Understanding water stress responses in maize and the genetic factors controlling these traits has direct application to breeding and genetic study. To understand water stress responses in more detail, this thesis characterizes a novel B73 ethyl methanesulfonate induced wilting maize mutant. This mutant is shown to express a wilting phenotype under both field and greenhouse conditions, exhibiting leaf roll, stunted stem growth and reduced fertility. Germination is unaffected in mutant seeds and no abnormal seedling phenotypes are observed. Onset of the phenotype is between V3 and V6 growth stage, and corresponds with a disruption of stem elongation. To characterize the genetic elements underlying the wilting phenotype, F2 and F3 mapping populations were phenotyped and genotyped. The mutant phenotype was found at variable frequencies between populations; ¼ or less of all mapping population members were observed as wilting, implicating a single genetic factor controlling the mutant phenotype. Background effects of the non-mutant parent and residual EMS mutations are hypothesized to be responsible for the unexpected frequency of wilting observed. Single nucleotide polymorphism and microsatellite markers localized the wilted mutant allele to a 7.4-Megabase region on the long arm of chromosome 7. The phenotype results and rough mapping data provide a base for further study and cloning of the mutant allele.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OGU.10214/3904 |
| Date | 04 September 2012 |
| Creators | Bruce, Robert |
| Contributors | Lukens, Lewis |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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