This research was funded by: USDA-NIFA, Albert Lea Seed House, Green Cover Seed, North Dakota State University, KWS and FP Genetics.
In a Nutshell:
- 11 cereal rye varieties were trialed at three Iowa State University research farms.
Key Findings:
- Challenging wet weather in June and July delayed harvest, and there were significant lodging issues.
- Across all sites and varieties, hybrid cereal rye varieties averaged 62 bu/ac while open-pollinated varieties averaged 45 bu/ac.
- Most hybrid varieties outyielded most open-pollinated varieties at Boone and Greenfield, but Hazlet and Aroostook (both open-pollinated) were among the top performing varieties overall at Nashua.
Rye test plots in Boone, IA just before harvest. Photo taken July 9, 2025.
Background
This was the seventh year that Practical Farmers of Iowa coordinated cereal rye variety trials at Iowa State University research farms at Nashua (northeast Iowa); it was the fifth year of trials at ISU research farms at Boone (central Iowa) and Greenfield (southwest Iowa). A fourth trial Kanawha (north-central Iowa) was not completed due to wet weather conditions around harvest.
In the previous seven years of rye variety trials on ISU farms, SU Cossani, SU Performer, SU Bebop, Tayo and Serafino have been the top yielding varieties across sites. Overall, yields in PFI’s small-grains variety trials have varied quite a bit between years due to weather conditions and the retention and addition of higher performing varieties in the trials [1–7]. In 2024, the average cereal rye yield across the four participating Iowa research farms was 89 bu/ac.[1] In contrast, cereal rye variety trials conducted by the University of Minnesota reported an average yield of 118 bu/ac in 2024 [2]. In 2023, the average cereal rye yield across the four Iowa research farms was 42.6 bu/ac [3]. In 2022, the average cereal rye yield across the four research farms was 81.3 bu/ac [4].
Methods
Variety trials were conducted at four locations in 2025: ISU Northern Research Farm in Kanawha; ISU Northeast Research Farm in Nashua; ISU Ag Engineering and Agronomy Farm in Boone; ISU Southwest Research Farm in Greenfield. Production characteristics and some breeding history about each of the trialed varieties can be found in Table 1. SU Bebop was trialed only at Nashua; Kanawha, Boone and Greenfield trialed ten varieties. Information on winter hardiness, days to heading, plant height and ergot susceptibility can be sourced from the University of Minnesota [8].
Rye management information is provided with the results from each location. No herbicide, insecticide or fungicide were applied at any location. Rye was planted at seeding rates (lb/ac) listed in Table 1 to achieve seeding rates of 25 seeds/ft2 for open-pollinated varieties and 18.4 seeds/ft2 for hybrid varieties. All varieties were planted on 7.5 in. row spacing at 1.25 in. depth. Each location measured grain yield, grain test weight, plant height at harvest and % lodging. No sites were able to measure and report straw biomass this season. Reported yields are corrected to 14% moisture content. Cumulative monthly precipitation and average monthly temperature during the cereal rye growing season sourced from the NASA POWER dataset are provided for each location [7, 8].
We analyze and report variety results separately for each trial location. At each location, the 3-year average yield is provided for individual varieties that have been trialed at the site in previous years. A “% of site average” is also included to aid in comparing yields of varieties within each location; this is the 2025 yield of a variety divided by the average yield across all varieties grown at the site in 2025. We used Analysis of Variance (ANOVA) followed by a Tukey’s Significant Difference test to determine if there were statistically significant differences in yield, test weight, plant height and lodging across varieties at individual sites. Tukey’s test calculates a statistic called the Minimum Significant Differences (MSD); if the difference in yield, etc. between two varieties is greater than the MSD, we consider the yields significantly different. Statistical significance is determined at the 90% confidence level, meaning that if the experiment were repeated, we would expect to see the same results nine times out of ten.
Results and Discussion
After a dry winter, weather conditions during the 2025 growing season were marked by near-record April, June and July rainfalls, making weed management and cereal rye harvest difficult. As a result, field managers at Kanawha were unable to harvest their cereal rye variety trial, and harvests at other sites were somewhat delayed. Lodging was a major issue in all varieties at Greenfield and Boone this year, though most severely in open-pollinated varieties.
Across all sites and varieties, average 2025 rye variety trial yield was 53 bu/ac, down from 89 bu/ac in 2024 but up from 43 bu/ac in 2023. Hybrid cereal rye varieties averaged 62 bu/ac while open-pollinated varieties averaged 45 bu/ac across all sites and varieties. There were few statistically significant differences in yield between the five hybrid varieties at individual sites, and no consistent differences across sites; no single variety had consistently higher yields. At Boone and Greenfield, Serafino, Performer and Receptor were numerically the three top-yielding varieties. There were similarly few statistically significant differences between yields of open-pollinated varieties, though Aroostook yielded significantly higher than ND Dylan at Boone and ND Gardner at Greenfield.
At Greenfield and Boone, most of the individual hybrid varieties significantly outyielded the individual open-pollinated varieties. Notably, at Nashua Aroostook (55 bu/ac) and Hazlet (58 bu/ac), both open-pollinated varieties, were among the top performing varieties this year, yielding significantly higher than hybrids Receptor (41 bu/ac) and Tayo (38 bu/ac).
No cereal rye varieties made test weight (56 lb/bu) this year at any of the three sites. Hybrid varieties were, on average, about 10 in. shorter than open-pollinated varieties.
ISU Southwest Research Farm, Greenfield
Previous crop: Soybean
Replications: 3
Harvested plot size: 5 ft X 60 ft
Fertilizer applied: 124 lb/ac P, 273 lb/ac K and 28 lb/ac S on Mar. 17, 2025
36 lb/ac N as urea on Mar. 24, 2025
Planting date: Oct. 16, 2024
Harvest date: Aug. 5, 2025
ISU Northeast Research Farm, Nashua
Previous crop: Soybeans
Replications: 3
Harvested plot size: 8.125 ft x 50 ft
Fertilizer applied: 31 lb P/ac and 200 lb K/ac on Oct. 25, 2024
31.8 lb S/ac as Supercal on Jan. 27, 2024
35 lb N/ac as urea on Mar. 27, 2025
Planting date: Oct. 11, 2024
Harvest date: Jul. 21, 2025 
ISU Ag Engineering and Agronomy Farm, Boone
Previous crop: Soybeans
Replications: 3
Harvested plot size: 59 ft x 13.5 ft
Fertilizer applied: 39 lb N/ac, 100 lb P/ac, 40 lb K/ac and 37 lb S/ac applied on Apr. 8, 2025
Planting date: Oct. 16, 2024
Harvest date: Aug. 13, 2025
Funding Acknowledgement
This work is supported by the Agriculture and Food Research Initiative, grant number F9000315202081 from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the U.S. Department of Agriculture.
We would also like to express our gratitude to Albert Lea Seed House, Green Cover, North Dakota State University, KWS and FP Genetics for donating seed for these variety trials.
References
[1] E. Link and S. Gailans, “Cereal Rye and Triticale Variety Trial 2024,” Practical Farmers of Iowa, 2024. [Online]. Available: https://practicalfarmers.org/research/cereal-rye-and-triticale-variety-trial-2024/
[2] J. Wiersma, “2024 Winter Rye Field Crop Trial Results,” University of Minnesota. [Online]. Available: https://varietytrials.umn.edu/winter-rye
[3] S. Gailans, “Cereal Rye and Triticale Variety Trial 2023,” Practical Farmers of Iowa, 2023. [Online]. Available: https://practicalfarmers.org/research/cereal-rye-and-triticale-variety-trial-2023/
[4] S. Gailans, “Cereal Rye and Triticale Variety Trial 2022,” Practical Farmers of Iowa, 2022. [Online]. Available: https://practicalfarmers.org/research/cereal-rye-and-triticale-variety-trial-2022/
[5] S. Gailans and L. English, “Cereal Rye Variety Trial 2021,” Practical Farmers of Iowa, 2021. [Online]. Available: https://practicalfarmers.org/research/cereal-rye-variety-trial-2021/
[6] S. Gailans and S. Carlson, “Cereal Rye Variety Trial 2019,” Practical Farmers of Iowa, 2019. [Online]. Available: https://practicalfarmers.org/research/cereal-rye-variety-trial-2019/
[7] S. Gailans and L. English, “Cereal Rye Variety Trial 2020,” Practical Farmers of Iowa, 2020. [Online]. Available: https://practicalfarmers.org/research/cereal-rye-variety-trial-2020/
[8] J. Wiersma, “2023 Winter Rye Field Crop Trial Results: Minnesota Agricultural Experiment Station,” University of Minnesota, 2023. [Online]. Available: https://drive.google.com/file/d/11qo8BPRxJBp2x9rzAeDRTC52UQltXlez/view
[9] A. H. Sparks, “nasapower: A NASA POWER Global Meteorology, Surface Solar Energy and Climatology Data Client for R,” J. Open Source Softw., vol. 3, no. 30, p. 1035, Oct. 2018, doi: 10.21105/joss.01035.
[10] A. Sparks, _nasapower: NASA-POWER Data from R_. (2024). [Online]. Available: https://CRAN.R-project.org/package=nasapower