CWRS wheat varieties evaluated for ultra-early seeding
Comparing five early- and five late-maturing CWRS wheat varieties, ultra-earlyseeded late-maturing CWRS wheat varieties generally yielded higher with more stable yields than either early-maturing cultivars or conventional seeding. Ultra-early seeding increased yield stability for nine of the ten cultivars.
Numerous studies have been conducted since 2020 on the potential for ultra-early seeding of Canada Western Hard Red (CWRS) spring wheat varieties. One study by Collier et al. 2021 assessed nine registered spring wheat varieties in the CWRS, CWSWS, CPSR, CWSP and CNHR wheat classes. This research found that ultra-early planting had improved grain yield stability and improved growing system stability across all varieties.
A new research project was conducted over three years from 2021 through 2023 to evaluate yield and yield stability and grain quality differences in early- and late-maturing CWRS wheat cultivars at two seeding dates across Western Canada.
Research was conducted at Beaverlodge, Edmonton, Lacombe and Lethbridge, AB. Five early and five late maturing CWRS varieties were assessed. The early varieties included AAC Redberry, Go Early, Jake, Parata and Tracker. The late varieties were AAC Brandon, AAC Viewfield, AC Stettler, CDC Stanley and Noor.
Daily soil temperatures were taken at 10 am. Once the soil reached the trigger temperatures of 2C (ultra-early) and 8C (conventional) at a two inch (5 cm) depth, seeding occurred the following day or when soil conditions allowed. Ultra-early seeding dates ranged from March 21 to April 30, and conventional dates from April 15 to May 15.
Seeding rate ranged from 30 to 40 seeds per square foot (300 to 400/m2) that targeted the regional yield potential. Seeding equipment and row spacing varied by site. Seeds were treated with Raxil Pro to help prevent seedling disease. Nitrogen and phosphate fertilizers, and pesticides were applied as required.
The ultra-early sown wheat had delayed emergence, as would be expected, compared to conventional seeding. However, there was little difference between the seeding dates on plant populations that ranged from 20 to 23.5 plants/ft2 (201 to 235 plants/m2).
Lodging ratings were low, ranging from 1.0 to 1.32. Lodging was not significantly different between the two seeding dates, with a few exceptions.
Early maturing AAC Redberry and Tracker, and late maturing CDC Stanley, and Noor were significantly shorter with ultra-early seeding.
Ultra-early sown CWRS wheat took 6.33 days longer to reach maturity from emergence than conventional sown wheat. Despite the longer days to maturity, because ultra-early wheat was sown seven to 34 days earlier, these treatments were ready to harvest earlier than the conventional seeding treatments.
Late-maturing wheat took 1.5 more days to reach maturity at both seed timings than the early-maturing varieties. The researchers concluded that since the difference was small, “the use of early-maturing CWRS wheat cultivars is not required to ensure plants reach maturity early within the growing season.”
As expected, the late-maturing varieties generally yielded significantly higher than early-maturing cultivars. Late maturing AAC Brandon yielded the highest at 61 bushels per acre (4.1 t/ha), which was significantly higher than the next two varieties, AAC Viewfield and AC Stettler.
Improved yield stability with ultra-early seeding
There were no significant yield differences between the ultra-early and conventional seeding timings. This suggests that environmental conditions during the critical growth periods were similar for both seeding timings, and that ultra-early seeding did not have a negative impact on yield.
However, yield stability was improved under ultra-early seeding. The research found that both late- and early-maturing wheat varieties had improved yield stability with ultra-early seeding. Four of the five late-maturing CWRS wheat cultivars evaluated yielded significantly higher and demonstrated similar yield stability to early-maturing CWRS wheat cultivars. This indicates that growers could use higher-yielding, late-maturing wheat varieties under ultra-early seeding to maximize yield and yield stability.
The researchers indicated that “ultra-early seeding had better yield stability through increased access to early-season soil moisture left by snowmelt and rains, and that plants that emerged earlier may accumulate more growing degree days by intercepting more radiation.”
Overall, ultra-early seeding was found to be a beneficial practice that maintains yield with improved yield stability of both early- and late-maturing CWRS wheat cultivars in Western Canada.
Funding was provided by Alberta Grains, Saskatchewan Wheat Development Council, NSERC and Western Grains Research Foundation with University of Alberta (U of A) Research Chair Support.
Jacey Toerper, Brian Beres, Dean Spaner, Muhammad Iqbal, Meng Li, and Linda Yuya Gorim. 2026. Ultra-early seeding enhances the yield stability of early- and late-maturing spring wheat in Western Canada. Canadian Journal of Plant Science. 106: 1-15. OPEN ACCESS https://doi.org/10.1139/cjps-2025-0093
Photo courtesy Linda Gorim
