediated Gene Flow From Glyphosate-Resistant Common Waterhemp (Amaranthus Rudis Sauer): Consequences For The Dispersal Of Resistance Genes, Debalin Sarangi, Andrew J. Tyre, Eric L. Patterson, Todd A. Gaines, Suat Irmak, Stevan Z. Knezevic, John L. Lindquist, Amit J. Jhala

Department of Agronomy and Horticulture: Faculty Publications

Gene flow is an important component in evolutionary biology; however, the role of gene flow in dispersal of herbicide-resistant alleles among weed populations is poorly understood. Field experiments were conducted at the University of Nebraska-Lincoln to quantify pollen-mediated gene flow (PMGF) from glyphosate-resistant (GR) to -susceptible (GS) common waterhemp using a concentric donorreceptor design. More than 130,000 common waterhemp plants were screened and 26,199 plants were confirmed resistant to glyphosate. Frequency of gene flow from all distances, directions, and years was estimated with a double exponential decay model using Generalized Nonlinear Model (package gnm) in R. PMGF declined by 50% …

Estimating Yield Gaps At The Cropping System Level, Nicolas Guilpart, Patricio Grassini, Victor O. Sadras, Jagadish Timsina, Kenneth Cassman

Department of Agronomy and Horticulture: Faculty Publications

Yield gap analyses of individual crops have been used to estimate opportunities for increasing crop production at local to global scales, thus providing information crucial to food security. However, increases in crop production can also be achieved by improving cropping system yield through modification of spatial and temporal arrangement of individual crops. In this paper we define the cropping system yield potential as the output from the combination of crops that gives the highest energy yield per unit of land and time, and the cropping system yield gap as the difference between actual energy yield of an existing cropping system …

Modeling Pollen-Mediated Gene Flow From Glyphosate-Resistant To -Susceptible Giant Ragweed (Ambrosia Trifida L.) Under Field Conditions, Zahoor A. Ganie, Amit J. Jhala

Department of Agronomy and Horticulture: Faculty Publications

A field experiment was conducted to quantify pollen mediated gene flow (PMGF) from glyphosateresistant (GR) to glyphosate-susceptible (GS) giant ragweed under simulated field conditions using glyphosate resistance as a selective marker. Field experiments were conducted in a concentric design with the GR giant ragweed pollen source planted in the center and GS giant ragweed pollen receptors surrounding the center in eight directional blocks at specified distances (between 0.1 and 35 m in cardinal and ordinal directions; and additional 50 m for ordinal directions). Seeds of GS giant ragweed were harvested from the pollen receptor blocks and a total of 100,938 …

Gene Silencing Of Argonaute5 Negatively Affects The Establishment Of The Legume-Rhizobia Symbiosis, Maria Del Rocio Reyero-Saavedra, Zhenzhen Qiao, Maria Del Socorro Sanchez-Correa, M. Enrique Diaz-Pineda, Jose L. Reyes, Alejandra A. Covarrubias, Marc Libault, Oswaldo Valdes-Lopez

Department of Agronomy and Horticulture: Faculty Publications

The establishment of the symbiosis between legumes and nitrogen-fixing rhizobia is finely regulated at the transcriptional, posttranscriptional and posttranslational levels. Argonaute5 (AGO5), a protein involved in RNA silencing, can bind both viral RNAs and microRNAs to control plant-microbe interactions and plant physiology. For instance, AGO5 regulates the systemic resistance of Arabidopsis against Potato Virus X as well as the pigmentation of soybean (Glycine max) seeds. Here, we show that AGO5 is also playing a central role in legume nodulation based on its preferential expression in common bean (Phaseolus vulgaris) and soybean roots and nodules. We also …

Muskmelon Variety Trial In Southwest Indiana — 2016, Wenjing Guan, Dennis Nowaskie

Purdue Fruit and Vegetable Research Reports

This is a compilation of 21 research trial reports from four land-grant universities in the Midwestern United States. Crops include cantaloupe, pickling cucumber, pepper, potato, pumpkin, summer squash and zucchini, sweet corn, tomato, and watermelon. Somecrops were evaluated in high tunnels or hoophouses. Most trials evaluated different cultivars or varieties. One report addressed plant spacing for sweet corn and one addressed soil block for production of tomato seedlings. A list of vegetable seed sources and a list of other online sources of vegetable trial reports are also included.

Watermelon Variety Evaluations In Southwest Indiana, 2016, Wenjing Guan, Dan Egel, Dennis Nowaskie

Purdue Fruit and Vegetable Research Reports

This is a compilation of 21 research trial reports from four land-grant universities in the Midwestern United States. Crops include cantaloupe, pickling cucumber, pepper, potato, pumpkin, summer squash and zucchini, sweet corn, tomato, and watermelon. Somecrops were evaluated in high tunnels or hoophouses. Most trials evaluated different cultivars or varieties. One report addressed plant spacing for sweet corn and one addressed soil block for production of tomato seedlings. A list of vegetable seed sources and a list of other online sources of vegetable trial reports are also included.

Potassium Applications And Yellow Shoulder Disorder Of Tomatoes In High Tunnels, Elizabeth Maynard, Israel S. Calsoya, Jill Malecki

Purdue Fruit and Vegetable Research Reports

Tomatoes grown in unheated high tunnels can suffer significant loss in quality due to yellow shoulder disorder, particularly in susceptible varieties. This paper reports on a preliminary trial to determine whether incidence and severity of the disorder could be influenced by applying potassium fertilizers. Plots with higher leaf potassium content tended to have less fruit with severe yellow shoulder disorder, but increasing the amount of potassium fertilizer applied did not significantly reduce the disorder. From this study it isn’t possible to make specific recommendations for reducing yellow shoulder disorder with potassium applications.