CFCRA Cropping Systems Cluster: Activity 8 – Corn germplasm development focused on key diseases

Objectives:

• Develop multiple disease resistant corn inbred lines to Fusarium/Gibberella and Goss’s wilt with acceptable agronomic performance, identify molecular markers associated with resistance genes, and design a genomic selection model.
• Survey for current and emerging diseases such as tar spot, screen inbred lines, and identify and validate new sources of tar spot resistant germplasm. Transfer the trait using marker assisted backcrossing.

Impacts:

• Disease-resistant germplasm and tools for corn hybrid seed companies to incorporate resistance to regionally relevant diseases into commercial hybrids for farmers.

Scientific Summary:

Canada annually produces more than 15 million metric tons of grain corn on 1.3 million hectares of farmland with a farm gate value of over $2 billion. Unfortunately, production and productivity of this important crop is challenged by established and emerging diseases.

Among the frequently occurring diseases, Gibberella ear rot (GER) ranks number one in the major corn growing provinces of Canada. Grain Farmers of Ontario estimated a total revenue loss to farmers of $200 million from the 2018 GER epidemic (with most yield loss occurring in southwestern Ontario where the disease was most prevalent). Goss’s wilt is another economically important disease occurring in Manitoba and Alberta. It can cause yield losses of up to 60% or 40 bushels per acre. The most recent disease affecting the corn industry in Canada, and the corn belt in the United States, is tar spot. It was first detected in Illinois and Indiana in 2015. From 2018–2020, a total of 241 million bushels of corn were lost to tar spot in the United States. According to a report by the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), tar spot was first detected in southwestern Ontario in 2020 and by 2021 it was confirmed in 20 counties. It is expected to spread further north in the coming years.

The most effective way to respond to these various disease challenges is by developing new disease-resistant germplasm. The corn genetics and germplasm development program of Agriculture and Agri-Food Canada (AAFC) is the only public sector research program developing resistant inbred lines for the seed sector to be used in developing their commercial hybrids. Over the last three decades this program has also been monitoring for new emerging diseases to guide germplasm development work.

The research objectives for this project will be achieved using conventional corn breeding methodology enhanced by double haploid inbred production, genomic and marker-assisted selection. Multiple yield trials in Quebec and Ontario will be conducted annually. Disease nurseries for GER and tar spot will take place in Ontario while research to examine Goss’s wilt will occur in Manitoba. Annual surveys for current and emerging diseases will be conducted to guide public/private breeding programs on which diseases need to be prioritized for research. Continued scouting will take place to monitor emerging diseases like tar spot.

External Funding Partners:

This activity was funded in part by the Government of Canada under the Sustainable Canadian Agricultural Partnership’s AgriScience Program, with industry support from the Canadian Field Crop Research Alliance (CFCRA) whose members include: Atlantic Grains Council; Producteurs de grains du Quebec; Grain Farmers of Ontario; Manitoba Corn Growers Association; Manitoba Pulse & Soybean Growers; Saskatchewan Pulse Growers; Prairie Oat Growers Association; SeCan; and FP Genetics.