Location: Cereal Crops Research
Title: Association mapping of resistance to leaf rust in emmer wheat using high throughput SNP markers Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 15, 2013
Publication Date: March 25, 2014
Citation: Sun, Q., Elias, E., Chao, S., Xu, S.S., Acevedo, M. 2014. Association mapping of resistance to leaf rust in emmer wheat using high throughput SNP markers [abstract]. Borlaug Summit on Wheat for Food Security, March 25-28, 2014, Ciudad Obregon, Mexico. p. 116. Technical Abstract: Emmer wheat (Triticum turgidum L. subsp. dicoccum) is known to be a useful source of genes for many desirable characters for improvement of modern cultivated wheat. Recently, a panel of 181 emmer wheat accessions has been genotyped with wheat 9K SNP (single nucleotide polymorphism) markers and extensively used to identify loci associated with resistance to several wheat diseases such as stem rust and stripe rust. The objectives of this study were to evaluate the emmer wheat panel for its resistance to leaf rust and detect novel Lr genes in the resistant lines through association mapping. The 181 emmer wheat accessions were evaluated for their reaction to leaf rust race BBGQ at seedling stage in greenhouse and were also evaluated at adult stage in a field nursery in Ethiopia. Evaluation data showed that 48 (26.5%) and 52 (28.7%) accessions showed resistance at seedling and adult stages, respectively. For identifying novel Lr genes in the resistant lines, 5,279 mapped SNPs and 178 of the emmer wheat accessions were used for linkage disequilibrium and association analysis. After comparing different models, association between markers and leaf rust resistance was tested using a linear mixed-effects model, where the marker was fit as a fixed-effect factor, population structure factors as covariates, and Kinship as a random-effect factor. The results revealed that a number of SNP markers located on chromosomes 2A, 2B, 3B, 4A, 5B, 7A and 7B were significantly associated with leaf rust resistance. Because no known Lr genes were previously identified in emmer wheat, the accessions with a high level of leaf rust resistance and a high number of favorable alleles at the significant SNP loci are potential sources of novel genes for leaf rust resistance.