Mapping of QTL for partial resistance to powdery mildew in two Chinese common wheat cultivars

Authors: XU, XIAOTIAN - Chinese Academy Of Agricultural Sciences; ZHU, ZHANWANG - Chinese Academy Of Agricultural Sciences; JIA, AOLIN - Chinese Academy Of Agricultural Sciences; WANG, FENGJU - Chinese Academy Of Agricultural Sciences; WANG, JINPING - Chinese Academy Of Agricultural Sciences; ZHANG, YELUN - Chinese Academy Of Agricultural Sciences; FU, CHAO - Chinese Academy Of Agricultural Sciences; FU, LUPING - Chinese Academy Of Agricultural Sciences; Bai, Guihua; XIA, XIANCHUN - Chinese Academy Of Agricultural Sciences; HAO, YUANFENG - Chinese Academy Of Agricultural Sciences; HE, ZHONGHU - Chinese Academy Of Agricultural Sciences

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2019
Publication Date: 12/7/2019
Citation: Xu, X., Zhu, Z., Jia, A., Wang, F., Wang, J., Zhang, Y., Fu, C., Fu, L., Bai, G., Xia, X., Hao, Y., He, Z. 2019. Mapping of QTL for partial resistance to powdery mildew in two Chinese common wheat cultivars. Euphytica. (2020)216:3. https://doi.org/10.1007/s10681-019-2537-8.
DOI: https://doi.org/10.1007/s10681-019-2537-8

Interpretive Summary: Extensive use of semi-dwarf cultivars and nitrogenous fertilizers significantly increases wheat powdery mildew epidemics, which results in significant yield losses in wheat. To identify quantitative trait loci (QTLs) for powdery mildew resistance, we constructed a high-density genetic map using the Wheat 660 K SNP array and in a doubled haploid (DH) population of Yangmai 16 x Zhongmai 895 and detected six stable QTLs for powdery mildew resistance. Among them, QPmyz.caas-5DS, QPmyz.caas-6BL and QPmyz.caas-7BS are likely new QTLs for powdery mildew resistance. One SNP linked to the most stable QTL, QPmyz.caas-6BL, was converted into a Kompetitive Allele-Specific PCR marker for marker-assisted selection. The novel QTLs identified in the present study should be useful to improvement of powdery mildew resistance in wheat.

Technical Abstract: The increasing severity and prevalence of powdery mildew aided by extensive use of semi-dwarf cultivars and high levels of nitrogenous fertilizers are causing significant yield losses in wheat. Resistant cultivars are the most cost-effective and environmentally friendly approach to manage the disease. The objective of this study was to identify quantitative trait loci (QTL) for powdery mildew resistance in a doubled haploid (DH) population from a cross between leading Chinese cultivars, Yangmai 16 and Zhongmai 895. A high-density genetic map comprising of 14,480 non-redundant markers (equal to 148,179 SNPs) in 21 wheat chromosomes was constructed by genotyping the population with the Wheat 660 K SNP array. The DH population was phenotyped for powdery mildew resistance at the adult plant stage in multiple field trials, including four environments in the 2016–2017 cropping season and two environments in 2017–2018. Composite interval mapping detected six stable QTL explaining 3.8–23.6% of the phenotypic variance across environments. QPmyz.caas-5DS, QPmyz.caas-6BL and QPmyz.caas-7BS, are probably new QTL for powdery mildew resistance. One SNP marker closely linked to QPmyz.caas-6BL, the most stable QTL, was converted into a Kompetitive Allele-Specific PCR marker (K_AX-94973433) and validated on 103 commercial wheat cultivars. Significantly lower maximum disease severities of cultivars with the resistance-associated allele than those with the susceptibility-associated allele at QPmyz.caas-6BL in some environments indicated partial effectiveness of the marker. The novel QTL and their closely linked markers identified in the present study should facilitate development of cultivars with improved powdery mildew resistance.