Wheat Variety Performance and Production Practices in Louisiana

Boyd Padgett, Noah DeWitt, Stephen Harrison, and Trey Price, LSU AgCenter Scientists

Article Highlights:

• Variety selection considerations (vernalization/heading date, disease resistance, yield, test weight)
• Crop management (planting date, seeding rates, fertilization strategies)

To access the Variety Performance Trial publications, go to the following website: Varieties

Variety selection:

Choice of varieties for planting is a crucial management decision that sets the stage for yield potential and input costs. While grain yield is the most important factor, test weight, disease resistance, and heading date are important considerations as they also impact economic return.

Test weight is important because low test weight results in dockage at the elevator. Heading day is a function of cold requirement (vernalization) and day length (photoperiod) response that determines when a variety heads out. Some varieties head very late or not at all in south Louisiana due to a long vernalization requirement or photoperiod response, while those same varieties may perform better in north Louisiana or Arkansas. Varieties that fully vernalize but head out late due to long photoperiod requirement perform poorly in south Louisiana due to grain fill during hot weather. By contrast, early heading varieties may yield poorly in north Louisiana due to late spring freeze damage. Vernalization and photoperiod response are the primary reasons for dividing Louisiana into North and South regions.

Early-heading and maturing varieties permit earlier harvest and more timely planting in a double-crop system, while later-heading varieties guard against damage from a late spring freeze and can be planted earlier in north Louisiana. Early-heading varieties should be planted in the second half of the recommended planting window to reduce the likelihood of spring freeze damage. Lodging resistance helps guard against reduction in test weight and yield loss that results when near-mature heads come in contact with the ground.

Disease resistance protects yield and reduces input costs. Disease susceptibility is very important in terms of yield and profitability. Reactions for naturally-occurring diseases are also listed for each variety in Variety Performance Trial publications. There are no varieties fully resistant to FHB, but some have high to moderately high to moderate levels of resistance. It should be noted that varieties less susceptible to disease may not always be the highest yielding, especially if disease pressure is not present. However, in high disease pressure situations, these varieties produce higher yields than susceptible varieties and enhance profitability by saving the costs of fungicide applications.

Crop management:

Planting dates for Louisiana wheat depend on location and variety. For southern and central Louisiana, optimum planting dates range from November 1 through November 30. The optimum planting for northern Louisiana is slightly earlier, ranging from October 15 through November 15. Early-heading varieties should generally be planted after the mid-date, while late-heading varieties can be pushed a little on the early side of the planting window. The weather in north Louisiana is cooler in the fall and early winter, which slows growth and prevents excess winter growth. It is important that the wheat crop be well-established and fully tillered before the coldest part of the winter. Additionally, because of the cooler conditions, the threat from fall pests (Hessian fly, army worms and rust) is decreased earlier in the fall compared to south and central Louisiana. While these dates are the optimum planting window averaged over years, the timing will vary in some years depending on weather patterns. Additionally, if wheat cannot be planted within these optimum windows, planting later than the optimum window is usually better than planting too early. Early planting can result in greater insect and fall rust establishment and also makes plants more prone to spring freeze injury due to excessive fall growth and development. Planting too late (more than 14 days after the optimum window) can result in significant yield loss due to slow emergence, poor stands from seed rotting and a decreased tillering period, which results in fewer and smaller heads.

Wheat can be planted by broadcasting seed and incorporation into the soil; however, it is preferred that the seed be drilled. Drilling the seed increases the uniformity of depth and uniform emergence. Use recommended planting rates for drilled wheat (60 to 90 lb/A) or broadcast wheat (90-120 lb/A) of quality seed into a good seedbed with adequate moisture. This higher seeding rate should be used under conditions in which good germination or emergence is not expected, as occurs with late-planted wheat or heavy, wet soils. Late-planted seed should be planted at a higher seeding rate using a drill to ensure rapid, adequate and uniform emergence.

Good surface drainage is critical to successful wheat production. Saturated fields lead to diseases such as root rots and downy mildew, reduced tillering and vegetative growth, and decreased root development and nutrient utilization. Yields in wheat fields suffering from waterlogging stress are greatly reduced. Fields with marginal drainage should be ditched to ensure that water stands for a minimum time after heavy rainfall.

Nitrogen (N) fertilization of wheat can be a challenging aspect of production. Total N application should normally range from 90 to 120 pounds per acre, but this will vary depending on soil type and rainfall after applications. Timing of N application depends on several factors. The wheat crop needs adequate N in the fall and early winter to establish ground cover and properly tiller; however, excessive levels of fall N can result in rank growth and increased lodging potential, as well as a higher probability of spring freeze damage from early heading. If the wheat crop is following soybeans, soil residual or mineralized N should be adequate for fall growth, and no pre-plant N is needed. However, if the wheat crop follows corn, sorghum, rice or cotton, the application of 15 to 20 pounds of N per acre would typically be beneficial. Where the wheat crop is planted later than optimum, additional N may be necessary to ensure adequate fall growth prior to winter conditions. If the wheat crop did not receive a fall application and appears to be suffering from N deficiency in January, the initial top dress N application can be made early to promote additional tillering. Early spring is when the majority of N for the wheat crop should be applied. There is no universal rule on how early spring N should be applied. Each field should be evaluated based on tillering, stage of development, environmental conditions and crop color. A crop that has good growth and good color should not need N fertilization prior to erect leaf sheath (Feekes 5), usually sometime in February. However, first spring fertilizer application should be applied prior to first node (Feekes 6) to ensure optimum head development, tiller retention and head size. Crop N stress around jointing (Feekes 6) will result in yield losses. Any additional N applied following flag leaf typically contributes very little to crop yield. Splitting topdress N into two or three applications is common in Louisiana production systems due to the increased risk of N losses often associated with heavy rainfall and our long growing season. Splitting N typically occurs by applying fertilizer N at or just prior to jointing with a second application occurring 14 to 28 days later. About 50 percent of the topdress N is normally applied with the first split, but this may be decreased if the first split is put out early and plants are not well enough developed to take up that much N.

Phosphorus, K, and micronutrients should be applied in the fall based on soil test reports. All fertilizers applied as well as lime should be incorporated into the soil prior to planting. Required lime should be applied as soon as possible because it takes time for the lime to begin to neutralize the acidity of most soils. The application of sulfur is a growing concern in Louisiana production systems, with increasing deficiencies appearing every year. Oftentimes, early spring sulfur (S) deficiencies are mistaken for N deficiencies and additional S is not applied. Because sulfur is mobile, similar to N, the application solely in the fall may not be adequate. Supplemental applications of S with spring N applications are often warranted.

For further questions or comments contact:

Steve Harrison, Small Grain Breeder, [email protected]

Noah DeWitt, Small Grain Breeder, [email protected]

Boyd Padgett, Wheat Extension Specialist/Plant Pathologist, [email protected]

Trey Price, Extension Research Plant Pathologist, [email protected]

LSU AgCenter Conducts Soybean Variety Trials at Research Stations and Farms

David Moseley and Tristan Watson, LSU AgCenter Scientists

Article Highlights:

• The LSU AgCenter evaluates soybean varieties through both replicated research station trials and on-farm demonstrations to provide regionally relevant performance data.
• Farmers are encouraged to select varieties that perform consistently across multiple environments and years to improve yield stability.
• In 2026, variety testing included evaluations for yield and abiotic/biotic stress resistance across diverse Louisiana environments and soil types.

Selecting the most well-adapted and high-yielding soybean varieties is one of the most critical decisions a farmer makes each year. To support this decision, the LSU AgCenter conducts Official Variety Trials (OVT) and on-farm Core-block demonstration plots, providing unbiased performance data to aid in variety selection. These trials are planted across multiple research stations and producer farms throughout the state, allowing data collection in diverse environmental conditions.

When choosing a variety, it is important for farmers to consider how it performs in environments similar to their own, as well as across a range of conditions. Varieties that consistently perform well across multiple locations and years are generally considered to have greater performance stability.

Official Variety Trial

The 2026 OVT included varieties with maturity groups ranging from 3.8 – 5.8. The maturity groups are divided into sections including 3.8 – 4.4; 4.5 – 4.7; 4.8 – 4.9; 5.0 – 5.3; and 5.4 – 5.8, and there were 8, 25, 20, 10, and 5 varieties submitted to the maturity group sections, respectively. Nine seed companies and one soybean breeding program participated in the 2026 OVT. The varieties consisted of different herbicide technologies. The trial was replicated at seven research stations across the state in different soil types including fine sandy loam, silt loam, and silty clay. At each location, the varieties were replicated four times.

On-farm Core-block Demonstration Plots

In addition to the OVT, the LSU AgCenter collaborates with soybean farmers to evaluate soybean varieties directly on farms. For the Core-block demonstration program, the LSU AgCenter parish agents cooperate with farmers to plant, maintain, and harvest strip trials submitted by seed companies and university soybean breeding programs. These demonstrations provide valuable data from across the state and in local growing conditions and agronomic practices.

In 2026, six seed companies submitted varieties for core-block demonstrations. Twenty-five demonstrations were planted across 13 parishes: 6 for MG 4.1–4.4, 11 for MG 4.5–4.9, and 7 for MG 5.0–5.5, along with an Enlist-only variety trial. Entries included four MG 4.1–4.4 varieties, nine MG 4.5–4.9 varieties, and five MG 5.0–5.5 varieties. Yield data are being collected and analyzed for dissemination.

In addition to on-farm variety trials that focus on yield, a total of six varieties from two companies (five entered as resistant and one as susceptible) were included in nematode resistance screening trials in Franklin, Tensas, Bossier, and Natchitoches parishes, in fields with known nematode pressure. Data included nematode assays and yield. A replicated small-plot trial complemented the on-farm work. Dr. Tristan Watson, LSU AgCenter nematologist, collected soil and plant samples and conducted greenhouse trials to determine resistance levels. Yield data are being collected and analyzed for dissemination.

Variety Testing and On-farm Demonstration Results

The performance data from the soybean OVT and on-farm demonstrations will be published by the LSU AgCenter in the annual soybean variety testing summary. Maturity date, height, lodging, and disease reaction information from the OVT will also be included. The 2026 OVT results will be published following harvest to assist with 2027 variety selections and planting decisions.

The variety publication for previous growing seasons (and the 2026 growing season when available) can be found at LSU AgCenter Soybean Variety Data.

For more information on soybean variety testing and selection, please read the article Using Variety Testing Data to Select Soybean Varieties: Guidelines for Practitioners, published in Crop, Forage & Turfgrass Management. This article presents practical methods for evaluating soybean varieties through both replicated small-plot trials and unreplicated on-farm demonstrations. It highlights the value of assessing variety performance across a range of environmental conditions and features examples from Louisiana-based trials. Additionally, it discusses key stress tolerance traits, including chloride toxicity and resistance to nematodes.

Fall and Spring Options for Controlling Ragweed Parthenium

Stephen Ippolito, LSU AgCenter Weed Scientist

Many fall and spring burndown programs include either 2,4-D or paraquat for their broad-spectrum postemergent weed control. 2,4-D can provide control of small ragweed parthenium; however, once the plant has bolted it can be more difficult to control. Paraquat does not provide sufficient control of ragweed parthenium alone. Saflufenacil (Sharpen) at 1-2 fluid oz/a plus 1% v/v methylated seed oil can provide excellent control of ragweed parthenium; thus, is an option for fall and spring burndown.

Research conducted in 2025 found that tiafenacil (Reviton), a new PPO inhibitor, also has activity on ragweed parthenium when applied with 1% v/v methylated seed oil. Preliminary data indicates that fall applied postemergent burndown applications of tiafenacil provide excellent control of 6 inch tall ragweed parthenium, 1 week after treatment. In addition, preliminary data indicates 2 fluid oz/a of tiafenacil provides good control of 10 to 12 inch tall volunteer corn, 1 week after treatment.

Tiafenacil may be a good addition to fall or spring burndown programs for ragweed parthenium control, however, there is some potential for it to regrow. Research is ongoing to evaluate the use of residual herbicides in addition to tiafenacil for ragweed parthenium control. The maximum rotation crop interval for field corn, soybean, and cotton is 0, 7, and 14 days, respectively. Therefore, it may be especially useful for controlling ragweed parthenium before planting in the spring. For more information about products and product specific use sites please refer to the product label as well as the Louisiana Suggested Chemical Weed Control Guide for Agronomic Crops. It is the responsibility of the applicator to read in entirety and follow the label’s instructions.

Image 1. Control 1 week after treatment, from saflufenacil at 1 fluid oz/a (A) and tiafenacil applied at 1-3 fluid oz/a (B-D) to 6 inch tall ragweed parthenium, compared to a nontreated check (E). 1% v/v methylated seed oil was included for all herbicide treatments. Photo by Stephen Ippolito

Fall Burndown Options for Morningglory, Prickly Sida (Teaweed), and Grass Weeds

Stephen Ippolito, Donnie Miller, Prashant Jha, and Colton Blankenship LSU AgCenter Weed Scientists

Some of the most common fall burndown programs are glyphosate co-applied with one of an auxin herbicide (2,4-D, dicamba), glufosinate, Sharpen, or Reviton (tiafenacil). Another good option is paraquat applied alone or co-applied with Reviton or metribuzin. While there are options, it is important that the choice be based on weed spectrum present in the target area. If there are more morningglory and other broadleaf species present, including an auxin herbicide may be beneficial for glyphosate-based programs. If the primary target of the application is prickly sida (teaweed), either glyphosate co-applied with glufosinate or paraquat applied alone are good options. Most grass weeds are well controlled by applications that include either glyphosate, clethodim, glufosinate, or paraquat; co-applying with Reviton can help to increase control. However, co-applying glyphosate or clethodim with an auxin herbicide such as 2,4-D or dicamba can reduce control of some grass weeds due to antagonism.

To prevent antagonism between glyphosate and a potentially antagonistic herbicide:

• Apply glyphosate at least 7 days prior to applying a potentially antagonistic herbicide for best results.
• If co-applying glyphosate with a potentially antagonistic herbicide, applying at a higher labeled rate may help to overcome potential antagonism.

Much of Louisiana has received little rainfall over the last few weeks. We are approaching application dates for residual herbicides. With little rainfall in the forecast, it may be beneficial to select a residual herbicide with a higher K_oc (sorption potential), allowing the herbicide to persist in the soil longer. Such as Goal (oxyfluorfen), Prowl (pendimethalin), metribuzin, or Valor (flumioxazin). Both S-metolachlor, and Zidua (pyroxasulfone) applied in the fall are good options for residual control of Italian ryegrass. However, pyroxasulfone tends to persist in the soil longer. Therefore, under present weather conditions, pyroxasulfone may have a better chance of persisting long enough to be incorporated by a rain event for Italian ryegrass control.

LSU AgCenter Specialists