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• Growers have "much better choices of peanut varieties today," says breeder Barry Tillman. "Varieties available to growers for 2013 are uniformly excellent," he said at the annual meeting of the Mississippi Peanut Growers Association.
SHERWIN RAY, from left, and Clayton Lawrence, both at Lucedale, Miss., and David Short, DuPont Crop Protection, Madison, Miss., were among those attending the annual meeting of the Mississippi Peanut Growers Association.
Plant more than one variety
In choosing varieties, Tillman says, “The thing we really preach to growers is minimizing risk. Last year, 77 percent of our three-state acreage was one variety. That can potentially be very dangerous from a production standpoint, given the potential for disease losses and for the possibility for a variety not reacting favorably in a single environment.
“I really encourage growers to plant more than one variety, and to evaluate new varieties in tests on your own farm. Plant them side by side so you can have a fair comparison of how they perform.”
One significant difference in varieties, Tillman says, is seed size.
“Over the years, we’ve seen an increase in seed size. Georgia Green had small seed, and you could plant fewer pounds per acre to get the same plant stand. It would take 120 pounds per acre of Georgia Green to get the same stand planting at 6 seeds per foot, compared to something like Georgia-06G at 150 pounds per acre. This can make quite a difference in what it costs to plant a crop.
“New varieties such as FloRun 107 and Georgia 109B are quite a bit smaller than the larger-seeded varieties we’re planting today. That could be a difference of as much as 30 or 40 pounds of seed per acre — and at 75 cents to 80 cents per pound, that could save as much as $30 per acre in seed costs.”
Breeders are “working hard,” Tillman says, “to get back to a more normal runner seed size.”
The evolution to larger-seeded varieties has come about, he says, “because the germplasm we were using for crosses had large seed, so our commercial selections have tended to also have large seed. In our numbered and new lines, we have several varieties with smaller seed that are performing quite well, and I think in the future we’ll be seeing releases from all the breeding programs that have smaller seed.”
Seed size is also related to calcium, he says. “Unlike other crops that respond quite well to fertility, in most situations peanuts don’t respond to nitrogen, phosphorus, or potassium. The nutrient we need to pay most attention to is calcium, because of its impact on germination, grade, and yield. The first symptom of minimal or marginal calcium is germination problems. With deficient calcium, peanut seeds can also fail to develop fully, which has an impact on grade.”
To insure adequate calcium, Tillman says, gypsum can be applied.
“For producing commercial farmer stock peanuts, not seed, you should be guided by a pegging zone soil test. If there is less than 500 lbs. of calcium per acre, we recommend applying gypsum. The soil test should be done in the 3-inch pegging zone, not the normal 6-inch soil test. If you’re growing peanuts for seed, we always recommend applying gypsum to insure adequate calcium for germination.
“We don’t recommend foliar calcium — it doesn’t translocate from the leaves into developing pods. Peanut pods have to absorb calcium directly from the soil; this has been proven over 60 or 70 years. The recommended procedure is to apply gypsum at bloom time.”
Applying lime on the soil surface may be effective, Tillman says, “But I emphasize ‘may.’ Some varieties absorb calcium better than others, even if seed size is not a factor. Typically large-seeded varieties require more calcium than smaller-seeded varieties, but not always. Liming the soil surface may be effective, but it does need to be applied well ahead of time to make the calcium available, because it doesn’t break down as quickly as gypsum.
“In varieties we have today, seed size is the primary factor to look at, and with the larger-seeded varieties you want to make sure you have enough calcium to prevent ‘pops’.”
As peanuts get more attention as a health food (the Mississippi Peanut Growers Association was recently certified to use the Heart-Check mark on its promotional peanut packages), high oleic oil varieties are coming to the fore, Tillman says.
“Why is the high oleic trait important? It helps to increase peanut shelf life, so they can stay fresh longer and not become rancid. That’s a big advantage for manufacturers of candies and confectionary products. Our competitors are producing these varieties — peanuts coming out of Argentina, Australia, and other parts of the world are high oleic.
“In tests, after just four weeks normal oleic peanuts were starting to go off flavor, but it took high oleic peanuts 32 weeks to reach the same point. Manufacturers are increasingly requiring us to do offer this, and it’s important for us to be able to compete in these markets.”
In a high oleic peanut variety, total oil is about 80 percent oleic, compared about 60 percent in a normal oleic variety. The linoleic portion of the oil is only 2 percent in a high oleic variety, compared to about 20 percent in a normal oleic variety.