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Title:From the simple to the complex: an examination of different herbicide resistances
Author(s):Huffman, Janel L.
Advisor(s):Tranel, Patrick J.; Hager, Aaron G.
Department / Program:Crop Sciences
Discipline:Crop Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:M.S.
Genre:Thesis
Subject(s):Genetic inheritance
herbicide metabolism
multigenic
monogenic
glyphosate
hydroxyphenylpyruvate dioxygenase (HPPD)
Abstract:Herbicide resistance is the result of an evolutionary adaptation that some agronomic weed species have obtained from intense human-driven selection. The mechanisms by which these plants resist herbicides can be diverse. For example, self-pollinating species, such as goosegrass (Eleusine indica), frequently have target-site resistance mechanisms controlled by a single gene. Outcrossing species, such as waterhemp (Amaranthus tuberculatus), in addition to having herbicide resistance conferred by a target-site mutation controlled by a single gene, often evolve non-target-site-based resistance mechanisms controlled by multiple genes. The overall purpose of this thesis was to determine the genetics and inheritance of both target-site- and non-target-based resistances to provide beneficial insights into resistance evolution, adaptation dynamics and management practices. Chapter 2 discusses research conducted to determine if a Tennessee glyphosate-resistant (TennGR) goosegrass population had target-site resistance (TSR) that previously had been associated with glyphosate resistance in other populations [specifically a Pro106Ser substitution in the 5-enolypyruvyl-shikimate-3-phosphate synthase (EPSPS) gene]. Sequencing of the entire TennGR goosegrass EPSPS gene was performed and compared to that of the sensitive Tennessee population (TennGS). The results indicated that the population did contain the anticipated Pro106Ser mutation. An F2 population was derived and used in a whole-plant dose-response experiment to compare the three segregating EPSPS genotypes. This experiment revealed that the Pro106Ser mutation was the sole mechanism of glyphosate resistance in the TennGR population. Chapter 3 discusses research conducted to determine the inheritance of two distinct non-target-site resistances, to atrazine and mesotrione, in a population of waterhemp (MCR). Crosses were performed to generate F1, backcross (BC), and F2 lines. Through separate atrazine and mesotrione dose responses experiments, it was determined that the responses of reciprocal F1 lines did not differ and were intermediate to that of the R and S parental populations, indicating resistance for both herbicides was nuclear inherited. Segregation analysis in F2 and BCS lines indicated inheritance was controlled by a single gene for atrazine resistance and multiple genes for mesotrione resistance. The fourth and final chapter provides concluding remarks and future research opportunities.
Issue Date:2015-06-30
Type:Thesis
URI:http://hdl.handle.net/2142/87971
Rights Information:Copyright 2015 Janel Huffman
Date Available in IDEALS:2015-09-29
Date Deposited:August 201


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