Pulse Beat Individual Articles

Short-Season Soybean Breeding at AAFC

Dr. Elroy Cober, Research Scientist, Agriculture and Agri-Food Canada – Fall/Winter (December) Pulse Beat 2021

The Ottawa Research and Development Centre hosts Agriculture and Agri-Food Canada’s (AAFC) short-season soybean breeding program. This program develops maturity group (MG) 00 and earlier soybeans for short-season regions across Canada. The breeding objectives include early maturity, high yields and disease resistance, as well as objectives for the food-grade market. These include higher protein and end-use traits, such as fewer dormant seeds after soaking and firmer tofu texture.

The first, preliminary yield trials are carried out at Morden, Manitoba and Ottawa, Ontario to allow selection for broad adaptation. Through more advanced levels of yield trials, locations are increased to Morden and Portage la Prairie in Manitoba, plus two locations in Ontario and two in Quebec. Following these trials, promising experimental lines are grown in variety evaluation trials across these provinces. Recent variety releases include AAC Dale to SeCan, AAC Halli to Interlake.org and AAC Springfield to Springfield Mills. New, as of yet unnamed, releases to SeCan include OT18-09 and OT18-15. AAC Edward is also a very early maturing variety released previously to SeCan.

The participation of the AAFC stations at Morden and Portage in early generation trials allows for testing of adaptation to Manitoba throughout the yield trial stages of the breeding program. This project and the Manitoba trial sites are only possible through the support of the partners of the Canadian Field Crops Research Alliance (CFCRA), which includes Manitoba Pulse & Soybean Growers and AAFC. The CFCRA short-season soybean breeding project is a collaboration between soybean breeding programs at AAFC–Ottawa, the Crop Development Centre at the University of Saskatchewan and the Centre de recherche sur les grains (CEROM) in Quebec. We share parents, exchange segregating populations and run coordinated yield trials to ensure that short-season soybeans are adapted across the major growing areas.

Molecular markers for early maturity are being used to screen potential parents to allow for targeting early maturity in crosses. Genomic scientists at AAFC–Ottawa work to develop more specific markers for early maturity. When the actual gene, which is responsible for an early maturity QTL, is identified, it is possible to develop markers within that gene. This becomes a “perfect marker” since it is no longer just associated with early maturity but is actually in the gene responsible for early maturity. It is also possible to know which version of a maturity gene a line contains since it is possible to have a late, intermediate or early version of a maturity gene in some cases.

Resistance to soybean pests is also a breeding objective of the AAFC program. Phytophthora root rot is evaluated at a naturally infested nursery in Ottawa. White mould is evaluated by AAFC scientists on Prince Edward Island, where the naturally cool and moist growing season favours white mould development. The white mould nursery is also inoculated with sclerotia to increase the disease’s pressure. Soybean cyst nematode (SCN) continues to expand into short-season growing areas in Ontario, Quebec and more recently Manitoba, so breeding for SCN resistance has been added to the AAFC program. The AAFC station at St-Jean-sur-Richelieu provides greenhouse screening of parents for resistance to two SCN races (now called HG types).

The Ottawa AAFC program has a long-running program developing food-type soybeans and has released natto, tofu and edamame varieties. The CFCRA soybean breeding project has an objective to increase soybean seed protein. Increased protein is valuable for producers in Manitoba as it helps improve the lower protein levels seen in western Canada. Higher protein is also important for food-grade soybeans, where growers receive premiums for export soybeans meeting the requirements of food manufacturers. The Grain Quality Lab at AAFC–Ottawa evaluates end-use traits for food-grade soybeans in testing for seed dormancy after soaking — the 11S:7S ratio (which is a measure of types of protein subunits with correlation to tofu quality and sulphur amino acid content) and tofu firmness. Soybean protein content and protein quality are independent traits and both higher protein concentration and quality are desirable.

Since soybean seed protein is often lower in western versus eastern Canada, a CFCRA project was funded to address lower soybean seed protein in western Canada. A series of 20 low to high protein lines have been grown since 2018 at sites across Canada. Seed protein content and quality are being evaluated and compared to climate data at each site. In a preliminary analysis undertaken by scientists at AAFC–Brandon, water accumulation during July was seen to play an important role in seed protein content (Figure 1). Drought stress may play a role in final seed protein since nitrogen (N) fixation will be reduced in soybean plants before photosynthesis starts to be reduced. Reduced N fixation may result from even minor drought stress and may be responsible for some of the lower seed protein levels seen in western Canada. The final year of this trial has been grown in 2021 and will allow us to examine the effect of drought stress across the prairies seen this summer. In addition, genomic scientists at AAFC–Ottawa are examining gene expression differences from multiple sites across this trial. The objective is the identification of geographically important genes for protein content.

Short-season soybean breeding at AAFC–Ottawa involves research partners from multiple disciplines and multiple locations across Canada. Thanks to the CFCRA funding partners, including MPSG, for providing the funding for this integrated, collaborative soybean breeding project.