Location: Hard Winter Wheat Genetics ResearchTitle: Molecular marker dissection of stem rust resistance in Nebraska bread wheat germplasm
|MOURAD, AMIRA - UNIVERSITY OF NEBRASKA|
|SALLAM, AHMED - UNIVERSITY OF NEBRASKA|
|BELAMKAR, VIKAS - UNIVERSITY OF NEBRASKA|
|WEGULO, STEPHEN - UNIVERSITY OF NEBRASKA|
|MAHDY, EZZAT - ASSIUT UNIVERSITY|
|EL-WAFA, ATIF ABO - ASSIUT UNIVERSITY|
|BAENZIGER, STEPHEN - UNIVERSITY OF NEBRASKA|
Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/23/2019
Publication Date: 8/12/2019
Citation: Mourad, A., Sallam, A., Belamkar, V., Wegulo, S., Bai, G., Mahdy, E., El-Wafa, A., Jin, Y., Baenziger, S.P. 2019. Molecular marker dissection of stem rust resistance in Nebraska bread wheat germplasm. Scientific Reports. 9:11694. https://doi.org/10.1038/s41598-019-47986-9.
Interpretive Summary: Stem rust is a major disease of wheat in the US Great Plains. To understand the genetic basis of stem rust resistance in Nebraska winter wheat, we evaluated 330 elite wheat breeding lines from the Nebraska breeding program for stem rust resistance and gene specific markers. Nine stem rust genes, Sr6, Sr31, Sr1RSAmigo, Sr24, Sr36, SrTmp, Sr7b, Sr9b, and Sr38, were identified using gene-specific markers. Breeding line NE15680 contained five stem rust resistance genes and had high resistance to stem rust. Seventeen SNPs tightly linked with the Sr38 could be used in marker-assisted selection after further validation.
Technical Abstract: Stem rust (caused by Puccinia graminis f. sp. tritici) is a major disease of wheat. To understand the genetic basis of stem rust resistance in Nebraska winter wheat, a set of 330 genotypes representing two nurseries (DUP2015 and TRP2015) were evaluated for resistance to a Nebraska stem rust race (QFCSC) in two replications. The TRP2015 nursery was also evaluated for its resistance to an additional 13 stem rust races. The analysis of variance revealed significant variation among genotypes in both populations for stem rust resistance. Nine stem rust genes, Sr6, Sr31, Sr1RSAmigo, Sr24, Sr36, SrTmp, Sr7b, Sr9b, and Sr38, were expected and genotyped using gene-specific markers. The results of genetic analysis confirmed the presence of seven stem rust resistance genes. One genotype (NE15680) contained target alleles for five stem rust resistance genes and had a high level of stem rust resistance against different races. Single marker analysis indicated that Sr24 and Sr38 were highly significantly associated with stem rust resistance in the DUP2015 and TRP2015 nurseries, respectively. Linkage disequilibrium analysis identified the presence of 17 SNPs in high linkage with the Sr38-specific marker. These SNPs potentially tagging the Sr38 gene could be used in marker-assisted selection after validating them in additional genetic backgrounds.