Trial Objectives and Procedures 

Performance trials for hybrid grain sorghum are conducted by the Oklahoma Cooperative Extension Service each year. These trials provide producers, Extension educators, industry representatives and researchers with information for grain sorghum hybrids marketed in Oklahoma. Performance trials were planted at eight locations in 2023. All emerged and had decent early-season growth. However, due to dry conditions at planting, the Tipton location was terminated. Trials at Chickasha, McCaull, and Goodwell were irrigated using overhead sprinkler irrigation. Yields presented in this document are for the early, medium and late maturity hybrids for all locations. Most cultivars are similar among all locations. The exception to this is several early and medium cultivars, which are solely marketed to the panhandle region. Therefore, a number of cultivars are present in only at the three panhandle locations.

Grain sorghum hybrid trial entrants were assigned by companies to their respective maturity groups (early represented less than <60 days to mid-bloom (DMB), medium was 60 to 70 DMB, with late being than >70 DMB). If a cultivar was exactly 60 or 70 DMB, previous years data was used to determine which maturity the cultivar fell into. Companies designated all hybrid characteristics are presented in Table 1. This information was not determined or verified by Oklahoma State University. Company participation was voluntary; therefore, not all hybrids marketed in Oklahoma were included in the trials.

In 2023, 38 hybrids were entered by five seed companies.  For the hybrid performance trials, each maturity group was tested independently with individual hybrids being arranged in a randomized complete block design and having a minimum of four replications. All locations were two row plots with 30-inch spacing and 35 feet in length. Plots were trimmed to 25 feet prior to harvest. Tractor-powered cone planters were used to plant all trials with seeding rates adjusted for the trial location. Trials were harvested with a Kincaid model 8XP plot combine.

Planting densities, cooperating producers, cultural practices, soil series, herbicides and insecticides used in all trials are listed individually in result tables. Rainfall data from the nearest Mesonet sites are also listed. Some trials are long distances from the nearest Mesonet site; therefore, rainfall could be greater or less than reported.

Soil fertility practices will be discussed for each individual location following their yield tables. All applications were made in accordance with OSU Extension best management practices for management. Soil samples were collected in the winter and early spring prior to planting and submitted to the Soil, Water and Forage Analytical Laboratory for analysis. All N, P, and K applications were made based on these results. Nitrogen applications were made based on a 120 bu/ac yield goal, with the exception of Goodwell and McCaull which were made based on a 150 bu/ac yield goal. At all research station sites, soil pH is managed to be suitable for grain sorghum production. Locations on grower's fields are not as controlled; however, all locations this season were within reasonable limits (5.5-7.5).

Due to the degree of variability between the sites in the study and grower's fields around the state, discussions regarding the growing conditions will be made prior to each individual location.

Results 

Grain yields are reported in pounds per acre and bushels per acre of threshed grain, adjusted to a moisture content of 14% (Tables 2 through 21). Test weight is also reported in pounds per bushel. Different plant populations at each location prevent accurate comparison between locations. Also, comparisons across maturity were not conducted as they were treated as independent trials. Producers should note that late-maturing hybrids, due to longer periods of vegetative and early reproductive growth, will generally yield more than early- and medium-maturity hybrids. The availability of moisture at critical crop development stages; however, often influences yield more than the yield differences associated with maturity groups. When choosing a maturity group, the type of cropping system, planting date, planting rate and potential moisture should be taken into consideration. For more information, consult Fact Sheet PSS-2034, Grain Sorghum Planting Rates and Dates, and Fact Sheet PSS-2113 Grain Sorghum Production Calendar.

Least Significant Difference (LSD) is a statistical test of yield differences and is shown at the bottom of each table. Unless two hybrids differ by at least the LSD shown, little confidence can be placed in one hybrid being superior to another, and the difference is probably not real.

The Coefficient of Variation (CV) is provided as an estimate  of the precision of the data with respect to the mean for that location and maturity group. To provide some indication of yield stability, multi-year means for yields and test weights are provided where trials have been conducted for more than one year with more than three entries per maturity group. Producers interested in comparing hybrids for consistency of yield in a specific area should consult these entries. Models with CV's greater than 25 have not been included in this report.

Acknowledgements 

The financial support of the participating companies and the Oklahoma Sorghum Commission is gratefully acknowledged, as well as the efforts and resources provided by the producer-cooperators: Brook Strader and Jordan Sheer. The authors are also grateful for research support from Michael Pettijohn of SCREC, Mike Schulz of SWREC, Cameron Murley and Skeate Beck of OPREC, Ted Newell of MVRS, and Kenneth Watkins of CVRS. We are also grateful for the help of County Agricultural Educators: Aaron Henson (Tillman County), Troy Gosney (Major County), Gus Holland (Tulsa County), and David Nowlin (Caddo County) who gave generously of their time to this project in 2023.

Total Rainfall
Figure 1. Departure from average rainfall for April 2023.

Total Rainfall
Figure 2. Departure from average rainfall for May 2023.

Total Rainfall
Figure 3. Departure from average rainfall for June 2023.

Total Rainfall
Figure 4. Departure from average rainfall for July 2023.

Total Rainfall
Figure 5. Departure from average rainfall in August 2023.

Total Rainfall
Figure 6. Departure from average rainfall in September 2023.

Figure 7. Average maximum air temperature for August 2023.

Figure 8. Average maximum air temperature for September 2023.

Chickasha 

The Chickasha location experienced a relatively normal year. Near normal rainfall throughout April and early May resulted in adequate to above average stands. However, since precipitation was not excessive, preplant herbicides were effective at maintaining a weed-limited environment during the first 30 days of growth. A flush of weeds during  vegetative growth required an application of Huskie prior to canopy closure. This was primarily made to control pigweeds and other miscellaneous broadleaf weeds. Subsequent flushes of weeds required manual removal. This occurred  during the early dough stages. Heat stress was experienced during the later stages of growth. Moisture stress was not experienced due to the ability to provide moderate irrigation in order to not lose the trial. One-inch weekly applications of moisture were applied during August and September but were terminated at first stages of black-layer of any cultivar.  These irrigation applications were made with a sprinkler irrigation system. Because irrigation was terminated at first  signs of black-layer, this did favor the early- and medium-maturing cultivars as they were at or near maturity, while the late-maturing cultivars were not quite at physiological maturity. This impact can be seen from the yields across the trial. Periodic moisture and some regrowth of tillers did make it necessary to desiccate the trial and an application of glyphosate was made prior to harvest. No major insect pests or diseases were experienced throughout the trial. Late-season charcoal rot evaluations resulted in no appreciable numbers.

Cooperator: Matt Pettijohn
Tillage Practice: Conventional
Soil Series: Dale Silt Loam
Seeding rate: 37,600 seeds/ac
Herbicide: Preemergence: 2.7 qt/ac Charger Max ATZ + 44oz glyphosate/ac
In-season: 16 oz Huskie in-season
Fertilizer: N- 140 lbs/ac
Planting Date: May 9
Harvest Date: September 18

Homestead 

This trial was located on a cooperator's field (Brook  Strader) near Homestead, Oklahoma. This location is typically rotated with a winter wheat cover or soybean. The Homestead location in 2023 was potentially one of the most consistent trials. Timely rainfall resulted in above-average stands early in the season. As with the other locations, early-season weed control was very good for the first 30 days. A break in control did happen during the vegetative growing period. Since this was primarily pigweed and marestail, this resulted in an application of Huskie. This was the only in-season weed management practice needed. Even with prolonged heat and drought stress, no supplemental irrigation was applied throughout the growing season. Light to moderate true and false chinch bug activity did result in light to moderate stress on the crop. However, when evaluating lodging for the crop, no significant lodging (the primary risk for chinch bugs) was noted for any cultivar or any region throughout the trial. No chemical applications were made for control. No other significant insect pests or diseases were present throughout the season.

Cooperator: Brook Strader
Tillage Practice: Conventional
Soil Series: Canadian Fine Sandy Loam
Seeding rate: 37,600 seeds/ac
Herbicide: Preemergence: 2.7 qt/ac Charger Max ATZ + 44oz glyphosate/ac In-season: 16 oz Huskie in-season
Fertilizer: N- 140 lbs/ac; P- 60 lbs/ac; K- 60 lbs/ac
Planting Date: May 3
Harvest Date: September 8 

Perkins 

The Perkins location was at the Cimarron Valley Research  Station near Perkins, Oklahoma. The previous crop was a mix of soybean agronomic trials from the previous year; however, none had a significant impact on trial variability. The trial was planted into a tilled field. Dry conditions in early spring paired  with excessive moisture in middle to end of April resulted in delayed preparation of site location. However, when the trial was able to be planted, adequate moisture and warming soil temperatures resulted in stands that were average to above-average which developed very quickly. Early season weed management was very good but continued moisture into May resulted in continued flushes of weeds that had to  be controlled with a combination of chemical applications and physical removal. Weeds continued to be an issue throughout the year and had to be continually managed. As this was primarily grassy weeds, physical removal continued to be the primary means of control. Even with prolonged heat and drought stress, no supplemental irrigation was applied throughout the growing season. Very light chinch bug activity  was noted in the middle of the season. However, this minor stress resulted in very little impact on the crop. No other disease or insect pressure was noted throughout the season.

Cooperator: Kenneth Watkins
Tillage Practice: Conventional
Soil Series: Teller Fine Sandy Loam
Seeding rate: 37,600 seeds/ac
Herbicide: Preemergence: 2.7 qt/ac Charger Max ATZ + 44oz glyphosate/ac
In-season: 16 oz Huskie in-season
Fertilizer: N- 140 lbs/ac; P- 60 lbs/ac; K- 60 lbs/ac
Planting Date: May 3
Harvest Date: September 8 

Bixby 

The Bixby location is the program's only eastern Oklahoma site, which is often noted for having more stable temperatures and consistent rainfall patterns. This allows for a different look at cultivar performance under these conditions. In 2023, this location was not exempt from hot and dry condition and experienced substantially higher temperatures and lower in-season precipitation than normal for this location, especially in the early months of the year. Similar to other locations, preplant herbicide applications did help with early-season weed control. This location is noted for having heavy pigweed and grass pressure. Grasses were not an issue throughout the growing season, with only minor issues with a patch of Bermudagrass located in early maturing cultivars in the third replication. This was managed through physical removal but did cause slight reductions in yields and increased variability. However, since the pressure was consistent across the early cultivars, this replication was maintained for analysis. Only a minor amount of pigweed was noted during the course of the year and was manually removed during early flowering/ grain fill stages. Chinch bug pressure was higher here than  any other location during 2023. A pyrethroid insecticide was applied across the trial at early reproductive growth via a high-clearance sprayer. These applications did not completely control the pests but did minimize additional growth of populations. While this location can be irrigated, no irrigation was applied due to mechanical issues with the irrigation pump, therefore this should be considered a completely dryland trial in 2023. No significant diseases were present throughout the  season. Recent research has also shown that N applications do not have to be as high at this location as it often follows several years of soybean, which was the reason for the lower N application rates.

Cooperator: Ted Newell
Tillage Practice: Conventional
Soil Series: Wynona Silty Clay Loam
Seeding rate: 37,600 seeds/ac
Herbicide: Preemergence: 2.7 qt/ac Charger Max ATZ + 44oz glyphosate/ac Fertilizer: N- 60 lbs/ac
Planting Date: May 30
Harvest Date: October 21 

Slapout 

This trial was on a grower field (Jordan Shearer) near  Slapout, Oklahoma. The trial is a traditional sorghum and wheat rotation for the region. The trial was planted in the middle of June, which was typically later than normal for this region. This was due to a combination of cooler soils and challenges with soil moisture. Due to rapid warming and good early soil moisture, the trial emerged very quickly and was able to get an adequate stand within the first 7-10 days (depending on  maturity). Growth and development of the trial continued and progressed very well during June and July due to consistent moisture patterns. This did lead to several flushes of weeds  in the trial that were managed by manual removal several times during the course of the season. This continued until mid-August when dry conditions and above average temperatures returned to the region. This occurred during later stages of reproductive growth and early grain fill, especially  for the longer maturity cultivars. This stress became severely yield limiting during the later stages of reproductive growth and limited the top end of yield potential for the cultivars. This later season stress can also be seen on the lower test weights for a majority of the cultivars compared to other trial locations in 2023. No major disease or insect issues were noted at the Slapout location and therefore were not managed.

Cooperator: Jordan Shearer
Tillage Practice: Conventional
Soil Series: Oklark-Alopark Loams
Seeding rate: 37,600 seeds/ac
Herbicide: Burndown: 24 oz glyphosate/ac + 10 oz dicamba/ac Preemergence: 1 pt atrazine/ac + 1.3 pt S-Metolachlor + 1 oz Saflufenacil/ac
Fertilizer: 60 lbs N/ac + 20 lbs P/ac
Planting Date: June 14
Harvest Date: November 8

Goodwell 

The Goodwell location was at the Oklahoma Panhandle Research and Extension Center (OPREC) and was under an overhead sprinkler irrigation system. The trial was strip tilled into the previous year's corn crop. The trial was fertilized through the strip-till unit. The location had adequate moisture prior to planting as well as good moisture following; therefore, emergence was not an issue, and an adequate stand was achieved. Due to moisture early in the season, weeds were a continual issue this season. These weeds were predominately volunteer corn early in the season and a mix of annual grasses and pigweed later in the season. These were controlled with a combination of chemical applications and manual removal (after chemicals were no longer labeled). Irrigation was needed throughout the middle and later portions of the season. Unfortunately, irrigation was delayed by a week or two due to mechanical issues. This could have attributed to the minor decrease in yields compared to other irrigated locations in the panhandle. However, this was not universal, and some cultivars exhibited greater stress compared to others. No significant  insect and disease pressure was noted at this location.

Cooperator: Cameron Murley
Tillage Practice: Strip-tilled into corn residue
Soil Series: Gruver Clay Loam
Target Population: 66,000 seeds/ac
Fertilizer: 200 lbs N/ac, 65 lbs P/ac
Planting Date: June 14
Harvest Date: November 8 

McCaull 

The trial location was at the McCaul Extension Farm near Elkhart, Kansas. The trial was strip tilled into previous wheat crop residue. All fertilizer was applied in the strip. The trial was irrigated with overhead sprinkler irrigation. The trial was on the inner irrigation spans of a quarter-acre pivot, with the outer spans planted to corn. With rainfall and irrigation applied prior to planting, soil moisture at planting was more than adequate. This resulted in very good stands shortly after planting. However, with the associated moisture, early flushes of weeds had to be sprayed  in order to maintain a weed-free environment. Successive flushes of weeds were controlled through manual removal. Minor delays in irrigation during the early portions of July and August did potentially increase stress of the trial, but significant yield limitations were not noted throughout the  trial. Lower yields for the later maturity cultivars can be explained by the increased temperature and lower natural rainfall during August and September. At the end of August, most of the early and medium cultivars had already begun to set and fill grain, while the later cultivars experienced this  stress during anthesis and early grain development. Stress during this period does tend to decrease yields compared to other later-season growth stages. No significant insect  or disease pressure was noted throughout the season.

Cooperator: Cameron Murley
Tillage Practice: Strip-tilled into wheat residue
Soil Series: Gruver Clay Loam
Target Population: 66,000 seeds/ac Fertilizer: 200 lbs N/ac, 65 lbs P/ac
Planting Date: June 14
Harvest Date: November 11