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By Chris Voigt, Executive Director, Washington State Potato Commission
Good potato breeding can solve many of our industry’s challenges. I often tell people that it is easier to breed people than potatoes. Potatoes are tetraploids, which means they have an extra set of chromosomes compared to people. This means that it is exceedingly difficult to get all the traits you want into one potato. In a quick summary, here is how our breeding program works. And let’s contrast it to how it could work by implementing innovative technologies.
How it Works
A potato breeder takes two potato varieties that he or she thinks will produce offspring that will have traits the industry wants. Perhaps one variety is resistant to Potato virus Y (PVY) and the other is high yielding. They take the pollen from one variety and fertilize the other. They continue to grow that fertilized plant in the greenhouse and harvest the true potato seed from the pods it produces. That plant could produce about 300 true potato seeds, and each seed is genetically different from one another. Those 300 seeds are planted in separate pots in the greenhouse where they will grow, and each potato plant will produce one or two mini tubers. At this point, we still do not know if any of the 300 plants have PVY resistance or are high yielding.
We take those mini tubers and carefully plant them in the field, making sure they are spaced far enough apart so that when the digger brings them to the surface in the fall, we can tell which tubers belong to which plant. Then people like you and I walk the field looking at each pile of tubers that have been dug. Do the potatoes have the proper shape? How does the skin look? Are the eyes shallow? How many potatoes did that plant produce? How big are they? If they look nice, we gather up the potatoes from that one plant, put them in a bag, tag the bag and store them for planting next season. Then the next season, we plant those tubers we stored from that one plant and ask those same questions at harvest. We still do not know if a plant is resistant to PVY or if it has the proper specific gravity or anything about its nutritional content. The only thing we know is if the tubers look pretty.
What is Needed
There are three things we can do to strengthen our breeding program.
First, we need to be smarter about the parents we select for crosses. We need a new type of scientist called a “bioinformatician.” They apply statistical methods and algorithms to interpret data and identify patterns that can lead to new insights in genetics. This will help us pick the absolute best parents for the traits we want in our next potato variety.
Second, we need more potato markers. Markers tell us which genes are responsible for a specific trait we are looking for. Once we have a marker for a trait, we can do a DNA test to see if the newly created cross has that marker and the traits we want. We currently have about a dozen markers and need many more.
Third, we need more greenhouse capacity with robots and automation. Breeding is a numbers game; the more crosses you can do, the more likely you are to find the next great potato. In the Tri-State breeding program, we only have the physical and financial resources to produce about 150,000 genetically different plants each year. We need to at least quadruple that.
How it Could Work
With the right investments, here is how our future breeding program could work. Our bioinformatician will crunch the data and tell the breeder the best two parents to use to improve our chances of getting the exact traits we want. The breeder will have expanded greenhouse space to be able to accommodate over 600,000 new clones each year. And when these clones are only five weeks old, a robot will come by and take a tissue sample from each plant and do a quick DNA analysis to see if it has all the key genetic markers we want in our new potato. If it does not have the markers, then we toss it out and never take it to the field for further evaluations. We’ll be able to learn in five weeks what can normally take us five years. We will still take about 150,000 plants to the field, but all of them will have the key genetic markers we want.
These are tested technologies and processes. This is happening in other places around the world, and the U.S. needs to catch up. Our first step is to hire a new USDA bioinformatician. Then we can start building a new genotyping lab and greenhouse. The Washington State Potato Commission will be working to secure funding for this improved potato breeding process.