Abstract Detail

Host/Plant Pathogen Interactions and Plant Health Management

Xue, Allen [1], Marchand, Geneviève [1], Chen, Yuanhong [1], Cober, Elroy [1], Zhang, shuzhen [2], Tenuta, Albert [3].

Races of Phytophthorasojae in Ontario, Canada, 2010 – 2012.

Phytophthora root rot (PRR), caused by the oomycete Phytophthora sojae Kaufm. & Gerd., is a devastating disease of soybean worldwide, and has been present in Canada since the 1950s. Major resistance to P. sojae (Rps) genes have been deployed by soybean breeders to mitigate yield losses, which has caused shifts in the pathogen population to more complex pathotypes and the emergence of new races. This study reports on a survey of races and pathotypes of P. sojae throughout 203 commercial soybean fields and two PRR nurseries in the province of Ontario, Canada, and is the first Canadian extensive survey since the late 1980s. A total of 22 races and one intermediate reaction type (IRT) were detected from 262 isolates from commercial soybean fields. Race 25 was the predominant race, comprising 43 isolates and representing 16% of the pathogen population, and races 3, 4, 5, 6, 7, 9, 28, and 45 were frequently detected, each of these races representing 5 to 11% of the pathogen population. A total of 16 races and two IRTs were detected in 96 isolates from the two PRR nurseries. Race 3 was the most abundant, representing 23% of isolates, and races 5, 6, 7, 8, 9, 14, 25 and 28 each represented between 5 and 10% of isolates. New races and more complex pathotypes have emerged since the last survey, and this will have implications for the future deployment of Rps genes or other forms of resistance to P. sojae.

1 - Agriculture and Agri-Food Canada, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, ON, K1A 0C6, Canada
2 - Northeast Agricultural University, Soybean Research Institute, Harbin, 150030, China
3 - Ontario Ministry of Agriculture and Food, P.O. Box 400, Ridgetown, ON, N0P 2C0, Canada

Keywords:
Phytophthora root rot
Phytophthora sojae
Soybean.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PPA041
Abstract ID:764
Candidate for Awards:None