|Principal Investigator||McLaren, Debra, Agriculture and Agri-Food Canada|
|MPSG Financial Support||$300,000|
|Total Project Funding||$683,909|
|External Funding Partners||Funding for this project has been provided by Agriculture and Agri‐Food Canada through the AgriInnovation Program|
|Report||Soybean Root Rot: Final Report|
The goal of this study is to investigate root rot of soybean in order to maximize growth returns through improvements in root rot management and ensure the long term sustainability of the soybean industry in western Canada.
- To determine the potential yield loss caused by Fusarium root rot pathogens of soybean in western Canada.
- To Identify the major root rot pathogens of soybean in western Canada and determine their aggressiveness toward soybean though pathogenicity testing.
Approximately 40 commercial soybean fields in Manitoba were evaluated annually for the incidence and severity of root rot. Over the past three years (2013-2015), 100% of the soybean fields examined had root rot, with the exception of 2015 (98%). In Alberta, root rot occurred in all crops surveyed in 2013, 2014 and 2015. Molecular diagnostic procedures have been developed for the rapid detection and identification of a number of root rot pathogens of soybean.
To develop resistant cultivars, the pathogens must be identified and the genetic variation within pathogen species needs to be described so that breeders can select for resistance to targeted pathogen populations. Given the importance of Fusarium root rot in Alberta and Manitoba, understanding the pathogen composition is essential for design of new control strategies. Genetic variation within Fusarium avenaceum, a predominant pea root pathogen, has been regularly monitored because this information can affect the strategies that are selected for the development of control methods.
In recent years soybean production has expanded into regions of southern Alberta where poor quality irrigation water and inadequate soil drainage often result in the accumulation of salts. Saline environments are a limiting factor for soybean development and productivity, but little is known about how such disturbances affect their susceptibility to pathogens. Results from greenhouse studies indicated that high salinity reduced seedling emergence and increased root rot severity to F. avenaceum and Rhizoctonia solani. Seven soybean cultivars showed greater emergence and reduced disease severity and will be evaluated under field conditions to confirm these results.
Field trials to determine the potential yield loss caused by root rot pathogens of soybean were conducted at field sites at Morden and Brandon, with an additional site at Saskatoon in 2015. Differences in seedling emergence, root rot severity and seed yield were frequently observed. In addition, differences between pathogens in their aggressiveness and impact on yield components were often evident. Research will continue to confirm these results to provide information on the importance of soybean root-infecting pathogens in western Canada, their aggressiveness and their contribution to reduced soybean productivity.
The long-term and most economical approach for managing Fusarium root rot is the use of resistant cultivars but no cultivars with a high level of resistance are available. Field trials to determine the root reactions of 68 soybean cultivars against the five root pathogens Fusarium acuminatum, F. cuneirostrum, F. avenaceum, F. proliferatum and F. oxysporum were carried out at field sites near Morden and Brandon (2013-2015), with the exception of 2014 at Brandon when flooding destroyed the trials. Differences in seedling emergence, root rot severity, root nodulation and yield were observed among the soybean cultivars. Research will continue to confirm these results and eventually information on the cultivar reactions to these root rot pathogens will be made available to growers.