Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

PDF

Iowa State University

Plant Sciences

Graduate Theses and Dissertations

Plant Breeding

Articles 1 - 15 of 15

Full-Text Articles in Entire DC Network

Genome-Wide Association And Epistasis Studies Of Sclerotinia Sclerotiorum Resistance In Soybean, Tara Catherine Moellers Jan 2016

Genome-Wide Association And Epistasis Studies Of Sclerotinia Sclerotiorum Resistance In Soybean, Tara Catherine Moellers

Graduate Theses and Dissertations

Sclerotinia stem rot or white mold (WM) [Sclerotinia sclerotiorum (Lib.) de Bary] is an important fungal disease affecting soybean [Glycine max (L.) Merr.] and causes yield and quality losses. WM is prevalent in cool and moist environments, particularly in the soybean growing regions of Northern United States and Canada. Although sources of complete resistance have not yet been identified, several quantitative trait loci (QTL) for partial resistance have been reported but generally using bi-parental mapping populations. Genome-wide association (GWA) studies have been used to dissect complex disease resistance traits in plants and to identify the genes controlling the expression. WM ...


Identification And Characterization Of Brown Stem Rot Resistance In Soybean, Chantal Elaine Mccabe Jan 2016

Identification And Characterization Of Brown Stem Rot Resistance In Soybean, Chantal Elaine Mccabe

Graduate Theses and Dissertations

Breeding for pathogen resistance is an important objective to improve and protect soybean yields. In 2010, 14.4% of total soybean yield was suppressed by diseases. Brown stem rot (BSR), caused by the fungus Phialophora gregata, reduces yield by as much as 38%. To date, three dominant BSR resistance genes have been identified: Rbs1, Rbs2, and Rbs3. The objectives of my research were 1) to determine if plant introductions contained novel BSR resistance genes, 2) to determine the correlation between P. gregata hyphae growth and foliar symptoms as well as characterize the response of the three BSR resistance genes to ...


Genomic Selection With Deep Neural Networks, Riley Mitchell Mcdowell Jan 2016

Genomic Selection With Deep Neural Networks, Riley Mitchell Mcdowell

Graduate Theses and Dissertations

Reduced costs for DNA marker technology has generated a huge amount of molecular

data and made it economically feasible to generate dense genome-wide marker maps of lines

in a breeding program. Increased data density and volume has driven an exploration of

tools and techniques to analyze these data for cultivar improvement. Data science theory

and application has experienced a resurgence of research into techniques to detect or ”learn”

patterns in noisy data in a variety of technical applications. Several variants of machine

learning have been proposed for analyzing large DNA marker data sets to aid in pheno-

type prediction and ...


Improvements To The Maize (Zea Mays L.) In Vivo Maternal Doubled Haploid System, Gerald Neil De La Fuente Jan 2015

Improvements To The Maize (Zea Mays L.) In Vivo Maternal Doubled Haploid System, Gerald Neil De La Fuente

Graduate Theses and Dissertations

The maize (Zea mays L.) in vivo maternal doubled haploid system has been widely applied to maize breeding and genetics in recent decades and is an important part of the majority of public and private maize breeding programs today. The principal advantage of the doubled haploid system is the ability to generate completely homozygous inbred lines in as little as two seasons. Other advantages to this system include more rapid integration of loci of interest and increased usefulness over traditional lines developed through self-pollination. In this dissertation, some of the major problems in the maternal doubled haploid system are addressed ...


Identification Of Qtl Associated With Nitrogen Metabolism In A Maize (Zea Mays L. Ssp. Mays) Testcross Population, Ignacio Trucillo Silva Jan 2015

Identification Of Qtl Associated With Nitrogen Metabolism In A Maize (Zea Mays L. Ssp. Mays) Testcross Population, Ignacio Trucillo Silva

Graduate Theses and Dissertations

Maize is a widely cultivated crop in the world and its production relies heavily on nitrogen (N) fertilization. N is an essential mineral nutrient for plant growth and development. However, during the last decades excessive quantities of N have been applied by farmers, a surplus to what maize plants can uptake, and several problems have arisen, such as pollution of the ecosystem and an economic loss to farmers. Breeding maize hybrids that are more efficient in the use of N is a long term goal for plant breeders. Nonetheless, previous to breeding, the genetic basis of N-metabolism in maize would ...


Gametophytic Cross-Incompatibility In Maize: Resequencing The Ga1 Locus, Marianne Lynn Emery Jan 2015

Gametophytic Cross-Incompatibility In Maize: Resequencing The Ga1 Locus, Marianne Lynn Emery

Graduate Theses and Dissertations

Maize is an important staple crop for many countries. Culture dictates maize use, processing, and incorporation into foods. The crop has a rich history of domestication and improvement. With its relative ease of genetic manipulation, maize is considered a model crop for plant genetic experimentation. Recent biotechnological advances, as well as the completed B73 reference genome sequence, have expedited maize improvement. One such profound advance that has greatly increased profitability of maize is the use of transgenes. Despite the many benefits, transgenic plants are problematic when they contaminate transgene-free maize. Maintaining the purity of transgene-free maize is crucial, but often ...


Genetic And Physiologic Analyses Of Soybean Grain Yields In Water Limited Environments, Dawn Gibson Jan 2015

Genetic And Physiologic Analyses Of Soybean Grain Yields In Water Limited Environments, Dawn Gibson

Graduate Theses and Dissertations

Increasing grain yield in soybean is an important breeding goal for plant breeders. While identification of yield QTL can result in identification of genomic regions for increasing yield, these regions are often not consistent across environments due to genetic and environment interactions. Water limitation for crop growth is one such environment in which yield QTL are not consistent. Water limitations during grain fill can be especially devastating to the final yield of a crop. The objective of this study was to identify and then map QTL in three families of recombinant inbred lines (RILs) developed from two plant introductions and ...


Adaptability Potential Of Corn For Groundcover Cropping Systems, Nickolas James Bowden Jan 2014

Adaptability Potential Of Corn For Groundcover Cropping Systems, Nickolas James Bowden

Graduate Theses and Dissertations

Experiments were conducted from 2008-2010 to determine genetic adaptability potential of corn when grown in competition with cover crops or living mulches. Cover crops were grown simultaneously with corn crop. Genetic potential was identified in female inbred lines more so than in male inbred lines when tested in hybrid combination.


A New Metric For Parental Selection In Plant Breeding, Ye Han Jan 2014

A New Metric For Parental Selection In Plant Breeding, Ye Han

Graduate Theses and Dissertations

Plant breeding is the art of genetic improvement through creation and selection for novel characteristics in plants. Parental selection provides the raw materials for creating each new generation of genetic improvements. Ultimately, the probability of successfully meeting the breeding objectives depends on selection of parents for intermating. With the application of operations research, we developed a new metric, parental breeding value (PBV), based on application of conditional probability distribution to help to solve the parental selection problem to accelerate the process of plant breeding and save resources at the same time. The water pipe model is provided in the thesis ...


Genetic Analysis Of The Ibm2syn10-Dh Maize Population For Response To Low And High Nitrogen Input, Pedro José Gonzalez-Portilla Jan 2014

Genetic Analysis Of The Ibm2syn10-Dh Maize Population For Response To Low And High Nitrogen Input, Pedro José Gonzalez-Portilla

Graduate Theses and Dissertations

Maize growth and development depends highly in the capacity of the plants to absorb Nitrogen (N) from the soil. Producing a high-yielding maize crop that requires less N input is currently one important goal of maize breeding programs. In order to understand the dynamics of N use in maize, the study of phenotypic and genetic response to N deficiency must be performed. Using lines from the high resolution IBM2Syn10-DH population, the goals of this study were: 1) to identify the phenotypic response of the root system architecture (RSA) of 14-day old maize seedlings grown under contrasting levels of N; 2 ...


Association Mapping Analysis For Brassinosteroid Candidate Genes And Plant Architecture In A Diverse Sorghum Bicolor Panel, Maria Betsabe Mantilla Perez Jan 2013

Association Mapping Analysis For Brassinosteroid Candidate Genes And Plant Architecture In A Diverse Sorghum Bicolor Panel, Maria Betsabe Mantilla Perez

Graduate Theses and Dissertations

Sorghum bicolor (L) Moench is a cultivated and self-pollinated species used traditionally for human consumption, livestock feed and forage production. Recently, sorghum has received attention as a bioenergy crop because of its high water use efficiency, yield biomass potential and biomass composition. To develop superior sorghum inbred lines for bioenergy production, it would be beneficial to understand the genetic mechanisms controlling plant architecture traits. Sorghum presents a remarkable diversity in the species bicolor that can be exploited to identify new genes associated with those traits of interest. Brassinosteroids (BR) are steroid hormones that control different aspects of plant growth and ...


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 ...


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 ...


Marker-Assisted Selection For Elevated Concentrations Of The Α′ Subunit Of Β-, Sheilah Emilie Oltmans-Deardorff Jan 2012

Marker-Assisted Selection For Elevated Concentrations Of The Α′ Subunit Of Β-, Sheilah Emilie Oltmans-Deardorff

Graduate Theses and Dissertations

Soybean [Glycine max (L.) Merr.] contains two major storage proteins, glycinin and β-conglycinin (BC). Glycinin accounts for approximately 40% and BC approximately 25% of total soybean seed protein (Nielsen et al., 1989). Glycinin is controlled by five genes coding for the acidic (A) and basic (B) subunits: Gy1, Gy2, Gy3, Gy4, and Gy5 (Cho et al., 1989; Nielsen et al., 1989). BC consists of gene families that encode the three major subunits α, α′, and β. The relative concentrations of the BC subunits are about 45% α, 35% α′, and 20% β (Maruyama et al., 1999). Soybean cultivars were discovered ...


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.