Other Plant Sciences Commons^™

Functional Characterization Of Cinnamyl Alcohol Dehydrogenase And Caffeic Acid O-Methyltransferase In Brachypodium Distachyon, Gina M. Trabucco, Dominick A. Matos, Scott J. Lee, Aaron J. Saathoff, Henry D. Priest, Todd C. Mockler, Gautam Sarath, Samuel P. Hazen

Department of Agronomy and Horticulture: Faculty Publications

Background: Lignin is a significant barrier in the conversion of plant biomass to bioethanol. Cinnamyl alcohol dehydrogenase (CAD) and caffeic acid O-methyltransferase (COMT) catalyze key steps in the pathway of lignin monomer biosynthesis. Brown midrib mutants in Zea mays and Sorghum bicolor with impaired CAD or COMT activity have attracted considerable agronomic interest for their altered lignin composition and improved digestibility. Here, we identified and functionally characterized candidate genes encoding CAD and COMT enzymes in the grass model species Brachypodium distachyon with the aim of improving crops for efficient biofuel production.

Results: We developed transgenic plants overexpressing artificial microRNA designed …

Transcriptome Analysis Of Two Buffalograss Cultivars, Michael Wachholtz, Tiffany Heng-Moss, Paul Twigg, Lisa Baird, Guoqing Lu, Keenan Amundsen

Department of Agronomy and Horticulture: Faculty Publications

Background: Buffalograss [Buchloë dactyloides (Nutt.) Engel. syn. Bouteloua dactyloides (Nutt.) Columbus] is a United States native turfgrass species that requires less irrigation, fungicides and pesticides compared to more commonly used turfgrass species. In areas where water is limited, interest in this grass species for lawns is increasing. While several buffalograss cultivars have been developed through buffalograss breeding, the timeframe for new cultivar development is long and is limited by a lack of useful genetic resources. Two high throughput next-generation sequencing techniques were used to increase the genomic resources available for buffalograss.

Results: Total RNA was extracted and …

Complete Plastid Genomes From Ophioglossum Californicum, Psilotum Nudum, And Equisetum Hyemale Reveal An Ancestral Land Plant Genome Structure And Resolve The Position Of Equisetales Among Monilophytes, Felix Grewe, Wenhu Guo, Emily A. Gubbels, A Katie Hansen, Jeffrey P. Mower

Department of Agronomy and Horticulture: Faculty Publications

Background: Plastid genome structure and content is remarkably conserved in land plants. This widespread conservation has facilitated taxon-rich phylogenetic analyses that have resolved organismal relationships among many land plant groups. However, the relationships among major fern lineages, especially the placement of Equisetales, remain enigmatic.

Results: In order to understand the evolution of plastid genomes and to establish phylogenetic relationships among ferns, we sequenced the plastid genomes from three early diverging species: Equisetum hyemale (Equisetales), Ophioglossum californicum (Ophioglossales), and Psilotum nudum (Psilotales). A comparison of fern plastid genomes showed that some lineages have retained inverted repeat (IR) boundaries originating …

Indoor Application Of Attractive Toxic Sugar Bait (Atsb) In Combination With Mosquito Nets For Control Of Pyrethroid-Resistant Mosquitoes, Zachary P. Stewart, Richard M. Oxborough, Patrick K. Tungu, Matthew J. Kirby, Mark W. Rowland, Seth R. Irish

Department of Agronomy and Horticulture: Faculty Publications

Background: Attractive toxic sugar bait (ATSB) sprayed onto vegetation has been successful in controlling Anopheles mosquitoes outdoors. Indoor application of ATSB has yet to be explored. The purpose of this study was to determine whether ATSB stations positioned indoors have the potential to kill host-seeking mosquitoes and constitute a new approach to control of mosquito-borne diseases.

Methods: Insecticides were mixed with dyed sugar solution and tested as toxic baits against Anopheles arabiensis, An. Gambiae s.s. and Culex quinquefasciatus in feeding bioassay tests to identify suitable attractant-insecticide combinations. The most promising ATSB candidates were then trialed in experimental …

Nutrient Partitioning And Grain Yield Of Tanam-Rnai Wheat Under Abiotic Stress, Mary J. Guttieri, Ricardo J. Stein, Brian M. Waters

Department of Agronomy and Horticulture: Faculty Publications

Aims — Decreased expression of TaNAM genes by RNAi results in delayed senescence and decreased grain protein, iron, and zinc concentrations. Here, we determined whether NAM expression level alters onset of senescence under stress conditions, whether delayed senescence in the TaNAM-RNAi line resulted in improved tolerance to post-anthesis abiotic stress, and determined the effects of post-anthesis abiotic stress on N and mineral remobilization and partitioning to grain.

Methods — Greenhouse-grown WT and TaNAM-RNAi wheat were characterized in two studies: three levels of N fertility or water limitation during grain fill. Studies were conducted under both optimal and heat stress …

Genetic Mapping And Confirmation Of Quantitative Trait Loci For Seed Protein And Oil Contents And Seed Weight In Soybean, Safiullah M. Pathan, Tri Vuong, Kerry Clark, Jeong-Dong Lee, J. Grover Shannon, Craig A. Roberts, Mark R. Ellersieck, Joseph W. Burton, P. B. Cregan, David L. Hyten, Henry T. Nguyen, David A. Sleper

Department of Agronomy and Horticulture: Faculty Publications

Demand for soybean [Glycine max (L.) Merr.] meal has increased worldwide and soybean importers often offer premiums for soybean containing higher contents of protein and oil. Objectives were to detect quantitative trait loci (QTL) associated with soybean seed protein, oil, and seed weight in a soybean mapping population and confirm detected QTL across genetic backgrounds and environments. Two populations of 216 and 156 recombinant inbred lines were developed from Magellan × PI 438489B and Magellan × PI 567516C crosses, respectively, and grown in two Missouri environments in 2008. More than 900 simple sequence repeat (SSR) and single nucleotide polymorphism …

Soybean Seed Amino Acid Content Qtl Detected Using The Universal Soy Linkage Panel 1.0 With 1,536 Snps, Benjamin D. Fallen, Catherine N. Hatcher, Fred L. Allen, Dean A. Kopsell, Arnold M. Saxton, Pengyin Chen, Stella K. Kantartzi, P. B. Cregan, D. L. Hyten, Vincent R. Pantalone

Department of Agronomy and Horticulture: Faculty Publications

Soybean [Glycine max (L.) Merr.] is the primary source of meal used in animal feed in the U.S. However, few studies have been conducted to evaluate genomic regions controlling amino acid composition is soybean. Designing soybean seed compositions that will benefit animal production is essential. The objective of this study was to identify genomic regions controlling essential and non-essential amino acid composition in soybean seed proteins. To achieve this objective, 282 F_5:9 recombinant inbred lines (RILs) developed from a cross of Essex × Williams 82 were used. Ground soybean seed samples were analyzed for amino acids and statistically …

Development And Evaluation Of Soysnp50k, A High-Density Genotyping Array For Soybean, 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 objective of this research was to identify single nucleotide polymorphisms (SNPs) and to develop an Illumina Infinium BeadChip that contained over 50,000 SNPs from soybean (Glycine max L. Merr.). A total of 498,921,777 reads 35–45 bp in length were obtained from DNA sequence analysis of reduced representation libraries from several soybean accessions which included six cultivated and two wild soybean (G. soja Sieb. et Zucc.) genotypes. These reads were mapped to the soybean whole genome sequence and 209,903 SNPs were identified. After applying several filters, a total of 146,161 of the 209,903 SNPs were determined to be …

The Plant Science Decadal Vision: Response To The Martin Commentary, David Stern, Sally Ann Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

The plant science community is being called upon as never before to carry out research that addresses challenges in food, climate, and health, to educate a populace inundated with science misinformation, and to excite and recruit a new generation of scientists from among that populace, all while investments in basic research are stagnant or even declining in many countries. The Decadal Vision (Plant Science Research Summit, 2013) represents a response from that community, one that launches a meaningful and ongoing dialogue about how best to accomplish these goals. In that spirit, we welcome this thoughtful commentary by Cathie Martin (Martin, …

Chloroplast Division Protein Arc3 Regulates Chloroplast Ftsz-Ring Assembly And Positioning In Arabidopsis Through Interaction With Ftsz2, Min Zhang, Aaron J. Schmitz, Deena K. Kadirjan-Kalbach, Allan D. Terbush, Katherine W. Osteryoung

Department of Agronomy and Horticulture: Faculty Publications

Chloroplast division is initiated by assembly of a mid-chloroplast FtsZ (Z) ring comprising two cytoskeletal proteins, FtsZ1 and FtsZ2. The division-site regulators ACCUMULATION AND REPLICATION OF CHLOROPLASTS3 (ARC3), MinD1, and MinE1 restrict division to the mid-plastid, but their roles are poorly understood. Using genetic analyses in Arabidopsis thaliana, we show that ARC3 mediates division-site placement by inhibiting Z-ring assembly, and MinD1 and MinE1 function through ARC3. ftsZ1 null mutants exhibited some mid-plastid FtsZ2 rings and constrictions, whereas neither constrictions nor FtsZ1 rings were observed in mutants lacking FtsZ2, suggesting FtsZ2 is the primary determinant of Z-ring assembly in vivo. arc3 …

Resource Allocation For Maximizing Prediction Accuracy And Genetic Gain Of Genomic Selection In Plant Breeding: A Simulation Experiment, Aaron Lorenz

Department of Agronomy and Horticulture: Faculty Publications

Allocating resources between population size and replication affects both genetic gain through phenotypic selection and quantitative trait loci detection power and effect estimation accuracy for marker-assisted selection (MAS). It is well known that because alleles are replicated across individuals in quantitative trait loci mapping and MAS, more resources should be allocated to increasing population size compared with phenotypic selection. Genomic selection is a form of MAS using all marker information simultaneously to predict individual genetic values for complex traits and has widely been found superior to MAS. No studies have explicitly investigated how resource allocation decisions affect success of genomic …

Evaluation Of Public Sweet Sorghum A-Lines For Use In Hybrid Production, Jeffrey F. Pedersen, Scott E. Sattler, William F. Anderson

Department of Agronomy and Horticulture: Faculty Publications

A fundamental need for commercialization of sweet sorghum [Sorghum bicolor (L.) Moench] as a bioenergy crop is an adequate seed supply, which will require development of hybrid varieties using dwarf seed-parent lines. A set of six public sweet sorghum A-lines (Dwarf Kansas Sourless, KS9, N36, N38, N39, and N4692) were crossed with a set of six public sweet sorghum cultivars (Brawley, Kansas Collier, Dale, Sugar Drip, Waconia, and Wray). Grain, fiber, and sugar yields were determined, and conversion formulas were applied to estimate ethanol yields. Hybrids were grown in fields at Ithaca, NE, USA, in 1983– 1984 fertilized with …

Yield Gap Analysis—Rationale, Methods And Applications—Introduction To The Special Issue, M.K. Van Ittersum, Kenneth Cassman

Department of Agronomy and Horticulture: Faculty Publications

Yield gap analysis is an increasingly popular concept. It is a powerful method to reveal and understand the biophysical opportunities to meet the projected increase in demand for agricultural products towards 2050, and to support decision making on research, policies, development and investment that is needed. This Special Issue presents the state-of-the-art about concepts, methods and applications of yield gap analysis. The methodological papers emphasize the need for agronomically sound and relevant analyses, from local to global scales. The fourteen papers provide examples of applications to different crops, climate zones and production conditions, at various spatial extents and with different …

Agricultural Innovation To Protect The Environment, Jeffrey Sayer, Kenneth Cassman

Department of Agronomy and Horticulture: Faculty Publications

In a world of 9.5 billion people, global demand for food, fiber, and biofuels has to be met with minimal possible increases in land, water, fossil fuels, and the minerals used to produce fertilizers (1–4). The problem is debated at three levels: first, that agriculture will not be able to produce enough because it will come up against both biophysical and environmental limits that restrict yields (3, 5, 6); second, that the need to expand and intensify agriculture will destroy the broader environmental values of forests, wetlands, marine systems, and their associated biodiversity (7–9); and third, that there are institutional …

New Technologies Reduce Greenhouse Gas Emissions From Nitrogenous Fertilizer In China, Wei-Feng Feng, Zheng-Xia Dou, Pan He, Xiao-Tang Ju, David Powlson, Dave Chadwick, David Norse, Yue-Lai Lu, Ying Zhang, Liang Wu, Xin-Ping Chen, Kenneth Cassman, Fu-Suo Zhang

Department of Agronomy and Horticulture: Faculty Publications

Synthetic nitrogen (N) fertilizer has played a key role in enhancing food production and keeping half of the world’s population adequately fed. However, decades of N fertilizer overuse in many parts of the world have contributed to soil, water, and air pollution; reducing excessive N losses and emissions is a central environmental challenge in the 21st century. China’s participation is essential to global efforts in reducing N-related greenhouse gas (GHG) emissions because China is the largest producer and consumer of fertilizer N. To evaluate the impact of China’s use of N fertilizer, we quantify the carbon footprint of China’s N …

Influence Of Two Herbicides On Soybean Cyst Nematode (Heterodera Glycines) Reproduction On Henbit (Lamium Amplexicaule) Roots, Rodrigo Werle, Mark L. Bernards, Loren J. Giesler, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Soybean cyst nematode (SCN) is the most yield-limiting pathogen of soybean in the United States. Henbit is a prevalent winter annual weed species in no-till fields and is reported to be an alternative host of SCN. A greenhouse study was conducted to evaluate how the development of SCN on henbit roots was affected by herbicide mode of action and time of herbicide application. Henbit plants were grown in watertight pots placed in a water bath bench that kept soil temperature constant (27 6 1 C) during the study. Ten d after transplanting, pots were inoculated with approximately 1,000 SCN eggs. …

Maternal Environment Effects On Phenolic Defenses In Abutilon Theophrasti Seeds, Brian J. Schutte, Sam E. Wortman, John L. Lindquist, Adam S. Davis

Department of Agronomy and Horticulture: Faculty Publications

A class of phenolic compounds, ortho-dihydroxyphenols (hereafter “o-DHP”), has been implicated with seed survival. Based on expectations of the growth-differentiation balance hypothesis, we predicted that seed o-DHP concentration exhibits a curvilinear response to increasing resource availability in the maternal environment, with maximum o-DHP occurring at moderate resource levels. To test this hypothesis, Abutilon theophrasti seeds were produced under field conditions at two locations. Each location included twelve maternal environments established through factorial combinations of soil compost (+/−), species assemblage (A. theophrasti with and without maize), and soil nitrogen fertilizer (0, 0.5× or 1× local …

Seed Burial Physical Environment Explains Departures From Regional Hydrothermal Model Of Giant Ragweed (Ambrosia Trifida) Seedling Emergence In U.S. Midwest, Adam S. Davis, Sharon Clay, John Cardina, Anita Dille, Frank Forcella, John Lindquist, Christy Sprague

Department of Agronomy and Horticulture: Faculty Publications

Robust predictions of weed seedling emergence from the soil seedbank are needed to aid weed management. A common seed accession (Illinois) of giant ragweed was buried in replicate experimental gardens over 18 site years in Illinois, Michigan, Kansas, Nebraska, Ohio, and South Dakota to examine the importance of site and climate variability by year on seedling emergence. In a nonlinear mixed-effects modeling approach, we used a flexible sigmoidal function (Weibull) to model giant ragweed cumulative seedling emergence in relation to hydrothermal time accumulated in each site-year. An iterative search method across a range of base temperature (T_b) …

Genetic Dissection Of Yield And Its Component Traits Using High-Density Composite Map Of Wheat Chromosome 3a: Bridging Gaps Between Qtls And Underlying Genes, Sachin Rustgi, Mustafa N. Shafqat, Neeraj Kumar, P. Stephen Baenziger, M. Liakat Ali, Ismail M. Dweikat, B. Todd Campbell, Kulvinder Singh Gill

Department of Agronomy and Horticulture: Faculty Publications

Earlier we identified wheat (Triticum aestivum L.) chromosome 3A as a major determinant of grain yield and its component traits. In the present study, a high-density genetic linkage map of 81 chromosome 3A-specific markers was developed to increase the precision of previously identified yield component QTLs, and to map QTLs for biomass-related traits. Many of the previously identified QTLs for yield and its component traits were confirmed and were localized to narrower intervals. Four novel QTLs one each for shoot biomass (Xcfa2262-Xbcd366), total biomass (wPt2740-Xcfa2076), kernels/spike (KPS) (Xwmc664-Xbarc67), and Pseudocercosporella induced lodging ( …

Dna Fingerprinting And Anastomosis Grouping Reveal Similar Genetic Diversity In Rhizoctonia Species Infecting Turfgrasses In The Transition Zone Of Usa, B. S. Amaradasa, B. J. Horvath, D. K. Lakshman, S. E. Warnke

Department of Agronomy and Horticulture: Faculty Publications

Rhizoctonia blight is a common and serious disease of many turfgrass species. The most widespread causal agent, Thanatephorus cucumeris (anamorph: R. solani), consists of several genetically different subpopulations. In addition, Waitea circinata varieties zeae, oryzae and circinata (anamorph: Rhizoctonia spp.) also can cause the disease. Accurate identification of the causal pathogen is important for effective management of the disease. It is challenging to distinguish the specific causal pathogen based on disease symptoms or macroscopic and microscopic morphology. Traditional methods such as anastomosis reactions with tester isolates are time consuming and sometimes difficult to interpret. In the present study universally …

Distinguishing Between Yield Advances And Yield Plateaus In Historical Crop Production Trends, Patricio Grassini, Kent M. Eskridge, Kenneth Cassman

Department of Agronomy and Horticulture: Faculty Publications

Food security and land required for food production largely depend on rate of yield gain of major cereal crops. Previous projections of food security are often more optimistic than what historical yield trends would support. Many econometric projections of future food production assume compound rates of yield gain, which are not consistent with historical yield trends. Here we provide a framework to characterize past yield trends and show that linear trajectories adequately describe past yield trends, which means the relative rate of gain decreases over time. Furthermore, there is evidence of yield plateaus or abrupt decreases in rate of yield …

Marketing Contracts, Overconfidence, And Timing In The Canadian Wheat Market, Fabio L. Mattos, Stefanie A. Fryza

Department of Agronomy and Horticulture: Faculty Publications

This paper investigates factors that impact marketing performance in the Canadian wheat market. Using data provided by the Canadian Wheat Board (CWB) for six crop years, results indicate that producers were not able to profitably use all marketing contracts offered by the CWB, earlier pricing tended to generate better performance, there was a negative relationship between activeness and performance (suggesting overconfidence in marketing skills), and performance was generally worse in volatile crop years. Further analysis reveals some of these findings differ when outperforming and underperforming producers are investigated separately, particularly with respect to activeness and volatility.

Initial Changes In Species Cover Following Savanna Restoration Treatments In Western Iowa, David A. Mckenzie, Thomas B. Bragg, David M. Sutherland

Great Plains Research: A Journal of Natural and Social Sciences (through 2013)

Study areas in the Iowa Loess Hills were used to evaluate short-term responses of understory species to three treatment methods designed to facilitate restoration of Quercus macrocarpa savanna. Treatments included burning alone, burning with thinning, and burning with clear-cutting. Plant abundance and diversity were compared before treatment and one year after treatment. Ninety-nine plant species were identified during the study, of which 40 were new following treatment, although most of these were forest associates. Increases in diversity of understory species were observed after treatment, particularly in plots with combined burning and thinning. The forb group was most consistent in response …

Composting Manure And Other Organic Materials, Charles S. Wortmann, Charles A. Shapiro

Department of Agronomy and Horticulture: Faculty Publications

The Composting Process

Composting is the aerobic decomposition of manure or other organic materials in the thermophilic temperature range (104-149oF). Composted material is odorless, fine-textured, and low-moisture. It can be bagged and sold for use in gardens or nurseries, or used as fertilizer on cropland with little odor or fly breeding potential. Composting improves the handling characteristics of any organic residue by reducing its volume and weight. Composting can kill pathogens and weed seeds.

Disadvantages of composting organic residues include loss of nitrogen and other nutrients, time for processing, cost for handling equipment, available land for composting, odors, marketing, diversion …

Escape From Preferential Retention Following Repeated Whole Genome Duplications In Plants, James C. Schnable, Xiaowu Wang, J. Chris Pires, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

The well supported gene dosage hypothesis predicts that genes encoding proteins engaged in dose–sensitive interactions cannot be reduced back to single copies once all interacting partners are simultaneously duplicated in a whole genome duplication. The genomes of extant flowering plants are the result of many sequential rounds of whole genome duplication, yet the fraction of genomes devoted to encoding complex molecular machines does not increase as fast as expected through multiple rounds of whole genome duplications. Using parallel interspecies genomic comparisons in the grasses and crucifers, we demonstrate that genes retained as duplicates following a whole genome duplication have only …

2011 Vadose Zone Nitrate Study At Hastings, Ne (Revised), Roy F. Spalding, Martin Toavs

Department of Agronomy and Horticulture: Faculty Publications

In an effort to assist Hastings Utilities in the management of their well-head protection area (WHP A) and to protect the groundwater from the impact of nitrate loading from potential nonpoint and point sources, Hastings Utilities subcontracted with the Department of Agronomy and Horticulture at the University of Nebraska for deep vadose zone coring. Continuous 60-ft soil cores were obtained at 36 sites within the apparent WHP A (Figure 1). The sites were selected by Marty Stange on the basis of availability for sampling, management, landuse , cropping history, and location within the WHPA. Nitrogen analyses of these deep soil …

Genome-Wide Analysis Of Syntenic Gene Deletion In The Grasses, James C. Schnable, Michael Freeling, Eric Lyons

Department of Agronomy and Horticulture: Faculty Publications

The grasses, Poaceae, are one of the largest and most successful angiosperm families. Like many radiations of flowering plants, the divergence of the major grass lineages was preceded by a whole-genome duplication (WGD), although these events are not rare for flowering plants. By combining identification of syntenic gene blocks with measures of gene pair divergence and different frequencies of ancient gene loss, we have separated the two subgenomes present in modern grasses. Reciprocal loss of duplicated genes or genomic regions has been hypothesized to reproductively isolate populations and, thus, speciation. However, in contrast to previous studies in yeast and teleost …

Brown Midrib2 (Bmr2) Encodes The Major 4-Coumarate: Coenzyme A Ligase Involved In Lignin Biosynthesis In Sorghum (Sorghum Bicolor (L.) Moench), Ana Saballos, Scott Sattler, Emiliano Sanchez, Timothy P. Foster, Zhanguo Xin, Chulhee Kang, Jeffrey F. Pedersen, Wilfred Vermerris

Department of Agronomy and Horticulture: Faculty Publications

Successful modification of plant cell-wall composition without compromising plant integrity is dependent on being able to modify the expression of specific genes, but this can be very challenging when the target genes are members of multigene families. 4-coumarate:CoA ligase (4CL) catalyzes the formation of 4-coumaroyl CoA, a precursor of both flavonoids and monolignols, and is an attractive target for transgenic down-regulation aimed at improving agro-industrial properties. Inconsistent phenotypes of transgenic plants have been attributed to variable levels of down-regulation of multiple 4CL genes. Phylogenetic analysis of the sorghum genome revealed 24 4CL(-like) proteins, five of which cluster with bona fide …

Quantitative Trait Locus Analysis Of Saturated Fatty Acids In A Population Of Recombinant Inbred Lines Of Soybean, Xianzhi Wang, Guo-Liang Jiang, Marci Green, Roy A. Scott, D. L. Hyten, P. B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Soybean [Glycine max (L.) Merr.] is an important crop which contributes approximately 58% of the world’s oilseed production. Palmitic and stearic acids are the two main saturated fatty acids in soybean oil. Different levels of saturated fatty acids are desired depending on the uses of the soybean oil. Vegetable oil low in saturated fatty acids is preferred for human consumption, while for industrial applications, soybean oil with higher levels of saturated fatty acids is more suitable. The objectives of this study were to identify quantitative trait loci (QTL) for saturated fatty acids, analyze the genetic effects of single QTL …

Natural Variation In Iron Use Efficiency And Mineral Remobilization In Cucumber (Cucumis Sativus), Brian M. Waters, Grace Troupe

Department of Agronomy and Horticulture: Faculty Publications

Aims: Iron (Fe) is an essential micronutrient, and plant-available Fe is often limited in alkaline soils. Fe deficiency chlorosis decreases plant growth and yield. Identification of germplasm with high and low Fe use efficiency will allow studies to better understand the genetic components for breeding Fe efficient varieties.

Methods: A screen using cucumber (Cucumis sativus) seedlings identified varieties that maintained contrasting levels of chlorophyll under Fe deficiency or limitation. A time course of mineral dynamics in cotyledons was conducted.

Results: The variety Ashley had the highest chlorophyll under Fe deficiency and per unit Fe in the leaf, while …