Finding Heat Stress Biomarkers

Clemson scientists study heat stress, which directly reduces peanut yield, causes other problems indirectly.

Agroup of researchers led by Clemson University Plant and Environmental Sciences assistant professor Sruthi Narayanan is working to develop heat-tolerant peanut varieties. Their latest work focuses on how lipids (fats) in peanut plant anthers are altered by heat stress.

“Understanding these changes will aid in understanding the mechanisms of heat tolerance and help us determine how to develop heat-tolerant peanut varieties,” Narayanan says.

Lipids provide energy for plant growth and survival. Anthers are plant male reproductive organs that produce pollen, which is transported to the stigma of the female reproductive organ in the flower, pistil, for pollination to occur and plants to reproduce.

Reduced Pollen, Reduced Yield

“Reduced pollen production and viability are the major reasons for yield loss when heat stress occurs during the flowering stage,” says Zolian Zoong Lwe, a former Clemson master’s student who conducted the study under Narayanan’s guidance and is now a doctoral student at Kansas State University. “Understanding the mechanisms underlying the decrease in pollen during heat stress will help develop tolerant peanut varieties.”

The study, funded by the National Peanut Board, the South Carolina Peanut Board and supported by the U.S. Department of Agriculture National Institute of Food and Agriculture, began in 2018. It involved six varieties: Bailey, Georgia 12Y, Phillips, Sugg, Tifguard, and Wynne and one breeding line, SPT06-07.

“These varieties were selected to have a range of cultivars from heat sensitive to more heat or drought-tolerant,” says Dan Anco, Clemson Extension peanut specialist and assistant professor at the Edisto Research and Education Center in Blackville, South Carolina, and one of the researchers on the study.

Test varieties were grown in fields at the Simpson Research Farm following field operation recommendations in the Clemson Peanut Money-Maker Production Guide. The plots received rainwater only.

Traits For Heat Tolerance Found

Heat tents were used to heat-stress the plants for 17 days in 2018 and 18 days in 2019. Lipids were extracted from anthers in flowers collected from the plots. Researchers found heat stress caused changes in lipids needed for the plants to reproduce. The study identified lipid metabolic traits associated with heat tolerance.

“This discovery is useful in determining lipid biomarkers (measurable/ observable changes) that have important applications in breeding climate-resilient varieties,” says Sachin Rustgi, a plant breeder at the Clemson Pee Dee REC in Florence who also is part of the research team.

Other researchers involved in the study are Salman Naveed, a doctoral student at Clemson University, and Ruth Welti, a biology professor at Kansas State University.

A paper about their study appears in the scientific reports journal’s Dec. 17, 2020, edition of Springer-Nature.

According to USDA’s National Agriculture Statistics Service, South Carolina had 62,000 acres of peanuts at a production value of more than $46 million in 2019 and 82,000 acres that produced 278 million pounds of peanuts in 2020. PG

Clemson assistant professor Sruthi Narayanan and graduate student Zolian Zoong Lwe study how heat stress affects peanuts as they work to develop heat-tolerant peanut varieties.

NewProducts

AGCO Innovations Earn Eight 2021 AE50 Awards

AGCO Corp. marks its 30th anniversary by receiving eight AE50 Awards from the American Society of Agricultural and Biological Engineers for 2021. Each year, 50 products are chosen by an international panel of industry experts as the most outstanding innovations in engineering and technology for agricultural, food and biological systems.

The 2021 AE50 award-winning products from AGCO include: Fendt Momentum planter, Fendt Ideal drive steering system, 9350 DynaFlex draper header with Auto Dock header docking system for Fendt Ideal combines, Fendt 700 Gen6 Series tractors, Fendt 1100 Vario MT Series track tractors, Fendt Teach In Headland Turn Assistant, Precision Planting FurrowForce two-stage closing system, Intelligent Agricultural Solutions’ Engage Spread Control for TerraGator Air-Max Precision application systems.

“AGCO is proud to be recognized for so many of our advanced technologies. Though just 30 years old, the company is built upon the legacy of brands with more than 500 years of combined experience bringing innovations to farmers. These award-winning products reflect that spirit and our continued quest to design and engineer smart, innovative equipment and agronomic-focused solutions for farmers around the globe,” says Brad Arnold, senior vice president, Global Crop Cycle and Fuse Connected Services at AGCO. “This recognition clearly demonstrates AGCO’s investment in and commitment to helping make farmers’ lives easier and their operations more productive and sustainable.”

For more information on these new products, visit your nearest AGCO dealer, www.agcocorp.com or agcovirtualshowroom.com.

More Decision-Making Tools From Case IH

Case IH announces the first major update of 2021 for the AFS Connect Farm desktop platform and mobile app, giving producers even more power and flexibility to manage their operation anytime, anywhere. From the fast, easy-to-use interface to advanced full-farm data visualization and overlaid geospatial boundaries, AFS Connect Farm provides users with a continually expanding feature set designed to optimize performance, productivity and flexibility at no cost to them.

“As producers take to the field this spring, we’re excited to give them a refined AFS Connect experience and even more decision-making tools to help them increase efficiency and turn potential into profit,” says Leo Bose, Case IH AFS marketing manager lead. “AFS Connect gives users instant access to their operation, helping them manage the farm from a remote location and make smart decisions using realtime and historical data.”

With the latest update to the AFS Connect Farm app, users have access to a wealth of field information when they select a map from the main map screen. With just a few taps, users can now view field-specific data, such as activity layers, scouting observations and soil zone data. Field- and vehicle-specific data is more accessible than ever, with complete field and vehicle lists visible alongside the map. This allows users to switch between a map screen, a field list and a vehicle list quickly and efficiently. Maximize the potential of AFS Soil Command with the all-new prescription creation tool. This will allow equipment settings to be customized to match conditions in different areas of the field while on the go. Producers can save fuel, conserve soil and appropriately tailor machine agronomic output throughout the field to the crop. Users can also create prescription files for variable depth or downforce on Case IH tillage tools equipped with AFS Soil Command.

For more about Case IH and AFS Connect, visit www.caseih.com.

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RESOURCES

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Defining IPM

know fields will exceed the economic injury level if a control practice is not used. An effective way to suppress these is to As we move into the sea- use a preventive treatment as the crop is being planted. son, we often think in terms Even deciding to use a resistant variety for a disease is of preventive treatments versus done when we plant and not after the peanuts emerge. reactive treatments to address This, too, is a core component of IPM because we are using agronomic issues and pests. In knowledge from the past and making a decision based on reality, we use both approach- the economic impact. We also have to take into account es. This is in part based on the yield of a resistant variety versus a susceptible variety if logistical constraints and the the pest is either controlled in some other way, in the case ability to be timely with inputs of a susceptible variety, or the pest does not develop, as in to correct a problem. the case of a resistant variety. What is the financial impact DAVID JORDAN We also may need to incor- in both of these scenarios? Because we don’t automatically

North Carolina State porate effective practices that plant the resistant variety does not mean we are ignoring

University Extension Agronomist prevent or minimize a problem because we may not have a IPM principles. And of course, we would have major yield losses in peanuts if we did not use preplant incorporated or corrective tool once something preemergence herbicides. We also know our weed populadevelops. The ability to address issues rapidly and complete- tions will be high enough in most fields to justify herbicide ly is important to protect peanut yield. If we are unable to use, and practical knowledge informs us that relying only on do that, we better do something ahead of time that keeps postemergence herbicides is not always, and in fact seldom, the issue from exploding and causing yield and financial completely effective. There is nothing wrong from an IPM loss. standpoint with using herbicides in a preventive manner.

I recently read a letter to the editor in the periodical There are many risks to peanut yields, and we have many Science titled, “Stay True to Integrated Pest Management.” tools to address these risks. The more we know about the The discussion was not specific to peanuts. However, the history of fields and production in those fields, the more letter seemed to say that using insecticide seed treatments effective we can be with IPM. Preventive treatments are was not consistent with the goals of IPM. just as much a part of IPM as the reactive treatments. IPM

This got me thinking about how we decide if a practice depends on our knowledge of the pest both historically and should be defined as a principle of IPM, which is import- contemporarily and the availability and effectiveness of the ant because I think managing pests using IPM principles tools at our disposal. is critical and because I teach an IPM course at N.C. State. We often think of IPM with respect to monitoring pest populations during the crop cycle and then treating based on economic thresholds that are established. Thresholds are based on pest numbers or levels of injury caused by the pest in relation to the impact on yield, crop price and cost of the treatment.

This is a core component of IPM. But knowledge and monitoring occurs well before the crop is planted, especially with peanuts. What happened in the field years ago needs to be considered. Effective fungicide seed treatments are essential in protecting peanut seedlings from pathogens and the diseases they cause to get an adequate stand. There is no substitute other than an in-furrow application of fungicide. Our stands will be low if we do not treat, even when seed quality is good.

We also know in North Carolina that if an insecticide is not applied to suppress thrips, we will get a yield hit in most fields. One can certainly wait until peanuts have emerged to apply insecticide, but a more effective way from a logistical standpoint is to apply a systemic insecticide in the seed furrow at planting. For both seedling disease and thrips, we

Water Efficiency In Prolonged Drought

Peanut has a shorter rooting depth than cotton and grows in sandy soils with low water-holding capacity. It requires approximately 20 to 30 inches of water (irrigation and rainfall) per growing season depending on weather conditions. Most of this water requirement will need to be EMI KIMURA supplied by irrigation, espeTexas A&M AgriLife cially for West Texas peanut Extension growers currently under the State Extension Peanut Specialist drought conditions. With the prolonged drought across the Southwest peanut growing regions, it is critical to estimate realistic yield goals

PeanutPointers

that match irrigation capacity and water quality. As water demand of peanut is higher than other crops typically grown in the regions and if irrigation water is limited, it is advisable to plant fewer acres and irrigate adequately than providing limited water to larger acres. The latter approach will not only reduce yield potential, but also increase disease susceptibility, weed pressure and lower the peanut grade.

Under limited water availability, irrigation management becomes very important. Water demand differs at each developmental stage. In general, water use is low in the early season. It is at its peak during the reproductive period, requiring approximately 2 inches of water per week. Adjust the weekly amount based on the transpiration and evaporation.

Planting Spanish and Valencia type peanuts may help in spreading irrigation water out over the season because these peanut types are early maturing compared to runner and Virginia peanut types. Many Southwest producers are already splitting pivots into two or more crops to further improve water-use efficiency. This approach will help to provide adequate water to peanut production. Other factors that can improve water-use efficiency for peanut production include maintenance of irrigation equipment, monitoring in-season soil moisture and checking water salinity.

Planting Decisions

Georgia Peanut Commission To Hold Referendum

The Georgia Peanut Commission will hold a referendum March 15 through April 16, giving peanut producers an opportunity to vote on reaffirming the commission. State law mandates a referendum be held every three years. Georgia peanut producers invest $2 per ton to fund the commission and its research, education, promotion and communication programs. Growers are beginning to The last referendum in 2018 passed with a 94.02 make plans on when to start percent reaffirmation.planting. I have already received “I urge all peanut producers to vote in this referen-several calls from growers ask- dum. Research, education, and promotion continue ing about planting in the first to be the core focus of the commission,” says Armond part of April if the soil tempera- Morris, GPC chairman. “It is extremely important tures and moisture are perfect for growers to continue to focus their efforts on sup-for planting. In answering this porting research and promotional efforts through question, there are several key their checkoff dollars. One way for farmers to do that things I would have growers is by continuing their support of the Georgia Peanut consider. The first thing for growers to consider is the risk for tomato SCOTT MONFORT University of Georgia Extension Agronomist Commission.” GPC Executive Director Don Koehler urges producers to contact him by email at don@gapeanuts.com spotted wilt virus. Remember, or 229-386-3470 if they have any questions about the planting in April presents a higher risk compared to mid- commission’s activities or the referendum. May. This does not mean growers do not need to plant in Peanut producers who do not receive a ballot may April. It just means they also need to adapt other strategies obtain one by calling the commission. The commis-for reducing TSWV, such as applying Thimet insecticide, sion requests that anyone who receives a ballot but is planting good quality seed, using a proper seeding rate, no longer farming to write, “no longer producing” on planting in twin rows and at the proper plating speed, apply- the certification envelope and return it to the commis-ing an in-furrow fungicide and planting into good soil mois- sion. This will assist the commission in updating its ture at the proper temperature. mailing list. The commission’s address is P.O. Box 967,

Available moisture is another key factor to consider when Tifton, Georgia 31793.deciding about April planting. In recent years, growers have The Certified Public Accounting Firm of Allen, had adequate moisture in late April but waited until May Pritchett, and Bassett will count the votes. due to soil temperatures being 65 degrees F instead of 68

PeanutPointers

degrees and/or they wanted to reduce their risk for TSWV. The problem is it turned off dry in early May, and they had to wait on rain until late May to early June, which reduced overall yield potential.

If a grower does not have irrigation, but has adequate moisture in late April and a soil temperature of 65 degrees or higher, with an unfavorable forecast for rainfall in the next week to 10 days, then it would be advisable to go ahead and plant.

This does not mean everyone should be planting in early to mid-April. The risk of TSWV is still very high on early plantings, even if everything else is done to lower the risk. Call your local county agent for more information or if you need further assistance.

Seeding Rate Recommendation

highest goal. With a forecast of warmer temperatures and having higher quality seed this year, there is no reason not to get an early start. Having high-quality seed coupled with good planting conditions brings up the topic of seeding rate. I have heard many times of producers planting higher seeding rates than our recommended six seed per foot of row. Because of this, I felt like we needed to reassess our recommendation to see if it is still correct for current varieties. Our standard seeding rate has always been based on 36-inch row peanuts at six seed per foot of row. This is what we recommend at planting to ensure that you get four plants per foot to achieve maximum yield. If you are on 30-inch rows, it would be five seed per foot. The seeding rate depends on the type of seed you have and the quality of that seed. If you have poor quality seed or a lower germination seed, then you would need to use a Now that we have entered higher seeding rate. the month of April, plant- To confirm our seeding rate recommendation, we had a ing is just around the corner. test this past year where we planted different rates to see if Everyone knows that there we could come up with a yield difference. We planted at always seems to be a cold spell 3.5, 4, 5.5, 6, 8 and 10 seed per foot of row. around Easter. Since the holi- All of the various rates yielded well in this test at more day is early in the month this than 6,200 pounds per acre. The lowest three were 5.5, 4 year, we should be confident and 8 seed per foot, which yielded the least amount. The enough that there’ll be consis- three highest rates were 10, 6 and 3.5. However, there was tently warm temperatures for no statistical difference between these top three rates, even

KRIS BALKCOM early planting by the end of though there was a slight numerical difference in yield. Auburn University the month. We will continue to look at seeding rate research, but we

Extension Specialist I am sure you haven’t forgot- still feel that the recommendation of six seed per foot of row ten the weather challenges we is adequate for achieving a good stand and an opportunity have faced two of the past three planting seasons. The earlier for maximum yield when you have good quality seed and start gives us a longer window of opportunity to achieve our favorable planting conditions.

SEND LEAF SPOT PACKING.

Add new MICROTHI™ to FRAC 3, 7 and 11 applications

University researchers have discovered that adding new MICROTHI micronized sulfur to FRAC 3, 7 and 11 fungicides can enhance leaf spot control in peanuts. MICROTHI actually boosts the effi cacy of these single-site fungicides that have developed resistance, or are at risk of developing leaf spot resistance. Just fi ve pounds per acre of MICROTHI added to your early and mid-season treatments is a convenient and economical way to improve disease control and improve your return on investment. To send leaf spot packing, ask your retailer or UPL representative about new MICROTHI, or visit microthi.com.