Botany Commons^™

Can Sub-Saharan Africa Feed Itself?, Martin K. Van Ittersum, Lenny G. J. Van Bussel, Joost Wolf, Patricio Grassini, Justin Van Wart, Nicolas Guilpart, Lieven Claessens, Hugo De Groot, Keith Wiebe, Daniel Mason-D'Croz, Haishun Yang, Hendrik Boogard, Pepijn A. J. Van Oort, Marloes P. Van Loon, Kazuki Saito, Ochieng Adimo, Samuel Adjei-Nsiah, Alhassane Agali, Abdullahi Bala, Regis Chikowo, Kayuki Kaizzi, Mamoutou Kouressy, Joachim H. J. R. Makoi, Korodjouma Ouattara, Kindie Tesfaye, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

Although global food demand is expected to increase 60% by 2050 compared with 2005/2007, the rise will be much greater in sub- Saharan Africa (SSA). Indeed, SSA is the region at greatest food security risk because by 2050 its population will increase 2.5-fold and demand for cereals approximately triple, whereas current levels of cereal consumption already depend on substantial imports. At issue is whether SSA can meet this vast increase in cereal demand without greater reliance on cereal imports or major expansion of agricultural area and associated biodiversity loss and greenhouse gas emissions. Recent studies indicate that the global increase …

Mechanism Of Resistance, Gene Flow, And Integrated Management Of Ragweeds (Ambrosia) In Nebraska, Zahoor Ahmad Ganie

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

Common ragweed (Ambrosia artemisiifolia L.) and giant ragweed (Ambrosia trifida L.) are native annual broadleaf weeds in the United States found in diverse agroecosystems, roadsides, and wastelands. They are economically important weed species in the Midwest and sources of pollen allergies. Confirmation of glyphosate-resistant (GR) common and giant ragweed in Nebraska justified the need to determine the mechanism of resistance, dispersal of resistance genes via pollen, and to develop an integrated management program. The objectives of this research were to: 1) determine the mechanism of glyphosate resistance in a common ragweed biotype from Nebraska; 2) evaluate the effect …

Modeling Long-Term Corn Yield Response To Nitrogen Rate And Crop Rotation, Laila A. Puntel, John E. Sawyer, Daniel W. Barker, Ranae Dietzel, Hanna Poffenbarger, Michael J. Castellano, Kenneth J. Moore, Peter J. Thorburn, Sotirios V. Archontoulis

Department of Agronomy and Horticulture: Faculty Publications

Improved prediction of optimal N fertilizer rates for corn (Zea mays L.) can reduce N losses and increase profits. We tested the ability of the Agricultural Production Systems sIMulator (APSIM) to simulate corn and soybean (Glycine max L.) yields, the economic optimum N rate (EONR) using a 16-year field-experiment dataset from central Iowa, USA that included two crop sequences (continuous corn and soybean-corn) and five N fertilizer rates (0, 67, 134, 201, and 268 kg N ha^-1) applied to corn. Our objectives were to: (a) quantify model prediction accuracy before and after calibration, and report calibration steps; (b) …

Characterization And Development Mechanism Of Apios Americana Tuber Starch, Hanyu Yangchen, Vikas Belamkar, Steven B. Cannon, Jay-Lin Jane

Department of Agronomy and Horticulture: Faculty Publications

Apios americana is a wild legume-bearing plant with edible tubers. Domestication of Apios is in progress because of the superior nutritional value and health benefits of the tuber. Objectives of this study were to: (1) characterize physicochemical properties of the Apios tuber starch; and (2) understand differences in starch structures and properties between the mother (seed) and child (progeny) tubers and the mechanism of starch development. Granules of the Apios tuber starch displayed ellipsoidal, rod, or kidney shape with diameter ranges of 1–30 m. The mother tuber starches displayed greater percentage crystallinity, larger gelatinization enthalpy-changes, longer branch-chain lengths of amylopectin, …

Genomics-Assisted Characterization Of A Breeding Collection Of Apios Americana, An Edible Tuberous Legume, Vikas Belamkar, Andrew Farmer, Nathan T. Weeks, Scott R. Kalberer, William J. Blackmon, Steven B. Cannon

Department of Agronomy and Horticulture: Faculty Publications

For species with potential as new crops, rapid improvement may be facilitated by new genomic methods. Apios (Apios americana Medik.), once a staple food source of Native American Indians, produces protein-rich tubers, tolerates a wide range of soils, and symbiotically fixes nitrogen. We report the first high-quality de novo transcriptome assembly, an expression atlas, and a set of 58,154 SNP and 39,609 gene expression markers (GEMs) for characterization of a breeding collection. Both SNPs and GEMs identify six genotypic clusters in the collection. Transcripts mapped to the Phaseolus vulgaris genome–another phaseoloid legume with the same chromosome number–provide provisional genetic …

Plants Having Increased Bomass And Methods For Making The Same, Aleel K. Grennan, Donald R. Ort, Stephen Patrick Moose, Damla D. Bilgin, Thomas Clemente, Fredy Altpeter, Stephen P. Long

Department of Agronomy and Horticulture: Faculty Publications

The impact of plastid size change in both monocot and dicot plants has been examined. In both, when plastid size is increased there is an increase in biomass relative to the parental lines. Thus, provided herein are methods for increasing the biomass of a plant, comprising decreasing the expression of at least one plastid division protein in a plant. Optionally, the level of chlorophyll in the plant is also reduced.

Arboretum Annual Report 2015-2016, Glenn Dreyer

Annual Reports

No abstract provided.

Cross Species Selection Scans Identify Components Of C4 Photosynthesis In The Grasses, Pu Huang, Anthony J. Studer, James C. Schnable, Elizabeth A. Kellogg, Thomas P. Brutnell

Department of Agronomy and Horticulture: Faculty Publications

C₄ photosynthesis is perhaps one of the best examples of convergent adaptive evolution with over 25 independent origins in the grasses (Poaceae) alone. The availability of high quality grass genome sequences presents new opportunities to explore the mechanisms underlying this complex trait using evolutionary biology-based approaches. In this study, we performed genome-wide cross-species selection scans in C₄ lineages to facilitate discovery of C₄ genes. The study was enabled by the well conserved collinearity of grass genomes and the recently sequenced genome of a C₃ panicoid grass, Dichanthelium oligosanthes. This method, in contrast to previous studies, …

Herbicide Resistantsorghum Mutants, Ismail M. Dweikat

Department of Agronomy and Horticulture: Faculty Publications

This disclosure provides for four different sorghum mutants that exhibit resistance to ALS-inhibiting herbicides. This dis closure also provides for methods of using such Sorghum mutants that exhibit resistance to ALS-inhibiting herbicides in breeding methods to make Sorghum hybrids, varieties, or lines. The Sorghum hybrids, varieties, and lines provided in this disclosure can be used in methods of controlling weeds.

Long-Term Sandhills Prairie Responses To Precipitation, Temperature, And Cattle Stocking Rate, John A. Guretzky, Cheryl Dunn, Heidi L. Hillhouse

Department of Agronomy and Horticulture: Faculty Publications

Understanding of Sandhills prairie, the most expansive sand dune region stabilized by perennial grasses in the Western Hemisphere, is limited by lack of long-term vegetation data. We used a 26-year dataset to evaluate Sandhills prairie responses to yearto- year variation in precipitation, temperature, and cattle stocking rate. Basal cover, a measurement that is constant seasonally and used to detect long-term changes in bunchgrass vegetation, was measured in 38–40 permanent plots positioned along four transects spanning 769 ha from 1979 to 2007. Across this period, total basal cover averaged 2.4 % and was dominated by warm-season grasses (81.1 %). Schizachyrium scoparium …

Effective Establishment Of Native Grasses On Roadsides In New England, Yulia Kuzovkina, John Campanelli, Cristian Schulthess, Robert Ricard, Glenn Dreyer

Other Publications and Reports

No abstract provided.

Information Thermodynamics Of Cytosine Dna Methylation, Robersy Sanchez Rodriguez, Sally Ann Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

Cytosine DNA methylation (CDM) is a stable epigenetic modification to the genome and a widespread regulatory process in living organisms that involves multicomponent molecular machines. Genome-wide cytosine methylation patterning participates in the epigenetic reprogramming of a cell, suggesting that the biological information contained within methylation positions may be amenable to decoding. Adaptation to a new cellular or organismal environment also implies the potential for genome-wide redistribution of CDM changes that will ensure the stability of DNA molecules. This raises the question of whether or not we would be able to sort out the regulatory methylation signals from the CDM background …

Ws-2 Introgression In A Proportion Of Arabidopsis Thaliana Col-0 Stock Seed Produces Specific Phenotypes And Highlights The Importance Of Routine Genetic Verification, Mon-Ray Shao, Vikas Shedge, Hardik Kundariya, Fredric R. Lehle, Sally Ann Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

Arabidopsis thaliana is an important model organism with a robust network of resources that has been of enormous value to the plant science research community. The use of isogenic material as a reference point or control is critical for many types of experiments in plant molecular biology and genetics. Recently, we noticed that some seed from a common source of the widely used Columbia-0 (Col-0) strain gave rise to plants showing features atypical for this strain. Whole-genome DNA-sequencing and allelespecific PCR assays confirmed that the abnormal individuals contain multiple introgressions from the ecotype Wassilewskija-2 (Ws-2), as described below. This …

Student-Conducted Farmer Video Interviews, Jenn K. Simons, Justin Van Wart, Charles Francis, Kristyn Harms

Department of Agronomy and Horticulture: Faculty Publications

High school agricultural education teachers have expressed concern about the lack of easily accessible educational materials dealing with contemporary topics in sustainable agriculture. There are numerous textbooks and monographs available for farmers and students at the college level, including the highly practical resources available from the Sustainable Agriculture Research and Education (SARE) book series on soil fertility (Magdoff and van Es, 2010), cover crops (Bowman et al., 2007) and building a farm business (DiGiacomo et al., 2003), among others. Although these are full of color photos and easily accessible graphs and tables, they are still in the print media category. …

Corn Era Hybrid Response To Nitrogen Fertilization, Krishna P. Woli, Matthew J. Boyer, Roger Wesley Elmore, John E. Sawyer, Lori J. Abendroth, Daniel W. Barker

Department of Agronomy and Horticulture: Faculty Publications

Corn (Zea mays L.) N use is of continued interest due to agronomic performance and environmental issues. This 2-yr study evaluated era hybrid response to fertilizer nitrogen (FN) rate in a factorial arrangement of one popular hybrid per five decades (1960–2000 eras) and five N rates (0–224 kg N ha^–1). An additional hybrid per era was grown at 168 kg N ha^–1. Hybrid productivity and nitrogen use efficiency (NUE) increased across the eras, but not between the 1980 and 1990 eras. Grain yield (GY) increased 65% and total plant biomass 43%, however, total plant nitrogen …

Letter From The Dean, Lona Robertson

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

No abstract provided.

Contents, Discovery Editors

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

No abstract provided.

Discovery: The Student Journal Of Dale Bumpers College Of Agricultural, Food And Life Sciences - Volume 17 2016, Several Authors

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

No abstract provided.

The Draft Genome Of The C3 Panicoid Grass Species Dichanthelium Oligosanthes, Anthony J. Studer, James C. Schnable, Sarit Weissmann, Allison R. Kolbe, Michael R. Mckain, Ying Shao, Asaph B. Cousins, Elizabeth A. Kellogg, Thomas P. Brutnell

Department of Agronomy and Horticulture: Faculty Publications

Background: Comparisons between C₃ and C₄ grasses often utilize C₃ species from the subfamilies Ehrhartoideae or Pooideae and C₄ species from the subfamily Panicoideae, two clades that diverged over 50 million years ago. The divergence of the C₃ panicoid grass Dichanthelium oligosanthes from the independent C₄ lineages represented by Setaria viridis and Sorghum bicolor occurred approximately 15 million years ago, which is significantly more recent than members of the Bambusoideae, Ehrhartoideae, and Pooideae subfamilies. D. oligosanthes is ideally placed within the panicoid clade for comparative studies of C₃ and C₄ grasses.

Results: …

Predicting Long-Term Cover Crop Impacts On Soil Quality Using A Cropping Systems Model, Fernando E. Miguez, Sotirios Archontoulis, Andrea D. Basche

Department of Agronomy and Horticulture: Faculty Publications

Increased attention is being paid to cover crops as an option to reduce water pollution and decrease soil degradation in Iowa. More producers are experimenting with cover crops to increase soil productivity. However, when this project began there was little research to demonstrate the long-term impacts that cover crops have on crop yields. There were no estimates to quantify how much environmental benefit a cover crop could provide in terms of erosion and soil carbon changes. Such estimates are beneficial to demonstrate the long-term improvements that a cover crop affords in Iowa, particularly for corn-soybean rotations where the winter planting …

Genomic Prediction Models For Grain Yield Of Spring Bread Wheat In Diverse Agro-Ecological Zones, C. Saint Pierre, Juan Burgueño, Jose Crossa, G. Fuentes Dávila, P. Figueroa López, E. Solís Moya, J. Ireta Moreno, V. M. Hernández Muela, V. M. Zamora Villa, P. Vikram, K. Mathews, C. Sansaloni, D. Sehgal, Diego Jarquin, P. Wenzl, Sukhwinder Singh

Department of Agronomy and Horticulture: Faculty Publications

Genomic and pedigree predictions for grain yield and agronomic traits were carried out using high density molecular data on a set of 803 spring wheat lines that were evaluated in 5 sites characterized by several environmental co-variables. Seven statistical models were tested using two random cross-validations schemes. Two other prediction problems were studied, namely predicting the lines’ performance at one site with another (pairwise-site) and at untested sites (leave-one-site-out). Grain yield ranged from 3.7 to 9.0 t ha⁻¹ across sites. The best predictability was observed when genotypic and pedigree data were included in the models and their interaction with …

Registration Of ‘Ne05548’ (Husker Genetics Brand Panhandle) Hard Red Winter Wheat, P. Stephen Baenziger, R. A. Graybosch, T. Regassa, R. N. Klein, Greg R. Kruger, D. K. Santra, L. Xu, D. J. Rose, S. N. Wegulo, Y. Jin, J. Kolmer, G. L. Hein, M.-S. Chen, G. Bai, R. L. Bowden, J. Poland

Department of Agronomy and Horticulture: Faculty Publications

Western Nebraska wheat producers and those in adjacent areas want taller wheat (Triticum aestivum L.) cultivars that retain their height under drought for better harvestability. ‘NE05548’ (Reg. No. CV-1117, PI 670462) hard red winter wheat was developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA-ARS and released in January 2014 by the developing institutions. NE05548 was released primarily for its superior performance under rainfed conditions in western Nebraska and adjacent areas of the Great Plains and its tall plant stature. NE05548 was selected from the cross NE97426/NE98574 made in 1999 where the pedigree of NE97426 is ‘Brigantina’/2*‘Arapahoe’ …

A Population Of Deletion Mutants And An Integrated Mapping And Exome-Seq Pipeline For Gene Discovery In Maize, Shangang Jia, Aixia Li, Kyla Morton, Penny Avoles-Kianian, Shahryar F. Kianian, Chi Zhang, David Holding

Department of Agronomy and Horticulture: Faculty Publications

To better understand maize endosperm filling and maturation, we used gamma irradiation of the B73 maize reference line to generate mutants with opaque endosperm and reduced kernel fill phenotypes, and created a population of 1788 lines including 47 Mo17 × F2s showing stable, segregating and viable kernel phenotypes. For molecular characterization of the mutants, we developed a novel functional genomics platform that combined Bulked Segregant RNA and Exome sequencing (BSREx-seq) to map causative mutations and identify candidate genes within mapping intervals. To exemplify the utility of the mutants and provide proof-ofconcept for the bioinformatics platform, we present detailed characterization of …

Accuracy Of Genomic Prediction In Switchgrass (Panicum Virgatum L.) Improved By Accounting For Linkage Disequilibrium, Guillaume P. Ramstein, Joseph Evans, Shawn M. Kaeppler, Robert B. Mitchell, Kenneth P. Vogel, C. Robin Buell, Michael D. Casler

Department of Agronomy and Horticulture: Faculty Publications

Switchgrass is a relatively high-yielding and environmentally sustainable biomass crop, but further genetic gains in biomass yield must be achieved to make it an economically viable bioenergy feedstock. Genomic selection (GS) is an attractive technology to generate rapid genetic gains in switchgrass, and meet the goals of a substantial displacement of petroleum use with biofuels in the near future. In this study, we empirically assessed prediction procedures for genomic selection in two different populations, consisting of 137 and 110 half-sib families of switchgrass, tested in two locations in the United States for three agronomic traits: dry matter yield, plant height, …

Alkaline Stress And Iron Deficiency Regulate Iron Uptake And Riboflavin Synthesis Gene Expression Differently In Root And Leaf Tissue: Implications For Iron Deficiency Chlorosis, En-Jung Hsieh, Brian M. Waters

Department of Agronomy and Horticulture: Faculty Publications

Iron (Fe) is an essential mineral that has low solubility in alkaline soils, where its deficiency results in chlorosis. Whether low Fe supply and alkaline pH stress are equivalent is unclear, as they have not been treated as separate variables in molecular physiological studies. Additionally, molecular responses to these stresses have not been studied in leaf and root tissues simultaneously. We tested how plants with the Strategy I Fe uptake system respond to Fe deficiency at mildly acidic and alkaline pH by measuring root ferric chelate reductase (FCR) activity and expression of selected Fe uptake genes and riboflavin synthesis genes. …

Engaging Middle School Students Through Locally Focused Environmental Science Project-Based Learning, Andrea D. Basche, Vincent Genareo, Adah Leshem, Amy Kissell, Judith Pauley

Department of Agronomy and Horticulture: Faculty Publications

Increasing scientific literacy through education is one way to promote awareness of current environmental challenges, and can be enhanced through project-based learning (PBL), a pedagogical approach in which students explore authentic topics and demonstrate their learning publically. The National Science Foundation–funded GK–12 program at Iowa State University partnered doctoral-level graduate students (fellows) with middle and high school science teachers. This study analyzed results from one such middle school partnership in Iowa, where a PBL approach was implemented. Classroom practices focused on local environmental case studies of energy development, water pollution, soil science, climate change, plant biology, and ecology. Results from …

Impact Of Pre-Anthesis Water Deficit On Yield And Yield Components In Barley (Hordeum Vulgare L.) Plants Grown Under Controlled Conditions, Zakaria I. Al-Ajlouni, Ayed Al-Abdallat, Abdul Latief A. Al-Ghzawi, Jamal Y. Ayad, Jamal M. Abu Elenein, Nisreen A. Al-Quraan, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Drought at pre-anthesis stages can influence barley growth and results in yield losses. Therefore, it is important to understand how drought at pre-anthesis can affect different traits associated with yield reduction in barley. The objective of this study was to understand the relevance of the genetic background of major flowering time genes in barley plants subjected to pre-anthesis drought and its impact on yield and yield components. A glasshouse experiment using a Randomized Complete Block Design was conducted to investigate the effect of drought and its timing on yield and yield components on eleven barley genotypes, which were selected to …

Corn Response To Nitrogen Management Under Fully-Irrigated Vs. Water-Stressed Conditions, Bijesh Maharjan, Carl J. Rosen, John A. Lamb, Rodney T. Venterea

Department of Agronomy and Horticulture: Faculty Publications

Characterizing corn (Zea mays L.) grain yield (GY) response to N is critical for maximizing profits, increasing N use efficiency and minimizing environmental impacts. Although a large database of GY response to N exists for highly productive soils, few data exist for less productive soils. While changes in precipitation are expected in the future, few studies have compared GY response to varying N management practices under conditions of varying water availability. We measured GY and basal stalk nitrate nitrogen (BSN) at harvest using split-applied urea at eight N rates under fully-irrigated (FI) and water-stressed (WS) conditions in a loamy …

Shrubland Resilience Varies Across Soil Types: Implications For Operationalizing Resilience In Ecological Restoration, Carissa L. Wonkka, Dirac L. Twidwell, Jacob B. West, William E. Rogers

Department of Agronomy and Horticulture: Faculty Publications

In ecosystems with alternative stable states, restoration success can be thought of as overcoming the resilience of an undesirable state to promote an alternative state that yields greater ecosystem services. Since greater resilience of undesirable states translates into reduced restoration potential, quantifying differences in resilience can enhance restoration planning. In the context of shrub- encroached rangeland restoration, shrubland resilience is the capacity of a woody vegetated state to absorb management interventions designed to produce a more desirable grass- dominated state, and remain within its current regime. Therefore, differences in the resilience of a state can be quantifi ed in a …

Construction Of High Resolution Genetic Linkage Maps To Improve The Soybean Genome Sequence Assembly Glyma1.01, Qijian Song, Jerry Jenkins, Gaofeng Jia, David L. Hyten, Vince Pantalone, Scott A. Jackson, Jeremy Schmutz, Perry B. Cregan

Department of Agronomy and Horticulture: Faculty Publications

Background: A landmark in soybean research, Glyma1.01, the first whole genome sequence of variety Williams 82 (Glycine max L. Merr.) was completed in 2010 and is widely used. However, because the assembly was primarily built based on the linkage maps constructed with a limited number of markers and recombinant inbred lines (RILs), the assembled sequence, especially in some genomic regions with sparse numbers of anchoring markers, needs to be improved. Molecular markers are being used by researchers in the soybean community, however, with the updating of the Glyma1.01 build based on the high-resolution linkage maps resulting from this research, …