Plant Breeding and Genetics Commons^™

Genetic Mapping Of Yield And Normalized Difference Vegetative Index In Soft Red Winter Wheat (Triticum Aestivum L.), Christopher Keith Addison

Graduate Theses and Dissertations

Wheat is the most widely cultivated cereal crop, being grown on 17% of the global crop land and as such must be adapted to an array of environmental stresses. In order to become a variety, wheat breeding lines must be tested across a range of environments for both high productivity and stability. Quantitative trait loci (QTL) mapping and indices are tools that can aid plant breeders in the selection of superior lines. Soft red winter wheat accounts for 20% of the total wheat production in the United States, being grown in the southeastern U.S. predominantly along the Mississippi River. However, …

Characterization Of A Novel Fungal-Specific Gene, Fug1, In Fusarium Verticillioides, John Byron Ridenour

Graduate Theses and Dissertations

Filamentous fungi are responsible for numerous plant and animal diseases. The filamentous ascomycete Fusarium verticillioides is a globally important pathogen of maize, capable of causing severe yield reductions and economic losses. Also of substantial concern is the contamination of infected kernels with fumonisins, toxic secondary metabolites linked to toxicoses in humans and livestock. The number of sequenced fungal genomes is rapidly increasing. However, functional characterization of fungal genes has not progressed at a comparable rate. In pathogenic fungi, uncharacterized genes represent a source for novel virulence factors or anti-fungal targets. Therefore, to fully understand the genetic mechanisms underlying fungal pathogenesis, …

European Consumers' Attitudes Towards Cisgenic Rice, Anne-Cécile Delwaide

Graduate Theses and Dissertations

The enhancement of existing plant breeding techniques, such as cisgenesis, allows plant breeders to enhance an existing cultivar quicker and with little to no genetic drag. Cisgenesis is the genetic modification of a recipient plant with natural gene(s) from a sexually compatible plant. Unlike transgenesis, which is the genetic modification of a recipient plant with gene(s) from any non‐plant organism, or from a donor plant that is sexually incompatible with the recipient plant, the results of cisgenesis could occur naturally over time. Currently, both cisgenic and transgenic products are classified as genetically modified organisms (GMOs) and are labeled as such …

Consumer Acceptance And Willingness To Pay For Genetically Modified Rice In China: A Double Bounded Dichotomous Choic Contingent Valuation Survey Calibrated By Cheap Talk, Jing Jin

Graduate Theses and Dissertations

Considering population growth, limitations on land and water resources, and contamination to the ecosystem due to agricultural activities, current rice production in China is facing pressure to fulfill national demand. Self-sufficiency of rice has been a long-held political objective of the Chinese government and it is national goal to maintain the equilibrium between the national production and consumption or even achieve a supply surplus in rice. With the developing bio-technology of genetic modification (GM), scientists believe that using genetically modified cultivars may ease the pressure mentioned above. However, both the government and the people are very cautious about large-scale cultivation …

Identification Of Quantitative Trait Loci / Genes For Low-Stachyose And High-Sucrose Content In Soybean Seeds, Sandra Liliana Florez Palacios

Graduate Theses and Dissertations

Seed carbohydrate content is an important aspect in breeding for food-grade soybeans commercialized in the soyfood market. Sucrose and stachyose are the primary carbohydrates in soybean seed. Sucrose affects the quality and taste of various soyfoods such as tofu, soymilk, and natto; however, consumption of soy-based products with high stachyose concentrations can cause diarrhea and flatulence. A mutant line (V99-5089) with high-sucrose and low-stachyose has been identified. The objectives of this research were: 1) to identify sucrose QTLs in a F2-derived mapping population; 2) to investigate the genetic relationship between two low-stachyose sources, V99-5089 and the germplasm line PI200508; and …

Molecular And Biochemical Mechanisms Of Pathogenesis In The Maize Foliar Pathogen Cercospora Zeae-Maydis, Winfred-Peck Dorleku

Graduate Theses and Dissertations

GLS is a serious foliar disease of maize, a major staple crop grown commercially in the USA for both human and animal feed production, and increasingly, for ethanol production. The disease is caused by two Cercospora species, C. zeae-maydis and C. zeina, both of which infect maize in the USA and in other parts of the world, with yield losses potentially greater than 50%, depending on local conditions. In culture, C. zeae-maydis produces a phytotoxic, host non-specific perylenequinone, cercosporin, and abscisic acid (ABA), for which there is no known pathological or physiological function in the fungus. Experimental evidence indicates …

Identification And Confirmation Of Quantitative Trait Loci For Seed Protein And Oil Content Of Soybean, Jiao Wang

Graduate Theses and Dissertations

Protein and oil are the major chemical constituents of soybean seed that affect the quality of soyfood, feed, and oil products. Therefore, soybean cultivars with high protein and/or high oil are desirable for the soyfood and feed markets. Use of molecular-marker-assisted selection will facilitate the breeding process of such cultivar development. The objectives of this research were to identify new quantitative trait loci (QTL) and confirm previously reported QTL associated with seed protein and oil content by using simple sequence repeat (SSR) markers and single nucleotide polymorphism (SNP) markers. Two recombinant inbred line (RIL) populations consisting of 242 individuals from …

Genome-Wide Association Mapping Identifies Qtls And Candidate Genes For Salt Tolerance In Soybean, Lei Huang

Graduate Theses and Dissertations

Salinity is a common abiotic stress causing soybean yield loss worldwide. Use of tolerant cultivars is an effective and economic approach to coping with this stress. Toward this, research is needed to identify salt-tolerant germplasm and better understand the genetic and molecular basis of salt tolerance in soybean. The objectives of this study were to identify salt-tolerant genotypes, to search for SNPs and QTLs associated with salt tolerance, and to identify candidate salt tolerance genes. A total of 192 diverse soybean lines and cultivars were screened for salt tolerance in the greenhouse based on visual leaf scorch scores after 15 …

Morphological And Molecular Taxonomic Identification And Phylogenetics Of Criconematoidea, Marco Cordero

Graduate Theses and Dissertations

The superfamily Criconematoidea has been studied since 1886. It is composed of two families: Criconematidae (subfam. Criconematinae, Hemicycliophorinae) and Tylenchulidae (subfam. Tylenchulinae, Paratylenchinae and Tylenchocriconematinae). Multiple species in genera have been identified and differences and similarities have been found. Species belonging to genera Mesocriconema and Criconemoides show very few differences making their identification difficult. Seventy two populations were studied. They were collected in Arkansas and/or received from the following states: California, Florida, Kansas, Missouri, North Carolina and Tennessee. Populations of the following species were identified: Mesocriconema curvatum, M. kirjanovae, M. onoense, M. ornatum, M. sphaerocephala, M. surinamense, M. vadense, M. …

Genetic Diversity Of Seed Dormancy And Molecular Evolution Of Weedy Red Rice, Te Ming Tseng

Graduate Theses and Dissertations

Rice is the grain with the third-highest global production. In the US, Arkansas is the largest rice producing state; however, an estimated 62% of the rice fields in the state are infested with red rice, and can cause up to 80% yield reduction in rice. Among its weedy traits, seed dormancy plays an important role in its persistence, and helps red rice escape weed management techniques thereby increasing the red rice soil seedbank. Red rice also has the potential to hybridize among themselves and with cultivated rice, thus resulting in diverse phenotypes and genotypes. In this study we measured variation …

Breeding For Modified Seed Composition In Soybean: Selection Of Genotypes, Yield Stability, And Environmental Effects, Luciano Miguel Jaureguy

Graduate Theses and Dissertations

The development of cultivars with modified seed composition represents an excellent alternative to cope with the world's need for more nutritious food. Understanding the genetic and environmental factors controlling crop seed quality traits is of crucial importance for such an endeavor. The objectives of this study were: a) to evaluate the efficiency of phenotype and marker-assisted selection for low stachyose and low phytate soybean breeding lines, and their yield stability, b) to study the effect of management practices planting date and delayed harvest on soybean seed composition, and c) to study the potential association between soil properties and leaf chemical …

Taxonomy And Dna Barcoding In The Genus Manfreda (Salisb.) Asparagaceae, William David Ritchie

Graduate Theses and Dissertations

The genus Manfreda Salisb. of Asparagaceae is a genus of potential horticultural interest and is currently subject to breeding efforts at the University of Arkansas. A lack of taxonomic clarity however undermines the classification of potential inter - and intrageneric hybrids. The study aims to assess existing species delimitation within the genus Manfreda employing morphology while investigating the potential utility of Consortium for the Barcode of Life Plant (CBOL) DNA Barcodes for identification of specific taxa and an External Transcribed Spacer (ETS) - Internal Transcribed Spacer (ITS) DNA barcode for developed hybridized taxa.

Observation of 855 herbarium specimens facilitated phylogenetic …

Evaluation Of The Recombination Efficiencies Of Flp Proteins, Linh Duy Nguyen

Graduate Theses and Dissertations

Site-specific recombination systems are powerful tools for genetic modification. They have been used to integrate a transgene into a pre-defined locus and to remove marker genes from a transgene locus. Two of the most widely used site-specific recombination systems in plants are the Cre/lox system from the bacteriophage P1 and the FLP/FRT system from the yeast Saccharomyces cerevisiae. The Cre/lox system is well-characterized and is the first choice in application of site-specific recombination system. However, some applications such as marker-free site-specific gene integration require the use of two recombination systems. In addition, the availability of alternative recombination systems can offer …

Genetic Diversity, Pathogenicity/Virulence Variation And Population Structure Of Rhizoctonia Spp. Associated With Rice Sheath Blight In Arkansas And Qtl Mapping For Disease Resistance, Vanina Lilian Castroagudin

Graduate Theses and Dissertations

Rice sheath blight (ShB) is one of the most prevalent diseases in rice. The significance of this disease is increasing due to more intensive production practices globally. Rhizoctonia solani Kühn AG 1 - IA [teleomorph: Thanatephorus cucumeris (A.B. Frank) Donk] is considered the primary ShB pathogen of rice. However, Rhizoctonia oryzae-sativae, Rhizoctonia oryzae, and R. solani AG 2 and AG 11, have also been isolated from sheath blight-like lesions on rice.Up to now, there is little information on genetic diversity and patterns of molecular evolution of the fungus, and there is no study on the structure of the R. solani …

The Identification Of Quantitative Trait Loci For Sucrose And Stachyose Content In Soybean Seed, Ailan Zeng

Graduate Theses and Dissertations

Sucrose is a desirable sugar in soybean seed that affects the quality and taste of soyfoods, while stachyose is a non-digestible sugar that induces flatulence in non-ruminant animals. Therefore, soybean cultivars with high sucrose and/or low stachyose would be valuable for soyfood and meal markets. The objectives of this study were to identify quantitative trait loci (QTL) or genes associated with seed sucrose and stachyose content using simple sequence repeat (SSR) or single nucleotide polymorphism (SNP) markers. A low sucrose line, MFS-553, was crossed with a high sucrose plant introduction, PI 243545, to develop the sucrose QTL mapping population. A …

The Evolution Of Natural Plant Communities Through Crop Migration And Crop-To-Weed Gene Flow, Meredith G. Schafer

Graduate Theses and Dissertations

With the rising demand for food and biofuels, the efficiency of crop production has become vital to assuring food security. Genetically engineered (GE) crop varieties are broadly thought to be a solution for improving the efficiency of crop production, but concerns regarding their release have heightened as more discoveries have focused on the influence of genetically engineered crops on native and weedy plant species. Risk assessment of GE crop varieties focuses on two main areas: feralization of crop systems and crop-weed hybridization. Risks include naturalization, transgene introgression, and the formation of novel genotypes in natural systems. In this study, roadside …

Cotton Response To High Temperature Stress During Reproductive Development, Justin B. Phillips

Graduate Theses and Dissertations

Temperature is a primary controller of the rate of plant growth, developmental events, and fruit maturation. Increased temperatures from global climate change are projected to cause substantial losses in crop productivity by the end of the twenty-first century. Elevated temperatures affect all stages of cotton development, but the crop seems to be particularly sensitive to adverse temperatures during reproductive development. In Arkansas, temperature stress is considered to be one of the main factors affecting cotton yield. Environmental stress during floral development is a major reason for the disparity between actual and potential yields. Field and growth chamber studies were conducted …

Characterization And Molecular Analysis Of University Of Arkansas Peach, Prunus Persica (L.) Batsch, Flesh Types And Development Of A Post-Harvest Evaluation Protocol For Arkansas Peach And Nectarine Genotypes, Paul James Sandefur

Graduate Theses and Dissertations

This study determined the effect of pre-cold storage treatment on P. persica genotypes, developed a protocol for the evaluation of breeding selection and cultivar storage performance, and provided information on post-harvest performance of these individuals. Additionally, characterization of the peach and nectarine flesh types, validation of endopolygalacturonase (endoPG) DNA markers, and investigation of endoPG marker allele combinations associated with the slow-melting-flesh (SMF) trait were done.

Fruit from 30 individuals were harvested at minimum- and well-mature states. After conditioning for 24 h at 20 ◦C, all 2010 fruit were exposed to 2 min of 1 ◦C 100 ppm chlorinated hydro-cooling, a …

Analysis Of Rice Blast Resistance Genes In The National Small Grains Collection (Nsgc), Moytri Roychowdhury

Graduate Theses and Dissertations

Identification of blast resistance genes in rice germplasm is one of the most important activities of rice breeding programs in worldwide. The objective of this research was to characterize two major blast resistance genes, Pi-z and Pi-b, in selected rice germplasm. A simple sequence repeat DNA marker, AP5659-1 linked to the Pi-z gene, and a Pib dominant marker derived from the Pi-b gene were first used to screen a rice core collection consisting of 1700 accessions estimated to represent 70% of the genetic diversity of rice in the US National Small Grains Collection. There were 131 rice germplasm accessions with …