Plant Breeding and Genetics Commons^™

Functional Analysis Of Squamosa-Promoter Binding Protein Like 13 In Controlling Flowering Time, Plant Architecture, Grain Size, And Grain Number In Wheat, Ajay Gupta

Electronic Theses and Dissertations

Higher and stable yield is always a major objective of wheat genetic improvement programs. The SQUAMOSA-promoter binding protein-like (SPL) genes constitute a small family of plant-specific transcription factors with diverse functions in plant development and growth and have great potential in improving yield and other major agronomic traits. However, the functional characterization of the SPL gene family in wheat is far behind other cereal crops such as rice. Using phylogenetic analysis, we identified 56 wheat orthologues of rice SPL genes belonging to 19 homoeologous groups. Among these 19 orthologous TaSPL genes, nine harbor the micro RNA 156 recognition element (MRE) …

Analysis Of Two Maize Mutations That Arose After Exposure To Radiation From A Plutonium-Beryllium Source And Developing Molecular Markers For Antimorph Aei1-5180, An Alternative To Aei To Increase Amylose Content In Maize Endosperm, Prameela Awale

Electronic Theses and Dissertations

This thesis consists of two independent projects dealing with two different aspects of maize. The first project is about the maize reproduction, where we try to uncover the candidate genes of two mutations that affect pollen viability and successful fertilization. The second project is about maize endosperm starch, where we developed molecular markers to characterize a mutant allele that knocks a major starch branching enzyme in maize.

Analysis of two maize mutations that arose after exposure to radiation from a plutonium-beryllium source
Maize is a monoecious and diclinous plant. Sexual reproduction takes place by the fusion of haploid male and …

Floral Trait Architecture In Crop Sunflower (Helianthus Annuus) Under Drought Conditions, Lauren Segarra

All Master's Theses

Longer and more intense droughts are predicted to become more common in the coming century due to anthropogenic climate change. Drought can reduce crop yield and decrease food security. In order to mitigate the negative effects of drought on crop production, it is important to elucidate the underlying mechanisms that promote drought stress resistance in crop plants. Floral traits impact yield, especially in oilseed crops such as sunflower (Helianthus annuus), but their susceptibility to drought stress is understudied. The goal of this study was to describe the floral trait architecture of H. annuus crop lines under drought versus …

The Morphological, Physiological, And Genetic Underpinnings Of Intraspecific Salinity Tolerance In Sorghum Bicolor, Ashley N. Henderson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Decreases in land quality and quantity threaten the efficient production of agriculturally and economically pivotal crops. Such reductions in arable lands are a consequence of population growth and urbanization, and often result in the introduction of various abiotic stresses. The most common abiotic stressors include water limitation (drought), water logging (over watering), poor water quality (salinity), and extreme temperatures (cold, frost, heat). Each of these stressors negatively impact plant growth, development, and yield. Soil salinity, specifically, is a considerable constraint affecting lands used in agriculture. Salts in the soil rise both naturally and through anthropogenic factors making the abundance a …

Phenotypic Study Of Anthracnose Resistance In Black Walnut And Building A Mapping Population, Sadie D. Land

Graduate Theses/Dissertations

Black walnut anthracnose, caused by Gnomonia leptostyla, is the most widespread and destructive disease affecting black walnut trees (Juglans nigra). Breeding cultivars for a higher resistance to anthracnose is a natural and efficient strategy for improving the health and production quality of black walnut trees. The two goals of this study were to reveal that the ‘Sparrow’ cultivar of black walnut contains a significantly higher resistance to anthracnose than the ‘Football’ cultivar when separated from environmental factors, and to expand the ‘Football’ × ‘Sparrow’ F1 mapping population to evaluate how the trait of resistance is inherited in the progeny. A …

Mapping A New Disease Resistance Locus In An F1 Progeny Derived From Two Grape Wild Relatives, Gaurab Bhattarai

Graduate Theses/Dissertations

Linkage maps and quantitative trait loci (QTL) analysis have become essential tools for the positional cloning of agronomically important genes and for marker-assisted breeding. In this study, two North American grape species, Vitis rupestris and Vitis riparia, and their 294 F₁ progeny were used to construct parental linkage maps and to perform QTL analysis for downy mildew resistance. Single nucleotide polymorphism (SNP) discovery was accomplished using genotyping-by-sequencing (GBS) and resulted in 348,888 SNPs. Of these, 11,063 informative SNP markers (3.17% of the original SNP dataset) were derived after filtering for various quality parameters and missing data. A two-way …

Addressing The Challenges Facing Wheat Production: Nebraska And International Breeding Efforts, Sarah Blecha

Doctor of Plant Health Program: Dissertations and Student Research

Bread wheat, Triticum aestivum L., provides 20 percent of the global daily calorie intake. It is the third most important food crop, after rice and corn. Biotic challenges significantly reduce wheat yield; chemical control can be a solution but can be cost prohibitive for subsistence farmers. For many farmers, genetic resistance to biotic stresses can be the most cost effective solution.

The International Center for Agricultural Research in the Dry Areas (ICARDA) and the Nebraska Small Grains Breeding Program have been addressing these wheat production challenges. ICARDA is part of an international research consortium to increase wheat yield and tolerance …

Global Responses Of Resistant And Susceptible Sorghum (Sorghum Bicolor) To Sugarcane Aphid (Melanaphis Sacchari), Hannah M. Tetreault, Sajjan Grover, Erin Scully, Tammy Gries, Nathan A. Palmer, Gautam Sarath, Joe Louis, Scott E. Sattler

Department of Entomology: Faculty Publications

The sugarcane aphid (Melanaphis sacchari) has emerged as a significant pest for sorghum. The use of sugarcane aphid-resistant sorghum germplasm with integrated pest management strategies appears to be an excellent solution to this problem. In this study, a resistant line (RTx2783) and a susceptible line (A/BCK60) were used to characterize the differences in plant responses to the sugarcane aphid through a series of experiments, which examined global sorghum gene expression, aphid feeding behavior and inheritance of aphid resistance. The global transcriptomic responses to sugarcane aphids in resistant and susceptible plants were identified using RNA-seq and compared to the …

Iris-Eda: An Integrated Rna-Seq Interpretation System For Gene Expression Data Analysis, Brandon Monier, Adam Mcdermaid, Cankun Wang, Jing Zhao, Allison Miller, Anne Fennell, Qin Ma

Agronomy, Horticulture and Plant Science Faculty Publications

Next-Generation Sequencing has made available substantial amounts of large-scale Omics data, providing unprecedented opportunities to understand complex biological systems. Specifically, the value of RNA-Sequencing (RNA-Seq) data has been confirmed in inferring how gene regulatory systems will respond under various conditions (bulk data) or cell types (single-cell data). RNA-Seq can generate genome-scale gene expression profiles that can be further analyzed using correlation analysis, co-expression analysis, clustering, differential gene expression (DGE), among many other studies. While these analyses can provide invaluable information related to gene expression, integration and interpretation of the results can prove challenging. Here we present a tool called IRIS-EDA, …

Refernment: An R Package For Annotating Rna Editing In Plastid Genomes, Tanner A. Robison, Paul G. Wolf

Biology Faculty Publications

PREMISE OF THE STUDY: In the absence of cDNA, the annotation of RNA editing in plastomes must be done manually, representing a significant time cost to those studying the organellar genomes of ferns and hornworts.

METHODS AND RESULTS: We developed an R package to automatically annotate apparent nonsense mutations in plastid genomes. The software successfully annotates such sites and results in no false positives for data with no sequencing or assembly errors.

CONCLUSIONS: Compared to manual annotation, ReFernment offers greater speed and accuracy for annotating RNA editing sites. This software should be especially useful for researchers generating large numbers of …

Development Of Computational Techniques For Identification Of Regulatory Dna Motif, Cankun Wang

Electronic Theses and Dissertations

Identifying precise transcription factor binding sites (TFBS) or regulatory DNA motif (motif) plays a fundamental role in researching transcriptional regulatory mechanism in cells and helping construct regulatory networks for biological investigation. Chromatin immunoprecipitation combined with sequencing (ChIP-seq) and lambda exonuclease digestion followed by high-throughput sequencing (ChIP-exo) enables researchers to identify TFBS on a genome-scale with improved resolution. Several algorithms have been developed to perform motif identification, employing widely different methods and often giving divergent results. In addition, these existing methods still suffer from prediction accuracy. Thesis focuses on the development of improved regulatory DNA motif identification techniques. We designed an …

Application Of Short Tandem Target Mimic (Sttm) Technique For Functional Analysis Of Micro-Rna396 In Transgenic Poplar Trees, Surattana Boonsai

Dissertations, Master's Theses and Master's Reports

Short Tandem Target Mimic (STTM) is a commonly technique used for functional studies of a number of genes in several plant model systems. However, very little is known about application of STTM technique in tree species. In this study, STTM was applied to knock down microRNA396 (miR396) in transgenic poplar trees for the first time. STTM396 expression resulted in dramatic decrease in miR396 expression levels leading to taller plants with larger leaves and larger leaf cell size. Additionally, an expression analysis of growth regulating factor genes (GRFs) that are members of miR396 target gene family showed up-regulation of GRF07 gene …

Genetic Regulation Of The Elicitation Of Glyceollin Biosynthesis In Soybean, Md. Asraful Jahan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Glyceollin phytoalexins are the pathogen-elicited defense metabolites that belong to the isoflavonoid family of molecules of soybean (Glycine max L. Merr). Phytophthora root and stem rot of soybean caused by Phytophthora sojae is a destructive disease throughout the soybean-growing regions worldwide causing devastating economic damages (globally $1-2 billion and over $250 million in the USA) every year. Engineering soybean plants that produce higher levels of glyceollins could confer resistance against this pathogen. Glyceollins also show anticancer and neuroprotective activities in mammals, therefore they are important for agriculture and medical research. Firstly, we were interested in understanding how biotic and …

Generation And Evaluation Of Modified Opaque-2 (O2) Popcorn Suggests A Route To Quality Protein Popcorn (Qpp), Ying Ren

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

I have been working on a Quality Protein Popcorn breeding project where QPM conversion is carried out simultaneously for several elite popcorn germplasms. During my study in the graduate program, I led the following aspects of the Quality Protein Popcorn Breeding Project:

1. Identified suitable QPMs as opaque-2 allele donors.

2.Examined the feasibility of quick introgression of the opaque-2 allele into popcorn lines via marker-assisted selection.

3. Monitored modification by SDS-PAGE zein profiling and light box phenotypic selection to make sure multiple modifier loci for opaque-2 were incorporated each time generation advancement was carried out.

4. Carried out high throughput …

Genome Wide Association Studies For Identification Of Markers Linked To Sucrose Traits In Sugarcane, Nathanael Darrell Fickett

LSU Doctoral Dissertations

Sugarcane, being a complex aneu-polyploid, poses unique challenges to fine mapping of quantitative trait loci (QTL) controlling agronomic traits of interest. Genome-wide association studies (GWAS) could be a better alternative to identify molecular markers associated with specific traits due to high linkage disequilibrium in sugarcane. In the first study, marker-trait associations (MTAs) were evaluated for three sucrose traits, Brix, total recoverable sugar (TRS), and percent sucrose on 48 elite and historic Louisiana breeding clones using 1,062 alleles. These sucrose traits were highly correlated (P-value < 0.0001) at >0.96. TASSEL 5.1 and JMP Genomics 8.0 were compared with eight models run in each program. …

The Determinants Of Nucleosome Patterns And The Impact Of Phosphate Starvation On Nucleosome Patterns And Gene Expression In Rice, Qi Zhang

LSU Doctoral Dissertations

In eukaryotic cells, DNA is a large molecule that must be greatly condensed to fit within the nucleus. DNA is wrapped around histone proteins to form nucleosomes, which facilitate DNA condensation, but on the other hand, may limit DNA processes. Organisms must respond to environmental stress in order to survive, and one strategy is by remodeling nucleosomes to promote changes in DNA accessibility to alter gene expression. Studies have demonstrated a clear correlation between nucleosome dynamics and transcriptional change in some eukaryotes, however factors that affect nucleosome positioning in plants are largely unknown, and the correlation between nucleosome dynamics and …

Breeding For Resistance In California Strawberry To Verticillium Dahliae, Zachary Christman

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

This article focuses on breeding resistant strawberries to the fungus Verticillium dahliae, common name Verticillium wilt. This is a serious fungal disease that can result in a loss of 50% or more of a strawberry harvest when grown in infested soil. The main goal is to provide an example of how a cultivar can be made more resistant to a plant pathogen with the use of plant breeding methods.

Since 1930 the University of California, Davis, has been developing strawberry cultivars that are adapted to the agricultural industry and regional farms. Developing cultivars that require fewer inputs are of …

Comparison Of Three Assembly Strategies For A Heterozygous Seedless Grapevine Genome Assembly, Sagar Patal, Zhixiu Lu, Xiaozhu Jin, Padmapriya Swaminathan, Erliang Zeng, Anne Y. Fennell Dr

Agronomy, Horticulture and Plant Science Faculty Publications

Background
De novo heterozygous assembly is an ongoing challenge requiring improved assembly approaches. In this study, three strategies were used to develop de novo Vitis vinifera ‘Sultanina’ genome assemblies for comparison with the inbred V. vinifera (PN40024 12X.v2) reference genome and a published Sultanina ALLPATHS-LG assembly (AP). The strategies were: 1) a default PLATANUS assembly (PLAT_d) for direct comparison with AP assembly, 2) an iterative merging strategy using METASSEMBLER to combine PLAT_d and AP assemblies (MERGE) and 3) PLATANUS parameter modifications plus GapCloser (PLAT*_GC).
Results
The three new assemblies were greater in size than the AP assembly. PLAT*_GC had the …

Quantitative And Molecular Analysis Of Habituation At The Maize R1 Locus, Robert C. Lindsay

Theses and Dissertations

Epigenetics is the study of heritable changes in phenotypes that are not the result of changes in DNA sequence. Examples of epigenetic affecters include methylation changes, chromatin modifications, transcription factors, and RNA-based changes. The molecular mechanisms behind epigenetic changes are not fully understood. Canalization is the buffering of gene expression against environmental changes over time, while habituation is semi-stable expression change over time due to selection. This work characterized the molecular changes associated with the kernel color changes of the R-sc:86-17pale allele at the maize red color1 (r1) locus to determine if the changes are epigenetic in nature. …

Natural And Anthropogenic Drivers Of Tree Evolutionary Dynamics, Brandon M. Lind

Theses and Dissertations

Species of trees inhabit diverse and heterogeneous environments, and often play important ecological roles in such communities. As a result of their vast ecological breadth, trees have become adapted to various environmental pressures. In this dissertation I examine various environmental factors that drive evolutionary dynamics in threePinusspecies in California and Nevada, USA. In chapter two, I assess the role of management influence of thinning, fire, and their interaction on fine-scale gene flow within fire-suppressed populations of Pinus lambertiana, a historically dominant and ecologically important member of mixed-conifer forests of the Sierra Nevada, California. Here, I find evidence …

The Soybean Rfg1 Gene Restricts Nodulation By Sinorhizobium Fredii Usda193, Yinglun Fan, Jinge Liu, Shanhua Lyu, Qi Wang, Shengming Yang, Hongyan Zhu

Plant and Soil Sciences Faculty Publications

Sinorhizobium fredii is a fast-growing rhizobial species that can establish a nitrogen-fixing symbiosis with a wide range of legume species including soybeans (Glycine max). In soybeans, this interaction shows a high level of specificity such that particular S. fredii strains nodulate only a limited set of plant genotypes. Here we report the identification of a dominant gene in soybeans that restricts nodulation with S. fredii USDA193. Genetic mapping in an F2 population revealed co-segregation of the underlying locus with the previously cloned Rfg1 gene. The Rfg1 allele encodes a member of the Toll-interleukin receptor/nucleotide-binding site/leucine-rich repeat class of …

Phenotypic Variation And Genetic Purity Of The Original 'Prime-Jim®' X 'Arapaho' Population, Loren M. Luther

Horticulture Undergraduate Honors Theses

In 2013, Castro et al., produced the first linkage map for primocane-fruiting blackberries using the cross ‘Prime-Jim®’ x ‘Arapaho.’ This mapping population has been maintained since the original experiment with the hopes of conducting future studies. Further research was determined to be needed on the population to better characterize additional phenotypic traits, and since nine years had passed since the seedlings were established, there was a need to assess the continued genetic purity of the population using molecular methods. Phenotypic data was collected to analyze the variation of the population including soluble solids content, titratable acidity, average weight, shape, and …

The Lx Report Of The Bean Improvement Cooperative No. 60, March 2017.

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

CONTENTS

LX Annual Report of the Bean Improvement Cooperative xi

BIC Coordinating Committee Membership - 1957 to 2017 . xii

BIC Meritorious Service and Distinguished Achievement Award Recipients - 1957 to 2015 xiii

BIC Awards Nomination Request for 2017 xvi

BIC/NAPIA Meeting in 2017 . xix

In Memory of Guillermo E. Galvez-Enriquez xx

RESEARCH PAPERS FOR 2017

OPTIMIZING SPORULATION OF Pseudocercospora griseola IN VITRO • Paula F. de Pádua1, Rafael Pereira1, Luanna B. W. Gomes1 and Elaine A. de Souza1* 1

FINE MAPPING THE BROAD SPECTRUM ANTHRACNOSE RESISTANCE GENE IN AMENDOIM CAVALO 3 • Gilio, T.A.S.1, Oscar P. Hurtado-Gonzales2, Giseli …

Neutral And Adaptive Genetic Variation In North American Hardwood Tree Species, Sudhir Khodwekar

Dissertations, Master's Theses and Master's Reports

'Northern Hardwoods,’ are a characteristic composition of multiple tree species and a part of the rich and diverse northeastern forests. Hardwoods e.g. oaks (Quercus: Fagaceae and Sugar maple), serve as foundation species and offer ecological and economical gains to wildlife and humans. Most of the forest trees go through many biotic and abiotic stresses, for example climate change in their long life span. To overcome these threats and to adapt to changing conditions, tree species need to maintain variation especially in adaptive genes. Therefore, it is necessary to analyze genetic diversity within forest tree populations and take appropriate …

Comparative Evolutionary Analysis Of Organellar Genomic Diversity In Green Plants, Weishu Fan

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

The mitochondrial genome (mitogenome) and plastid genome (plastome) of plants vary immensely in genome size and gene content. They have also developed several eccentric features, such as the preference for horizontal gene transfer of mitochondrial genes, the reduction of the plastome in non-photosynthetic plants, and variable amounts of RNA editing affecting both genomes. Different organismal lifestyles can partially account for the highly diverse organellar genomes across the tree of green plants. For example, endosymbiotic and parasitic lifestyles can dramatically affect the genomic architectures of plant mitochondria and plastids. In this study, the organellar genomes of several green plants with atypical …

Distribution Of Genomic Variation In The Usda Soybean Germplasm Collection And Relationship With Phenotypic Variation, Nonoy Batiller Bandillo

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

The USDA Soybean Germplasm Collection harbors a large stock of genetic diversity with potential to accelerate soybean cultivar development. The extent and nature of favorable alleles contained in the collection are not well known nor is the distribution of genetic variation and how it relates to phenotypic variation. The genotyping of the entire USDA Soybean Germplasm Collection marked the beginning of a systematic exploration of genetic diversity for genetic research and breeding. In this research, we conducted the first comprehensive analysis of population structure on the collection of ~14,400 soybean accessions [Glycine max (L.) Merr. and G. soja Siebold …

Is A Mitochondrial Plasmid Really A Virus?, Mackenzie Strehle

UCARE: Research Products

In addition to containing a large and complex mitochondrial genome, the mitochondria of several species of plants have been shown to contain an independent, self-replicating DNA molecule in the form of a plasmid. Plants in the Brassica genus contain a linear plasmid that is approximately 11.6 kilobases in length. The plasmid is characterized by the presence of terminal inverted repeats and covalently bonded proteins at its termini (Handa 2008). The plasmid also contains six ORFs that encode DNA and RNA polymerases and a number of unknown proteins (Figure 1). Currently, both the function of this plasmid and the mechanisms by …

Transgenerational Plasticity Is Sex-Dependent And Persistent In Yellow Monkeyflower (Mimulus Guttatus), Kayla C. Akkerman, Arash Sattarin, John K. Kelly, Alison G. Scoville

Student Published Works

Transgenerational phenotypic plasticity, whereby environmental cues experienced by parents alter the phenotype of their progeny, has now been documented in diverse organisms. Transmission of environmentally determined responses is known to occur through both maternal and paternal gametes, but the underlying mechanisms have rarely been compared. In addition, the persistence of induction over multiple generations appears to vary widely, but has been characterized for relatively few systems. Yellow monkeyflower (Mimulus guttatus) is known to exhibit transgenerational induction of increased glandular trichome production in response to simulated insect damage. Here, we test for differences between maternal and paternal transmission of …

Bio-Piracy: Creating Proprietary Rights In Plant Genetic Resources, James O. Odek

Journal of Intellectual Property Law

No abstract provided.

Effect Of Cry1f Maize On The Behavior Of Susceptible And Resistant Spodoptera Frugiperda And Ostrinia Nubilalis, Ana María Vélez, Analiza P. Alves, Erin E. Blankenship, Blair Siegfried

Department of Entomology: Faculty Publications

Understanding the behavior of pests targeted with Bacillus thuringiensis Berliner (Bt) crops is important to define resistance management strategies. Particularly the study of larval movement between plants is important to determine the feasibility of refuge configurations. Exposure to Bt maize, Zea mays L. (Poaceae), has been suggested to increase larval movement in lepidopteran species but few studies have examined the potential for resistance to interact with behavioral responses to Bt toxins. Choice and no-choice experiments were conducted with Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) and Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) to determine whether Cry1F resistance influences neonate movement. Leaf discs …