One of the most important management decisions for improving yields is variety selection. Depending on growing conditions, individual varieties may perform differently from year to year. Growing more than one variety helps to reduce the risk of a crop failure. Planting the majority of acreage to a proven variety while testing new varieties on a smaller scale is a good practice.
In Ontario, over 250 soybean varieties are grown. The average life span for a soybean variety is 3-5 years. Hundreds of new varieties are tested each year. Variety selection for a grower mainly focuses on maturity and yield. Additional factors when choosing varieties are:
- Herbicide resistance traits
- Standability (Lodging)
- Disease resistance
- Soybean Cyst Nematode resistance
- End-use – if intended for on-farm livestock feed, choose a variety with a high protein index.
In selecting superior varieties, three main sources of information exist:
- Performance trial data
- On-farm strip trial data
- Company information on variety characteristics
The Ontario Soybean and Canola Committee (OSACC) co-ordinates annual performance trials at various locations across the province. These trials are “third party” experiments to assess yields and other characteristics of varieties grown in Ontario. Results are published each fall and are available at www.gosoy.ca. Yields, as well as ratings for maturity, plant height, lodging and other characteristics are published. To aid in selection, seed companies also provide additional detailed information on the varieties they sell.
Plant lodging is a signification problem some years, which can reduce yield. Varieties with good standability or lodging scores should be selected for production on medium-to-light-textured soils, fields that have regular manure application, and fields with high residual nitrogen levels. Lodging can also be reduced by lowering seeding rates.
Identity-Preserved (IP) Varieties
Identity preservation is the segregation of a variety from planting until delivery to an end user. IP varieties exist in a number of markets such as seed production and the production of food-grade soybeans. The introduction of GMO varieties has resulted in consumer demand for identity preserved, non-GMO soybeans. The market offers various levels of premiums and contracts to the producer to grow IP soybeans due to their increased management. When growing IP varieties which are usually white hilum types, a shorter-season variety (lower maturity group) than adapted will ensure quality at harvest. The hilum is the point at which the soybean seed connects with the pods. The hilum can differ in colour depending on the variety. The hilum’s colour can range from yellow (Y), imperfect yellow (IY), grey (GR), buff (BF), brown (BR), black (BL), or imperfect black (IBL).
IP acreage planted should be limited to a size that can be harvested in a timely manner. Performance information for specialty-trait varieties may not be available or may be only available from the company selling the seed. To determine whether the premium is adequate, assess the agronomic qualities of an IP variety, such as yield, disease resistance, and maturity before planting. Seed size and yield are not strongly correlated, meaning seed size does not have a significant impact on yield. The Ontario Soybean and Canola Committee (OSACC) conducts performance trials of food-grade soybeans, as well as GMO varieties. For crop insurance purposes, Agricorp provides a yield adjustment factor for a number of specialty types since specific varieties may yield less.