Agricultural Science Commons^™

Herbicides Applied At Or Shortly After Seeding Are Effective For Weed Control In Seedling Buffalograss, Luqi Li, Matthew D. Sousek, Zachary Reicher

Department of Agronomy and Horticulture: Faculty Publications

Herbicides applied shortly after seeding of buffalograss [Buchloe dactyloides (Nutt.) Engelm.] can help reduce weed pressure and maximize establishment of buffalograss. This study evaluated 12 relatively recently developed herbicides for turf safety and weed control when applied at seeding or 0 or 2 weeks after emergence (WAE) of ‘Bowie’ or ‘Sundancer’ buffalograss. Primary weed species on the site were common purslane (Portulaca oleracea L.), redroot pigweed (Amaranthus retroflexus L.), and/or yellow foxtail [Setaria lutescens (Weigel ex Stuntz) F.T. Hubb.]. Regardless of cultivar, untreated checks had53% weed cover by 6 WAE, whereas most of the herbicide treatments resulted …

Synfind: Compiling Syntenic Regions Across Any Set Of Genomes On Demand, Haibao Tang, Matthew D. Bomhoff, Evan Briones, Liangsheng Zhang, James C. Schnable, Eric Lyons

Department of Agronomy and Horticulture: Faculty Publications

The identification of conserved syntenic regions enables discovery of predicted locations for orthologous and homeologous genes, evenwhennosuchgeneispresent.Thiscapabilitymeansthatsynteny-basedmethodsarefarmoreeffectivethansequencesimilaritybased methods in identifying true-negatives, a necessity forstudying gene loss and gene transposition. However, the identification of syntenicregionsrequirescomplexanalyseswhichmustberepeatedforpairwisecomparisonsbetweenanytwospecies.Therefore,as the number of published genomes increases, there is a growing demand for scalable, simple-to-use applications to perform comparative genomic analyses that cater to both gene family studies and genome-scale studies. We implemented SynFind, a web-based tool that addresses this need. Given one query genome, SynFind is capable of identifying conserved syntenic regions in any set of targetgenomes.SynFindiscapableofreportingper-geneinformation,usefulforresearchersstudyingspecificgenefamilies,aswellas genome-wide data sets of syntenic gene and predicted gene …

A Population Structure And Genome-Wide Association Analysis On The Usda Soybean Germplasm Collection, Nonoy Bandillo, Diego Jarquin, Qijian Song, Randall L. Nelson, Perry Cregan, James Specht, Aaron Lorenz

Department of Agronomy and Horticulture: Faculty Publications

Population structure analyses and genome-wide association studies (GWAS) conducted on crop germplasm collections provide valuable information on the frequency and distribution of alleles governing economically important traits. The value of these analyses is substantially enhanced when the accession numbers can be increased from ~1,000 to ~10,000 or more. In this research, we conducted the first comprehensive analysis of population structure on the collection of 14,000 soybean accessions [Glycine max (L.) Merr. and G. soja Siebold & Zucc.] using a 50KSNP chip. Accessions originating from Japan were relatively homogenous and distinct from the Korean accessions. As a whole, both Japanese and …

Adding Genetically Distant Individuals To Training Populations Reduces Genomic Prediction Accuracy In Barley, Aaron Lorenz, Kevin P. Smith

Department of Agronomy and Horticulture: Faculty Publications

One of the most important factors affecting genomic prediction accuracy appears to be training population (TP) composition. The objective of this study was to evaluate the effect of genomic relationship on genomic prediction accuracy and determine if adding increasingly unrelated individuals to a TP can reduce prediction accuracy. To accomplish this, a population of barley (Hordeum vulgare L.) lines from the University of Minnesota (lines denoted as MN) and North Dakota State University (lines denoted as ND) breeding programs were used for model training. Predictions were validated using two independent sets of progenies derived from MN  MN crosses …

Switchgrass Germplasm Resources, Michael D. Casler, Kenneth P. Vogel, Melanie Harrison

Department of Agronomy and Horticulture: Faculty Publications

Switchgrass (Panicum virgatum L.) is an important native grass and dominant member of the tallgrass prairie ecosystem. It is used for conservation, restoration, livestock feed production, and bioenergy feedstock production. The purpose of this review is to describe the biological and geographical basis for switchgrass germplasm diversity and to provide a resource for scientists and outreach personnel to find switchgrass germplasm to meet their needs. Upland and lowland ecotypes represent the most important polymorphism in switchgrass, with distinct but overlapping geographic distributions. Variation in ploidy exists within both ecotypes, with 2n = 4x = 36 the dominant ploidy …

Community Seed Banks: Origins, Evolution, And Prospects, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

As a survey of contemporary community-level seed banks, this is an excellent compilation and instructive guide. The first section provides an overview of how seed banks originated, their varied goals and activities, several contrasting forms of management, and how they organize and perform to meet these goals. An intriguing claim in the book is that the concept of “seed banks is only some three decades old,” while in fact the practice of saving, preserving, and exchanging seed within a community is probably as old as human communities themselves.

Organized seed banks often serve specific functions: preserving seeds, providing seed access …

Occurrence Of An Herbicide-Resistant Plant Trait In Agricultural Field Margins, Karla L. Gag, David J. Gibson, Bryan G. Young, Julie M. Young, Joseph L. Matthews, Stephen C. Weller, Robert G. Wilson

Department of Agronomy and Horticulture: Faculty Publications

Agricultural environments allow study of evolutionary change in plants. An example of evolution within agroecological systems is the selection for resistance to the herbicide glyphosate within the weed, Conyza canadensis. Changes in survivorship and reproduction associated with the development of glyphosate resistance (GR) may impact fitness and influence the frequency of occurrence of the GR trait. We hypothesized that site characteristics and history would affect the occurrence of GR C. canadensis in field margins. We surveyed GR occurrence in field margins and asked whether there were correlations between GR occurrence and location, crop rotation, GR crop trait rotation, crop type, …

Genetic Engineering Online Lessons Improve Teaching And Increase Knowledge And Accepting Attitudes Among Students, Grace Troupe

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

Genetic engineering has been used in the production of food in the U.S. for nearly three decades, however, science literacy in genetic engineering among consumers is still low. To address this problem, an online resource called The Journey of a Gene (passel.unl.edu/ge) was created to help incorporate genetic engineering education in high school and college curriculums. Here we report two studies conducted to evaluate the effectiveness of The Journey of a Gene in 1) improving student knowledge and attitudes about genetic engineering and 2) helping teachers increase their knowledge as well as quantity and quality of genetic engineering instruction. In …

Comparing Yield Monitors With Weigh Wagons For On-Farm Corn Hybrid Evaluation, Bjorn P. Nelson, Roger Wesley Elmore, Andrew W. Lenssen

Department of Agronomy and Horticulture: Faculty Publications

For many years, on-farm yield evaluations of corn (Zea mays L.) hybrids were done with weigh wagons, handheld moisture testers, and measuring wheels. Today, most combines have continuous flow yield and moisture sensors. Published research results comparing the accuracy of combine-mounted sensor systems with that of weigh wagons are limited for on-farm corn hybrid evaluation. This study examined the accuracy of combine-mounted yield sensors with traditional weigh wagon methodology in on-farm corn hybrid strip trials. Data from combine-mounted sensors for plot weight, moisture percentage, and yield were compared with weigh wagon weight, handheld moisture testers, and calculated yield …

Microsatellite Variations Of Elite Setaria Varieties Released During Last Six Decades In China, Guanqing Jia, Xiaotong Liu, James C. Schnable, Zhengang Niu, Chunfang Wang, Yuhui Li, Shujun Wang, Suying Wang, Jinrong Liu, Erhu Guo, Hui Zhi, Xianmin Diao

Department of Agronomy and Horticulture: Faculty Publications

Crop improvement is a multifaceted micro-evolutionary process, involving changes in breeding approaches, planting configurations and consumption preferences of human beings. Recent research has started to identify the specific genes or genomic regions correlate to improved agronomic traits, however, an apparent blank between the genetic structure of crop elite varieties and their improving histories in diverse modern breeding programs is still in existence. Foxtail millet (Setaria italica) was one of the earliest cereal crops to be domesticated and served as a staple crop for early civilizations in China, where it is still widely grown today. In the present trial, …

Comparing Avian Diversity And Anthropogenic Disturbance At Sendero Los Quetzales Cerro Punta, Panamá, Sloane Merdinger

Independent Study Project (ISP) Collection

This report summarizes the survey of land and avian diversity along a transect that runs from the exterior to the interior of the Los Quetzales Trail of Parque Nacional Volcán Barú in Cerro Punta, Chiriquí, Panamá. The region of Cerro Punta is Panamá’s primary producer of produce and also home to one of the most biodiverse land reserves in the world. Despite protection efforts the area is continuously threatened by human development. The study juxtaposes calculated Shannon-Wiener Biodiversity Indices across graduated levels of anthropogenic disturbance to determine if there is a significant difference in biodiversity between areas with low, intermediate, …

Soil Total Organic Carbon And Farmers’ Perceptions Associated With Bokashi Application In Cerro Punta, Panama, Emma Searson

Independent Study Project (ISP) Collection

Sustainable use and maintenance of agricultural soils are important for maintaining long-term agricultural productivity and environmental quality. These issues are especially important in Cerro Punta, known as the breadbasket of Panama, which is experiencing severe erosion. While current practices and agrochemical usage damage soil health and function over time, application of organic material improves soil physic-chemical properties such as nutrient and total organic carbon (TOC) content. Bokashi, a fermented organic soil amendment with effective microorganisms (EM), is thought to be especially beneficial due to its ability to augment populations of soil microbes, which deliver plant-available nutrients to crops and improve …

Evaluation And Association Mapping Of Resistance To Tan Spot And Stagonospora Nodorum Blotch In Adapted Winter Wheat Germplasm, Zhaohui Liu, Ibrahim El-Basyoni, Gayan Kariyawasam, Guorong Zhang, Allan Fritz, Jana Hansen, Francois Marais, Andrew Friskop, Shiaoman Chao, Eduard Akhunov, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Tan spot and Stagonospora nodorum blotch (SNB), often occurring together, are two economically significant diseases of wheat in the Northern Great Plains of the United States. They are caused by the fungi Pyrenophora tritici-repentis and Parastagonospora nodorum, respectively, both of which produce multiple necrotrophic effectors (NE) to cause disease. In this work, 120 hard red winter wheat (HRWW) cultivars or elite lines, mostly from the United States, were evaluated in the greenhouse for their reactions to the two diseases as well as NE produced by the two pathogens. One P. nodorum isolate (Sn4) and four Pyrenophora tritici-repentis isolates (Pti2, …

Characterization Of Novel Sorghum Brown Midrib Mutants From An Ems-Mutagenized Population, Scott E. Sattler, Ana Saballos, Zhanguo Xin, Deanna L. Funnell-Harris, Wilfred Vermerris, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Reducing lignin concentration in lignocellulosic biomass can increase forage digestibility for

ruminant livestock and saccharification yields of biomass for bioenergy. In sorghum (Sorghum bicolor (L.) Moench) and several other C4 grasses, brown midrib (bmr) mutants have been shown to reduce lignin concentration. Putative bmr mutants isolated from an EMS-mutagenized population were characterized and classified based on their leaf midrib phenotype and allelism tests with the previously described sorghum bmr mutants bmr2, bmr6, and bmr12. These tests resulted in the identification of additional alleles of bmr2, bmr6, and bmr12, and, in addition, six bmr …

Patch Burning: Implications On Water Erosion And Soil Properties, Altingul Ozaslan Parlak, Mehmet Parlak, Humberto Blanco-Canqui, Walter H. Schacht, John A. Guretzky, Martha Mamo

Department of Agronomy and Horticulture: Faculty Publications

Patch burning can be a potential management tool to create grassland heterogeneity and enhance forage productivity and plant biodiversity, but its impacts on soil and environment have not been widely documented. In summer 2013, we studied the effect of time after patch burning (4 mo after burning [recently burned patches], 16 mo after burning [older burned patches], and unburned patches [control]) on vegetative cover, water erosion, and soil properties on a patch-burn experiment established in 2011 on a Yutan silty clay loam near Mead, NE. The recently burned patches had 29 ± 8.0% (mean ± SD) more bare ground, 21 …

Model And Sensor-Based Recommendation Approaches For In-Season Nitrogen Management In Corn, L. J. Thompson, R. B. Ferguson, N. Kitchen, D. W. Frazen, M. Mamo, H. Yang, J. S. Schepers

Department of Agronomy and Horticulture: Faculty Publications

Nitrogen management for corn (Zea mays L.) may be improved by applying a portion of N in-season. This investigation was conducted to evaluate crop modeling (Maize-N) and active crop canopy sensing approaches for recommending in-season N fertilizer rates. These approaches were evaluated during 2012–2013 on 11 field sites, in Missouri, Nebraska, and North Dakota. Nitrogen management also included a no-N treatment (check) and a non-limiting N reference (all at planting). Nitrogen management treatments were assessed for two hybrids and at low and high seeding rates, arranged in a randomized complete block design. In 9 of 11 site-years, the sensor-based …

Calibration And Validation Of The Hybrid-Maize Crop Model For Regional Analysis And Application Over The U.S. Corn Belt, Xing Liu, Jeff Andresen, Haishun Yang, Dev Niyogi

Department of Agronomy and Horticulture: Faculty Publications

Detailed parameter sensitivity, model validation, and regional calibration of the Hybrid-Maize crop model were undertaken for the purpose of regional agroclimatic assessments. The model was run at both field scale and county scale. The county-scale study was based on 30-yr daily weather data and corn yield data from the National Agricultural Statistics Service survey for 24 locations across the Corn Belt of the United States. The field-scale study was based on AmeriFlux sites at Bondville, Illinois, andMead, Nebraska. By using the one-at-a-time and interaction-explicit factorial design approaches for sensitivity analysis, the study found that the five most sensitive parameters of …

Potential For Crop Production Increase In Argentina Through Closure Of Existing Yield Gaps, Fernando Aramburu Merlos, Juan Pablo Monzon, Jorge L. Mercau, Miguel Taboada, Fernando H. Andrade, Antonio J. Hall, Esteban Jobbagy, Kenneth Cassman, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Favorable climate and soils for rainfed crop production, together with a relatively low population density,results in 70–90% of Argentina grain production being exported. No assessment to date has tried to estimate the potential for extra grain production for soybean, wheat and maize, which account for 78%of total harvested area, by yield gap closure on existing cropland area and its impact at a global scale.The objectives of this paper are (i) to estimate how much additional grain could be produced without expanding crop area by closing yield gaps in Argentina, (ii) to investigate how this production and yield gaps varies across …

Qtl For Seed Protein And Amino Acids In The Benning × Danbaekkong Soybean Population, C. V. Warrington, H. Abdel‑Haleem, D. L. Hyten, P. B. Cregan, J. H. Orf, A. S. Killam, N. Bajjalieh, Z. Li, H. R. Boerma

Department of Agronomy and Horticulture: Faculty Publications

Soybean, rather than nitrogen-containing forages, is the primary source of quality protein in feed formulations for domestic swine, poultry, and dairy industries. As a sole dietary source of protein, soybean is deficient in the amino acids lysine (Lys), threonine (Thr), methionine (Met), and cysteine (Cys). Increasing these amino acids would benefit the feed industry. The objective of the present study was to identify quantitative trait loci (QTL) associated with crude protein (cp) and amino acids in the ‘Benning’ × ‘Danbaekkong’ population. The population was grown in five southern USA environments. Amino acid concentrations as a fraction of cp (Lys/cp, Thr/cp, …

Fingerprinting Soybean Germplasm And Its Utility In Genomic Research, Qijian Song, D. L. Hyten, Gaofeng Jia, Charles V. Quigley, Edward W. Fickus, Randall L. Nelson, P. B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

The United States Department of Agriculture, Soybean Germplasm Collection includes 18,480 domesticated soybean and 1,168 wild soybean accessions introduced from 84 countries or developed in the U.S. This collection was genotyped with the SoySNP50K BeadChip containing greater than 50K SNPs. Redundant accessions were identified in the collection and distinct genetic backgrounds of soybean from different geographic origins were observed that could be a unique resource for soybean genetic improvement. We detected a dramatic reduction of genetic diversity based on linkage disequilibrium and haplotype structure analyses of the wild, landrace and North American cultivar populations and identified candidate regions associated with …

A Genomic Selection Index Applied To Simulated And Real Data, J. Jesus Ceron-Rojas, Jose Crossa, Vivi N. Arief, Kaye Basford, Jessica Rutkoski, Diego Jarquin, Gregorio Alvarado, Yoseph Beyene, Kassa Semagn, Ian Delacy

Department of Agronomy and Horticulture: Faculty Publications

A genomic selection index (GSI) is a linear combination of genomic estimated breeding values that uses genomic markers to predict the net genetic merit and select parents from a nonphenotyped testing population. Some authors have proposed a GSI; however, they have not used simulated or real data to validate the GSI theory and have not explained how to estimate the GSI selection response and the GSI expected genetic gain per selection cycle for the unobserved traits after the first selection cycle to obtain information about the genetic gains in each subsequent selection cycle. In this paper, we develop the theory …

First Approximations Of Prescribed Fire Risks Relative To Other Management Techniques Used On Private Lands, Dirac L. Twidwell, Carissa L. Wonkka, Michael T. Sindelar, John R. Weir

Department of Agronomy and Horticulture: Faculty Publications

Fire is widely recognized as a critical ecological and evolutionary driver that needs to be at the forefront of land management actions if conservation targets are to be met. However, the prevailing view is that prescribed fire is riskier than other land management techniques. Perceived risks associated with the application of fire limits its use and reduces agency support for prescribed burning in the private sector. As a result, considerably less cost-share support is given for prescribed fire compared to mechanical techniques. This study tests the general perception that fire is a riskier technique relative to other land management options. …

Transgenic Wheat Expressing A Barley Udp-Glucosyltransferase Detoxifies Deoxynivalenol And Provides High Levels Of Resistance To Fusarium Graminearum, Xi Li, Sanghyun Shin, Shane Heinen, Ruth Dill-Macky, Franz Berthiller, Natalya Nersesian, Thomas Clemente, Susan Mccormick, Gary J. Muehbauer

Department of Agronomy and Horticulture: Faculty Publications

Fusarium head blight (FHB), mainly caused by Fusarium graminearum, is a devastating disease of wheat that results in economic losses worldwide. During infection, F. graminearum produces trichothecene mycotoxins, including deoxynivalenol (DON), that increase fungal virulence and reduce grain quality. Transgenic wheat expressing a barley UDP-glucosyltransferase (HvUGT13248) were developed and evaluated for FHB resistance, DON accumulation, and the ability to metabolize DON to the less toxic DON-3-O-glucoside (D3G). Pointinoculation tests in the greenhouse showed that transgenic wheat carrying HvUGT13248 exhibited significantly higher resistance to disease spread in the spike (type II resistance) compared with nontransformed controls. Two transgenic …

Understanding Rice Adaptation To Varying Agro-Ecosystems: Trait Interactions And Quantitative Trait Loci, Shalabh Dixit, Alexandre Grondin, Cheng-Ruei Lee, Amelia Henry, Thomas-Mitchell Olds, Arvind Kumar

Department of Agronomy and Horticulture: Faculty Publications

Background: Interaction and genetic control for traits influencing the adaptation of the rice crop to varying environments was studied in a mapping population derived from parents (Moroberekan and Swarna) contrasting for drought tolerance, yield potential, lodging resistance, and adaptation to dry direct seeding. A BC₂F₃-derived mapping population for traits related to these four trait groups was phenotyped to understand the interactions among traits and to map and align QTLs using composite interval mapping (CIM). The study also aimed to identify QTLs for the four trait groups as composite traits using multivariate least square interval mapping (MLSIM) …

Aquaporins Contribute To Aba-Triggered Stomatal Closure Through Ost1-Mediated Phosphorylation, Alexandre Grondin, Olivier Rodrigues, Lionel Verdoucq, Sylvain Merlot, Nathalie Leonhardt, Christophe Maurel

Department of Agronomy and Horticulture: Faculty Publications

Stomatal movements in response to environmental stimuli critically control the plant water status. Although these movements are governed by osmotically driven changes in guard cell volume, the role of membrane water channels (aquaporins) has remained hypothetical. Assays in epidermal peels showed that knockout Arabidopsis thaliana plants lacking the Plasma membrane Intrinsic Protein 2;1 (PIP2;1) aquaporin have a defect in stomatal closure, specifically in response to abscisic acid (ABA). ABA induced a 2-fold increase in osmotic water permeability (P_f) of guard cell protoplasts and an accumulation of reactive oxygen species in guard cells, which were both abrogated in …

Proteomic Profiling Of Maize Opaque Endosperm Mutants Reveals Selective Accumulation Of Lysine-Enriched Proteins, Kyla J. Morton, Shangang Jia, Chi Zhang, David R. Holding

Department of Agronomy and Horticulture: Faculty Publications

Reduced prolamin (zein) accumulation and defective endoplasmic reticulum (ER) body formation occurs in maize opaque endosperm mutants opaque2 (o2), floury2 (fl2), defective endosperm*B30 (DeB30), and Mucronate (Mc), whereas other opaque mutants such as opaque1 (o1) and floury1 (fl1) are normal in these regards. This suggests that other factors contribute to kernel texture. A liquid chromatography approach coupled with tandem mass spectrometry (LC-MS/MS) proteomics was used to compare non-zein proteins of nearly isogenic opaque endosperm mutants. In total, 2762 proteins were identified that were enriched for biological processes such as protein transport and folding, amino acid biosynthesis, …

Tonoplast Sugar Transporters (Sbtsts) Putatively Control Sucrose Accumulation In Sweet Sorghum Stems, Saadia Bihmidine, Benjamin T. Julius, Ismail M. Dweikat, David M. Braun

Department of Agronomy and Horticulture: Faculty Publications

Carbohydrates are differentially partitioned in sweet versus grain sorghums. While the latter preferentially accumulate starch in the grain, the former primarily store large amounts of sucrose in the stem. Previous work determined that neither sucrose metabolizing enzymes nor changes in Sucrose transporter (SUT) gene expression accounted for the carbohydrate partitioning differences. Recently, 2 additional classes of sucrose transport proteins, Tonoplast Sugar Transporters (TSTs) and SWEETs, were identified; thus, we examined whether their expression tracked sucrose accumulation in sweet sorghum stems. We determined 2 TSTs were differentially expressed in sweet vs. grain sorghum stems, likely underlying the massive difference in sucrose …

Selection For Silage Yield And Composition Did Not Affect Genomic Diversity Within The Wisconsin Quality Synthetic Maize Population, Aaron Lorenz, Timothy M. Beissinger, Renato Rodrigues Silva, Natalia De Leon

Department of Agronomy and Horticulture: Faculty Publications

Maize silage is forage of high quality and yield, and represents the second most important use of maize in the United States. The Wisconsin Quality Synthetic (WQS) maize population has undergone five cycles of recurrent selection for silage yield and composition, resulting in a genetically improved population. The application of high-density molecular markers allows breeders and geneticists to identify important loci through association analysis and selection mapping, as well as to monitor changes in the distribution of genetic diversity across the genome. The objectives of this study were to identify loci controlling variation for maize silage traits through association analysis …

A Roadmap For Functional Structural Variants In The Soybean Genome, Justin E. Anderson, Michael B. Kantar, Thomas Y. Kono, Fengli Fu, Adrian O. Stec, Qijian Song, Perry B. Cregan, James E. Specht, Brian W. Diers, Steven B. Cannon, Leah K. Mchale, Robert M. Stupar

Department of Agronomy and Horticulture: Faculty Publications

Gene structural variation (SV) has recently emerged as a key genetic mechanism underlying several important phenotypic traits in crop species. We screened a panel of 41 soybean (Glycine max) accessions serving as parents in a soybean nested association mapping population for deletions and duplications in more than 53,000 gene models. Array hybridization and whole genome resequencing methods were used as complementary technologies to identify SV in 1528 genes, or approximately 2.8%, of the soybean gene models. Although SV occurs throughout the genome, SV enrichment was noted in families of biotic defense response genes. Among accessions, SV was nearly eightfold less …

Overexpression Of The Transporters Atzip1 And Atmtp1 In Cassava Changes Zinc Accumulation And Partitioning, Eliana Gaitán-Solis, Nigel J. Taylor, Dimuth Siritunga, William Stevens, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Zinc deficiency in humans is a serious problem worldwide with an estimated one third of populations at risk for insufficient zinc in diet, which leads to impairment of cognitive abilities and immune system function. The goal of this research was to increase the bioavailable zinc in the edible portion of cassava roots to improve the overall zinc nutrition of populations that rely on cassava as a dietary staple. To increase zinc concentrations, two Arabidopsis thaliana genes coding for ZIP1 and MTP1 were overexpressed with a tuber-specific or constitutive promoter. Eighteen transgenic events from four constructs, out of a total of …