Occurrence of new races and virulence changes of the wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici) in Egypt

Abstract

Wheat stripe rust, caused by Puccinia striiformis tritici (Pst), is a widespread disease of wheat, and causing significant losses in yield. Twenty-five races were identified from 160 samples in greenhouse tests. Samples were collected from wheat fields in governorates; Kafrelsheikh, Al-Sharqia, Dakahlia and Gharbia were tested. The most important commercial wheat cultivars, i.e. Misr1, Misr2, Giza171, and Sakha61, which were resistant to the previously characterised races in Egypt, became susceptible under field conditions. Also, infections of stripe rust were observed on some wheat lines with Yr genes previously known to be resistant, i.e. Yr1, Yr17, Yr27, Yr32 and YrSp in trap nurseries. The results confirmed a new race that is virulent to Yr1, which was first detected in Egypt. In addition, a race very similar to the "Warrior" race with virulence to Yr1, Yr2, Yr3, Yr4, Yr6, Yr7, Yr9, Yr17, Yr25, Yr32, YrSp and YrAmb was also confirmed in the 2015/2016 growing season. The detection of the new races indicated continual changes of virulence in the Pst population. Due to these new races, some wheat cultivars previously known to be resistant have become susceptible. This is the first report of the "Warrior" race of wheat stripe rust in Egypt.

Keywords:

• Wheat
• stripe rust
• Warrior race
• virulence pattern
• Egypt

Acknowledgements

The author would like to express his sincere gratitude and deep gratefulness to Prof. Dr. Xianming Chen., USDA-ARS, Wheat Genetics, quality, Physiology and Disease Research Unit and Department Plant Pathology, Washington State University, USA, for the valuable criticism and constructive suggestions during the reading of the manuscript before submission and the anonymous reviewers for valuable suggestions.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.