Virulence Structure of the Wheat Powdery Mildew Population in Serbia

Mirjana Lalošević,Radivoje Jevtić,Stevan Maširević,Branka Orbović,Vesna Župunski

doi:10.3390/agronomy12010045

Mirjana Lalošević, Radivoje Jevtić + Show 3 more

Open Access

https://doi.org/10.3390/agronomy12010045

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Abstract

Powdery mildew is a common, economically important disease in the wheat growing area of Serbia. A large-scale virulence survey of its causal agent Blumeria graminis f. sp. tritici population was performed in the period 1995–2013. A total of 1013 isolates were recovered from the collected chasmothecial samples. Among them, 862 unique pathotypes were identified using a differential set of 20 wheat lines with known powdery mildew (Pm) resistant genes. The pathogen was highly diverse. Number of virulence genes (virulence complexity) per isolate was large, supporting a constant need to extend the differential set of wheat with newly identified Pm genes. Virulence frequencies to Pm6, Pm7, and Pm5+8 were high throughout the 19-year period, in contrast with that to Pm5+6, which was consistently at a low level. The most significant change in the population was observed for virulence to the Pm2+4b+6 gene combination, with an increasing frequency of virulence to this gene combination over the years. High virulence complexity and genetic diversity of the population are the most influential factors for the damaging epidemics that this pathogen can cause.

Highlights

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is a common disease in wheat growing areas worldwide
A total of 1013 B. graminis f. sp. tritici isolates were recovered from the chasmothecial samples collected from 1995 to 2013 (Table 2)
Powdery mildew surveys that took place over a long period of time provided data of great importance for keeping track of the change in virulence occurring in powdery mildew populations and planning wheat breeding program strategies

Summary

Introduction

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is a common disease in wheat growing areas worldwide. Tritici, is a common disease in wheat growing areas worldwide. It can cause significant yield and quality losses. In Serbia, sexual reproduction occurs in late spring (prior to wheat senescence) by producing chasmothecia. This fruiting body is a means of pathogen survival of unsuitable summer conditions, and a source of sexual recombination. The chasmothecia ascospores may be released and act as a primary source of inoculum for new infections in late spring or early summer. Initial infections are followed by multiple cycles of asexual reproduction. The number of these cycles depends on weather conditions

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