Line straining improves varieties for Red River Valley grower
A North Dakota potato grower, a plant breeding lab at Michigan State University and a minituber seed grower in Michigan are working together to improve the quality of red potatoes from the Red River Valley. The project is the result of a conversation at the 2006 National Potato Council’s Seed Seminar between Tom Campbell of Tri-Campbell Farms in North Dakota and Don Sklarczyk of Sklarczyk Seed Farm in Johannesburg, Mich.
A potato variety may start off with few undesirable qualities, but over the years those poor qualities become more prominent, said Tom Campbell, co-owner of Tri-Campbell Farms, a grower/shipper/packer in the Red River Valley of North Dakota.
Tri-Campbell works closely with breeding programs to develop new varieties. In 2007, the company had about 110 varieties in its test plots, said Campbell, co-owner of the company. But the company also is focusing on its existing varieties to make them even better.
We’re always trying to come up with a better potato,” he said. “I think there’s some possibility of having some breakthroughs in the near future.”
The line straining program involves growing a test plot, then culling out tubers with undesirable qualities and using only the best potatoes to grow out. The farm is trying to improve the color of its Dark Red Norlands, because more pink color has crept into the line over time.
“We cherry pick,” Campbell said. “We keep the best of the best.”
The process is expensive and labor intensive, but Campbell Farms has a field person dedicated to the program. Harvesting has to be done by hand to visually inspect the tubers so only the best specimens are used in this case, the tubers with the most red color.
Cleaning up a line is all about quality, Campbell said. If the Red River Valley potatoes aren’t red enough, customers will notice and he will hear about it.
“A lot of farmers aren’t involved in the marketing,” he said. “I hear if we have quality issues. I hear it right from the horse’s mouth.”
There are two primary reasons for conducting a line straining program to improve the vigor of a line or to improve visual quality. The Tri-Campbell Farms program is the latter, but it’s not much different from how breeding used to done. But with modern lab techniques and tissue culture cloning, what used to take a lifetime of weeding out and reseeding can now be completed in as little as two years. The variety that Tri-Campbell Farms is improving, Dark Red Norland, is the result of such a breeding program. From the Norland variety, the Red Norlands were developed and the reddest of those were bred to be the Dark Red Norland.
After the best potatoes have been selected from the Tri-Campbell Farms plot, they’re sent to Dave Douches’s Potato Breeding and Genetics Team in the Department of Crop and Soil Sciences at Michigan State University (MSU). The lab there “cleans” the line, ensuring the samples are free of viruses.
“We’ve committed to do this program because we’re focused in the lab on removing virus from the plant,” Douches said. “From a regulatory point of view, we need to have virus-free plants.”
“When you bring that clone back into the lab, it has to be free of virus and bacteria,” said Don Sklarczyk, president of Sklarczyk Seed Farm.
The process of removing viruses and bacteria from the plant can be done with a chemical treatment, thermal therapy or a combination of both, Douches said. Typically, the process starts with the chemical treatment, which involves sterilizing the sprouts and putting them in culture to grow. The uncontaminated sprouts are tested and if a virus is detected the sprouts will undergo additional rounds of treatment until the plant is disease-free. The thermal therapy is a series of alternating heat spikes and cool-down periods that grow the sprouts in a “fever” condition. The sprouts grow during the temperature spikes, and the ends of the sprouts are virus-free.
“In most cases we’ve been able to clean the line without thermal therapy,” Douches said. “Only in cases where we’re having trouble removing viruses, such as PVY or PVS which is easily picked up in the fields do we use the thermal process.”
Once the samples are determined to be free of disease, they are sent to tissue culturing for production of clone tubers. MSU does this with its many variety trials, but this is the first time it’s being conducted as a free enterprise project, where the grower pays for the service. Douches said MSU hasn’t determined if it’s profitable for the lab, but if it turns out to be a moneymaking endeavor then other growers might be able to take advantage of the MSU lab.
“That’s something that others could contract with us,” said Douches, professor of breeding and genetics at MSU. “There really isn’t that resource around the country.”
With most of MSU’s germplasm material, once it has tested clean it can be used in crosses or evaluated for different characteristics. But in the partnership with Tri-Campbell Farms, the germplasm will be sent to Sklarczyk Seed Farm in northern Michigan for cloning. While the lab at the seed farm could do the line cleaning, Sklarczyk said it is more effective to use the university’s lab because it has a staff that only works on cleaning germplasm, and working with the lab may give it money to pay for future research.
Sklarczyk Seed Farm grows minitubers in a sterile environment, controlling every aspect of plant growth except for sunlight. The advantage to this seed production is that the clones remain virus-free and they carry those favorable traits that were selected in the field.
Cooperation among growers, seed farms and researchers isn’t new, but this three-step line cleaning program could be a new model for the industry. The retail market is demanding change from the potato industry, and that means either new varieties or better versions of the current varieties. Working together requires time and labor, but the result for Tri-Campbell Farms will be a deeper red that customers are looking for, Campbell said. It’s a process that used to take decades, but with new techniques and better processes and equipment it can be done in just a few years.
