New, Improved Peanut Varieties Lead Way For U.S. Production
By: Paul Hollis, Southeast Farm Press
7/2/2013 10:00:57 AM
While some think U.S. peanut production may have peaked in 2012 - with an average U.S. yield of more than 2 tons per acre and a crop topping 3 million tons - others believe it was only a preview of things to come.
"There are varieties currently in the pipeline that show even more promise than the ones currently available," says Marshall Lamb, research director for the National Peanut Research Laboratory and advisor for the Farm Press Peanut Profitability Awards.
It's no coincidence that a steady rise in average U.S. peanut yields has followed the release of new and improved varieties, reaching a new height in 2012 of 4,192 pounds per acre.
U.S. peanut producers have seen a steady improvement in average yields in recent years, sometimes even despite non-ideal weather conditions, owing in no small part to improved genetics, says Lamb.
"We have a great team of scientists working on improved varieties, and if we can keep them funded, we're on the verge of some major breakthroughs that'll solve some big-time problems for the industry," he says.
The genetics and biotechnology program at the National Peanut Lab, in collaboration with Auburn University and with plant breeders at the University of Georgia and University of Florida, is in the midst of exciting work, says Lamb.
"Conventional lines will be coming out that are comparable to GA-06G," he says.
"Some have a lower outturn, which we need to get back to as an industry. We've gone way overboard with the kernel sizes on some of these new cultivars.
WILL SAVE ON SEED COSTS
"This will not only save money for producers on seed cost, it will also give shellers a more uniform outturn. That's important, enabling them to sell to multiple markets instead of having a lot of jumbos to deal with."
High-oleic oil chemistry is another focus as researchers move forward with developing new varieties, says Lamb.
"Charles Chen looked at the mini-core germplasm collection to try and see if there were ways we could isolate certain properties within that," says Lamb.
"This germplasm collection within the min-core offers us the opportunity to identify markers that we might could then bring back into the breeding program to have better properties for peanuts."
Some within the collection had 50-percent oil, extremely high relative to the traditional mean of 48 to 49 percent, he adds.
"Our genomic research takes us all the way through a variety release, or we can use biotechnology within that system and into a variety release. It is a long process," explains Lamb.
"We're dealing with the biological organism for peanuts, and it takes awhile to get these cultivars developed."
In an attempt to focus on something that would have an immediate agronomic impact, Lamb says researchers have set their sights on tolerance to early and late leafspot disease.
"One of the things growers spend a lot of money on each year is early and late leafspot. They're spraying every 10 to 14 days, spending a lot of money on fungicides, fuel and labor.
"Anything we can do to reduce or eliminate leafspot will save growers' money and help us environmentally from a sustainability viewpoint. We looked at leafspot screening for transgenic and non-transgenic peanuts in our greenhouse."
Genes have been found in the public domain that offer a certain level of leafspot resistance, says Lamb, and one of the genes was inserted into peanuts very successfully.
"We used a molecular biology tool that allows us to do gene amplification so it would measure the expression genetically. We were able to propagate these genes into the tissue of living plants. It was verified visually and through molecular techniques.
"Once we have these transformed peanuts, we hand them off to pathologists, and Auburn University pathologists are looking at these now."
Crosses will then be made with transformed peanuts into elite varieties like GA-06G or a newer line - one that shows very good agronomic production practices, he says.
The old variety AgraTech 271516 has been released as a germplasm, and it has proven to be a very good transforming peanut, says Lamb. "It has a very high success rate, so we are making some crosses with some high-yielding, high-grading varieties."
Researchers then have to check for a gene's stability and continue the backcross, he says.
"This is the part that takes time. We're dealing with a biological organism, and we have to make sure that once we come up with a line, that over several generations, it is breeding true, and we make selections to keep it breeding true.
"Then, there's the process of going to the field and testing for release.
"We made crosses between the transgenic peanuts that are showing extremely high levels of leafspot resistance into conventional lines.
"This cross-pollination was completed this past January. In our environmental control facility at the lab, we built a greenhouse so that we could overwinter these peanuts here instead of sending them to Puerto Rico. We can heat soil, saving us a year in getting these crosses made."
Auburn University pathologists will be inoculating the peanuts that have been transformed, and they'll be testing them rigorously for resistance to leafspot, he says.
"I won't use the word immunity, because I don't know if we'll have immunity, which is 100 percent, but we're trying to reach a very high level of resistance."
Scientists also are identifying drought regulating gene markers, says Lamb.
"Even though we're blessed this year with a lot of ponds and creeks full of water from good rainfall this winter, our water use issues are not going away, and we've got to keep looking at ways to reduce irrigation and to empower dryland growers to withstand drought periods a little bit longer.
"We're trying to buy a little time until we get a rainfall. This is not genetic modification. This is part of the genomic initiative to identify markers within peanuts that we can then get into other elite varieties. Breeding and biotechnology is "a numbers game, and we've been able to have success."
PEANUT RUST, AFLATOXIN
Peanut rust and aflatoxin contamination also are getting attention from researchers, says Lamb.
"We had samples sent to us from experiment stations we thought were purely rust samples. But there was bacterial feeding on the samples.
"We amplified them within the lab and found out this bacteria was very aggressive and possibly could be used as a bio-control. We're looking at the activity of this same bacteria on other pathogens as well."
The goal with aflatoxin, he says, is to identify which genes, through genetic expression, are responsible for overcoming the defense mechanism within peanut plants.
"We're talking about genes in the aflavus mold that secrete the aflatoxin. The plants produce phytoalexins for protection - just as do the white blood cells in our bodies.
"The plants send out the phytoalexins to wherever the aflavus mold is located, the aflavus mold detects the phytoalexins, and then it has a genetic expression that creates enzymes that it secretes to phytoalexins, breaking them down.
"Our scientists have identified the three genes that are in aspergillus and the two potential phytoalexins that are being broken down. This is a big breakthrough."
Lamb says he expects some of these improved varieties to be released or available for seed increase soon.
He emphasizes there are no transgenic peanuts in edible markets today, that the varieties "are only in the experimental stage, and it will be years before any transgenic varieties will even be considered for release."
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