Details

Association Mapping of Endosperm Colour in Durum Wheat (Triticum turgidum L. var. durum)

by Reimer, Sherisse Opal

Abstract (Summary)
Association mapping (AM), based on linkage disequilibrium, is a complementary strategy to traditional quantitative trait loci (QTL) mapping for describing associations between genotypes and phenotypes in crop plants. Yellow endosperm colour, an important quality trait in durum wheat (Triticum turgidum L. var. durum), was studied to determine the potential of AM to (1) identify previously reported QTL using a genome wide scan and (2) to determine allelic association of the phytoene synthase 1 (Psy1) gene using a candidate gene analysis. At present, a number of QTL for endosperm colour have been identified, and phytoene synthase, the initial enzyme of the carotenoid biosynthetic pathway, has been associated with QTL on the group 7 chromosomes which are considered to play a significant role in expression of yellow pigment concentration. CIE 1976 b*, a light reflectance measurement, and water-saturated butanol extracted pigments were assessed on a collection of 93 elite accessions from a variety of geographic origins, and genotyped with 245 markers. Population structure was assessed using genetic distance and Bayesian model based approaches, identifying five sub-populations consistent with breeding origin and pedigree. Association analysis identified significant associations with yellow endosperm colour on all chromosomes, including several previously identified QTL as well as new regions for genomic dissection. Pairwise LD mapping of Psy1-B1 and Psy1-A1 located the genes to chromosomes 7B and 7A respectively, to regions which have previously been identified for yellow pigment concentration QTL. The results of this study indicate that AM can be used to complement traditional QTL mapping techniques, and identify novel QTL for further study.
Bibliographical Information:

Advisor:Scoles, Graham; Warkentin, Tom; Belzile, Fran├žois J.; Coulman, Bruce; Pozniak, Curtis

School:University of Saskatchewan

School Location:Canada - Saskatchewan

Source Type:Master's Thesis

Keywords:phytoene synthase population structure association mapping durum wheat yellow pigment

ISBN:

Date of Publication:01/07/2009

© 2009 OpenThesis.org. All Rights Reserved.