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No more brown chips

During the march to the Final Four, there were plenty of bowls of potato chips and dip strategically placed around jumbo-sized TV screens. Even though chip companies go to great lengths to remove the loathed brown chips that are both displeasing to the eye and often bitter, inevitably a few make it into the bag and bowl. But what if a spud could be created that was less likely to produce brown chips?

Potato chips are a major market for Michigan-grown potatoes, so finding a way to improve quality to align itself with customer needs is an attractive thought.

And it’s not just a thought; it’s reality in the making. Since the genome of the potato was mapped two years ago, researchers at Michigan State University and other facilities and universities across the globe are diligently working to identify traits associated with various markers.

Key Points

• Potato genome sequence helps target areas that control certain traits.

• Intragenic modification uses material from the same species.

• MSU releases three specialty potatoes; two chipping varieties are in the works.

Researchers are using microscopic tools to reveal unique physical characteristics of the potato plant’s 12 chromosomes in each of its four sets.

Brown chips are generally caused by storage that results in starches being converted to sugars, which when fried, turn brown.

“We are working at improving the processing quality of potatoes by identifying varieties that have lower sugar, lower bruising and lower asparagine,” says Dave Douches, an MSU crop and soil sciences professor specializing in potato breeding.

When those desirable traits are identified in the newly sequenced potato genome, they can be more accurately inserted into commercial varieties.

“The industry is changing, and by knowing where these markers are, we can target a gene we want to insert and put it right where we want it,” Douches says. “In the past, we really didn’t know where it was going to land and if it may disrupt a gene that we had not intended. This is precision gene replacement. We can also turn off a gene by using enzymes to cut a piece of it out, which would silence it.”

By silencing some sugars, those brown chips may become an irritant of the past.

“USDA may consider turning off a gene to be non-GM [genetically modified], which may open up great possibilities and a lot less paperwork,” Douches says.

The industry already has two successful examples, as researchers have identified potato genes resistant to Potato Virus Y and late blight, the culprit behind the great Irish potato famine in the mid-19th century. Studies are developing commercial varieties, although their deregulation is at least four years away.

Consumer acceptance

Potatoes are taking the lead on intragenics, which is a genetic modification that artificially transfers genetic material from other plants within the same species.

Intragenic modification is different from transgenic modification. While both methods enhance the original plant, Intragenic modification uses genetic material from plants within the same species.

Transgenic modification created the first EPA-approved genetically modified potato plants in 1995 — plants that produced the Bacillus thuringiensis toxin. The Bt inserted into the plant came from a bacterium not normally found in the plant.

Researchers are hoping the use of intragenic modification might be a softer sell to consumers.

“This is really about consumer acceptance,” says Joe Coombs, MSU Potato Breeding and Genetics Research technician. “Will intragenetically modified potatoes be looked at differently, particularly in parts of the world, like the European Union, that are not behind this technology?”

Douches says MSU is conducting both types of modification, “but we think the intragenic approach is important to focus on at this time to get GM potatoes accepted by the public.”

An Idaho company called Simplot has gotten behind the intragenic approach and developed three new processing varieties, which it has submitted to USDA for deregulation for the 2013 crop, that offer low bruise, low sugar and low asparagine.

It’s been 17 years since the first genetically modified crops were introduced, and Douches says European scientists are beginning to argue for the technology and push for more acceptance. “It’s a new world, and a step in the right direction,” he says. “We’re starting to see other countries get involved.

Brazil has developed a virus-resistant dry bean that may be imported here. We’re seeing non-American product development, and it’s being developed by the government and not the private sector. That all bodes better with consumers.”China and India are also on the verge of releasing biotech crops.

On the horizon

While biotechnology offers great opportunity for the potato industry, MSU is also making advances in conventional breeding, as well as experimenting with innovative methods to remove viruses.

Douches says two chip processing potatoes are nearing commercial release. Varieties MSJ126-9Y and MSL292-A were bred to offer longer storage life.

For the specialty market, including home gardens and restaurants, three new varieties were released, and seed production has started. Spartan Splash is a yellow-flesh potato with splashes of purple on the skin. Colonial Purple is purple outside and white inside, and Raspberry is red inside and out.

To wipe out viruses, Douches and his crew are trying cryotherapy to freeze-dry plants in tubes with liquid nitrogen. “Everything freezes and dies but the maristem tip; it regenerates,” Douches explains. “What we’re left with tends to be virus-free in a shorter time than other procedures currently being used.”

For more on potato research, contact Douches at or call 517-256-7674.

What is a genome?

Life is specified by genomes. Every organism, including humans, has a genome that contains all of the biological information needed to build and maintain a living example of that organism. The information contained in a genome is encoded in its DNA and is divided into discrete units called genes. Genes code for proteins that attach to the genome at the appropriate positions and switch on a series of reactions called gene expression.

Potato’s value to top 10 producing states

1. Idaho — $753,250,000

2. Washington — $627,995,000

3. Wisconsin — $246,330,000

4. California — $228,452,000

5. North Dakota — $174,994,000

6. Michigan — $164,430,000

7. Minnesota — $159,390,000

8. Oregon — $151,293,000

9. Colorado — $151,206,000

10. Maine — $151,104,000

*2009 figures


04123001C.tifIN THE LAB: Several different plant experiments get their beginning at the Michigan State University lab in the Plant and Soil Sciences building.

VIRUS-FREE: Dave Douches, a Michigan State University crop and soil sciences professor specializing in potato breeding, holds up tubes with potato plants in them. He uses a freezing technique to wipe out viruses in a plant.

GRADUATE HELP: Michael Hardigan is a graduate student helping with tissue cultures on potato plants.

This article published in the April, 2012 edition of MICHIGAN FARMER.

All rights reserved. Copyright Farm Progress Cos. 2012.