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13c-Metabolic Flux Analysis Of Soybean Somatic Embryos For Identification Of Metabolic Control Points In Developing Seed, Quyen Xuan Truong Dec 2012

13c-Metabolic Flux Analysis Of Soybean Somatic Embryos For Identification Of Metabolic Control Points In Developing Seed, Quyen Xuan Truong

Graduate Theses and Dissertations

Of the world's major agronomic food crops soybeans rank highest in protein content (~40% Dwt) while also containing significant quantities of oil (~20% Dwt). Based on these unique characteristics soy has become a mainstay in world agriculture, providing a protein source for livestock and human nutrition (68% of global vegetable protein meal consumption in 2011) as well as a primary source of vegetable oil (28% of global vegetable oil consumption in 2011; http://www.soystats.com/2012). The value of soy is therefore found both in its oil and protein content and increasing the content of both is therefore ...


Performance Evaluation Of Nine Varieties Of Miscanthus In Iowa, Muhammad Aurangzaib Jan 2012

Performance Evaluation Of Nine Varieties Of Miscanthus In Iowa, Muhammad Aurangzaib

Graduate Theses and Dissertations

Miscanthus is a tall perennial grass species native to parts of Asia. It has the potential to produce relatively high dry matter yields across a wide range of environmental and soil conditions. The Miscanthus cultivar most commonly recommended for biofuel production is a sterile hybrid (M. × giganteus) of M. sacchariflorus × M. sinensis , but there are some challenges for its production. One of them is the occurrence of cold damage during the first winter after planting when plant losses can be high. These losses could be exacerbated by incomplete or late senescence. A field trial was established in spring 2010 with ...


Bayesian Prediction Of Crop Performance Modeling Genotype By Environment Interaction With Heterogeneous Variances, Massiel Andrea Orellana Jan 2012

Bayesian Prediction Of Crop Performance Modeling Genotype By Environment Interaction With Heterogeneous Variances, Massiel Andrea Orellana

Graduate Theses and Dissertations

Yield trials data are essential to the process as they provide information regarding the performance of the genetic material being tested across multiple locations and seasons. The analysis of the data is complicated by the presence of genotype-by-environment interaction (GEI). A Bayesian approach was used to estimate variance components in a hierarchical model that allows for heterogeneous error and GEI variances applied to corn yield data from the Iowa Crop Performance Test carried out between 1995 and 2005. An average of 508 hybrids per year was tested with very little overlap between locations and years, which resulted in a very ...


Variability In Soybean Agronomic Performance Traits In Response To 41 C Heat And High Relative Humidity Seed Stress, Ruth Ann Rolling Jan 2012

Variability In Soybean Agronomic Performance Traits In Response To 41 C Heat And High Relative Humidity Seed Stress, Ruth Ann Rolling

Graduate Theses and Dissertations

Incorporation of genetic diversity into soybean [Glycine max (L.) Merr.] cultivars can be used to increase yield and plant adaptation to stresses. Genetic variation has been found in commercial soybean cultivars, but using a seed stress to generate intra-cultivar variation has not been studied. The first objective of this study was to use seed stress in an attempt to generate variation in soybean agronomic traits of field stand, plant maturity, plant height, seed size, seed yield, seed protein content, seed oil content, seed standard germination and seed vigor. The second objective was to evaluate if changes in variation were heritable ...


A Study Of Chloroplast Biogenesis Within Variegated Mutants Of Arabidopsis, Andrew Alexander Foudree Jan 2012

A Study Of Chloroplast Biogenesis Within Variegated Mutants Of Arabidopsis, Andrew Alexander Foudree

Graduate Theses and Dissertations

immutans(im) is a recessive Arabidopsis mutant that is involved in chloroplast biogenesis. In the absence of IMMUTANS (IM) green and white leaf sectors form. This thesis is concerned with the development of these green and white sectors and the methods used to investigate the mechanism of their formation. IM resides in the chloroplast thylakoid membrane and has been implicated in the adjustment of electron flux through the photosynthetic electron

transport chain. Without IM white sector formation occurs due to the inability of im to

produce colored carotenoids. It is still a mystery as to how green sectors are able ...


Tassels Replace Upper Ears1 Encodes A Putative Transcription Factor That Regulates Maize Shoot Architecture By Multiple Pathways, Wei Li Jan 2012

Tassels Replace Upper Ears1 Encodes A Putative Transcription Factor That Regulates Maize Shoot Architecture By Multiple Pathways, Wei Li

Graduate Theses and Dissertations

Plant shoot architecture has many features including inflorescence sex, branching and internode elongation, which is largely controlled by the activities of shoot apical meristem (SAM) and axillary meristems (AxM). The pleiotropic maize mutant tassels replace upper ears1 (tru1) shows reduced apical dominance with elongated upper shanks tipped by lateral tassels and shortened upper stem, altered tassel phenotypes with shortened tassel length and branch length, and reduced tassel branch number. To investigate the effect of tru1 on shoot architecture, morphological analysis of tru1-ws mutant was performed, including treatments of supplemental gibberellic acid (GA3), far red (FR) light and decapitation, and genetic ...


Genetic Dissection Of Canonical Models Of Maize Kernel Growth And Development, Kendra Ann Meade Jan 2012

Genetic Dissection Of Canonical Models Of Maize Kernel Growth And Development, Kendra Ann Meade

Graduate Theses and Dissertations

An understanding of the genetics of maize kernel growth and development will provide valuable insight into a complicated physiological process. The genetics of kernel growth and development is of interest not only to plant scientists who seek to understand the underlying molecular mechanism but also to plant breeders who seek to develop improved hybrids with faster growing, larger kernels. In order to better understand the genetics of kernel growth and development, biomass accumulation and moisture content were observed in a sample of hybrids and a set of doubled haploids derived from a cross of elite inbred lines and testcrossed to ...


Diversifying Monoculture Crops By Incorporating Prairie Buffer Strips, Sarah Marie Hirsh Jan 2012

Diversifying Monoculture Crops By Incorporating Prairie Buffer Strips, Sarah Marie Hirsh

Graduate Theses and Dissertations

Monoculture crop production and prevailing farming practices have greatly reduced perennial plants on the landscape and nearly eliminated native Iowa prairie vegetation. The STRIPs (Science-based Trials of Row crops Integrated with Prairies) project is a watershed-scale experiment at the Neal Smith National Wildlife Refuge, in Jasper County, Iowa, US, in which strips of prairie vegetation were planted within watersheds of corn (Zea mays) and soybean (Glycine max) production to aid in soil and water conservation. The project includes 12 0.5- to 3.2-ha watersheds. Nine watersheds included buffer strips in one of three design treatments that varied the number ...


Strategies For Recombinant Protein Production In Maize, Xing Xu Jan 2012

Strategies For Recombinant Protein Production In Maize, Xing Xu

Graduate Theses and Dissertations

Maize is not only one of the world's most important crops, but it is also the first field-grown plant-based recombinant expression system developed for commercial purposes. With advantages of low cost, high yield, high protein stability, and well-developed transformation technology over other plant systems, maize is considered to be an ideal recombinant production system. However, there are three major challenges limiting the use of maize for producing recombinant proteins: 1) maize lacks mammalian-like post-translational modification ability that may be required for pharmaceutical and industrial proteins; 2) transgenic pollen containment in open-field production; and 3) low expression of recombinant products ...


Transcriptional Mechanisms Of Brassinosteroid Regulated Plant Growth And Stress Responses, Huaxun Ye Jan 2012

Transcriptional Mechanisms Of Brassinosteroid Regulated Plant Growth And Stress Responses, Huaxun Ye

Graduate Theses and Dissertations

Plant Steroid hormones, Brassinosteroids (BRs), play important roles in plant growth, development and responses to various stresses. BR signal through receptor BRI1 and BAK1 and a series signaling intermediates to control the activities of BES1/BZR1 family transcription factors that control the expression of thousands of genes, half of which are induced and the other half repressed by BR. While BES1 is known to activate BR-induced genes by itself or cooperating with co-activators, such as transcription factors, histone modification enzymes and transcription elongation factors, how BES1 mediates the BR-repressed gene expression is not known. In chapter Ⅱ, MYBL2, a small ...


Glyphosate-Tolerant Asiatic Dayflower (Commelina Communis L.): Ecological, Biological And Physiological Factors Contributing To Its Adaptation To Iowa Agronomic Systems, Jose Maria Gomez Jan 2012

Glyphosate-Tolerant Asiatic Dayflower (Commelina Communis L.): Ecological, Biological And Physiological Factors Contributing To Its Adaptation To Iowa Agronomic Systems, Jose Maria Gomez

Graduate Theses and Dissertations

Asiatic dayflower is a difficult weed to control with glyphosate, and has become a problem in glyphosate-tolerant soybean and corn for some Iowa farmers. Asiatic dayflower is an annual plant that is widely distributed in the temperate zones of the world. Also, this weed produces aerial dimorphic seeds, a common feature in other weeds belonging to the Commelinaceae. Asiatic dayflower dimorphic seeds can be described as truncated at one end and the other type described as being concave (i.e. non-truncated). Research investigating the biological and ecological characteristics that gives Asiatic dayflower an ecological advantage in glyphosate tolerant crops is ...


The Impact Of A School Garden Program On Agriculture Learning By Primary School Children In Rural Uganda, Amanda Snodgrass Jan 2012

The Impact Of A School Garden Program On Agriculture Learning By Primary School Children In Rural Uganda, Amanda Snodgrass

Graduate Theses and Dissertations

The FAO of the UN recognizes food-based systems as a platform to address the cornerstones of sustainable development: learning, nutrition, and income. Food security has a strong relationship to primary education and as access to primary education increases, food insecurity decreases. This study measured the impact of a school garden program on agriculture learning of pupils living in a food insecure region of rural Uganda and aimed to identify if the pupils acquire agriculture knowledge and skills through a school garden program. Agriculture learning of pupils attending a school with a school garden program or attending a school without a ...


Analysis Of The Function And The Regulation Of Autophagy In Arabidopsis Thaliana, Yimo Liu Jan 2012

Analysis Of The Function And The Regulation Of Autophagy In Arabidopsis Thaliana, Yimo Liu

Graduate Theses and Dissertations

Plants have developed sophisticated mechanisms to survive under adverse growth conditions. Autophagy is activated in response to multiple abiotic stresses, pathogen infection and senescence in plants. Upon induction of autophagy, portions of cytoplasm are engulfed by double membrane structures termed autophagosomes and are delivered to vacuole for degradation. Over the past decade, the identification of many autophagy-related genes in plants has greatly enhanced our molecular and physiological understanding of plant autophagy. However, the upstream regulatory components in the autophagy pathway and the function of autophagy under various stresses are still unclear. This thesis summarizes my efforts in studying the function ...


The Arabidopsis Crinkly4 Receptor-Like Kinase And Homologs: Regulation Of Kinase Activity Through Intra- And Intermolecular Interactions, Matthew Richard Meyer Jan 2012

The Arabidopsis Crinkly4 Receptor-Like Kinase And Homologs: Regulation Of Kinase Activity Through Intra- And Intermolecular Interactions, Matthew Richard Meyer

Graduate Theses and Dissertations

Arabidopsis CRINKLY4 (ACR4) is a receptor-like kinase (RLK) that is required for the global development of the plant. In aerial tissues ACR4 promotes the differentiation of the outer, epidermal layer in the leaves and reproductive tissues. Loss of ACR4 function results in malformed, `crinkled' leaves due to graft-like fusions of vegetative tissues. Underground, ACR4 is responsible for stem cell differentiation in the root tip and for the initiation of lateral roots. Acr4 mutant plants show increased proliferation of stem cells and increase lateral root initiation sites. ACR4 has architectural features analogous to receptor tyrosine kinases (RTK). It includes an extracellular ...


Agronomic Productivity Of Conventional And Low-External-Input Cropping Systems And Their Effect On Giant Foxtail (Setaria Faberi) Population Dynamics, Robin Gomez Jan 2012

Agronomic Productivity Of Conventional And Low-External-Input Cropping Systems And Their Effect On Giant Foxtail (Setaria Faberi) Population Dynamics, Robin Gomez

Graduate Theses and Dissertations

The first two articles of this dissertation describe field studies carried out to compare agronomic productivity and weed seed decay in a conventional 2-year rotation and two low-external-input crop rotations. The third article comprises a matrix model study of giant foxtail population dynamics in a 2-year corn-soybean and in a 4-year corn-soybean-small grain+alfalfa-alfalfa rotation. These studies found similar or higher corn and soybean yield in low-external-input (LEI) cropping systems that included small grain and legumes than in a simpler 2-year corn-soybean rotation. Economic return was highest in a three year corn-soybean-oat+red clover LEI rotation. In the LEI systems ...


Persistence And Ecological Implications Of Maize-Expressed Transgenic Endo-1,4-Β-D-Glucanase (E1) In Agricultural Soils, Adam Joseph Kenny Jan 2012

Persistence And Ecological Implications Of Maize-Expressed Transgenic Endo-1,4-Β-D-Glucanase (E1) In Agricultural Soils, Adam Joseph Kenny

Graduate Theses and Dissertations

Plant expression of thermostable endoglucanase (E1) [pdb:1ECE] has been proposed for improved conversion of lignocellulose to ethanol for fuel production. Since E1 was isolated from hot springs and has thermostable properties, it may have increased stability when released to agricultural soils during post-harvest residue decomposition. Endoglucanases are a subclass of cellulases and act by cleaving β-1,4 glycosidic bonds in cellulose polymers at amorphous sites. In addition, they are important in carbon cycling and can be useful indicators of possible ecological perturbations in soil. It is estimated that where genetically-engineered maize expressing E1 is grown, it will add 17-120 ...


Field Characterization Of Maize Photosynthesis Response To Light And Leaf Area Index Under Different Nitrogen Levels: A Modeling Approach, Laila Alejandra Puntel Jan 2012

Field Characterization Of Maize Photosynthesis Response To Light And Leaf Area Index Under Different Nitrogen Levels: A Modeling Approach, Laila Alejandra Puntel

Graduate Theses and Dissertations

A better characterization of nitrogen (N) demand is essential for an improved estimation of N requirements by maize crops. Crop growth models can provide a tool for greater understanding of the variable responses of yield to different N levels observed experimentally. Photosynthesis-based models require a detail characterization of the effect of N on the photosynthetic machinery of the leaves and leaf area index (LAI) for capturing N variability and demand. Photosynthetic light response curve at different N levels (0, 90, and 225 kg ha-1) were measured in a field experiment conducted at the Agronomy Research Farm, Iowa State University during ...


Applications Of Non-Parametric Kernel Smoothing Estimators In Monte Carlo Risk Assessments, Allan Francis Trapp Ii Jan 2012

Applications Of Non-Parametric Kernel Smoothing Estimators In Monte Carlo Risk Assessments, Allan Francis Trapp Ii

Graduate Theses and Dissertations

This dissertation addresses two separate issues involving the estimation of risk. The first issue regards the creation of a schedule for the viability testing of seeds stored in long-term storage facilities. The second problem pertains to the time required to simulate risk by using a two-dimensional Monte Carlo.

Genebank managers conduct viability tests on stored seeds so they can replace lots that have viability near a critical threshold, such as 50 or 85 % germination. Currently, these tests are typically scheduled at uniform intervals; testing every 5 years is common. A manager needs to balance the cost of an additional test ...


The Assessment Of Non-Pathogenic Related Effects Of The Seed Treatment Stamina On Germinating Maize Under Cold Stress, Christopher Cody Hejlik Jan 2012

The Assessment Of Non-Pathogenic Related Effects Of The Seed Treatment Stamina On Germinating Maize Under Cold Stress, Christopher Cody Hejlik

Graduate Theses and Dissertations

Maize is an important crop grown in the Midwest. Low temperatures in this region can cause irreversible damage to maize, limiting stand establishment and ultimately affecting yield. Fungal contamination also contributes to poor stand establishment, affecting yield. A new seed treatment fungicide for maize (Stamina) has shown positive effects on maize plants under cold stress, not related to protection against fungi. The goal of this project was to determine whether the seed treatment Stamina protects maize seedlings from cold stress or freezing injury by enhancing superoxide dismutase (SOD) activity in maize seedlings. In this study, three seed treatments (Stamina and ...


Breeding For Cob Traits In Maize, Constantin Jansen Jan 2012

Breeding For Cob Traits In Maize, Constantin Jansen

Graduate Theses and Dissertations

The advantages of maize cobs as cellulosic feedstock are based on their compact architecture and high fraction of cellulose and hemicellulose. Cobs are low in ash content, nutrients, and minerals and their harvest will likely not deplete the soil. Dual-purpose maize, with larger cob biomass and high tissue density, could reduce transport costs providing more farmers with additional income from cob sales. The objective of this study was to lay the foundation for developing dual-purpose maize, combining high cob biomass and grain yield. This included a morphological and genetic analysis of cob characters under varying environments, as well as their ...


Evaluation Of Polypyrimidine Tract-Binding Protein Gene Promoters In Potato (Solanum Tuberosum Cv. Désirée), Nathaniel Martin Butler Jan 2012

Evaluation Of Polypyrimidine Tract-Binding Protein Gene Promoters In Potato (Solanum Tuberosum Cv. Désirée), Nathaniel Martin Butler

Graduate Theses and Dissertations

Polypyrimidine tract-binding (PTB) proteins are RNA-binding proteins that target specific RNAs for post-transcriptional processing by binding CU-rich motifs. PTBs have established functions in a range of RNA processes including splicing, translation, stability, and long-distance transport. Six PTB-like genes identified in potato have been grouped into two clades based on homology to other known plant PTBs. StPTB1 and StPTB6 are closely related to a PTB protein discovered in pumpkin, designated CmRBP50, and contain four canonical RNA-recognition motifs. CmRBP50 is expressed in phloem tissues and functions as the core protein of a phloem-mobile RNA/protein complex. Sequence from the potato genome database ...


Evaluation Of Rootstock And Crop Load Effects On The Performance Of `Gibson Golden Delicious' And Three Scab-Resistant Apple Cultivars, Dennis Ndahura Katuuramu Jan 2012

Evaluation Of Rootstock And Crop Load Effects On The Performance Of `Gibson Golden Delicious' And Three Scab-Resistant Apple Cultivars, Dennis Ndahura Katuuramu

Graduate Theses and Dissertations

At the beginning of the 20th century, Iowa ranked sixth in national apple production. Iowa currently provides about 15 percent of the 1.3 million bushels of fresh apples eaten by Iowans annually (Pirog, 1999) and is ranked at 28th in the nation in production. The reduction in rank was mostly due to the Armistice Day freeze that killed many apple trees in 1940. Given the time needed to establish an orchard and mechanization of grain crops, many farmers changed to corn and soybeans that are less vulnerable to low temperature injury. However, current changing economic conditions and food sourcing ...


Effects Of Maturity Group, Seed Composition And Storage Conditions On The Quality And Storability Of Soybean (Glycine Max L. Merrill) Seed, Gladys Y. Mbofung Jan 2012

Effects Of Maturity Group, Seed Composition And Storage Conditions On The Quality And Storability Of Soybean (Glycine Max L. Merrill) Seed, Gladys Y. Mbofung

Graduate Theses and Dissertations

Soybean seed is usually not carried-over to the next planting season because it deteriorates rapidly in storage, resulting in poor growth when planted. This rapid deterioration is a serious problem in seed production. The short shelf life of soybean seed is the result of its high lipid content and high levels of polyunsaturated linolenic and linoleic acids. The soybean production practice of planting early to maximize yield has led to routine use of seed treatments to protect the seeds and seedlings during the early stages of development. The amount of treated seed is increasing every year as research identifies more ...


Nitrogen Based Establishment And Seedbanking Potential Of Kentucky Bluegrass And Perennial Ryegrass In Athletic Fields, Andrew Hansen Hoiberg Jan 2012

Nitrogen Based Establishment And Seedbanking Potential Of Kentucky Bluegrass And Perennial Ryegrass In Athletic Fields, Andrew Hansen Hoiberg

Graduate Theses and Dissertations

This dissertation outlines work done that investigated the potential of perennial ryegrass and Kentucky bluegrass to form useful, transient seedbanks in athletic field scenarios as well as speeding both spring and fall establishment of said species with increased nitrogen rates. Under the conditions of the studies, neither Kentucky bluegrass nor perennial ryegrass exhibited long term viability, i.e. seedbanking potential, when seeded to bare ground at three different seeding rates and two seeding schedules (one time vs. multiple). Seed was exhausted in the single seeding schedule as most seed germinated and little was left over to germinate later in the ...


Analysis Of Iron Transporters In The Soybean (Glycine Max (L.) Merr.) Genome, Dan Stribe Jan 2012

Analysis Of Iron Transporters In The Soybean (Glycine Max (L.) Merr.) Genome, Dan Stribe

Graduate Theses and Dissertations

Iron plays a significant role in numerous cellular functions. Improved uptake and efficiency of use can have strong positive effects on the health of plants, animals and humans. Major players in iron homeostasis are the Iron-Regulated Transporters (IRT). The purpose of this research is to identify putative Iron-Regulated Transporter genes in soybean, structurally characterize these genes and examine their relational phylogeny. Additionally, gene sequence data and gene expression patterns will be considered to differentiate each gene's potential role in iron homeostasis of soybean. In this study, we identified fourteen soybean gene models with significant predicted protein similarity to A ...


Breeding For Β-Glucan Content In Elite North American Oat (Avena Sativa L.) Using Molecular Markers, Franco Garcia Asoro Jan 2012

Breeding For Β-Glucan Content In Elite North American Oat (Avena Sativa L.) Using Molecular Markers, Franco Garcia Asoro

Graduate Theses and Dissertations

This dissertation explored genomewide association study (GWAS) and conducted actual breeding program in oat using different selection methods to identify molecular markers and improve beta-glucan content- a trait with positive health benefits. Results from GWAS suggested that beta-glucan content in elite oat is controlled by many QTL with small effects. Some of the important markers in our study co-localized with QTL in previous linkage studies. For the selection study, results demonstrated that after two cycles of selection the population means from marker-assisted selection and genomic selection methods were higher than BLUP phenotypic selection. The study also showed that the top ...


Where's The Nitrogen? The Timing And Impacts Of Internal Nitrogen Cycling On Switchgrass (Panicum Virgatum L.) Yield And Biofuel Quality, Danielle Marie Wilson Jan 2012

Where's The Nitrogen? The Timing And Impacts Of Internal Nitrogen Cycling On Switchgrass (Panicum Virgatum L.) Yield And Biofuel Quality, Danielle Marie Wilson

Graduate Theses and Dissertations

Research focused on dedicated bioenergy crops that can be used to meet our advanced biofuels goal, i.e., made from non-food sources like agricultural residues and lignocellulosic feedstocks, has found switchgrass (Panicum virgatum L.) to be a leading candidate species. Switchgrass requires nitrogen (N) in greater quantities, compared to other nutrients, for plant biomass production, but high N concentration ([N]) is undesirable in the harvested biomass feedstock for two reasons: 1) it is economically and environmentally expensive to replace N removed from cropping system and 2) N reduces the conversion efficiency of biomass to biofuels via thermochemical conversion. Immediate reductions ...


Evaluating Usefulness Of 10 Genomic Regions Associated With Sudden Death Syndrome Resistance In Soybean, Alexander Stephen Luckew Jan 2012

Evaluating Usefulness Of 10 Genomic Regions Associated With Sudden Death Syndrome Resistance In Soybean, Alexander Stephen Luckew

Graduate Theses and Dissertations

Soybean sudden death syndrome (SDS) is one of the most important soybean diseases in the Midwestern United States soybean producing region, leading to losses of $190 million per year from 1996 to 2007. The causal agent of SDS is the soilborne fungus, Fusarium virguliforme. The main management practice used to reduce the impact of SDS is planting resistant soybean cultivars. Resistance to SDS is known to be quantitative with 12 known quantitative trait loci (QTL). To identify the QTL with the largest effects on reducing disease severity recombinant inbred lines (RIL) were crossed among themselves and their progeny screened for ...


The Effect Of Carotenoid Candidate Genes On The Photosynthetic Capacity Of Sorghum As Assessed By Linkage Disequilibrium Mapping, Katie Jo Strand Jan 2012

The Effect Of Carotenoid Candidate Genes On The Photosynthetic Capacity Of Sorghum As Assessed By Linkage Disequilibrium Mapping, Katie Jo Strand

Graduate Theses and Dissertations

Carotenoids are accessory pigments that play roles in photosynthesis and photoprotection in plant leaves. Genetic studies to associate carotenoid candidate genes with variation in photosynthetic capacity however, have not been conducted. The objectives of this research project were to characterize the phenotypic variation of photosynthetic rate (A), effective quantum yield (πPSII), and photochemical quenching (qP) in sorghum (Sorghum bicolor L.), and to determine the level of association between phenotypic variation and polymorphisms in carotenoid candidate genes. A LI-COR 6400XT portable photosynthesis unit was used as a high-throughput assessment tool in all experiments. Preliminary studies were performed to evaluate experimental ...


Agronomic And Seed Traits Of Soybean Lines With Genes For Aphid Resistance, Inheritance And Mapping Of Cowpea Mild Mottle Virus-Like Resistance In Soybean, And Fatty Ester Composition Of Low-Phytate, Low-Saturate Soybean Lines, Ryan Christopher Brace Jan 2012

Agronomic And Seed Traits Of Soybean Lines With Genes For Aphid Resistance, Inheritance And Mapping Of Cowpea Mild Mottle Virus-Like Resistance In Soybean, And Fatty Ester Composition Of Low-Phytate, Low-Saturate Soybean Lines, Ryan Christopher Brace

Graduate Theses and Dissertations

Evaluation of aphid resistant backcross (BC) lines containing the Rag1 or Rag2 alleles alone, or with the two alleles combined, indicated that the mean yields of resistant BC lines were less than the mean of the two entries of their susceptible recurrent parent in each of the three experiments. This reduction in mean yield was significant for BC lines containing Rag1 and its combination with Rag2, but not for BC lines with only Rag2. Among the BC lines in each experiment, only a small percentage were significantly different from the mean yield of their susceptible recurrent parent. Significant differences in ...