Association Mapping for Common Bunt Resistance in Wheat Landraces and Cultivars

Philipp Matthias Steffan,Gunter Backes,Anders Borgen,Anna Maria Torp,Søren K Rasmussen

doi:10.3390/agronomy12030642

Philipp Matthias Steffan, Gunter Backes + Show 3 more

Open Access

https://doi.org/10.3390/agronomy12030642

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Abstract

Common bunt is a seed borne disease of wheat whose importance is likely to increase due to the growing organic seed market, which, in addition to seed phytosanitary measures, relies on genetic resistances towards the disease. Genome wide association studies in wheat have been proven to be a useful tool in the detection of genetic polymorphisms underlying phenotypic trait variation in wheat. Here 248 wheat landraces and cultivars representing 130 years of breeding history were screened for two years in the field for their resistance reactions towards common bunt. The majority of lines exhibited high levels of susceptibility towards common bunt, while 25 accessions had less than 10% infection. Using Diversity Array Technology (DArT) markers for genotyping and correcting for population stratification by using a compressed mixed linear model, we identified two significant marker trait associations (MTA) for common bunt resistance, designated QCbt.cph-2B and QCbt.cph-7A, located on wheat chromosomes 2B and 7A, respectively. This shows that genome wide association studies (GWAS) are applicable in the search for genetic polymorphisms for resistance towards less studied plant diseases such as common bunt in the context of an under representation of resistant lines.

Highlights

Common bunt is a seed borne disease of wheat (Triticum aestivum L. subsp. aestivum) worldwide [1–5] and yield losses due to this pathogen have been estimated to be equal to the percent infection [6]
The majority of wheat accessions were highly susceptible to common bunt, with 25 out of 248 wheat accessions having less than 10% infection across the two years (Figure 1)
Wheat accessions explained the majority of the observed phenotypic variation, the effect of the years was estimated to be low, and the correlation between the common bunt assessment values in 2011 and 2012 was high

Summary

Introduction

Common bunt is a seed borne disease of wheat (Triticum aestivum L. subsp. aestivum) worldwide [1–5] and yield losses due to this pathogen have been estimated to be equal to the percent infection [6]. Common bunt is a seed borne disease of wheat Germination of seed transmitted spores coincides with wheat germination and fungal infection hyphae penetrate the emerging wheat coleoptile and reach the apical meristematic tissue in susceptible wheat cultivars within 50–60 days [7]. At wheat maturity sori tissue becomes brittle, and disrupts during threshing and thereby releasing spores onto healthy wheat seeds. If these seeds remain untreated, the spores attached to them are a likely cause of infection in the generation of wheat production

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