Combination of all-stage and high-temperature adult-plant resistance QTL confers high level, durable resistance to stripe rust in winter wheat cultivar Madsen

Authors: LIU, LI - Washington State University; WANG, MEINAN - Washington State University; FENG, JUNYAN - Sichuan Academy Of Agricultural Science; See, Deven; Chao, Shiaoman; Chen, Xianming

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2018
Publication Date: 5/26/2018
Citation: Liu, L., Wang, M., Feng, J., See, D.R., Chao, S., Chen, X. 2018. Combination of all-stage and high-temperature adult-plant resistance QTL confers high level, durable resistance to stripe rust in winter wheat cultivar Madsen. Theoretical and Applied Genetics. https://doi 10.1007/s00122-018-3116-4.
DOI: https://doi.org/10.1007/s00122-018-3116-4

Interpretive Summary: Wheat cultivar Madsen has maintained a high level resistance to stripe rust over 30 years. To map quantitative trait loci (QTL) underlying the high level, durable resistance, 156 recombinant inbred lines (RILs) developed from cross Madsen × Avocet S were phenotyped with selected stripe rust races in the greenhouse seedling tests, and in naturally infected fields during 2015-2017. The RILs were genotyped by molecular markers. Three QTL for all-stage resistance were mapped on chromosomes 1AS, 1BS and 2AS, and two additional QTL for high-temperature adult-plant (HTAP) resistance were mapped on 3BS and 6BS. The most effective QTL on 2AS, explaining 8.97-23.10% of the phenotypic variation in seedling tests and 8.60-71.23% in field tests, contained Yr17 for all-stage resistance and an additional gene for HTAP resistance. The 6BS QTL, detected in all field tests, was identified as Yr78. The 1AS QTL, conferring all-stage resistance, was identified as a new gene, which explained 20.45 and 30.23% of variation in resistance to races PSTv-37 and PSTv-40, respectively, and contributed significantly to field resistance at Pullman in 2015-2017, but was not detected at Mount Vernon. The interactions among QTL were mostly additive, and RILs with all five QTL had the highest level of resistance in the field, similar to Madsen. Genotyping 148 U.S. Pacific Northwest wheat cultivars with markers for the 1AS, 2AS and 6BS QTL validated the genes and markers, and indicated their usefulness for marker-assisted selection.

Technical Abstract: Wheat cultivar Madsen has maintained a high level resistance to stripe rust over 30 years. To map quantitative trait loci (QTL) underlying the high level, durable resistance, 156 recombinant inbred lines (RILs) developed from cross Madsen × Avocet S were phenotyped with selected races of Puccinia striiformis f. sp. tritici in the greenhouse seedling tests, and in naturally infected fields during 2015-2017. The RILs were genotyped by SSR and SNP markers from genotyping by sequencing and the 90K wheat SNP chip. Three QTL for all-stage resistance were mapped on chromosomes 1AS, 1BS and 2AS, and two QTL for high-temperature adult-plant (HTAP) resistance were mapped on 3BS and 6BS. The most effective QTL on 2AS, explaining 8.97-23.10% of the phenotypic variation in seedling tests and 8.60-71.23% in field tests, contained Yr17 for all-stage resistance and an additional gene for HTAP resistance. The 6BS QTL, detected in all field tests, was identified as Yr78. The 1AS QTL, conferring all-stage resistance, was identified as a new gene, which explained 20.45 and 30.23% of variation in resistance to races PSTv-37 and PSTv-40, respectively, and contributed significantly to field resistance at Pullman in 2015-2017, but was not detected at Mount Vernon. The interactions among QTL were mostly additive, and RILs with all five QTL had the highest level of resistance in the field, similar to Madsen. Genotyping 148 U.S. Pacific Northwest wheat cultivars with markers for the 1AS, 2AS and 6BS QTL validated the genes and markers, and indicated their usefulness for marker-assisted selection.