What is in this article?:
- Research aims to take the guesswork out of determining peanut maturity
- Make an indeterminate peanut act more determinate
- Eliminate immature peanuts and improve the flavor profile
Determining peanut maturity has always been an inexact science.
Research is looking at terminating flowering to improve maturity distribution.
USING HERBICIDES TO terminate peanut flowering could lead to a more exact way of determining maturity, says Marshall Lamb, research director for the National Peanut Research Laboratory in Dawson, Ga. Lamb is shown here at a field day this past summer.
Eliminate immature peanuts and improve the flavor profile
“When this project began, it was funded by one of the major peanut manufacturers because if we can eliminate immature peanuts, we will improve the flavor profile of peanuts.
“Also, if we can eliminate the immature peanuts, it makes them easier to dry because the immature peanuts are higher in water than mature ones.
“In addition, you’d eliminate off-flavors. So we’ve been looking at this mainly from a quality standpoint. But we’ve found other advantages as well.”
The research has included the painstaking task of counting the flowers in a 3-foot section across the treatments on a daily basis, says Lamb.
“Within these 3-foot sections, we had about 15 flowers every day — some of the old ones would drop off, and some of the new ones would come on. We counted the new additions. Where we had herbicide treatments, we basically took flowing to zero over about 18 days. Even the flowers that were on the plants were not viable flowers. The pollen in them was not viable.
Where they are treated, the flowers are about one-fourth the size of a normal flower, and they’re very opaque or white as compared to the usual bright yellow flowers. The process totally destroyed how they were flowering.”
This past year’s counts followed exactly the same trend, he says, but there were not as many flowers on peanuts in 2013 as in 2012. That’s an environmental factor due to more rainfall this past year.
“We determine when to dig with the hull-scrape profile and the black column. In the control or untreated plots, we had only five pods in the black column, and that’s an indicator to begin digging.
“As a grower, you’re ready to go whenever you fill the black column. Where we had the treatments, we had a three to four-fold increase in the amount of pods that were in the black column on the profile board.”
That indicates, he says, that the treatments were successful in petitioning energy away from the immature pods and into the mature pods.
“We were mainly looking for quality attributes, and we tested all of these for residues, fatty acids, protein, fat, sugar and moisture. Maturity is directly related to some of these factors. We also tested for roasted peanut flavor. One of the biggest complaints received by manufacturers is off-flavor, and this is typically associated with immaturity. The peanut contains too much water, and it doesn’t roast the same.”
Lamb says he also wanted to look at the effect on yield and grade, though he didn’t expect the yield benefit.
“We saw a yield benefit, which was very surprising. The non-treated and the dryland averaged 3,250 pounds per acre. With some of the diflufenzopyr treatments, we were making about 3,600 pounds per acre, about a 400-pound yield increase. I started looking into this — out of every plot, we took 100 kernels of jumbos, mediums and number ones, separately — and we actually measured the density of the kernels.
“The kernels that were treated were denser, and that makes them heavier, so we had an increase in yields of about 400 pounds, and, on the non-irrigated an increase of 1 ½ percent in sound mature kernels and sound splits, which all goes back to the kernels being denser.”
It’s important, he says, to get the rates right because some of the heavier glyphosate rates damaged yields.
“We saw an even bigger effect on the irrigated, which we weren’t expecting. The non-treated peanuts averaged 4,700 pounds per acre. Where we treated — mainly with diflufenzopyr Na — we were up to 5,300 and 5,500 pounds per acre, or an increase in yield of roughly 600 pounds with these treatments, and a 2.5 percent increase in grade, which is also significant.”
Lamb cautions that the research is in its early stages. “But it could be a way to petition the energy in the plant towards what we’re going to harvest by eliminating the part of the fruit-load that we don’t want to harvest but is taking the most energy.
“It’s just research, and we’re not making any recommendations. Give us a couple more years on this study, and I think we’ll have these rates and the timings bracketed down to where we’ll have a recommendation for producers.”