• Topics: Agronomy | Tillman, Barry L | North Florida REC-Quincy | Peanut Varieties | Gomillion, Mark W | McKinney, Justin L

Peanut Variety Performance in Florida, 2005 – 2008¹

Variety choice is a critical management decision in producing a peanut crop. Several good peanut varieties are available to choose from, so it is essential to know the attributes of each variety and how various varieties might fit into a farm plan.

When trying a new peanut variety for the first time, plant a relatively small test plot (20-50 acres) to make sure you see the differences between varieties first-hand. When choosing which varieties to plant, consider pod yields and grades, but also consider a variety's disease resistance, maturity, seed supply, and anticipated planting dates.

Growers planting more than 100 acres of peanuts should plant at least two varieties. Planting more than one variety can help to spread risk of losses from weather, reduce opportunities for disease, and limit delays in harvest operations. For example, if a field has a history of white mold, use varieties that have a better resistance to that disease compared to other varieties. Use the Peanut Disease Risk Index to evaluate variety disease resistance -- http://www.caes.uga.edu/commodities/fieldcrops/peanuts/2009peanutupdate/peanutrx.html. Your county agent can provide other useful resources. A summary table from the Peanut Disease Risk Index is included in Table 5.

The potentially devastating effects of tomato spotted wilt virus (TSWV) in the southeastern United States are another reason variety choice is very important. Severity of TSWV varies from year to year, and scientists are unable to predict disease levels for a coming crop season. Because TSWV is unpredictable, planting a peanut variety with good resistance to TSWV can significantly reduce the risk of losses from that disease.

Among the sites in Florida where peanut-variety resistance to TSWV has been tested, TSWV is usually most severe in Marianna, so variety performance in that location will give a good indication of the TSWV resistance of a given variety. Results often are very different between Marianna, Gainesville, and Jay, depending on TSWV pressure, other disease pressure within those areas, and environmental conditions, including soil type and rainfall. Variety resistance to TSWV is summarized in Table 5, which is from the 2009 Peanut Disease Risk Index.

This report provides data from University of Florida trials conducted in Florida at IFAS research centers located in Gainesville (Citra), Marianna, and Jay from 2005-2008. Tests in Marianna and Gainesville were grown with irrigation. The tests at Jay were not irrigated. All tests were managed for optimum production, including the use of pesticides to control various diseases, insects and weeds. In-furrow insecticides (Temik or Thimet) were used in Gainesville and Jay and were used in 2008 in Marianna.

Figure 1. 

Certified Seed Acreage in Alabama, Florida, and Georgia in 2005.

Credit: Chart developed by Barry Tillman with data from the Southern Seed Certification Association and the Georgia Crop Improvement Association.
[Click thumbnail to enlarge.]

Peanut Varieties in the Southeastern United States

Historically, peanut acreage in the southeastern United States has been dominated by one variety during a given time period. For about 20 years, from the early 1970s and continuing through the early 1990s, 'Florunner' was the dominant peanut variety grown in this region of the United States. In the mid

1990s, however, TSWV began to cause severe losses in Florunner and in other varieties used at the time that did not have TSWV resistance. Since the late 1990s, 'Georgia Green' has been the dominant cultivar planted in this region. The main reasons for the popularity of Georgia Green were its moderate resistance to TSWV, good grades and good pod yield. In 1996, when Georgia Green was released, it was the only medium-maturity runner variety with resistance to TSWV.

As the TSWV epidemic of the 1990s demonstrated, the practice of relying heavily on one cultivar at a time is dangerous for the peanut industry. Like Florunner before it, Georgia Green in 2005 occupied about 75 percent of the certified seed acreage in Alabama, Florida and Georgia (Figure 1). In the 10 or more years before 2005, Georgia Green had also occupied at least that amount of acreage in these states. In 2006, however, other peanut varieties began to displace Georgia Green in certified seed acreage in this region. By 2008, Georgia Green occupied about 38 percent of the seed acreage in Alabama, Florida and Georgia (Figure 2).

Figure 2. 

Certified Seed Acreage in Alabama, Florida, and Georgia in 2008.

Credit: Chart developed by Barry Tillman with data from the Southern Seed Certification Association and the Georgia Crop Improvement Association.
[Click thumbnail to enlarge.]

On an industry-wide scale, it seems preferable that no one variety occupy more than 50 percent of the certified seed acreage. Diversity in peanut varieties planted can reduce the risk of losses from disease and provide a buffer against differential environmental impacts on a given variety. Considering that the seed-increase ratio of peanuts is low, having several varieties in seed production at significant levels allows a much quicker shift to

different varieties if needed. Using the information on variety performance provided below, it is possible to devise a plan that uses several varieties so to spread risk of losses from disease. This information also helps in choosing varieties based on their relative maturity and disease resistance to help spread harvest and planting operations over a longer period of time.

Recently Released Varieties

Several new runner varieties were released in 2007 and 2008. The University of Florida released 'Florida-07', 'McCloud', 'York' and 'AP-4'. Florida-07 is a medium- to medium-late maturing, large-seeded runner with excellent resistance to TSWV, good resistance to white mold, and some tolerance to leaf spots. Florida-07 has high oleic oil chemistry and has demonstrated excellent yield potential and good grades. McCloud is a medium-maturity, large-seeded runner with high oleic oil chemistry. McCloud has better TSWV resistance than Georgia Green and is similar to Georgia Green in its resistance to other diseases. McCloud has demonstrated good yield potential and excellent grades. York is a late-maturing runner with typical runner seed size, similar to Georgia Green. York has an excellent disease-resistance package with a high level of resistance to TSWV, white mold and leaf spots. York has high oleic oil chemistry and has demonstrated excellent yield potential and good grades. Seed of Florida-07, York and McCloud should be readily available for the 2009 season.

AP-4 is a large-seeded runner with good resistance to TSWV and moderate resistance to white mold. AP-4 is better than Georgia Green in both of these important measures. AP-4 has also demonstrated excellent pod yield and very good grades. AP-4 has normal oleic oil chemistry. Seed of AP-4 should be available for the 2010 season.

The new virginia variety, 'Florida Fancy', was released by the University of Florida in 2007. Florida Fancy has high oleic oil chemistry and standard virginia pod and seed size. Florida Fancy has demonstrated very good yield potential and has among the best resistance to TSWV available in a virginia variety. Seed of Florida Fancy should be available for the 2010 season.

The University of Georgia has three new runner varieties, 'Georgia-06G', which was released in 2006, and 'Georgia Greener' and 'Georgia-07W', which were released in 2007. All three of these varieties have normal oleic oil chemistry, excellent grades, medium maturity and competitive pod yield. Georgia-06G is a large-seeded runner with very good TSWV resistance. Georgia Greener has normal runner size seed and very good resistance to TSWV. Georgia-07W has large seed and very good resistance to TSWV and white mold. Seed of Georgia-06G should be generally available for the 2009 season, whereas seed of Georgia Greener should be available in 2010, and seed of Georgia-07W should be generally available in 2011.

The U.S. Department of Agriculture (USDA) released a new runner variety in 2007 -- 'Tifguard'. It is a medium-maturing, large-seeded runner and the first variety to combine resistance to TSWV and a high level of resistance to root knot nematode. That combination of resistance to disease and nematodes will allow growers in the southeastern United States to take advantage of the same root knot nematode resistance as in 'NemaTam', a peanut variety developed in Texas and released in 2002. Seed of Tifgaurd should be generally available for the 2010 season. Growers who normally use Telone to control nematodes should be able to use Tifguard on nematode-infested site without using Telone.

Golden Peanut Company released two runner types, 'AT215' and 'AT3085RO'. AT215 is a large-seeded runner type with early relative maturity, similar to 'Andru II' and 'Virugard', and with high oleic oil chemistry. AT215 is susceptible to TSWV, so is not a candidate for early planting. However, AT215's early maturity could be a benefit in situations that require planting in late May or early June. Seed of AT215 should be available in 2010 and beyond.

AT3085RO is a medium-maturity, large-seeded runner with good resistance to TSWV and high oleic oil chemistry. Seed of AT3085RO should be generally available for the 2009 season.

2008 Results

Table 1 details pod yields, total sound mature kernels percentage (TSMK), maturity and TSWV ratings for tests at three locations in Florida in 2008. Each entry was harvested (dug) at its apparent optimum-maturity stage, i.e., E = 125-130 days after planting (DAP); M = 133-139 DAP; L = 145-155 DAP. Ratings for TSWV were on a 1-10 scale, where 1 = no disease, and 10 = all plants with severe damage or dying.

Spotted wilt was nearly non-existent in 2008, and yields were relatively high compared to previous years (Table 2). Only two early-maturing varieties were tested, Andru II and Virugard, and yields of these varieties were similar. Among the medium-maturity varieties tested, Florida-07, Georgia -06G, Georgia-07W, 'Carver' and AP-4 had a statistically greater yield that year than did Georgia Green.

Georgia-06G had the highest average yield, and Florida-07, Gerogia-07W, Carver, AP-4 and AT3085RO were not statistically lower in yield. Among the virginia varieties, VAC92R, 'Gregory', Florida Fancy, and 'Georgia-05E' had the highest pod yield in 2008.

Multi-Year Results

Averaging over two or more years and locations is a powerful method of determining how a peanut variety will perform over a wide array of environments. The performance of runner market-type peanut varieties in Florida over the past four years (2005-2008) is shown in Table 2.

Among the medium-maturity cultivars tested during 2007 - 2008, Florida-07, AP-4, Georgia-06G, Georgia-07W and Georgia Greener had the highest pod yield. Georgia-06G and Georgia Greener had the highest TSMK grade among the medium maturity types. In the three-year (2006-2008) and four-year (2005-2008) test averages, Florida-07 had the highest pod yield. With the exception of Georgia Green, the resistance to TSWV among the medium maturity group is very good.

Pod yield among the late-maturing varieties tested from 2005-2008 was similar. The grade of York was less than the other three late-maturing varieties. High TSMK is a strength of both Georgia-01R and Georgia-02C, and TSMK percentage, averaged over 2005 – 2008, was around 79 percent for those varieties. Acreage of Georgia-01R has been limited because of poor seed quality, a problem shared by several late-maturing varieties.

The performance of virginia market-type varieties in Florida over the four-year period 2005-2008 is shown in Table 3. Most of these varieties are more susceptible to TSWV than the popular runner varieties. If these TSWV-susceptible varieties contract the disease, yield losses could be substantial. Two new virginia varieties -- Georgia-05E and Florida Fancy -- appear to have better TSWV resistance than the others. Georgia-05E and Florida Fancy also have very competitive pod yield. Florida Fancy has high oleic oil chemistry which is a significant benefit for virginia types when they are prepared by salting and roasting in-shell. This preparation significantly hastens oxidation and rancidity of normal oleic types, but high oleic types do not oxidize as quickly which preserves their flavor longer.

Location Results

The pod yield of peanut cultivars grown at three Florida locations is shown in Table 4. In general, the highest-yielding entries in one location also did well in the other locations. Yields are generally lower in Jay because the peanuts are not irrigated. Pod yields in Gainesville are generally higher because TSWV is very mild in this area. In Marianna, yields can be severely limited by TSWV. For that reason, varieties that are most resistant to TSWV usually have the highest yield in Marianna. In 2006 and 2008 TSWV pressure in Marianna was much lower compared to 2005 and 2007.

Varieties with the Best Resistance to TSWV and Other Diseases

Disease resistance is a very important factor in choosing a peanut variety. The reaction of most varieties to the most prevalent peanut diseases in Florida is detailed in Table 5. To optimize the disease-resistance benefits of these varieties, choose varieties based on their disease resistance in relation to diseases known to be problematic or suspected of being problematic in a particular field or farm.

Use Table 5 to find a variety with the right disease package for your situation. If white mold is a problem in some of your fields, the following varieties would be good choices: AP-3, AP-4, C-99R, Florida-07, Tifguard, York, Georgia-06G, Georgia-07W, or Georgia-02C. For another example, York, C-99R, Tifgruard and Georgia-07W are varieties with good leaf- spot resistance. Use of these varieties in fields with a history of leaf spot and/or in situations that could allow for a reduction in the frequency of fungicide sprays needed for leaf-spot control, compared to the need for use of such sprays with leaf-spot susceptible varieties. The new variety, Tifguard, has resistance to root knot nematode and so would be a good choice in fields with a history of that disease pest; AP-3 has also demonstrated tolerance to root knot nematode. Varieties that have enough resistance to TSWV to be planted relatively early include the following: AP-3, Florida-07, Georgia-06G, Tifguard, Georgia-07W, and York.

Figure 3. 

Performance of Six Medium Maturity Varieties in 1-2 Acre Replicated Plots in Columbia County, Fla., in 2005-2008. (The fields were not irrigated, and 2005 and 2008 were the first year of peanut following four to five years of bahiagrass. The 2006 and 2007 tests were planted in the same field following four to five years of bahiagrass.)

[Click thumbnail to enlarge.]

On-Farm Tests

During the four-year period that includes 2005, 2006, 2007 and 2008, scientists conducted farm-scale variety tests in Columbia County, Fla., using a limited number of peanut varieties. These tests consisted of replicated plots of one to two acres within a peanut field managed under conditions normal for the farmers who cooperated in the tests. Management included a full-season fungicide program. The typical rotation on this farm is two to three years of peanut followed by four to five years or more of bahiagrass. Soil-borne disease pressure is usually low, but leaf spot disease pressure can be intense. These tests were helpful to verify results from research trials under low disease pressure.

Over the four years of the test of the medium-maturity varieties, AP-3 and Georgia Green had similar average yield (Figure 3). Georgia-03L yielded well in 2007 and 2008 and was similar to AP-3 and Georgia Green. Yields of two tons per acre are well above the state average of 2,500 - 2,800 pounds even though in some cases the tests were planted the season after a previous peanut crop. The results show that the yield potential of these varieties is similar under near-ideal conditions with little or no TSWV. The value of the long-term bahiagrass rotation with peanuts is especially striking. In 2008, three new varieties were added. Of these, Georgia-06G and Florida-07 yielded more than 6,000 lbs. per acre. These results corroborate results from the small-plot tests described above and show excellent yield potential of Florida-07 and Georgia-06G.

Summary

Variety choice is a critical management decision for peanut production. Many varieties with good to excellent resistance to TSWV are suitable for production in the southeastern United States. Additionally, several of these TSWV-resistant varieties also have resistance to other diseases. Growing disease-resistant varieties can reduce risk and production cost. The varieties C-99R, York, and Georgia 01R all have considerable resistance to leaf spot. Use of these varieties, in combination with good crop rotation, might allow for reduced use of fungicide sprays and, therefore, lower production costs. Some of the cultivars – Florida-07, Georgia-07W, AP-4, Georgia-06G, Georgia-03L, C-99R, and AP-3 – have good resistance to soil-borne diseases, such as white mold (S. rolfsii). Additionally, Georgia 01R, Georgia 02C, and Carver have some resistance to Cylindrocladium black rot (CBR).

When choosing a variety and making arrangements for seeds of the varieties that best fit your needs, evaluate your production and marketing situation. Seed of Florida-07, York, Georgia-06G and McCloud should be readily available for the 2009 season. Seed of AP-4, Georgia Greener, Tifguard, and Florida Fancy should be available for the 2010 season.

Tables

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, Dean.

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