Development, validation, and re-selection of wheat lines with pyramided genes Yr64 and Yr15 linked on the short arm of chromosome 1B for resistance to stripe rust

Authors: QIE, YANMIN - Washington State University; LIU, YAN - Washington State University; WANG, MEINAN - Washington State University; LI, XING - Washington State University; See, Deven; AN, DIAOGUO - Chinese Academy Of Sciences; Chen, Xianming

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/26/2018
Publication Date: 11/2/2018
Citation: Qie, Y., Liu, Y., Wang, M., Li, X., See, D.R., An, D., Chen, X. 2018. Development, validation, and re-selection of wheat lines with pyramided genes Yr64 and Yr15 linked on the short arm of chromosome 1B for resistance to stripe rust. Plant Disease. 103(1):51-58. https://doi.org/10.1094/PDIS-03-18-0470-RE.
DOI: https://doi.org/10.1094/PDIS-03-18-0470-RE

Interpretive Summary: Stripe rust is one of the most destructive diseases on wheat worldwide. The disease is most preferably managed by developing and growing resistant cultivars. To achieve high-level and long-lasting resistance, we developed a wheat line by pyramiding previously identified Yr64 and Yr15 genes, both providing high resistance to all tested races of the stripe rust pathogen and mapped on the short arm of chromosome 1B, in a recombinant inbred line (RIL-Yr64/Yr15) developed from a cross between RIL-Yr64 (Yr64) and AvSYr15NIL (Yr15). To validate RIL-Yr64/Yr15 possessing both genes, we backcrossed it to Avocet S. The F4 RIL population from this cross were phenotyped with different races under controlled greenhouse conditions and also under natural infection of the pathogen in the field. The population was genotyped with molecular markers along chromosome 1B. Both phenotype and genotype data confirmed the co-presence of Yr64 and Yr15 in RIL-Yr64/Yr15, and the high-resolution linkage map dissected the chromosomal regions and traced their origins. New lines possessing these genes were selected from the F5 population of cross AvS × RIL-Yr64/Yr15 by marker-assisted selection. These lines with the two highly effective genes should be more useful than individual gene lines for developing high-level, durable resistant wheat cultivars.

Technical Abstract: Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases on wheat worldwide. The disease is most preferably managed by developing and growing cultivars with high-level, durable resistance. To achieve high-level and long-lasting resistance for easy use in breeding programs, we developed a wheat line by pyramiding previously identified Yr64 and Yr15, both providing high resistance to all tested races of the stripe rust pathogen and mapped on the short arm of chromosome 1B (1BS), in a F4 recombinant inbred line (RIL-Yr64/Yr15) developed from a cross between RIL-Yr64 (Yr64) and AvSYr15NIL (Yr15). To validate RIL-Yr64/Yr15 possessing both genes, we backcrossed it to Avocet S (AvS). The F4 RILs from this cross were phenotyped with Pst races under controlled greenhouse conditions and also under natural Pst infection in the field. The population was genotyped with SSR markers previously reported to be linked to the resistance gene loci and with additional SSR and SNP-KASP markers along chromosome 1B. Both phenotype and genotype data confirmed the co-presence of Yr64 and Yr15 in RIL-Yr64/Yr15, and the high-resolution linkage map dissected the chromosomal regions and traced their origins. New lines possessing these genes were selected from the F5 population of cross AvS × RIL-Yr64/Yr15 by marker-assisted selection. These lines with the two highly effective genes should be more useful than individual gene lines for developing high-level, durable resistant wheat cultivars.