Botany Commons^™

Evaluation Of A Global Spring Wheat Panel For Stripe Rust: Resistance Loci Validation And Novel Resources Identification, Ibrahim Elbasyoni, Walid M. El-Orabey, Sabah Morsy, P. S. Baenziger, Zakaria Al Ajlouni4, Ismail M. Dweikat

Department of Agronomy and Horticulture: Faculty Publications

Stripe rust (incited by Puccinia striiformis f. sp. tritici) is airborne wheat (Triticum aestivum L.) disease with dynamic virulence evolution. Thus, anticipatory and continued screening in hotspot regions is crucial to identify new pathotypes and integrate new resistance resources to prevent potential disease epidemics. A global wheat panel consisting of 882 landraces and 912 improved accessions was evaluated in two locations in Egypt during 2016 and 2017. Five prevalent and aggressive pathotypes of stripe rust were used to inoculate the accessions during the two growing seasons and two locations under field conditions. The objectives were to evaluate the panel for …

Metabolic Dynamics Of Developing Rice Seeds Under High Night-Time Temperature Stress, Balpreet K. Dhatt, Nathan Abshire, Puneet Paul, Kalani Hasanthika, Jaspreet Sandhu, Qi Zhang, Toshihiro Obata, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

High temperature stress during rice reproductive development results in yield losses. Reduced grain yield and grain quality has been associated with high temperature stress, and specifically with high night-time temperatures (HNT). Characterizing the impact of HNT on the phenotypic and metabolic status of developing rice seeds can provide insights into the mechanisms involved in yield and quality decline. Here, we examined the impact of warmer nights on the morphology and metabolome during early seed development in six diverse rice accessions. Seed size was sensitive to HNT in four of the six genotypes, while seed fertility and seed weight were unaffected. …

Legacy Effects Of Biodegradable Mulch And Soil Amendments On Vegetable Crops And The Soil, Elise V. H. Reid

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

Plastic film mulches are used in horticulture to manage weeds, improve water retention, and increase soil temperature. Bioplastics and biofabrics are potentially sustainable alternatives to plastic film; however, they have different rates of in soil degradation. Polylactic acid (PLA) is a 100% biobased polymer that degrades slowly, but could fulfill organic certification to be soil incorporated. Mater-Bi is a commercially available biodegradable plastic (bioplastic), which degrades quickly, but cannot be incorporated in organic systems. Our objectives were to determine the individual and combined effects of soil amendments and residual mulch on vegetable crop yield and soil fertility. In a two-year …

Ghd8 Controls Rice Photoperiod Sensitivity By Forming A Complex That Interacts With Ghd7, Peng Wang, Rong Gong, Ying Yang, Sibin Yu

Department of Agronomy and Horticulture: Faculty Publications

Background: Flowering time is one of the most important agronomic characteristics that ultimately determine yield potential and eco-geographical adaptation in crops. Ghd8 and Ghd7, two major flowering genes, have similar functions and large pleiotropic effects in controlling the heading date, plant height and grain yield of rice. However, these gene interactions at the genetic and molecular levels have not been determined to date.

Results: In this study, we investigated the genetic interaction between Ghd8 and Ghd7 by using a set of near-isogenic lines and a panel of natural germplasm accessions in rice. We found that Ghd8 affected multiple agronomic traits …

Application Of Autofluorescence For Confocal Microscopy To Aid In Archaeoparasitological Analyses, Johnica Jo Morrow, Christian Elowsky

Department of Agronomy and Horticulture: Faculty Publications

Confocal laser scanning microscopy (CLSM) was used to examine archaeoparasitological specimens from coprolites associated with La Cueva de los Muertos Chiquitos (CMC) located near present-day Durango, Mexico. The eggs for 4 different types of parasites recovered from CMC coprolites were imaged using CLSM to assist with identification efforts. While some of the parasite eggs recovered from CMC coprolites were readily identified using standard light microscopy (LM), CLSM provided useful data for more challenging identifications by highlighting subtle morphological features and enhancing visualization of parasite egg anatomy. While other advanced microscopy techniques, such as scanning electron microscopy (SEM), may also detect …

Quantifying Pollen Traits To Build A Mathematical Model Of Pollen Competition - A Biologist's Perspective, Rob Swanson, Alex Capaldi

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Cytotoxic Xanthones From Hypericum Stellatum, An Ethnomedicine In Southwest China, Yuanyuan Ji, Ruifei Zhang, Chen Zhang, Xingyu Li, Adam Negrin, Chaonan Yuan, Edward J. Kennelly, Chunlin Long

Publications and Research

Hypericum stellatum, a species endemic to China, is used to treat hepatitis by several ethnic groups in Guizhou Province. This research was inspired by the traditional medicinal usage of H. stellatum, and aims to explore the phytochemistry and bioactivity of H. stellatum to explain why local people in Guizhou widely apply H. stellatum for liver protection. In this study, two new prenylated xanthones, hypxanthones A (8) and B (9), together with seven known compounds, were isolated from the aerial parts of the plant. Spectroscopic data as well as experimental and calculated ECD spectra were used to establish the structures of …

Molecular Systematics Of Isoëtes (Isoëtaceae) In Eastern North America, Peter William Schafran

Biological Sciences Theses & Dissertations

Isoëtes (Isoëtaceae, Isoetales, Lycopodiophyta) is a cosmopolitan genus of aquatic lycophytes, occurring on every continent except Antarctica. Of approximately 200 total taxa, about half are in a clade of species mostly occurring in North and South America. Eastern North America accounts for 22% of global taxonomic diversity, containing 32 fertile taxa and 16 named hybrids. This taxonomic diversity is built upon relatively little morphological difference, and even combined with phylogenetic analysis using several nuclear and chloroplast DNA markers, no well-resolved systematic treatment within this clade exists.

This study aims to clarify the relationships between all species and subspecies of Isoëtes …

Canavalia And Dolichos Extracts For Sustainable Pest Biocontrol And Plant Nutrition Improvement In El Salvador, Carlos Martinez

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

Botanical repellents and pesticides are now being rediscovered as new tools for integrated pest management in order to reduce the use of toxic chemicals in crop production. Canavalia gladiata and Dolichos lablab are two Fabaceae very well adapted to farmlands of El Salvador, effective as living barriers and mostly as cover crops, however, they are not yet very well disseminated. This document describes the potential for using the liquid extracts and the dry flour of raw seeds of those plants for economic benefit and practical convenience for pest management in Salvadorian agriculture under field conditions. Seed extracts were useful when …

Santa Rosa Island Restoration Study: Fog Fences Vs. No Fences, Aimee Newell, Stephen Bednar, Kathryn Mceachern

STAR Program Research Presentations

Santa Rosa Island, Channel Islands National Park, was grazed by cattle, sheep, pigs, elk, and deer for 154 years, degrading the island’s vegetation and causing erosion. In 1998, the livestock were removed, and in 2011 the remaining big game animals were removed, allowing ecosystem recovery to begin. This study evaluated growth of two native species planted in 2016, at the cloud forest restoration site on the Soledad Ridge. Baccharis pilularis (coyote brush) was planted as nursery stock from 2-inch pots, while Quercus pacifica (island scrub oak) was planted as sprouted acorns. The plants were watered with drip irrigation 2016-2018, …

Systematics Of Carex Section Laxiflorae (Cyperaceae), Jenna Dorey

Dissertations, Theses, and Capstone Projects

Carex, with more than 2100 species, is the most species-rich genus of flowering plants in temperate regions of the world. Members of the family Cyperaceae are colloquially known as sedges, and members of the genus Carex are called “true sedges.” Carex occur on every continent except for Antarctica, they thrive in a panoply of habitats, and are ecologically important as a forage source for wildlife, carbon sequestration, prevention of soil erosion, and providing habitat for fresh water invertebrates. Despite their importance many sedges are still poorly known, such as the woodland sedges in Carex section Laxiflorae, which is …

Arkansas Wheat Cultivar Performance Tests 2018-2019, R. E. Mason, R. G. Miller, D. E. Moon, J. P. Kelley

Arkansas Agricultural Experiment Station Research Series

Wheat cultivar performance tests are conducted each year in Ark- ansas by the University of Arkansas System Division of Agriculture’s Arkansas Agricultural Experiment Station, Department of Crop, Soil and Environmental Sciences. The tests provide information to companies developing cultivars and marketing seed within the state and aid the Arkansas Cooperative Extension Service in formulating cultivar recommendations for small-grain producers. The tests are conducted at the Northeast Research and Extension Center at Keiser, the Vegetable Substation near Kibler, the Lon Mann Cotton Research Station near Marianna, the Newport Extension Center near Newport, the Rohwer Research Station near Rohwer, the Pine Tree …

Diffuse Light And Wetting Differentially Affect Tropical Tree Leaf Photosynthesis, Z. Carter Berry, Gregory R. Goldsmith

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

‐Most ecosystems experience frequent cloud cover resulting in light that is predominantly diffuse rather than direct. Moreover, these cloudy conditions are often accompanied by rain that results in wet leaf surfaces. Despite this, our understanding of photosynthesis is built upon measurements made on dry leaves experiencing direct light.

‐Using a modified gas exchange setup, we measured the effects of diffuse light and leaf wetting on photosynthesis in canopy species from a tropical montane cloud forest.

‐We demonstrate significant variation in species‐level response to light quality independent of light intensity. Some species demonstrated 100% higher rates of photosynthesis in diffuse light …

An Integrated Genomics And Phenomics Approach To Study The Evolution Of C4 Photosynthesis, Daniel Santana De Carvalho

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

The C4 photosynthetic pathway was first described over 50 years ago. Today, it is known that C4 evolved independently > 60 in plant lineages, which involves understanding not only the genetic, but also the metabolic features and differences involved in this process. Also, several adaptations are involved in the evolution of this type of photosynthesis, for example: changes in leaf anatomy and the evolution of kranz anatomy, physiology and metabolic pathways. In order to further investigate this pathway, different technologies and methods have been developed to unravel genes involved in C4 photosynthesis. With the advances in molecular biology and bioinformatics tools …

Microbial Response To Biodegradable Mulch: Can Degradation Rate Be Accelerated By Management?, M. Benjamin Samuelson

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

Single-use, petroleum-based polyethylene mulch is ubiquitous in certified organic mulched vegetable systems, representing a broken nutrient cycle and a waste concern. Current organic-allowable biodegradable mulches cannot match the performance of polyethylene, in part because of the requirements that they contain 100% bio-based feedstock, and biodegrade within two years after soil incorporation. It is valuable to understand whether management can influence postharvest degradation rate of mulch films. Two biodegradable mulches: a potentially organic nonwoven polylactic acid and wood particle prototype (PLA), and a widely-adopted non-organic starch/copolymer blend, Bio360® (BLK), were used in field trials in two distinct ecoregions of Nebraska, at …

Investigating Parental Effects On End-Use Quality In Hard Winter Wheat (Triticum Aestivum L.) Hybrids, Anthony Delaney

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

To optimize the performance and marketing of hybrid wheat, breeders need to understand the impact parents have on end-use quality. The goal of this study was to investigate the inheritance of end-use quality traits of hard winter wheat reciprocal hybrids produced by Easterly (2017). The 2016 analysis included 71 reciprocal hybrid combinations from 13 parents and the 2017 analysis included 79 reciprocal hybrid combinations from 14 parents. The reciprocals were composed of crosses between the top performing and bottom performing parents with respect to end-use quality as quantified by a Mixograph, a SDS sedimentation assay, and a SDS-SRC hybrid assay. …

Rust And Viral Mosaic Diseases In Biofuel Switchgrass, Anthony A. Muhle

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

Switchgrass (Panicum virgatum L.) is a perennial warm-season monocot that is indigenous to locations in North America east of the Rocky Mountains, and is considered a model grass for biofuel feedstock production. As switchgrass production increases, diseases pose a potential threat to biomass production and ethanol extraction. The two predominant switchgrass diseases in Nebraska are rust caused by Puccinia spp. and a viral mosaic disease caused by Panicum mosaic virus (PMV) and its associated Satellite panicum mosaic virus (SPMV). In this thesis, one study determined how SPMV affects PMV infection and systemic spread in two populations of switchgrass at different …

Hormonal Signaling Induced In Soybean By Lysobacter Enzymogenes Strain C3, Jessica C. Walnut

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

The biological control bacterium Lysobacter enzymogenes strain C3 has been shown to suppress fungal diseases by producing a suite of lytic enzymes and antimicrobial secondary metabolites. Previous studies have found that C3, when applied to grass and cereal plants, also is capable of inducing local and systemic resistance against fungal pathogens. It is unknown, however, whether the bacterium has the ability to induce resistance in dicots and what signaling pathways are involved. This study assessed the ability of C3 to trigger local and systemic induced resistance responses in soybean (Glycine max ‘Williams82’) by analyzing relative expression of salicylic acid …

The Effects Of Clipping On The Biomass Production Of Native Warm Season Grasses On Reclaimed Abandoned Coal Mine Soils, James A K Daniel

Electronic Theses & Dissertations

THE EFFECTS OF CLIPPING ON THE BIOMASS PRODUCTION OF NATIVE

WARM SEASON GRASSES ON RECLAIMED

ABANDONED COAL MINE SOILS

James A K Daniel

Strip mining leaves behind highly disrupted plant and soil communities. Mined land reclamation returns the land back to a natural or economically usable state, however, reclamation cannot completely restore the soils to their original state. Subsequently, normal frequencies of management practices may not be as effective as in undisturbed soils. Understanding how the severity of soil disturbance affects plant production is important for habitat rehabilitation and determining effective management techniques to be implemented following reclamation. This project …

How Do Ecological Resilience Metrics Relate To Community Stability And Collapse?, Caleb P. Roberts, Dirac L. Twidwell Jr, David G. Angeler, Craig R. Allen

Department of Agronomy and Horticulture: Faculty Publications

The concept of ecological resilience (the amount of disturbance a system can absorb before collapsing and reorganizing) holds potential for predicting community change and collapse—increasingly common issues in the Anthropocene. Yet neither the predictions nor metrics of resilience have received rigorous testing. The crossscale resilience model, a leading operationalization of resilience, proposes resilience can be quantified by the combination of diversity and redundancy of functions performed by species operating at different scales. Here, we use 48 years of sub-continental avian community data aggregated at multiple spatial scales to calculate resilience metrics derived from the cross-scale resilience model (i.e., cross-scale diversity, …

Estimating Live Fuel Moisture Using Smap L-Band Radiometer Soil Moisture For Southern California, Usa, Shenyue Jia, Seung Hee Kim, Son V. Nghiem, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Live fuel moisture (LFM) is a field-measured indicator of vegetation water content and a crucial observation of vegetation flammability. This study presents a new multi-variant regression model to estimate LFM in the Mediterranean ecosystem of Southern California, USA, using the Soil Moisture Active Passive (SMAP) L-band radiometer soil moisture (SMAP SM) from April 2015 to December 2018 over 12 chamise (Adenostoma fasciculatum) LFM sites. The two-month lag between SMAP SM and LFM was utilized either as steps to synchronize the SMAP SM to the LFM series or as the leading time window to calculate the accumulative SMAP SM. …

Identification Of Loci Controlling Adaptation In Chinese Soya Bean Landraces Via A Combination Of Conventional And Bioclimatic Gwas, Ying-Hui Li, Delin Li, Yong-Qing Jiao, James C. Schnable, Yan-Fei Li, Hui-Hui Li, Huai-Zhu Chen, Hui-Long Hong, Ting Zhang, Bin Liu, Zhang-Xiong Lui, Qing-Bo You, Yu Tian, Yong Guo, Rong-Xia Guan, Li-Juan Zhang, Ru-Zhen Chang, Zhiwu Zhang, Jochen Reif, Xin-An Zhou, Patrick S. Schnable, Li-Juan Qiu

Department of Agronomy and Horticulture: Faculty Publications

Landraces often contain genetic diversity that has been lost in modern cultivars, including alleles that confer enhanced local adaptation. To comprehensively identify loci associated with adaptive traits in soya bean landraces, for example flowering time, a population of 1938 diverse landraces and 97 accessions of the wild progenitor of cultivated soya bean, Glycine soja was genotyped using tGBS. Based on 99 085 high-quality SNPs, landraces were classified into three subpopulations which exhibit geographical genetic differentiation. Clustering was inferred from STRUCTURE, principal component analyses and neighbour-joining tree analyses. Using phenotypic data collected at two locations separated by 10 degrees of latitude, …

Nitrogen Fixation In Roots Of Ceanothus, W. John Hayden

Biology Faculty Publications

Roots are usually out of sight and, therefore, out of mind. But as any good gardener will tell you, it is of utmost importance to understand those unique plant organs, even if their essential functions occur hidden from cursory observation. The red roots of the 2019 VNPS Wildflower of the Year, Ceanothus americanus, are particularly important because they host symbiotic bacteria that perform the essential function of nitrogen fixation. These prominent, knobby, distinctively pigmented roots are also the inspiration for the common name Redroot, applied to many species in the genus.

Warm Stratification Increases Germination Of Dendromecon Rigida And Ehrendorferia Chrysantha, Cesar Garcia

Electronic Theses, Projects, and Dissertations

We explored the seasonal factors that might play a role in triggering germination of Dendromecon rigidaand Ehrendorferia chrysantha.D. rigida and E. chrysantha have been found difficult to germinate using common greenhouse techniques, Keeley and Fotheringham successfully germinated both species after storing their seeds in the field over a year and treating them with smoke. Identifying the specific seasonally changing factors that stimulated germination could have implications for understanding germination requirements for these and other hard-to-germinate chaparral species.

Dendromecon rigidaand Ehrendorferia chrysanthaare part of the Papaveraceae family and both are found in the chaparral environment in …

Introduction To Sorghum Paper Production, Zachary Christman

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

Sorghum is a tall grass used for many commercial products such as fodder and syrup. The 10 to 15 feet stalk of the plant has lower lignin than wood and provides a fiber length of 2.31 mm in the outer covering and 1.38 mm for the leaf. Sorghum fiber makes a high quality, strong paper suitable for printing, packaging and paperboard.

In Vitro Propagation Of A Critically Endangered African Violets (Saintpaulia Rupicola B.L. Burtt), Thomas W. Lowry Iii

Masters Theses, 2010-2019

The in vitro propagation is a promising method for the production of plants in species that are endangered, commercially valuable, and/or otherwise difficult to propagate through traditional horticultural methods. Leaf and petiole explants of critically endangered African violets (Saintpaulia rupicola B.L. Burtt) were cultured on a chemically defined medium that was supplemented with six different concentrations of thidiazuron (TDZ). The concentrations were used for either an induction medium on which the explants remained throughout development, or an induction medium on which the explants remained for 10 days followed by a basal growth medium for the remainder of the 12 …

Understanding Neglect Of Plant Biology Education In Michigan Middle Schools, Kim Smith

All NMU Master's Theses

The purpose of this study was to identify historical trends of neglect in plant biology education, their continuation today in Michigan middle school classrooms, and to uncover reasons for this neglect. A content analysis of state and national science standards and an online survey of Michigan middle school life science teachers were conducted. Findings showed a trend of increasing references in national standards from animals or plants to general organisms, as well as a decrease in the overall number of specific references in the standards. The data also revealed that nearly half of the teachers surveyed spent less than ten …

Use Of Annual Forage Mixtures In Crop/Livestock Production Systems In Nebraska, Nathan Paul Pflueger

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

Success of integrating annual forages into crop and livestock systems throughout Nebraska may be variable depending on field location, field/forage crop management, and precipitation. There are many different warm- and cool-season annual forage species available for integrating crop and livestock systems at different times of the year. Mixtures of cereal species, such as oats (Avena sativa)) and spring peas (Pisum sativum)), are often used to optimize forage quantity and forage quality. Our two-year, three location study across Nebraska’s precipitation gradient suggested that forage quantity and quality may vary by location due to different precipitation amounts received …

Dna Barcoding Of Pratylenchus From Agroecosystems In The Northern Great Plains Of North America, Mehmet Ozbayrak

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

Pratylenchus species are among the most common plant parasitic nematodes in the Great Plains Region. The objectives of this study were to barcode Pratylenchus specimens for species identification in the Great Plains region using mitochondrial CO1 DNA barcode. In order to (1) determine species boundaries, (2) assess the host associations of barcoded Pratylenchus, (3) to determine the distribution patterns across the Great Plains Region and, (4) to evaluate the species status of P. scribneri and P. hexincisus by a multivariate morphological analysis of haplotype groups identified by DNA barcoding. Soil samples, primarily associated with eight major crops, were collected …

Establishment Of Perennial Legumes With An Annual Warm-Season Grass As A Companion Crop, Martina N. La Vallie

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

The yields of perennial forage legumes are often hindered during the establishment year due to slow germination rates and weed competition. This study was conducted to determine if sorghum-sudangrass (Sorghum bicolor x S. bicolor var. sudanese) is a compatible annual companion crop for increased forage production, weed suppression, and legume establishment. In 2016, sorghum-sudangrass was paired with alfalfa (Medicago sativa L. ‘Ranger’), birdsfoot trefoil (Lotus corniculatus L.), Illinois bundleflower [Desmanthus illinoensis (Michx.) MacMill. ex B.L. Rob. & Fernald], purple prairie clover (Dalea purpurea Vent.), red clover (Trifolium pratense L.), and roundhead lespedeza (Lespedeza capitata Michx.). We studied effects of a …