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Iowa State University

Plant Sciences

Graduate Theses and Dissertations

Plant breeding

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Phenotypic And Molecular Characterization Root System Architecture In Diverse Soybean (Glycine Max L. Merr.) Accessions, Kevin G. Falk Jan 2019

Phenotypic And Molecular Characterization Root System Architecture In Diverse Soybean (Glycine Max L. Merr.) Accessions, Kevin G. Falk

Graduate Theses and Dissertations

Root system architecture (RSA), or the spatial arrangement of the root and its morphology, functions to anchor the plant, provide water and nutrient acquisition, nutrient storage and to facilitate plant-microbe interactions such as nodulation in legumes such as soybean [Glycine max L. Merr.)]. Root structure also correlates to environmental advantages, such as nutrient acquisition, drought, flood tolerance, and lodging resistance. After centuries of indirect selection for RSA, there is a focus to harness soybean RSA diversity for exploitation and implementation into cultivar development programs. Researchers have generally taken one of three strategies to approach root phenotyping including controlled laboratory, moderately ...


Optimal Population Value Selection: A Population-Based Selection Strategy For Genomic Selection, Matthew Daniel Goiffon Jan 2016

Optimal Population Value Selection: A Population-Based Selection Strategy For Genomic Selection, Matthew Daniel Goiffon

Graduate Theses and Dissertations

In order to feed the world’s growing population, an interdisciplinary effort is needed. In this thesis, operations research tools of mathematical modeling, optimization, and simulation are used to improve an existing plant breeding method, genomic selection. To do this, a new method, called optimal population value (OPV) selection, is proposed. In this paper, OPV selection is first defined as an optimization problem that selects a breeding population using a population metric, instead of individual metrics. Then, OPV selection is thoroughly tested in a simulation study against the existing methods of genomic selection, weighted genomic selection, and optimal haploid value ...


An Integrative Approach For Germplasm Utilization, Genetic Diversity And Qtl Mapping In Camelina Spp. And Crop-Production Issues In Thlaspi Arvense, New Promising Oilseed Crops For Bioenergy And Industrial Uses, Ivan Mauricio Ayala Diaz Jan 2014

An Integrative Approach For Germplasm Utilization, Genetic Diversity And Qtl Mapping In Camelina Spp. And Crop-Production Issues In Thlaspi Arvense, New Promising Oilseed Crops For Bioenergy And Industrial Uses, Ivan Mauricio Ayala Diaz

Graduate Theses and Dissertations

Fuel demands continue to increase to satisfy current energy needs. Fossil fuels are the primary source of energy and supply 80% of the total demand, 58% of which is used for transportation purposes. However, decreasing oil reserves, rising prices and negative environmental implications have all contributed to growing demand for alternative energy sources, such as bioenergy crops. Ideally a good bioenergy crop has low input requirements (able to grow in marginal zones), fast growth and maturity, tolerance to biotic and abiotic stress conditions, and high productivity. Camelina (Camelina sativa (L.) Crantz) and pennycress (Thlaspi arvense L.) have been targeted as ...


New Methods For Haploid Selection In Maize, Yichia Tseng Jan 2012

New Methods For Haploid Selection In Maize, Yichia Tseng

Graduate Theses and Dissertations

The major aim of this study was to evaluate new methods to select haploids for maize breeding. The first method was to evaluate different inbreds for sensitivity to herbicides that could be developed as a tool for haploid selection, and the second was to evaluate automated sorting based on near-infrared reflectance spectroscopy (NIRS) and SIMCA analysis.


Agronomic And Phenotypic Responses To 75 Years Of Recurrent Selection For Yield In The Iowa Stiff Stalk Synthetic Maize Population, Brent Howard Brekke Jan 2010

Agronomic And Phenotypic Responses To 75 Years Of Recurrent Selection For Yield In The Iowa Stiff Stalk Synthetic Maize Population, Brent Howard Brekke

Graduate Theses and Dissertations

The plant density at which Zea mays L. hybrids achieve maximum grain yield has increased throughout the hybrid era while grain yield on a per plant basis has increased little. Changes in plant traits including grain yield, moisture, test weight, stalk and root lodging, flag leaf angle, anthesis-silking interval(ASI), plant height, tassel branch number, and total number of leaves have been well characterized in comparisons of commercial hybrids representing different eras of hybrid maize production but have yet to be examined in a recurrent selection program.

The objective of this experiment was to determine if direct selection for grain ...