Identification and mapping of QTL for resistance against Zymoseptoria tritici in the winter wheat accession HTRI1410 (Triticum aestivum L. subsp. spelta)

Authors

  • Frances Karlstedt Julius Kühn-Institut

DOI:

https://doi.org/10.5073/dissjki.2020.004

Abstract

Zymoseptoria tritici, the causal agent of Septoria tritici blotch (STB), causes yield losses of up to 50 % in wheat, globally. Growing of resistant cultivars is the most cost effective and envi-ronmental friendly way to avoid these losses. Zymoseptoria tritici is present worldwide and has gained evident importance due to changes in wheat growing practices. Fungicides such as strobilurins and azoles lost their efficiency in controlling STB. Therefore, there is a need to conducted screening of gene bank accessions for resistance, get information on the genetics of resistance and develop molecular markers for the efficient deployment of new resistances in wheat breeding. In extensive screening programs for resistance, the spelt wheat gene bank accession HTRI1410 turned out to be resistant in field trials and to be a valuable source for improvement of resistance to Zymoseptoria tritici in wheat, therefore. In order to get information on the genetics of the STB resistance in HTRI1410, a DH population consisting of 135 lines derived from crosses of HTRI1410 to three susceptible cultivars, i.e. ‘Alcedo’, ‘Jenga’ and ‘Sol-itär’, was generated. Based on two years and three locations, the heritability for STB resistance was calculated at h²= 0.55. In addition to the extensive field trials, artificial inoculation in de-tached leaf assays was conducted using three isolates (IPO323, IPO98022, IPO98050) and the necrotic mean leaf area was determined. A quantitative variation for the reaction to a Zy-moseptoria infection was observed and a significant genotypic effect detected. In parallel the DH population was genotyped by the wheat 90k iSelect SNP chip. The genotypic data were used for map construction. About 6,000 SNPs turned out to be polymorphic between HTRI1410 and the three susceptible cultivars. Out of these, 1,118 SNPs were mapped to the A genome, 1,326 SNPs mapped to the B genome and 267 SNPs to the D genome. QTL anal-yses based on field trials revealed QTL on chromosomes 5A, 4B and 7B. In addition, based on the detached leaf assay, 17 QTL were detected on chromosomes 1A, 2A, 3A, 4A, 6A and 1B, 2B, 5B. Furthermore, KASP markers for respective QTL were developed facilitating effi-cient marker based selection for resistance to STB.

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Published

2020-02-25

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Section

Dissertation