Resisting a devastating duo

Soybean cyst nematode (SCN) and soybean sudden death syndrome (SDS) are the number one and two yield-reducing pests for soybeans, respectively, causing average losses of $80 million annually, though the severity can vary with weather patterns. Both pests have been spreading almost hand-in-hand across Ontario’s soybean-growing areas. To combat these threats, a team of researchers from the University of Guelph, led by breeder Milad Eskandari, is developing soybean varieties resistant to both SCN and SDS.

SCN is a microscopic roundworm that damages soybean roots, while SDS is a fungal disease causing root rot and leaf damage. Both pests often occur together, worsening the damage.

The breeding program focuses on creating high-yielding soybean varieties adapted to Ontario's climate, with resistance to both SCN and SDS. The goal is to develop varieties that can maintain yields and reduce economic losses for farmers. The research is supported by various organizations, including the Grain Farmers of Ontario and the Ontario Ministry of Agriculture.

To address SCN resistance, the team is exploring alternative resistance sources beyond the commonly used PI 88788, which is losing effectiveness. They are working with other sources like PI 548402 (Peking), PI 437654 (Hartwig), and PI 89772 to provide more options for farmers. The screening for SCN resistance is conducted in collaboration with Agriculture and Agri-Food Canada (AAFC) in Harrow, Ontario, ensuring rigorous testing and evaluation.

The team also uses molecular markers to identify SCN-resistant breeding lines more efficiently. These markers help in consistent and reliable evaluation of resistance, complementing field assessments.

For SDS resistance, the research is more recent. The team is evaluating various soybean lines for SDS resistance and identifying genetic factors involved. They are also developing molecular markers for SDS resistance and creating new breeding lines by crossing elite lines with exotic SDS-resistant lines.

Overall, the efforts aim to ensure sustainable and resilient soybean production in Ontario by developing soybean varieties resistant to SCN and SDS.