Understanding Quality Standards for Cereal Rye to Help Farmers Access Value-Added Markets for Malting, Distilling, and Baking

Winter Rye Variety Trial - 2017/2018

Heights, lodging, yield and test weight was measured prior to cereal rye harvest (Table 11). Wheeler was the tallest variety, whereas Brasetto was the shortest.  Wheeler did not experience any lodging, yet Brasetto, Danko, Guardian, Huron, and VNS were not statistically different from Wheeler. It is also worth noting that lodging was very low across the board, with Musketeer and ND Dylan showing only 4% lodging for the growing season.  The average lodging for the trial was 1.63%. Yields are presented at harvest moisture.  Yields at harvest ranged between 2511 and 4210 lbs ac^-1 with Brasetto, Guardian, ND Dylan, and VNS as the top performing varieties.  The ideal test weight for rye is 56 lbs bu^-1; top performing varieties reaching this mark in descending order were Danko, Musketeer, VNS, Spooner, Guardian, and Aroostook. 

The ten cereal varieties were analyzed for crude protein content, falling number, and the vomitoxin DON (Table 12).  Wheeler had the highest crude protein at 13.96%, and was significantly higher than the other varieties in the trial.  Falling number ranged between 216 and 272; an ideal falling number falls around 260 seconds.  The top performing variety was Brasetto at 272 seconds, but was not statistically significant fom Danko,Guardian, ND Dylan, Spooner, Wheeler, and Bono, who were also top performers.   Danko had very low DON levels, and was not significantly different from Aroostook, Huron, Spooner, and Wheeler.

Table 11: Harvest measurements of winter rye varieties, Alburgh, VT 2018.

*Treatments with an asterisk are not significantly different than the top performer in bold.

LSD – Least significant difference.

Winter Rye Variety Trial - 2018/2019

Weather data was recorded with a Davis Instrument Vantage Pro2 weather station, equipped with a WeatherLink data logger at Borderview Research Farm in Alburgh, VT (Table 13). During the time of this trial, temperatures were below average for every month except July. During the 2018-2019 season, most months saw below average precipitation with the exception of November (’18), December (’18), April (‘19) and May (’19) which saw above average precipitation. There were 5199 growing degree days (GDDs) across the whole season, 20 growing degree days more than the historical average. While winter survival was not measured in this trial, there were some treatment plots in which the rye did not over-winter and were not harvested as a result.

Table 13. Temperature and precipitation summary for Alburgh, VT, 2018 and 2019.

Based on weather data from a Davis Instruments Vantage Pro2 with WeatherLink data logger. Historical averages are for 30 years of NOAA data (1981-2010) from Burlington, VT. (http://www.nrcc.cornell.edu/page_nowdata.html).

There was significant differences between some of the varieties in terms of survival (Table 14). Musketeer had the highest survival, but was statistically similar, in descending order, to Huron, Guardian, Danko, Spooner, Brasetto, ND Dylan, Dolero, Bono, and Wheeler. Wrens Aburzzi and Merced had the lowest winter survival and as a result, no yield or quality data was collected for either variety.

Table 14. Spring survival for winter rye varieties, Alburgh, VT, 2019.

*Treatments with an asterisk are not significantly different than the top performer.

Heights, lodging, yield, test weight, and amount of ergot present was measured prior to cereal rye harvest (Table 15). There were significant differences in lodging, yield, and test weight. Huron was the tallest variety, whereas Dolero was the shortest. Varieties Bono, Brasetto, and Hazlet did not experience any lodging. It is also worth noting that lodging was very low across the board, with ND Dylan showing only 3% lodging for the growing season.  The average lodging for the trial was 1.18%. Yields are presented at 13.5% moisture.  Yields ranged between 480 and 3674 lbs ac^-1 with Brasetto and Dolero as the top performing varieties. Brassetto had no ergot present, but ten other varieties were statistically similar. Helltop and Wheeler had highest amount of ergot with 20.9% and 11.4% respectively. The ideal test weight for rye is 56 lbs bu^-1; none of the varieties met or exceeded this ideal test weight. Guardian had the highest test weight (54.7 lbs bu^-1), but there was no statistical difference between varieties.

 Table 15: Pre-harvest measurements of winter rye varieties, Alburgh, VT 2019.

*Treatments with an asterisk are not significantly different than the top performer.

NS – No significant difference between treatments.

The 13 winter rye varieties were analyzed for crude protein concentration, falling number, and the vomitoxin DON (Table 16). There were significant differences in crude protein and in falling number between varieties. Overall DON levels were low this year and all varieties had DON levels below the 0.5ppm threshold of the Veratox DON 5/5 Quantitative test. Wheeler had the highest crude protein at 15.1%, and was significantly higher than the other varieties in the trial.  Falling number ranged between 161 and 299; an ideal falling number falls around 260 seconds.  The top performing variety was Dolero at 299 seconds.

Winter Rye Nitrogen Rate Trial - 2018/2019

Ergot incidence ranged from 6.7% in the split 45 lbs N ac^-1 fall and 45 lbs N ac^-1 spring application to 10.0% in the control, however there was no statistically significant difference between treatments (Table 17). Highest yields occurred in the split 45 lbs N ac^-1 fall and 45 lbs N ac^-1 spring application with similarly high yields from the 90 lbs N ac^-1 fall application. However, there was no statistically significant difference between treatments. Test weights were highest for the control plots and the 90 lbs N ac^-1 spring application, but once again there was no significant difference between treatments within the trial.

Table 17: Harvest measurements by treatment, Alburgh, VT, 2019.

NS – No significant difference between treatments.

The four treatments were analyzed for crude protein concentration at 12% moisture and falling number (Table 18). There were no significant differences between treatments for either crude protein or falling number. Crude protein ranged from 10.6% to 11.1%. The 90 lbs N ac^-1 fall application had the highest crude protein concentration, but lowest falling number. Falling number ranged between 185 and 202; an ideal falling number falls around 260 seconds for wheat flour however, lower falling numbers around 150 seconds have been acceptable to bakers while using rye flour. The 90 lbs N ac^-1 spring application had the highest falling number of 202 seconds. Overall, DON levels were low this year and all treatments had levels of DON less than the 0.5 ppm detection threshold for the Veratox DON 5/5 Quantitative test.

ϯNS: Not significant

Winter Rye Trials - 2019/2020

Seasonal precipitation and temperature recorded at Borderview Research Farm in Alburgh, VT are displayed in Table 19.  The winter temperatures were warmer than average, leading to strong winter survival.  A cooler than average spring but warmer and drier summer led to 3,433 Growing Degree Days (GDDs) accumulated April to July, which was 55 GDDs above the 30-year average.  Precipitation from April to July was 3.81 inches below normal.  Overall, precipitation across the entire growing season from September to July, was 1.61 inches below average, with a total of 5317 GDDs from September through July, which was 30 less than average.

 Table 19. Temperature and precipitation summary for Alburgh, VT, 2019 and 2020.

Based on weather data from a Davis Instruments Vantage Pro2 with WeatherLink data logger. Historical averages are for 30 years of NOAA data (1981-2010) from Burlington, VT. (http://www.nrcc.cornell.edu/page_nowdata.html).

Winter Rye Variety Trial - 2019/2020

Winter survival was measured in the spring of 2020 and is presented as a percentage, 1% showing severe winter kill within plots and 100% showing little to no winter kill within plots. There were significant differences between some of the varieties in terms of survival (Table 20). Aroostock, Sangasti and Dolero had the highest winter survival, 100%, but was statistically similar to every other variety except Brasetto.  Brasetto had the lowest winter survival, a statistically significant difference from the other varieties, with 93.75% survival. Across the board, there were much higher rates of winter survival in the 2020 growing season for the Rye Variety Trial than there were in the 2019 growing year. 

Table 20. Winter survival for winter rye varieties, Alburgh, VT, 2020.

†Winter survival rated on a 0 to 100% scale where 0 = 0% survival and 100 = 100% survival.

ᵵWithin a column, values labelled with the same letter have no significant difference between treatments (p=0.10).

Heading date, heights, yield and test weight measurements were taken prior to rye harvest (Table 21). There were significant differences in each measurement. Wheeler and Sangasti were the tallest varieties at 169 and 170 cm, respectively, and were also among the latest to head out, and among the lowest yield and test weight.  The average height across the variety trial was 135 cm. There was very little lodging in the variety trial this year so measurements were not recorded.  Yields are adjusted for a 13.5% moisture basis.  Yields ranged between 2410 and 6524 lbs ac^-1 with Dolero and Bono as the top performing varieties. The ideal test weight for rye is 56 lbs bu^-1; only Hazlet reached this test weight, at 56.3, with every other variety ranging from 50.1 to 55.6.  The ideal moisture content for grain storage is below 13.5%.  Moisture measurements were recorded at harvest with every variety except for Wheeler and Serafino measuring below 13.5% moisture.  Harvesting grain with high moisture requires additional drying prior to storage, adding time and labor costs. 

Table 21: Harvest and pre-harvest measurements of winter rye varieties, Alburgh, VT, 2020.

ϯWithin a column, values labelled with the same letter have no significant difference between treatments (p=0.10).

ᵵLSD; least significant difference at p=0.10.

The 13 winter rye varieties were analyzed for crude protein, falling number, and the vomitoxin DON (Table 22). There were significant differences in crude protein and in falling number between varieties. Overall, DON levels were low this year and all varieties had DON levels below the 1.0 ppm threshold required for human consumption (data not shown). Wheeler had the highest crude protein at 12.8% and was significantly higher than all other varieties in the trial.  Falling number ranged between 206 (Wheeler) and 368 (Serafino).  The ideal falling number range for wheat is 250-350, however lower falling numbers around 150 seconds have been acceptable, or even preferable, to bakers using rye flours. See the 2020 Rye Harvest Date Trial Report for more details about falling number in rye.

Table 22: Crude protein and falling number of winter rye varieties, Alburgh, VT, 2020.

ϯWithin a column, values labelled with the same letter have no significant difference between treatments (p=0.10).

ᵵProgass is a rye variety best suited for forage so grain quality not analyzed.

Winter Rye Harvest Date Trial - 2019/2020

Impact of Harvest Date

Yield, harvest moisture, and test weight were measured at the time of harvest (Table 23). From the four different harvest dates (HD), yields were highest at HD1 on 23-Jul at 4648 lbs ac^-1.  Yields from the first two harvest dates were significantly different from the second two harvest dates. Harvest moisture varied across the month long period with highest harvest moisture occurring during the last period on 12-Aug. The lowest harvest moisture was observed on the first harvest date on 23-Jul. Test weight was highest in HD1 at 56.4 lbs bu^-1 with no other harvest dates statistically similar. The lowest test weight was observed at HD4 at 50.4 lbs bu^-1.

 Table 23: Harvest measurements for winter rye harvest dates, Alburgh, VT, 2020.

ϯTreatments marked with the same letter do not differ significantly.  NS – no significant differences.

ᵵLSD; least significant difference at p=0.10.

The four harvest dates were analyzed for crude protein concentration, adjusted to 12% moisture, and falling number (Table 24). Crude protein ranged from 7.9% to 8.4% with the highest values observed during HD1, HD2 and HD4, which were all statistically similar and the lowest protein observed during HD3 which was statistically lower. Falling number was highest at HD1 with a value of 237 seconds, statistically higher than to HD2 at 226 seconds. After the first two harvest dates, values decreased greatly for HD3 at 136 seconds and HD4 at 127 seconds. Overall, tested DON levels were low this year and all varieties had a DON level suitable for human consumption.

ϯTreatments marked with the same letter do not differ significantly.  NS – no significant differences.

ᵵLSD; least significant difference at p=0.10.

Impact of Variety

While yields did not differ as an impact of harvest date, there were varietal differences between Danko and Hazlet with an average trial yield of 4052 lbs ac^-1 and 4102 lbs ac^-1 respectively, though the yield differences were not significant (Table 25). There were significant differences in test weight by variety, Danko at 54.6 bu ac ^-1 and Hazlet at 53.5 bu ^ac-1 and falling number with Danko averaging 224 seconds and Hazlet averaging 139 seconds. Overall, Danko had insignificantly lower yields and protein and significantly higher test weight and falling number.   

 Table 25. Harvest measurements and grain quality for winter rye varieties and harvest dates, Alburgh, VT 2020.

ϯTreatments marked with the same letter do not differ significantly.  NS – no significant differences.

ᵵLSD; least significant difference at p=0.10.

Harvest date x variety interactions

There were statistically significant harvest date x variety interactions for falling number and harvest moisture. These interactions indicate that the varieties responded differently to harvest date for these parameters. In terms of harvest moisture, lowest values for Danko were seen prior to the fourth harvest date (18.3%), whereas lowest values for Hazlet were seen on HD1 (14.3%) and HD3 (14.1%).

Falling number

Falling number measures viscosity by recording the time in seconds it takes for a plunger to fall through a slurry to the bottom of a test tube.  The viscosity is an indicator of enzymatic (alpha-amylase) activity in the kernel which most often results from pre-harvest sprouting in the grain.  Low falling number means high enzymatic activity, or more pre-harvest sprouting damage.  This is most common if there are rain events as the grain is ripening prior to harvest.  Falling number is a widely understood indicator of wheat flour quality, though it’s use as an indicator of rye flour quality is less understood.  Low falling number in wheat, below 250, has a negative impact on bread quality and can lead to lower prices paid for the wheat or possible rejection at the mill.  The ideal range for wheat is 250-350.  High falling numbers, over 400 seconds, can potentially lead to slower fermentation, poorer loaf volume and drier bread texture, depending on the end product. Because rye bread relies on different grain components to create high-quality bread, and ferments more quickly than wheat, it is expected that lower falling numbers are preferred for rye than for wheat, possibly closer to 100-200. 

Looking at falling number, in the 2019 Harvest Date Trial Hazlet had a more severe drop in values over the 4-week period, decreasing by 139 seconds from HD1 to HD4, compared to Danko which decreased by 96 seconds from HD1 to HD4.  In this year’s trial, however, Danko had a more severe drop over the 4-week harvest period, decreasing by 124 seconds from HD1 to HD4, while Hazlet decreased 97 seconds over the same period.  Hazlet did have significantly lower falling number values overall in the trial. 

Figure 2 shows the same falling number trends from Figure 1 alongside observed rainfall between each harvest date.  From 1-Apr to 23-Jul (HD1) there was 9.24 inches of rainfall, nearly 4 inches less than the 30-year average.  One inch of rain fell between HD1 and HD2, over 4 inches fell between HD2 and HD3, and less than a quarter inch between HD3 and HD4.  On 4-Aug there was a 2.98-inch rainfall event which most likely began the sprouting process in HD3 and HD4.  The HD3 occurred three days after the rainfall, with an additional 0.12 inches falling before HD4 (Table 26).  Though small amounts of rainfall, or even prolonged periods of humid weather, can increase the risk of pre-harvest sprouting and, in turn, lower the falling number, this is a clear example of that happening in early August.

 Table 26. Precipitation received between the harvest dates, Alburgh, VT 2020.

Winter Rye Nitrogen Trial - 2019/2020

Table 27 displays field and harvest measurements.  Highest yields occurred in the 90 lbs N ac^-1 spring application with similarly high yields from the 90 lbs N ac^-1 fall application, though the yield differences were not statistically significant across all four treatments. Test weights were highest for the control plots and lowest the 90 lbs N ac^-1 spring application, but once again there was no significant difference between treatments within the trial.  All plots reached the industry ideal test weight of 56 lbs ^bu-1.  Although there was no significant difference in plant height between treatments, there were significant differences in lodging.  The plots with split 45 lbs N ac^-1 fall/spring and 90 lbs N ac^-1 spring applications lodged much more than the 90 lbs N ac^-1 fall and control plots.  Nitrogen can weaken plant stems which may make plants like rye, which tend to be taller than other grains, more susceptible to lodging.  Plots with spring-applied N lodged much more significantly than plots with only fall-applied N or the control plots which received no N. 

Table 27: Harvest measurements by treatment, Alburgh, VT, 2020.

ϯTreatments marked with the same letter do not differ significantly.  NS – no significant differences.

ᵵLSD; least significant difference at p=0.10.

The four treatments were analyzed for crude protein concentration, adjusted for 12% moisture, and falling number (Table 28). There was a significant difference between treatments for crude protein, with plots receiving an N application in the spring having higher protein levels.  Falling number also had significant differences between treatment with 45/45 lbs N ac^-1 having the highest falling number and 90 lbs N ac^-1 spring having the lowest.  An ideal falling number falls for wheat is between 250 and 300 seconds, however, lower falling numbers around 150 seconds have been acceptable to bakers using rye flour. Falling number for all treatments appear to be within an acceptable range for baking.  Overall, DON levels were low this year and all treatments had levels of DON less than the 1 ppm threshold for safe human consumption. 

 ϯTreatments marked with the same letter do not differ significantly.

 ᵵLSD; least significant difference at p=0.10.