Search finds partial resistance to sclerotinia stem rot in canola

Study seeks overseas canola lines with partial resistance to sclerotinia

Diseases
Dr Lars Kamphuis, left, and Dr Mark Derbyshire, both from the GRDC-invested Centre for Crop and Disease Management, infecting canola plants with sclerotinia stem rot. PHOTO Yuphin Khentry, CCDM

Dr Lars Kamphuis, left, and Dr Mark Derbyshire, both from the GRDC-invested Centre for Crop and Disease Management, infecting canola plants with sclerotinia stem rot. PHOTO Yuphin Khentry, CCDM

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Canola growers to reap rewards of global search for resistance to sclerotinia stem rot.

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Second only to blackleg, sclerotinia stem rot (SSR) is a destructive fungal disease of canola and, under the right conditions, crop yield losses can exceed 20 per cent - inflicting a big hit on profits.

Sclerotinia can be hard to manage and, while fungicides can be effective, growers are keen to find a more reliable way to protect their crops.

Researchers at the Centre for Crop and Disease Management (CCDM) are searching for insight into the pathogen that causes the disease, hoping to use genetics to combat its spread and impact.

"With the significant co-investment of GRDC and Curtin University behind us, our researchers are making substantial inroads into the disease challenges facing Australia's canola industry," says CCDM co-director Professor Mark Gibberd.

"Aligning our expertise and resources with leading international research partners helps escalate our understanding of SSR and the knowledge base needed to combat it."

International search

CCDM is researching the pathogenic fungus that causes SSR, Sclerotinia sclerotiorum, with the aim of generating Australian canola varieties with greater disease resistance.

We are working closely with international partners in Canada, Europe and the UK to study worldwide populations to find out whether overseas traits can provide solutions to help Australian growers.

Through collaboration with Agriculture and Agri-Food Canada (AAFC), we're searching for germplasm with stronger genetic resistance.

We have inoculated the most highly-aggressive sclerotinia isolates we could find from Western Australian varieties on plants sourced from South Korea, Japan and Pakistan.

These plants had already been tested and shown, by AAFC's Dr Lone Buchwaldt, to be partially resistant to Canadian sclerotinia isolates.

Importantly, some of the overseas canola plants held up well against aggressive isolates that cause major problems here in Australia.

Our end goal is to enable better resistance in future varieties for Australian growers by identifying sclerotinia stem rot resistant traits that can be adapted and developed by breeders. - Centre for Crop and Disease Management researcher Dr Lars Kamphuis

Breeding solutions

The next step is to link the work with AAFC to Australian breeders, to investigate how germplasm from the more resistant global canola lines can be adapted to Australian canola populations.

We have also looked at how the genetic make-up of Australian pathogen strains differs from other countries where SSR is also a major problem. This will help to build an understanding of how the pathogen has evolved and spread across global populations.

Working with both AAFC in Canada, as well as Dr Sylvain Raffaele, from the French National Institute for Agricultural Research, we have identified two major population clusters in fungal samples from Australia, Africa, Europe and North America.

One cluster showed genetically similar isolates between Canadian, American and French populations, and a second showed similarities between Australian and Moroccan isolates.

By pinpointing genetic differences in these populations, we can potentially determine which genes are important to improving plant survival against Australian disease-causing isolates.

Understanding the pathogen

The more we know about how the pathogen that causes SSR targets canola varieties around the globe the better prepared we can be in Australia to monitor and counteract any evolving risk here.

We are now expanding the study to test isolates from canola varieties on Australia's east coast.

The end goal is to improve resistance in future varieties for Australian growers by identifying SSR-resistant traits that can be adapted and developed by breeders.

GRDC Research Code CUR00023

More information: Dr Lars Kamphuis, Curtin University, 08 9266 2606, lars.kamphuis@curtin.edu.au

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