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The Brown Midrib 2 (Bm2) Gene Of Maize Encodes Methylenetetrahydrofolate Reductase, Ho Man Tang Jan 2011

The Brown Midrib 2 (Bm2) Gene Of Maize Encodes Methylenetetrahydrofolate Reductase, Ho Man Tang

Graduate Theses and Dissertations

Brown-midrib (bm) mutants are associated with reductions in lignin concentration and alterations in lignin composition. Biomass with reduced lignin concentration is more easily digested by ruminants and is a more efficient feedstock for biofuel production. Analysis of bm genes can enhance our understanding of the biochemical pathways that lead to lignin accumulation, therefore offering the promise of designing crops with reduced lignin concentration. This information could also provide an alternative way to capture carbon in soil to reduce the atmospheric level of carbon dioxide. Here, we report the mapping, cloning and functional analysis of the bm2 gene of maize. The ...


Effect Of Dew And Intercepted Precipitation On Radar Backscatter Of A Soybean Canopy, Eric Scott Russell Jan 2011

Effect Of Dew And Intercepted Precipitation On Radar Backscatter Of A Soybean Canopy, Eric Scott Russell

Graduate Theses and Dissertations

Soil moisture is a small but very active part of the hydrologic cycle. Recently many studies and reviews have been conducted on its impacts on climate change and short-term forecasting. Satellites could be used as a means for monitoring global soil moisture evolution. In November, 2009, the European Space Agency launched the first satellite dedicated to measuring soil moisture: Soil Moisture Ocean Salinity (SMOS). NASA is planning on launching its own satellite that will incorporate both a passive sensor (like SMOS) and an active sensor in hope of increasing the spatial resolution of the measurements. From September 23, 2008 (DOY266 ...


Screening And Genotyping Of Ga1 Gene, And Genotype X Environment Interaction Of Cross Incompatibility In Maize, Moises David Gonzalez Jan 2011

Screening And Genotyping Of Ga1 Gene, And Genotype X Environment Interaction Of Cross Incompatibility In Maize, Moises David Gonzalez

Graduate Theses and Dissertations

The steady increase of genetically-modified (GM) corn (Zea mays L.) in the U.S. makes production of transgene-free corn more difficult to achieve. A strategy to minimize cross-contamination of non-GM corn with GM corn is by using unilateral cross-incompatibility controlled by the Ga1S allele. This allele is transferred to desired germplasm through backcrossing before cross-incompatible Ga1S/Ga1S lines are obtained. The usefulness of this system in preventing cross-fertilization with foreign ga1 pollen might be affected by a combination of environmental effects and heritability of the trait. Methods used for selection of cross-incompatibility in maize are based on differential incompatibility of ...


Leaf Wetness: Implications For Agriculture And Remote Sensing, Tracy L. Rowlandson Jan 2011

Leaf Wetness: Implications For Agriculture And Remote Sensing, Tracy L. Rowlandson

Graduate Theses and Dissertations

Information regarding leaf wetness duration (LWD) has been used in disease management schemes for decades by researchers in the plant disease and agricultural meteorology communities. LWD is currently measured predominantly by electronic leaf wetness sensors or through the use of a model that represents latent heat transfer. Studies have been conducted that examine the placement, orientation and treatment of leaf wetness sensors. Some studies have compared empirical and physical models to LWD measurements obtained from leaf wetness sensors. However, an article that summarizes all aspects of leaf wetness sensors and models, addressing the benefits and disadvantages, has not been provided ...


An Epidemiological Comparison Of The Us And Canadian Plum Pox Virus Eradication Programs, Andrew Gougherty Jan 2011

An Epidemiological Comparison Of The Us And Canadian Plum Pox Virus Eradication Programs, Andrew Gougherty

Graduate Theses and Dissertations

Plum pox virus (PPV) is one of the most damaging viral diseases of Prunus spp. worldwide. The virus was first detected in North America in Pennsylvania in 1999, and in Ontario, Canada in 2000. Following the detection of PPV in Pennsylvania and Ontario, both countries implemented PPV survey and eradication programs. The eradication program was successful in Pennsylvania, as PPV was officially declared eradicated in 2009. However, PPV remains present in Ontario. The US and Canadian eradication programs had differing effects on the epidemiology of PPV in their respective countries. The objectives of this research, therefore, were to: (i) quantify ...


Characterization And Management Of Genetic Diversity In Phytophthora Sojae Populations, Silvina Maria Stewart Jan 2011

Characterization And Management Of Genetic Diversity In Phytophthora Sojae Populations, Silvina Maria Stewart

Graduate Theses and Dissertations

SUMMARY

Phytophthora root and stem rot (PRR) of soybean, caused by , has been managed traditionally through breeding for resistance. Breeding efforts have focused on incorporating major Rps gene resistance into soybean lines but the pathogen is rapidly and continuously evolving, the complexity of pathotypes is increasing, and the durability of the Rps in the field is short.

It has been suggested that a large reservoir of genetic diversity exists in populations of , however, only a few studies have tried to characterize this diversity using genetic markers. In this study, we assessed diversity of in Iowa using microsatellite (SSR) markers (Objective ...


Potassium-Magnesium Antagonism In High Magnesium Vineyard Soils, Joseph Michael Hannan Jan 2011

Potassium-Magnesium Antagonism In High Magnesium Vineyard Soils, Joseph Michael Hannan

Graduate Theses and Dissertations

The Iowa wine and grape industry underwent a rapid phase of growth at the turn of the 21st century that is continuing to evolve and develop today. Cultivar trials across the state found that `Marquette' grapevines were performing poorly in eastern Iowa while other cultivars performed well. A preliminary investigation suggested a magnesium induced potassium deficiency and/or above optimum soil pH as the cause of poor growth of `Marquette'. Soils in the upper Mississippi Valley are derived from limestone and dolomite bedrock resulting in their characteristically high pH and high magnesium properties, which often inhibits potassium uptake. Recommendations to ...


Utilization Of Near-Isogenic Lines To Identify Genes Underlying Iron-Efficiency Qtl, Gregory Allan Peiffer Jan 2011

Utilization Of Near-Isogenic Lines To Identify Genes Underlying Iron-Efficiency Qtl, Gregory Allan Peiffer

Graduate Theses and Dissertations

Nutrient deficiencies are a significant abiotic stress of soybean. Iron deficiency chlorosis is a major concern in the upper midwestern region of the United States due to the prevalence of calcareous soils. Soybean's susceptibility to iron stress results in yield losses into the hundreds of millions each year. Understanding the molecular differences between resistant and susceptible cultivars will significantly affect future yield and revenue. Through the use of near-isogenic lines (NILs), molecular markers, and gene expression we have identified the donor parent introgressions through both classical SSR mapping and a novel method of SNP clustering which can be preformed ...


Competitive Ability Of Creeping Bentgrass Cultivars And Their Potential For Renovating Existing Putting Greens Through Interseeding, Marcus Jones Jan 2011

Competitive Ability Of Creeping Bentgrass Cultivars And Their Potential For Renovating Existing Putting Greens Through Interseeding, Marcus Jones

Graduate Theses and Dissertations

Golf is a key industry that generates jobs, commerce, economic development, and tax revenues for communities throughout the United States. A survey conducted in Iowa showed that golf generated 769.6 million dollars in total economic output while providing over 10,000 jobs to the state. The integrity of turf swards is routinely compromised by invasion from annual bluegrass (Poa annua L.), and higher levels of inputs are needed to maintain acceptable quality. New cultivars of creeping bentgrass (Agrostis stolonifera L.) offer improved agronomic characteristics and are better able to resist invasion from annual bluegrass. The overall objective of this ...


Effects Of Phosphorus And Potassium Fertilization Rate And Placement Method On Soybean (Glycine Max L.) Seed Quality And Long-Term Storability, Keaton Krueger Jan 2011

Effects Of Phosphorus And Potassium Fertilization Rate And Placement Method On Soybean (Glycine Max L.) Seed Quality And Long-Term Storability, Keaton Krueger

Graduate Theses and Dissertations

The fertilization rate and placement methods of phosphorus and potassium fertilizers can positively affect soybean [Glycine max L. (Merr.)] seed composition and yield in some environments, but not in others. Soybean seed production costs and chemically-treated seed disposal costs have increased, coinciding with farmers' adoption of planting chemically-treated soybean seeds. Seeds are treated with fungicides and sometimes with insecticides to provide protection from pathogens and insects before seed emergence. These changes in production costs have renewed seed industry's interest in identifying agronomic practices that enhance soybean quality, composition, and storability. Soybean seeds do not store well and seed quality ...


Optimization Of Doubled Haploid Production In Maize (Zea Mays L.), Adam Edward Vanous Jan 2011

Optimization Of Doubled Haploid Production In Maize (Zea Mays L.), Adam Edward Vanous

Graduate Theses and Dissertations

Maize breeding lines developed using doubled haploids produced through in vivo induction of maternal haploids are completely homozygous and homogeneous. In the past decade, this type of breeding has become more increasingly used due to progress in the logistics behind doubled haploid line production. Applications of these lines in hybrid breeding include (i) increased efficacy of selection, (ii) reduced breeding cycle length, (iii) reduced effort for line maintenance, and (iv) ability for molecular marker applications. This thesis reviews the experimental foundation of (i) in vivo induction of maternal haploids, (ii) the dominant anthocyanin marker gene, R1-nj, as a means of ...


Earlier Harvest And Drying Of Soybean Seed Within Intact Pods Maintains Seed Quality, Ross David Ennen Jan 2011

Earlier Harvest And Drying Of Soybean Seed Within Intact Pods Maintains Seed Quality, Ross David Ennen

Graduate Theses and Dissertations

Soybean [Glycine max (L.) Merr.] seed quality (viability and vigor) is critical to seed producers, emphasizing the need to maximize the quality of the harvested seeds. Currently, soybean seeds are harvested at a moisture content of ≤ 160 g kg-1, similar to the moisture content of harvested soybean grain. However, soybean seed quality peaks at physiological maturity (PM). Allowing soybean seeds to desiccate in the field increases vulnerability to seed deterioration, disease, and harvest losses. Early harvest of soybean seeds and drying within intact pods might maintain seed quality. Our research examined the effect of maturity stage (green-, yellow-, or ...


Soybean Aphid Development And Agronomic Performance Of Soybean Lines With The Rag1 And Rag2 Genes For Insect Resistance, Shaylyn Lena Wiarda Jan 2011

Soybean Aphid Development And Agronomic Performance Of Soybean Lines With The Rag1 And Rag2 Genes For Insect Resistance, Shaylyn Lena Wiarda

Graduate Theses and Dissertations

The soybean aphid (Aphis glycines Matsumura) can reduce the yield of soybean [Glycine max (L.) Merr.] cultivars that are susceptible to the insect. Two genes that confer resistance to some biotypes are Rag1 (R1) from PI548663 and Rag2 (R2) from PI200538. These genes individually can limit the development of soybean aphids and prevent yield loss. The impact of these genes combined is not known. One objective of my research was to determine the impact of the Rag1 and Rag2 genes on the performance of lines for agronomic and seed traits. A second objective of my research was to compare the ...


Novel Approaches To Improving Qualities Of Maize Endosperm, Anastasia Lorellen Bodnar Jan 2011

Novel Approaches To Improving Qualities Of Maize Endosperm, Anastasia Lorellen Bodnar

Graduate Theses and Dissertations

Maize is a high yielding crop that provides a relatively high calorie source of food and feed, but focus on yield has not improved nutritional qualities. Some nutrients that are lacking in maize are iron and essential amino acids. In this dissertation some ways that genes from maize might be used to improve nutritional quality of maize are discussed, including improvement of bioavailable iron with maize globin and exploration of maize seed storage proteins. In addition, strategies to improve maize are explored, including breeding with mutations and transgenes and investigation of the effects of selection on transgenes.

Maize globin was ...


Mineral Evaluation And Quantitative Trait Loci Mapping In A Soybean (Glycine Max (L.) Merr.) Population Developed For Iron Deficiency Chlorosis Resistance, Keith E. King Jan 2011

Mineral Evaluation And Quantitative Trait Loci Mapping In A Soybean (Glycine Max (L.) Merr.) Population Developed For Iron Deficiency Chlorosis Resistance, Keith E. King

Graduate Theses and Dissertations

The identification of the causal gene(s) of disease resistance is paramount in plant breeding. Nutrient analysis in plant tissues can lead to the identification of these gene(s). The objectives of this research were 1) to map quantitative trait loci (QTL) for seed and leaf iron and zinc concentration in the soybean population Anoka x A7, 2) to determine if QTL for iron and zinc accumulation co-localized to the same regions of the genome, 3) to determine if any of newly identified QTL for Fe and/or Zn concentration correlate with QTL previously identified for Fe efficiency, 4) to ...


Soil Ph And Lime Management For Corn And Soybean, Agustin Pagani Jan 2011

Soil Ph And Lime Management For Corn And Soybean, Agustin Pagani

Graduate Theses and Dissertations

The objectives of this work were to (1) asses how Shoemaker-McLean-Pratt (SMP), Sikora, and Mehlich buffers, titratable acidity, and soil properties relate to soil pH change due to liming, (2) study the variation of soil pH and crop response to lime within fields, (2) identify optimum soil pH for corn and soybean, (3) evaluate the effect of subsoil pH on crop response to lime in Iowa, and (4) evaluate the rate of soil pH increase from application of different lime sources. Fourteen replicated strip trials with lime were established in Iowa from 2007 to 2009 using precision agriculture technologies and ...


Pleiotropic Effects Of Genes Involved In Cell Wall Lignification On Agronomic Characters, Yongsheng Chen Jan 2011

Pleiotropic Effects Of Genes Involved In Cell Wall Lignification On Agronomic Characters, Yongsheng Chen

Graduate Theses and Dissertations

Brown midrib (bm) mutants in maize, which are characterized with altered lignin composition, reduced lignin content and thus with enhanced cell wall digestibility (CWD), are often associated with inferior agronomic traits. To understand how the undesirable associations happen would help us better design strategies to manipulate the cell wall lignification for CWD enhancement without sacrificing biomass yield. First, I reviewed the current knowledge and approaches to study the nature of trait correlations. We proposed that dissection of the trait correlations into DNA polymorphism level is beneficial for plant breeding as intergenic, intragenic, or true pleiotropy will have different impact. Secondly ...


Impact Of The Mon89788 Event For Glyphosate Tolerance On Agronomic And Seed Traits Of Soybean And Molecular Characterization Of The Mutant Fap3(A22) Allele For Reduced Palmitate Concentration In Soybean, Brian De Vries Jan 2011

Impact Of The Mon89788 Event For Glyphosate Tolerance On Agronomic And Seed Traits Of Soybean And Molecular Characterization Of The Mutant Fap3(A22) Allele For Reduced Palmitate Concentration In Soybean, Brian De Vries

Graduate Theses and Dissertations

Glyphosate is a popular herbicide for weed control in fields planted to soybean [Glycine max (L.) Merr.] cultivars with a transgene that provides tolerance to the chemical. A transgenic event MON89788, known commercially as Roundup Ready 2 Yield y, was developed by the Monsanto Co. as an alternative to the event 40-3-2 for glyphosate tolerance in soybean. The objective of our study was to compare the agronomic and seed traits of glyphosate-tolerant (GT) lines and glyphosate-susceptible (GS) lines from populations segregating for MON89788. The transgene was backcrossed into three GS cultivars to develop BC2 populations. There were 27 GT and ...


Use Of Geographic Information Systems At Gifft Hill School, St. John, U.S. Virgin Islands, Kevin Richard Duerfeldt Jan 2011

Use Of Geographic Information Systems At Gifft Hill School, St. John, U.S. Virgin Islands, Kevin Richard Duerfeldt

Graduate Theses and Dissertations

Board members, administrators, and faculty at Gifft Hill School, St. John, U.S. Virgin Islands, required a method for recording, organizing, and communicating information about the property and facilities on the school grounds. This information will be used while planning and managing facilities expansion. In addition to these physical attributes of the property and facilities Iowa State University desired a way of recording growing conditions to inform the design and manage of a school garden program. Geographic information systems (GIS) were evaluated as a possible solution to managing this spatially variable information. Using ArcGIS, Global Positioning System (GPS), data available ...


A Look Into The Molecular Mechanisms Of Parasitism Including The Functional Characterization Of Heterodera Schachtii Secreted Effector Proteins And The Response Of Plant Small Rna To Nematode Infection, Peter Jacob Howe Jan 2011

A Look Into The Molecular Mechanisms Of Parasitism Including The Functional Characterization Of Heterodera Schachtii Secreted Effector Proteins And The Response Of Plant Small Rna To Nematode Infection, Peter Jacob Howe

Graduate Theses and Dissertations

Cyst nematodes are some of the most destructive plant pathogens. These biotrophic parasites form elaborate feeding sites, syncytia, in the roots of their host plants and remove valuable nutrients from the plant. During the formation of the syncytium the nematode secretes effector proteins into root cells, which causes extensive molecular changes in the cell and allows the parasite to manipulate cellular processes. The work reported here describes the functional characterization of three nematode effector proteins and a report profiling the role of host small RNAs in the infection process.


Argillic Horizons And Clay-Sized Particles - An Alternative Interpretation Of Their Dynamics In Sola Development And Across Catenas, Mostafa Abdelssamie Abdelkhalik Ibrahim Jan 2011

Argillic Horizons And Clay-Sized Particles - An Alternative Interpretation Of Their Dynamics In Sola Development And Across Catenas, Mostafa Abdelssamie Abdelkhalik Ibrahim

Graduate Theses and Dissertations

Soil is one of the main resources for most terrestrial life. Soil Sciences study soils from many different perspectives. They are very important for agriculture, construction and mining. This dissertation has two overarching aims: (1) to better understand how and where the argillic horizon forms; and, (2) to better understand how the clay-sized fraction of soil behaves within the sola and catenas of Iowa. As pedologists, we are interested in studying argillic horizons because they have unique characteristics that formed by different mechanisms of clay accumulation. Formation of the argillic horizon has been investigated for decades. In this dissertation I ...


Oat (Avena Sativa L.) Quality Improvement For Increased Beta-Glucan Concentration, Mark Newell Jan 2011

Oat (Avena Sativa L.) Quality Improvement For Increased Beta-Glucan Concentration, Mark Newell

Graduate Theses and Dissertations

Oat (Avena sativa L.) is a grass crop highly recognized for its positive human health benefits when consumed as a whole grain. These health benefits are due in part to mixed-linkage-(1,3;1,4)-beta-D-glucan (referred to as beta-glucan), a soluble fiber found mainly in the endosperm cell walls. Because of the implications associated with consumption of oat beta-glucan, this research explores the genetic basis of beta-glucan synthesis in oats.


Replication Protein A And Its Role In The Iron Stress Response Of Soybean, Sarah Atwood Jan 2011

Replication Protein A And Its Role In The Iron Stress Response Of Soybean, Sarah Atwood

Graduate Theses and Dissertations

Soybean (Glycine max (L.) Merr.) is the second most abundant crop in the United States, with a total crop value of nearly $39 billion in 2010. U.S. soybean exports are used as an important protein and oil source in over 80 countries. Abiotic stress, such as iron deficiency chlorosis (IDC), threatens soybean yields, which affect farmers' profits in the United States as well as nutrition of consumers all over the world. IDC occurs when iron is unavailable to soybean roots, often in the calcareous soils of the upper Midwest United States. Iron stress causes a decrease in chlorophyll production ...


Direct Determination Of 1-Aminocyclopropane-1-Carboxylic Acid In Plant Tissues By Using A Gas Chromatograph With Flame-Ionization Detection, Katey H. Warnberg Jan 2011

Direct Determination Of 1-Aminocyclopropane-1-Carboxylic Acid In Plant Tissues By Using A Gas Chromatograph With Flame-Ionization Detection, Katey H. Warnberg

Graduate Theses and Dissertations

1–aminocyclopropane–1–carboxylic acid is the immediate precursor for ethylene, a phytohormone that is produced in many plant tissues, which is effective in trace amounts (≤ 1 yl/l). Quantitative determination of ACC in biological tissues is paramount to understanding the regulation of this metabolic process. The most widely accepted method for quantifying 1–aminocyclopropane–1–carboxylic acid requires its oxidation to ethylene, which then is measured by gas chromatography. Our objective was to develop a method for the rapid, direct quantification of 1–aminocyclopropane–1–carboxylic acid by using a gas chromatograph with a flame–ionization detector. Ethylene production ...


Environmental Analyses And Candidate Gene Expression Of Ms9 Male-Sterility Locus And Computational Identification Of Candidate Genes For Male-Sterility Loci In Soybean, Christiana Wiebbecke Jan 2011

Environmental Analyses And Candidate Gene Expression Of Ms9 Male-Sterility Locus And Computational Identification Of Candidate Genes For Male-Sterility Loci In Soybean, Christiana Wiebbecke

Graduate Theses and Dissertations

Rapid growth rate of the human population is driving the increased demand for cultivated soybean [Glycine max (L.) Merrill], a major source of protein and oil in global food, feed, and biofuel production. Increasing yield at a pace faster than traditional breeding methods presently achieve has become a need and future commitment. In soybean, a self-pollinated crop, a possibility to increase yield may result from the development of hybrid cultivars. Researchers have been interested in floral development and pollination, as these factors have a direct impact on maintaining and enhancing crop yields. Soybean breeders also need to understand phenotypic differences ...


Establishment Of Switchgrass In Corn Across A Landscape Gradient: Establishment, Yield, And Quality Of Biomass Feedstock, Theodore P. Gunther Jan 2011

Establishment Of Switchgrass In Corn Across A Landscape Gradient: Establishment, Yield, And Quality Of Biomass Feedstock, Theodore P. Gunther

Graduate Theses and Dissertations

Biofuel production in the United States is expected to offset a significant portion of current fuel use through continued use of corn (Zea mays L.) grain and increasingly from alternative feedstocks. Switchgrass (Panicum virgatum L.) is one such species with potential to be used as an alternative feedstock, but establishment is slow and requires long term commitment of land to reach maximum productivity. Switchgrass can be established while producing a corn crop using 2-4-D and atrazine herbicide and seeding switchgrass prior to corn planting, reducing the risk of producing switchgrass as a crop. Relative performance of both corn and switchgrass ...


Genetic Basis Of Maize Whole Kernel, Embryo, And Endosperm Oil, Karen Elaine Grote Jan 2011

Genetic Basis Of Maize Whole Kernel, Embryo, And Endosperm Oil, Karen Elaine Grote

Graduate Theses and Dissertations

Maize hybrids with elevated oil content have potential value as livestock feed directly and as a source of oil for human consumption. Selection on embryo and/or endosperm oil content could supplement selection at the whole kernel level and enable the development of hybrids with tissue-specific oil accumulation. The genetic basis of embryo and endosperm oil content was investigated in two separate populations: a set of elite commercial inbreds which varied for whole kernel oil content and in a segregating set of lines derived from a cross between high and low whole kernel oil parents. The traits were repeatable across ...


Antioxidants And Dehydrin Metabolism Associated With Osmopriming-Enhanced Stress Tolerance Of Germinating Spinach (Spinacia Oleracea L. Cv. Bloomsdale) Seeds, Keting Chen Jan 2011

Antioxidants And Dehydrin Metabolism Associated With Osmopriming-Enhanced Stress Tolerance Of Germinating Spinach (Spinacia Oleracea L. Cv. Bloomsdale) Seeds, Keting Chen

Graduate Theses and Dissertations

Osmopriming is a pre-soaking treatment that improves seed germination performance as well as stress tolerance. In this study, we use spinach (Spinacia oleracea cv. Bloomsdale) as the model to study cellular mechanisms contributing to the improved stress tolerance during post-priming germination. We first determined an optimal osmopriming protocol for `Bloomsdale' spinach, i.e. priming seeds with -0.6 MPa PEG 8000 at 15 yC for 8 d. This protocol also improved germinating seeds' tolerance to temperature (sub- and supra-temperature) and desiccation stress. To explore the biochemistry contributing to the priming-induced stress tolerance, we examined two extensively studied stress-responsive components: antioxidant ...


The Effect Of Fungicides On Soybean In Iowa Applied Alone Or In Combination With Insecticides At Two Application Growth Stages On Disease Severity And Yield, Nathan Bestor Jan 2011

The Effect Of Fungicides On Soybean In Iowa Applied Alone Or In Combination With Insecticides At Two Application Growth Stages On Disease Severity And Yield, Nathan Bestor

Graduate Theses and Dissertations

The use of foliar fungicides on soybean, Glycine max [L.] Merr., has not been recommended in most years in Iowa. But with economic factors such as price of grain, rebate offers on early purchases of fungicides, and rising production costs, the use of fungicides and other pesticides has increased dramatically over the last decade. There is little information regarding the impact of spraying foliar fungicides in Iowa. We tested the effect of fungicide applications at growth stage R1 (beginning of flowering) and R3 (beginning of pod set) on disease control and yield responses. Diseases present in this study included Septoria ...


Did Recurrent Selection For Yield Affect Iowa Stiff Stalk Synthetic Maize Population Grain Fill Characteristics?, Steve James Eichenberger Jan 2011

Did Recurrent Selection For Yield Affect Iowa Stiff Stalk Synthetic Maize Population Grain Fill Characteristics?, Steve James Eichenberger

Graduate Theses and Dissertations

Hybrid maize yield increases, new product development, and increased stress tolerance can be more easily achieved with a better understanding of the physiological and genetic basis for phenotypic changes in response to recurrent selection for yield. The purpose of this study was to identify changes in grain fill characteristics and their interaction with plant density in a closed population and identify a model that accurately predicts grain fill in this population. We hypothesize that recurrent selection for increased yield indirectly impacted the grain fill characteristics of maize including final kernel weight, kernel fill duration, and kernel fill rate in the ...