Abstract
BackgroundPowdery mildew (PM), one of the major diseases in wheat, severely damages yield and quality, and the most economical and effective way to address this issue is to breed disease-resistant cultivars. Accordingly, 371 landraces and 266 released cultivars in Henan Province were genotyped by a 660 K microarray and phenotyped for adult plant resistance (APR) to PM from 2017 to 2020, and these datasets were used to conduct multilocus genome-wide association studies (GWASs).ResultsThirty-six varieties showed stable APR in all the environments, and eleven quantitative trait nucleotides (QTNs) were found by multiple methods across multiple environments and best linear unbiased prediction (BLUP) values to be significantly associated with APR. Among these stable QTNs, four were previously reported, three were newly discovered in this study, and the others need to be further investigated. The major and newly discovered QTN, Qpm-3BL, was located at chr03BL_AX-109,052,670, while another newly discovered QTN, Qpm-1BL, was located between chr01BL_AX-108,771,002 and chr01BL_AX-110,117,322. Five and eight landraces were identified to be resistant based on Qpm-1BL (haplotype TC) and Qpm-3BL (allele T), respectively. To validate Qpm-3BL, a new kompetitive allele-specific PCR (KASP) marker was developed to scan 155 F2 individuals, and the average resistance score supported the value of Qpm-3BL in marker-assisted breeding. Near Qpm-3BL, PmBMYD was identified by KEGG, gene expression and comparative genomics analyses to be a candidate. Its resistance mechanism may involve gene tandem repeats.ConclusionsThis study reveals a previously unknown gene for PM resistance that is available for marker-assisted breeding.
Highlights
Powdery mildew (PM), one of the major diseases in wheat, severely damages yield and quality, and the most economical and effective way to address this issue is to breed disease-resistant cultivars
The broad-sense heritability of resistance to PM was 0.76, indicating the existence of large genetic variation for this trait. This screening led to the identification of 36 (5.65 %) consistently resistant accessions, including 21 landraces and 15 released cultivars (Additional file 1: Table S1).The high correlations (r2 = 0.6258–0.9044; P-value < 0.01) of the PM scores across various field environments indicated the high quality of the datasets (Additional file 1: Table S2)
Linkage disequilibrium (LD) and population structure analysis A total of 637 wheat varieties were genotyped by 660 K single-nucleotide polymorphism (SNP) genotyping arrays
Summary
Powdery mildew (PM), one of the major diseases in wheat, severely damages yield and quality, and the most economical and effective way to address this issue is to breed disease-resistant cultivars. Powdery mildew (PM), a worldwide leaf disease caused by Blumeria graminis f. Tritici (Bgt), occurs mainly in cold and humid areas, such as China, Europe, and the Southern Cone of South America [2]. PM can reduce wheat yield by 5–62 % and severely affect flour quality [3, 4]. With the popularization of dwarf and semidwarf wheat cultivars and the improvement in water and fertilizer conditions, more favorable conditions have been created for the occurrence and spread of PM in wheat, and the incidence area has gradually expanded. The most economical, green and effective way to address this issue is to breed disease-resistant cultivars
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