January 16, 2008

5 Min Read

Each year, Atkinson County Extension Agent Mark von Waldner and I conduct a peanut variety trial to help growers determine the best varieties to plant the next year.

This past year's variety trial was conducted at Mike Nugent's farm and the 2005 and 2006 trials were conducted at Troy Aldridge's farm.

These trials are valuable in helping us evaluate varieties, especially with so many new varieties becoming available.

In 2007, we had 10 varieties, including three new ones from the University of Florida (Florida-07, McCloud and York). All varieties were randomly replicated four times in single rows. All replications were large plots over a tenth of an acre. The trial was irrigated, but we don't believe irrigation was a major factor in the high yields since Mike had some dryland Georgia Greens within 500 yards of the trial that topped 5,000 pounds per acre.

The keys to the high yields were a great rotation and Mike's superb management. Mike had 14 straight years of cotton prior to this year's peanut crop. The trial was no-till and University of Georgia Extension recommendations were meticulously followed, which resulted in minimal inputs.

Soil test recommendations called for no fertilizer (soil or foliar) or landplaster. Mike's great rotation allowed us to use a reduced fungicide program so not only did he average close to 5,000 pounds per acre over his entire crop, but he did so with minimal costs.

This trial showed the genetic potential of each variety under minimal disease pressure. In short, there is no dominant peanut variety like DPL 555 in cotton. We have seven or eight really good peanut varieties where three years of research trials and field experience have shown that any one of these varieties has the potential of being the top yielding.

Growers need to consider all of a variety's characteristics, including disease resistance, which is especially important if they have a short rotation or field history of disease. They also should consider their past experience with a certain variety, maturity, grade, and vine production.

Mark and I noticed that both AT-3081R and AT-3085RO were very susceptible to late leafspot in this past year's variety trial. Albert Culbreath, University of Georgia plant pathologist, also noted that both of these varieties were more susceptible to late leafspot in his trials. A good fungicide program will need to be maintained with these varieties, especially with a poor rotation.

AT-3085RO was our top yielder, but low grades were noted in not only our variety trial, but in several fields in Coffee County. A question arose if we dug the AT-3085RO too early and this accounted for the low grades. A hull scrape was done on the AT-3085ROs indicating they were ready to dig.

Unfortunately, all of the mid-season varieties were dug a few days past optimum maturity due to rain. We were beginning to lose peanuts due to over-maturity with all the mid-season varieties so any further delay in digging the AT-3085RO would have resulted in more dollar loss from reduced yields than we would have gained in grade.

AT-3085RO's high percentage of hulls contributed to its low grades. AT-3085RO and Georgia-03L had the highest percentage of hulls at 25 percent; AP-3, AT-3081R and Florida 07 had 24 percent; York-23.5 percent; McCloud and C-99R-22 percent; Georgia Green-21 percent; and Georgia-02C-20 percent.

AT-3085RO is a high oleic variety that the peanut industry is trying to trend towards. High oleic peanuts have higher oleic acid concentrations and lower linoleic concentrations. Lower linoleic acid concentrations benefit peanut processors by substantially increasing the shelf-life of peanut products.

Higher oleic acid concentrations benefit consumers by reducing blood LDL cholesterol levels and improving flavor. The enhanced peanut chemistry is comparable to olive oil, which is valued by health conscious consumers.

Georgia-02C had surprisingly high grades considering it is a large-seeded runner variety. It is a high oleic variety which is helping it overcome its poor flavor reputation with manufacturers and gaining more widespread acceptance in the industry.

When yield and grade are considered, Georgia-02C was the most profitable variety in the 2007 trial. This is probably our best late-season variety and can help spread out harvest when combined with mid-season varieties.

Another advantage of late-season varieties such as Georgia-02C is they tend to maintain their yields (they lose less peanuts to over-maturity) and increases in grade are possible if dug late compared to the mid-season varieties.

Mid-season varieties may increase in grade if dug late, but tend to have significant yield decreases due to losing peanuts from weak stems or sprouting.

AP-3 has been our most vigorous growing variety and produced the most vines. It has a light green vine color which easily distinguishes it from the other nine varieties during the growing season. It had surprisingly good grades considering its thick hull. Normally, we see a 2-3 grade points reduction compared to Georgia Green.

Georgia Green is still Georgia's leading variety with more than 50 percent of the state's acreage. It doesn't have the disease resistance package of most of the other varieties in the trial, but still is a high performer with a good rotation and low tomato spotted wilt virus pressure.

The University of Florida had three new releases in the trial and their seed will be limited this year. Florida-07, McCloud and York are all high oleic varieties. Florida-07 was the same maturity as Georgia Green in our trial, but the University of Florida has it listed as a medium-late maturity range meaning it is later than Georgia Green but earlier than C-99R and Georgia-02C. It has typical runner growth habit and seed size that is similar to

C-99R is a large-seeded variety. It has good to excellent resistance to tomato spotted wilt virus, some white mold resistance and tolerance to leafspot.

McCloud is a medium-maturity variety with typical runner growth habit. Its seed size is larger than Georgia Green and its main disease resistance is to tomato spotted wilt virus.

York is a late maturing variety similar to Georgia-02C and C-99R. It has a seed size similar to Georgia Green and excellent resistance to tomato spotted wilt virus, white mold and leafspot.

We plan on including all 10 of these varieties plus two promising new releases from the University of Georgia, Georgia-06G and Georgia Greener, in this year's variety trial in both twin and single rows.

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