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Sexless as in cloning. We grow Solarian tuberosia not by planting potato seeds but by planting seed potatoes – potatoes specifically grown for growing more potatoes. If we were to plant potato seeds – we would get a new variety; by planting seed potatoes we get more of the same variety.
And that’s what we want when we plant our potatoes – more of our New England Kennebecs, Katahdins, Norlands and Green Mountains, and more of the colorful blue Caribes, Cranberry Reds and Yukon Golds. So we plant seed potatoes.
Uniformity breeds susceptibility
However, while sexless – aka vegetative propagation – provides us with more of the same, it comes at a high cost. “It’s a solution as well as a problem, says Maine potato guru Will Bonsall (see next page), “because with uniformity comes susceptibility.” It not only passes on the “single” parent potato’ s genes to the next generation, it also passes on whatever diseases (fungi, viruses, bacteria) the parent harbored.
In case you haven’t noticed, potatoes have the potential of harboring many diseases. At last count there were about 160 from blights to wilts to scab to… As one speaker at the World Potato Congress in Boise, Idaho, last August told his audience, “There is no limit to the maladies that can befall the potato.”
At least one such malady, the fungus Phytophthora infestansaka or “Late Blight,” made its way into the history books in the mid-19th century ala the Irish Potato Famine, when millions of people in Ireland starved or were forced to immigrate when entire potato crops rotted in the fields or in storage because of the fungus.
And in case you thought the Late Blight was history; it’s not; it’s still around but being kept in careful check thanks to efforts by potato-producing states like Maine to control the many diseases that afflict potatoes – efforts that produce what are called “certified” seed potatoes – potatoes that not only provide more of the same but do so without the high cost of sameness.
Starting out in a test tube
Maine’s Certified Seed Potatoes – some 40 to 50 varieties – start out life as disease-free tissue culture, growing in test tubes in the laboratories of the state-owned Porter Seed Farm in Masardis, Maine.
According to farm manager Vikram Bisht, once out of the test tube, they are grown in greenhouses and fields for another four generations before making it to market. Along the way they are propagated /cloned first by “foundation” seed growers. There are about 13 such growers in Maine who, in turn, sell them to “seed” potato growers. There are about 110 such growers in Maine who sell them to farmers, hardware stores and mail order seed companies.
With each generation of seed potato, the supply of tubers increases ten-fold. With each generation the potential for disease also increases. That’s where certification comes in.
On to Homestead, Florida
To keep those diseases in check and at an acceptable level, state inspectors evaluate the disease level of the field grown plant at least three times during the growing season before post harvest samples are sent to a state-owned farm in Homestead, Florida, for a final evaluation.
Homestead, Florida? As Allison Todd, Maine’s superintendent of seed potato inspectors, recently explained: “Where else can you grow potatoes in January?”
It’s there that the crop gets its final check up. Approximately 1,000 samples a year are planted in November; they are evaluated for disease in January.
To carry the Maine-certified seed potato label, the post harvest grow out can contain no more than 5 percent total virus; to qualify as certified foundation potato, no more than one half of 1 percent. Certification does not mean the seed potato is free of disease, it just means it has met the limits set by the Maine Potato Board.
According to Todd, about 11,000 acres or one quarter of Maine’s potato acreage is planted to seed potatoes; the rest is for “Tablestock” and “Processing.” At one point Maine had 65,000 acres planted to seed potatoes. Today, that is more than all the acreage planted to all kinds of potatoes. Todd cites the decline in seed production to competition from the Canada and the American Southwest.
Growing Potatos in Scatterseed
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Will Bonsall with the heirloom Beauty of Hebron.Will Bonsall of Industry and the Scatterseed Project grows between 600 to 800 varieties of potatoes a year- potatoes with exotic names such as Agassiz, Bertita and Papa Amarilla – potatoes you won’t find in the supermarket.
As “curator of potatoes” for the Iowa-based Seed Savers Exchange, Bonsall grows these heirloom (handed down) varieties to keep them from extinction. He’s been at it for 25 years, ever since his neighbor Orlando Small introduced him to his first New England heirloom potato: a rough skinned purple potato curved like a cow horn that some thought had resistance to the Colorado Potato Beetle. The rest is history.
He admits that there is a good reason that some of the potatoes he collects and grows are not found in the supermarket or in the garden; but he says they may have in their collective genes resistance to diseases, current or future, that plague potatoes. “It doesn’t pay to put all of your eggs in one basket,” says Bonsall, “especially if it is as precariously balanced as is American agriculture.”
Bonsall, who says his job is opposite that of a plant breeder – to keep the variety just as it is – plants his potato collection on about a half acre; about six hills per variety. Come October, he puts the tubers from each variety in labeled brown paper bags and arranges them alphabetically on shelves in the moist, cool, dirt floored basement of his house. Come June, he replants his collection… alphabetically.
Hard put to name his favorite variety – he says it depends on whether you’ll be boiling baking or making potato salad. Do you want an early potato or do you want a good keeper? Pressed for an answer, Bonsall says one of his favorites is Daisy Gold, a large potato with smooth yellow skin, deep yellow, moist flesh and a flaky texture. Good
Growing Potatoes
• Start with certified seed potatoes. Look for the blue certification tag on the barrel of seed potatoes at the local hardware store. If you are looking for organic certified seed (double certification), check out the Web sites of Wood Prairie Farm on Bridgewater, the Maine Potato Lady in Guilford, or Fedco in Waterville. See below.
• No wood ashes, please. “Sweet” soils (high pH) or ones loaded with fresh manure provide the perfect environment for the soil-born fungus disease known as “scab” a.k.a. Streptomyces scabies. If you’ve had problems with scab, plant Russet, Norland or Superior.
• Rotate. Rotate. Rotate. Don’t plant in the same place every year or else there will be a build-up of scab. Never follow the potato’s cousin – the tomato – or beets, or carrots; they are all susceptible to scab. Return in three to four years
• Plant pieces with two buds or “eyes.” If it’s the size of a golf ball or walnut, plant it whole as that is a good hedge against soil born diseases; if larger, cut into pieces with two “eyes.” It is from the “eye” that the cloned potato plant will spring. Plant the piece eyes up, 8 -10 inches apart in furrows about 30 inches apart and 4-6 inches deep. Cover with one to two inches of soil for a fast start.
• Hilling up is critical. The more you hill up around the plant (at least three times during the season) the more potatoes you will get. Hilling up also keeps out the light that turns potatoes and not just their skin toxic green. Last, but not least, it provides protection against air-born diseases washing down from infected leaves.
• Water is important. It’s especially important while the plants are flowering; that’s when the “tubers” are starting to form. Too dry a soil can result in scab; erratic watering can cause cracking and “hollow heart.”
• Rotenone the flea beetles; hand pick the Colorado potato beetles. Look for the first potato beetle of the season by checking the upper leaves of the young potato plants every morning. When you find it, start looking for the orange eggs it laid on the underside of the leaves. Continue looking and “squishing” throughout the season. If you are diligent and vigilant, the crop of beetles will be small. One way to avoid the beetles altogether is to plant in late June, when the season of the beetles has passed.
Editor’s Note: This story first appeared in the Daily Bulldog print issue in 2008.
