Record Details
Multi-location analysis for the identification of quantitative trait loci underlying disease resistance against Cephalosporium gramineum and Puccinia striiformis f. sp. tritici by linkage mapping in wheat (Triticum aestivum L.)
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Multi-location analysis for the identification of quantitative trait loci underlying disease resistance against Cephalosporium gramineum and Puccinia striiformis f. sp. tritici by linkage mapping in wheat (Triticum aestivum L.) |
| Names |
Vazquez, Maria Dolores
(creator) Zemetra, Robert (advisor) Mundt, Christopher (advisor) |
| Date Issued | 2014-03-11 (iso8601) |
| Note | Graduation date: 2014 |
| Abstract | Wheat (Triticum aestivum L.) is one of the major crops produced in the U.S. Pacific Northwest, a region known for its wheat production for international export. Wheat production in the region is threatened by diseases such as Cephalosporium stripe and stripe rust. Cephalosporium stripe is a vascular wilt disease of wheat caused by the persistent soil-borne fungus and suspected necrotrophic pathogen Cephalosporium gramineum Nisikado & Ikata, and is a recurring disease in many localities when susceptible cultivars are grown. Stripe rust, a foliar disease of wheat caused by the air-borne biotrophic fungus Puccinia striformis f. sp. tritici is a disease present in every region around the world where commercial wheat is grown. Attaining durable resistance to stripe rust would greatly benefit wheat producers in the region. Combining stripe rust resistance with resistance to other diseases, such as Cephalosporium stripe, is challenging. Wheat cultivars with high levels of resistance to several diseases are favorable candidates for genetic studies to determine the inheritance of resistance and facilitate the development of a method to genotypically select for disease resistance. Two populations of recombinant inbred lines were developed from 'Tubbs'/'NSA-98-0995' (TxN) and 'Einstein'/'Tubbs' (ExT) with population sizes of 271 and 259 F[subscript (5:6)], respectively. Tubbs is susceptible to stripe rust and Cephalosporium stripe while Einstein and NSA-98-0995 demonstrate moderate to high resistance to both diseases. Both populations were assessed across seven environments (combinations of locations and years) for stripe rust resistance under natural infection and four environments for Cephalosporium stripe resistance under artificial inoculation. The populations were mapped using diversity array technology (DArT) and simple sequence repeat (SSR) markers for quantitative trait loci (QTL) analysis. Results for Cephalosporium stripe resistance was quantitatively inherited with several QTL detected (>5), including some QTL in the same chromosome location in both populations. For stripe rust resistance, seven QTL were identified in the TxN population, suggesting quantitative resistance contributed by several minor genes. In the ExT population two QTL with major effects and with epistatic interactions between them were identified. One of them, a major QTL from Tubbs on chromosome 2AS that may be Yr17, was not expressed in the TxN population or in Tubbs, perhaps owing to suppressor(s). Expression of the 2AS QTL in the ExT population may be due to interaction with the QTL on chromosome 6AL from the resistant parent Einstein or to any other gene in the background of the population. QTL on chromosomes 2AS, 5AL, and 6BS were associated with resistance to both Cephalosporium stripe and stripe rust. These results highlight a complex set of interactions among major genes, minor genes, the presence of different stripe rust races, epistasis, genetic background, and possibly a suppressor of resistance. Results from this study are expected to assist in selecting molecular markers to genotypically select for resistance to these diseases, improving the chances of developing wheat cultivars with durable resistance to both diseases in the future. |
| Genre | Thesis/Dissertation |
| Access Condition | http://creativecommons.org/licenses/by-nc-nd/3.0/us/ |
| Topic | Cephalosporium stripe |
| Identifier | http://hdl.handle.net/1957/47251 |
