Report Summary

• A total of 26 experimental breeding lines and reference cultivars were evaluated at the Caddo Research Station for agronomic characteristics and soilborne diseases (Sclerotinia blight and pod rot).
• The disease trial was planted on June 16. True botanically Spanish and Valencia peanuts were dug on Oct. 13,119 days after planting, while runner and Virginia peanuts were dug on Nov. 1, 140 days after planting.
• Weather: The season was marked by below-average temperatures for August and October (3 to 4 degrees Fahrenheit below the 15-year average). July and October had less rain than the 15-year average, while August had 2.6 inches above the 15-year average.
• Disease Levels: Cool nighttime temperatures in September and October resulted in high levels of Sclerotinia blight, but little pod rot was observed in this trial.
• Runner Market Type Results: The six-entry runner market-type trial included Lariat, FloRun ‘107’, Southwest Runner, ACI N104 and USDA-ARS ARSOK breeding lines  R112L and R113L. Runner entries with the numerically highest yield (≥4,051 pounds per acre, lbs./A) and crop values (≥$708 per acre using a contract price per ton) were Lariat and Southwest Runner. Southwest Runner had the least amount of Sclerotinia blight, followed by Lariat.
• Spanish and Valencia Market Type Results: Sixteen entries were evaluated. For the Valencia market, five botanically true Valencia lines and one red-seeded runner (Georgia-Val/HO) were tested. For the Spanish market, three tan-seeded Valencia lines, five small-seeded runners and two botanically true Spanish entries were evaluated. The highest yields overall were obtained from two tan-seeded Valencia lines, NM2 and NM1 (4,829 and 4,794 lbs./A, respectively). The advanced New Mexico State University breeding line, NM23-75 and TamVal OL14 had the highest yield among the Valencia market types (>3,899 lbs./A). Sclerotinia blight resistance was highest in two tan-seeded Valencia lines, NM5 and NM2, and the most susceptible entry was Georgia-Val/HO.
• Virginia Market Type Results: The Virginia trial evaluated four entries: Jupiter, Comrade, Bailey II, Emery and USDA-ARS breeding line ARSOK V103-1, which had the highest yield at 3,991 lbs./A and was the most resistant to Sclerotinia blight.

A major goal of the USDA-ARS peanut research program in Stillwater is to develop and release high-oleic peanut cultivars for the Southwest with improved yield, disease resistance and seed characteristics. In 2025, we evaluated commercial and advanced peanut breeding lines of runner, Spanish, Valencia and Virginia market types in small plots at Oklahoma State University's Caddo Research Station in Fort Cobb. The objectives of these field studies were to compare advanced breeding lines to commercially available cultivars for resistance to Sclerotinia blight and agronomic characteristics, such as yield, seed and pod qualities.

Methods for Evaluating Advanced Breeding Lines and Cultivars

A total of 26 breeding lines and reference cultivars (six runner, 10 Spanish, six Valencia and four Virginia market types) were evaluated. Virginia peanut market types were grown and evaluated separately. Botanically true runner genotypes, including those with small or red seeds that are marketed as Spanish or Valencia, were planted and harvested with the other runner entries because they have similar days to maturity. However, results from the small- and red-seeded runners were analyzed with the botanically Spanish and Valencia genotypes. All advanced breeding lines were high oleic.

Each entry was planted at a density of 5 seeds per foot (seeds/ft) in plots consisting of two 15-foot-long rows with 36-inch-wide beds. A randomized complete block design was used by dividing the field into four sections (blocks) to account for potential disease gradients and environmental variables. All plots were planted approximately one month later than normal (June 16) to ensure green foliage was available for late-season development of Sclerotinia blight. The botanically Spanish/Valencia entries were dug Oct. 13 – 119 days after planting. The runner and Virginia plots were dug Nov. 3 – 140 days after planting.

All plots were irrigated 19 times (total 12.8 inches) between June 18 and Oct. 21 using a center pivot system. Each row in the two-row plots was inoculated with 0.5 grams of Sclerotinia minor sclerotia on Sept. 3. Fields were managed for weeds, foliar diseases and southern blight (caused by Agroathelia rolfsii) following Extension recommendations but were not managed for Sclerotinia blight, pod rot or nematodes. Entries were evaluated for Sclerotinia on Oct. 13. Disease incidence was measured by counting the number of 6-inch sections within each plot that had symptoms of Sclerotinia blight. Soil samples were collected on Oct. 27 for nematode analyses for a subset of the runner entries. Six soil cores (1-inch diameter and 4-6 inches deep) were collected near the root zone from each plot in blocks 1, 2 and 3 of Lariat, ACI N104 and FloRun ‘107’. All plots were examined for pod rot on the same day the plants were inverted.

Peanut grades were determined following USDA-Agricultural Marketing Service guidelines, using two 200-gram samples from each plot. Two 500-gram samples per plot were used to measure pod size of the Virginia entries. Yield was adjusted by factoring in the area lost due to plots being in the path of the center pivot wheels or due to poor seed germination. Data were analyzed using one-way ANOVA in PROC GLIMMIX of SAS (ver. 9.4). The Type I error rate for pairwise comparisons of breeding lines and cultivars was controlled at α = 0.05 using the ADJUST=SIMULATE option. Crop value for each market type was calculated using the following contract prices per ton: $500 for runners, $850 for Valencia, $650 for Spanish and $600 for Virginia.

Summary of 2025 Field Conditions

A total of 2,824 and 2,962 growing degree days in Fahrenheit accumulated for the 2025 Spanish/Valencia and runner/Virginia disease trials, respectively (Table 1). The season was marked by below-average temperatures for August and October (3 to 4 degrees below the 15-year average). July and October had less rain (<1.9 inches) than the 15-year average, while August had 2.6 inches above the 15-year average. Despite relatively warm daytime temperatures, cool evening temperatures in September and October favored the development of Sclerotinia blight. Little southern blight and pod rot were observed.

¹ All plots planted on June 16. Digging dates for botanical Spanish/Valencia and runner/Virginia were Oct. 13 and Nov. 3, respectively.
² June data for entire month and after planting on June 16 (in parentheses).
³ Incomplete Mesonet records.
⁴ Peanut degree-day heat units calculated by Mesonet using low and high thresholds of 55°F and 95°F, respectively.

Performance of the Runner Market-Type Entries

• Runner entries with the highest numerical yield (≥4,051 lbs./A) and crop values (≥$708 per acre) were Lariat (Table 2). Average seed grade varied among entries from 73% to 58%, with the highest in ARSOKF R113L.
• High levels of Sclerotinia blight were observed by early October, and the most resistant entries included Southwest Runner (22.5%) and Lariat (32%). In contrast, FloRun ‘107’, the susceptible control, and ACI N104 had over 87% disease incidence.
• ACI N104 is supposed to be resistant to root-knot nematodes, but soil samples resulted in higher counts than in FloRun ‘107 (400 versus 200 nematodes per 100 cubic centimeters (cc) of soil). Root-knot nematode counts from Lariat were extremely high (1,720 nematodes per 100 cc), and high numbers of ring nematodes (≥400 per cc) were found in all three lines.
• Two-year averages were calculated for four entries (Table 3). Lariat and Southwest Runner had similar yields and higher seed grades than FloRun ‘107’. Southwest Runner, the Sclerotinia-resistant control, and Lariat had the least Sclerotinia blight at 12% and 23%.

¹ Entries sorted by highest to lowest contract revenue per acre. Plots were dug Nov. 3 - 140 days after planting (DAP) and 2,962 growing degree days in Fahrenheit (GDD). Numbers with the same lowercase letter within columns are not significantly different.
² Based on a contract price per ton of $500 for runners. Calculations do not include deductions for excess splits or damaged and other kernels.
³ Grade = % total sound mature kernels + sound splits.
⁴ Incidence of Sclerotinia blight (SB) rated on Oct. 3.
⁵ Number of root-knot (RKN) and ring nematodes per 100 cubic centimeters of soil.
⁶ Seed count per ounce (CPO).

1 Entries sorted by highest to lowest two-year yield. Numbers with the same lowercase letter within columns are not significantly different.
² Days after planting (DAP) when dug; peanut growing degree days (GDD) heat units in Fahrenheit calculated by Mesonet. Planting and digging dates: 2025, June 16 and Nov. 3; 2024, June 20 and Nov. 1.
³ Seed grade (GRD) = % total sound mature kernels + sound splits.
⁴ Incidence of Sclerotinia blight (SB) rated on Oct. 3.

Performance of the Spanish/Valencia Market-Type Entries

• Among the Spanish market-type entries, the three tan-seeded Valencia lines, NM2, NM1 and NM5, had the highest numerical yields (≥4,477 lbs./A; Table 4). Yields were lowest for Span 17 and Span 24 (<2,948 lbs./A). For the Valencia market types, breeding line NM23-75 and TamVal OL14 generated the highest yields (4,083 and 3,899 lbs./A). Georgia-Val/HO was the least productive Valencia market type at 1,819 lbs./A.
• The best seed grades were found in the small-seeded runners ARSOK S95-1, Spunner and ARSOK S107-1L (<71%). TamValOL14, NM5 and Olé had the lowest seed grades (<64%).
• The most Sclerotinia blight (>72%) was found on Georgia-Val/HO, ARSOK S107-1L and Span 17. Spunner and ARSOK S95-1 had the least Sclerotinia blight out of the small-seeded runners (<43%). Sclerotinia blight resistance was highest in the tan-seeded Valencia lines, NM5 and NM2 (<10%). Among the Valencia market-type entries, the most resistance was found in NM23-75, TamVal OL14 and NM15 (<28%).
• OLé and ARSOK S95-1 had the highest numerical yield among 11 entries evaluated for the past two years (Table 5). The highest and lowest grades were found in ARSOK S107-1L (72%) and TamVal OL14 (64%). The least Sclerotinia blight was found on Olé and Myer’s Matador, and the most disease was found on Georgia-Val/HO, Span 17 and S107-1L.

¹ Entries ordered from highest to lowest yield. Botanical Spanish and Valencia entries were dug on Oct. 13 (119 days after planting; 2,824 growing degree days in Fahrenheit); botanical runner entries were dug on Nov. 3 (140 DAP; 2,962 GDD). Numbers with the same lowercase letter within columns are not significantly different.
² Tan-seeded Valencia: NM2, NM1, NM5. Small-seeded runner: Spunner, ARSOK S95-1, ARSOK S107-L, Span 24, Span 17. Red-seeded runner: Georgia-Val/HO
³ Grade = % total sound mature kernels + sound splits.
⁴ Based on a contract price per ton of $650/ton for Spanish and $850/ton for Valencia market types. Calculations do not include deductions for excess splits or damaged and other kernels.
 ⁵ Incidence of Sclerotinia blight (SB) rated on Oct. 3.
 ⁶ Seed count per ounce (CPO).

¹ Entries sorted by highest to lowest two-year yield. Numbers with the same lowercase letter within columns are not significantly different.
² Small-seeded (ss) runner: Spunner, ARSOK S95-1, ARSOK S107-L, Span 24, Span 17. Red-seeded (rs) runner: Georgia-Val/HO
³ Seed grade (GRD) = % total sound mature kernels + sound splits.
⁴ Incidence of Sclerotinia blight (SB).
⁵ Number of days after planting (DAP) when dug; peanut growing degree days (GDD) heat units in Fahrenheit calculated by Mesonet. Planting and digging dates: June 16 and Nov. 3 in 2025; June 20 and Nov. 1 in 2024.
⁶ In 2025, Spanish and Valencia botanical types were dug 120 DAP, and runner botanical types were dug 140 DAP.

Performance of the Virginia Market-Type Entries

• ARSOK V103-1 had the highest yield (3,991 lbs./A), and Emery had the lowest yield (2,099 lbs./A). The entries were not statistically different for seed grade.
• ARSOK V103-1 had significantly less Sclerotinia blight than other entries at 31%.

Acknowledgements

We thank Angie Harting, Lyndsey Aguirre, Kyren Bunyard, Payton Piperato and Elizabeth Williams at USDA-ARS, and Harley Houston, Brennan Leighton and Michael Pettijohn at the Caddo Research Station, for invaluable technical support. Nathan Walker and Kelli Black provided the nematode analyses. Seeds for several commercial lines were originally provided by Birdsong and Hampton Farms.

This research is supported by the USDA-ARS Current Research Information System (CRIS) Project No. 3072-21220-009-00D, the Oklahoma Peanut Commission, the National Peanut Board and OSU Ag Research. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. The USDA is an equal opportunity provider, employer and lender. 

¹ Entries sorted by highest to lowest contract revenue per acre. Plots were dug Nov. 3 (140 days after planting; 2,962 growing degree days in Fahrenheit). Numbers with the same lowercase letter within columns are not significantly different.
² Based on a contract price per ton of $600 for Virginia. Calculations do not include deductions for excess splits or damaged and other kernels. 
³ Grade = % total sound mature kernels + sound splits.
⁴ Incidence of Sclerotinia blight (SB) rated on Oct. 3.
⁵ Seed count per ounce (CPO).
⁶ Number of pods per ounce for pods riding slotted screens sized for super jumbo (40/64 x 3” slots), jumbo (37/64 x 3”), fancy (32/64 x 3”).