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1. This document is SS-AGR-330, one of a series of the Agronomy Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date March 2010. Visit the EDIS Web site at http://edis.ifas.ufl.edu. 2. Barry Tillman, assistant professor, Agronomy Department, North Florida Research and Education Center (NFREC) Marianna, FL; Mark Gomillion, biological scientist, NFREC Marianna, FL; George Person, senior biological scientist, NFREC Quincy, FL; Justin McKinney, senior biological scientist, Agronomy Department, Research and Demonstration Site Citra, FL; and, Bill Thomas, agronomy extension agent IV, Columbia County Extension Office, Lake City, FL; Institute of Food and Agricultural Sciences, University of Florida; Gainesville 32611. 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, as well as 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 acres) that will allow you to see the differences between varieties firsthand. Be aware, however, that comparing varieties planted in different fields, or even in different parts of the same field, can be misleading due to the potentially confounding differences between fields such as soil type, irrigation/rainfall, soil borne diseases, and planting date. UF | IFAS publication AG341 / SS-AGR-331 Methods for On-Farm Testing of Peanut Varieties in Florida with Results from 2005 http://edis.ifas.ufl.edu/AG341 outlines methods of on-farm testing of new varieties on this scale; these methods will more accurately determine variety differences and minimize the confounding effects mentioned above. 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 2010 Disease Risk Index is included in this article (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 varieties have 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. Table 5 includes summarized data for variety resistance to TSWV. This report provides data from University of Florida trials conducted in Florida at IFAS research centers located in Gainesville (Citra), Marianna, and Jay from 2006. 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 (aldicarb [Temik] or phorate [Thimet]) were used in Gainesville and Jay throughout the trials, and were used in 2008 and 2009 in Marianna. Historically, peanut acreage in the southeastern United States has been dominated by one variety during a given 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 as well as 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, rising quickly in popularity for its moderate resistance to TSWV, good grades, and good pod yieldwhen it was released in 1996, it was the only medium-maturity runner variety with resistance to TSWV. Nevertheless, as the TSWV epidemic of the 1990s had 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 2009, Georgia Green occupied only about 10 percent of the seed acreage in Alabama, Florida, and Georgia (Figure 2). Clearly, 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 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. Several new runner varieties were released in 2007 and 2008. University of Florida released 'Florida-07', 'McCloud', and 'AP-4'. Florida-07 is a mediumto 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 it 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, but is similar to Georgia Green in its resistance to other diseases. McCloud has demonstrated good yield potential and excellent grades. Seed of Florida-07 should be readily available for the 2010 season. Seed quantities of McCloud will be limited in 2010. AP-4 is a large-seeded runner with good resistance to TSWV and moderate resistance to white mold. AP-4 outperforms 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-type variety, 'Florida Fancy', was released by University of Florida in 2007. Florida Fancy has high oleic oil chemistry and standard Virginia-type pod and seed size. Florida Fancy has demonstrated very good yield potential, and it has among the best resistance to TSWV available in a Virginia-type variety. Seed of Florida Fancy should be available for the 2010 season. University of Georgia has three new runner varieties: 'Georgia-06G', released in 2006, and 'Georgia Greener' and 'Georgia-07W', both 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 good TSWV resistance. Georgia Greener has smaller seed than Georgia-06G 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 2010 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 1,3-D (Telone) to control nematodes should be able to cultivate Tifguard on nematode-infested sites 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. AT3085RO is a medium-maturity, large-seeded runner with good resistance to TSWV and high oleic oil chemistry. Seed quantity of AT3085RO will be limited in 2010. Table 1 details pod yields, total sound mature kernels percentage (TSMK), maturity and TSWV ratings for tests at three locations in Florida in 2009. Each entry was harvested (dug) at its apparent optimum-maturity stage, i.e., E = 125 days after planting (DAP); M = 133 DAP; L = 145 DAP. Ratings for TSWV were on a 1 scale, where 1 = no disease, and 10 = all plants with severe damage or dying.
Spotted wilt was nearly non-existent in 2009, and yields were relatively very good. Among the medium-maturity varieties tested, Florida-07, Georgia -06G, Georgia-07W, AP-3, Georgia Greener, and AP-4 had similar pod yield that was greater than the other medium-maturity varieties. Among the Virginia-type varieties, 'Bailey' and 'Georgia-08V' had the highest pod yield. Results from any single year should not be used to determine variety performance for the purpose of variety selection. Rather, the results from 2009 presented here are simply a reflection of the growing season that occurred in that year and how varieties performed. The multi-year results are better suited for comparison of the performance of varieties year over year. 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 (2006-2009) is shown in Table 2. Among the medium-maturity cultivars tested during 2008, Florida-07, AP-4, Georgia-06G, Georgia-07W, and Georgia Greener had the highest pod yield. Georgia-07W, AT215, Georgia-06G, and Georgia Greener had the highest TSMK grade among the medium-maturity types. Among the medium-maturity varieties tested for the three-year period (2007), Florida-07, AP-4, Georgia-06G, and Georgia Greener had the highest pod yield. Among medium-maturity varieties tested for four years (2006), Florida-07 had the highest pod yield. With the exception of Georgia Green and AT215, the resistance to TSWV among the medium-maturity group is very good. Spotted wilt was less severe in 2008 and 2009 than in 2006 and 2007. For more a accurate representation of spotted wilt reaction, see Table 5. Pod yield among the late-maturing varieties tested from 2006 was similar. The grade of York was less than the other three late-maturing varieties. High TSMK is a strength of Georgia-02C, and TSMK percentage, averaged over 2006, was around 79 percent. Acreage of York has been limited because of poor seed quality, a problem shared by several late-maturing varieties. The performance of Virginia-type market varieties in Florida over the four-year period 2006 is shown in Table 3. Most of these varieties are more susceptible to TSWV than the popular runner varieties. If these TSWV-susceptible varieties contracted the disease, yield losses could be substantial. Three new Virginia-type varieties'Georgia-08V', 'Bailey', and Florida Fancyappear to have better TSWV resistance than the others. Florida Fancy and Georgia-08V have high oleic oil chemistry, which is a significant benefit for Virginia-types when prepared by salting/roasting in-shell. This preparation method significantly hastens oxidation and rancidity of normal oleic types, but high oleic types do not oxidize as quickly, thus preserving their flavor longer. 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 there were 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 Marianna, TSWV pressure was much lower in 2006, 2008, and 2009 compared to 2007. 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, Georgia07W, 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 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 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. Variety choice is clearly 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 and York have considerable resistance to leaf spot. Use of these varieties in combination with good crop rotationmight allow for reduced use of fungicide sprays and, therefore, lower production costs. Some of the cultivarsFlorida-07, Georgia-07W, AP-4, Georgia-03L, C-99R, and AP-3have good resistance to soil-borne diseases, such as white mold (S. rolfsii). Additionally, Georgia 02C and Georgia Greener have some resistance to Cylindrocladium black rot (CBR). Choosing varieties based on their strength relative to disease resistance can help to reduce the risk of yield loss, and perhaps reduce production costs.
*Data for these new varieties is limited and risk ratings will undergo changes as needed in the future. Adequate research data is not available for all varieties with regards to all diseases. Additional varieties will be included as data to support the assignment of an index value are available. High oleic variety. Varieties Georgia-02C and Georgia Greener have increased resistance to Cylindrocladium black rot (CBR) than do other varieties commonly planted in Georgia. Varieties AP-3 and C-99R are less resistant to CBR and are not recommended for fields where this disease is a problem. The malady referred to as "funky" or "irregular" leaf spot tends to be more severe in Georgia-02C and Georgia-03L than in other varieties. Although this condition can look like early leaf spot (Cercospora arachidicola), the cause of "funky" leaf spot is unknown. Disease losses are not typically associated with funky leaf spot. 6The new variety Tifguard has excellent resistance to the peanut root-knot nematode