Knowing Your Roots

Posts tagged ‘Wisconsin Certified Seed’

Potato Viruses: The Silent Enemy of Seed Potato Production

Blog 9

It’s July in northeast Wisconsin. The air is fresh, the birds are chirping, and the potato fields on the isolated seed potato farm in Langlade County are a healthy green. This is a highly-specialized farm where precious disease-free tubers from the state’s elite seed farm are carefully nursed to supply the diverse requirements of commercial growers. Everything on the seed farm seems to be going well this year, and even the eagle-eyed inspectors have not found any evidence of disease. The farmer looks up at the bluebird sky and smiles at the promise of a warm summer day, unaware that a silent enemy may be approaching. In swirls and currents of air coming from the south, a scattering of feather-light insects is alighting unseen on the edges of his fields. They are anxious to insert their needle-sharp mouthparts into the leaves and begin feeding. These are aphids, which act as unwitting flying hypodermics, quietly moving from one plant to the next, sampling the sap they need to live. These harmless creatures are from southern growing areas where a myriad of crops exist that can potentially infect them with any number of virus diseases that they can carry to potatoes. Unlike the July sky, the enemy the aphids carry promises trouble.

Hijackers, tricksters and deceitful agents, plant viruses are some of the most devious and threatening enemies of seed potato growers in North America. They are the number one cause of seed lots failing to meet the standards necessary to wear the Wisconsin Certified Seed label. How do they do it, you ask?  Scientists have studied potato viruses for decades. They are very small micro-organisms that can enter plant cells with the aid of vectors, such as the aphids, but are incapable of multiplying without the help of the potato host’s resources.  Once inside a cell, virus particles use different strategies to hijack the cell’s resources to make more copies of themselves. Plants, like humans and other organisms, have defense systems that will recognize the presence of an enemy and try to stop its attack. But some viruses, like Potato virus Y, counterattack by turning off, or ‘silencing’ the plant’s defenses, allowing them to keep using the plant’s resources to multiply.   (more…)

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How do potatoes get to your holiday table? – It all begins with the seed!

Blog 7

Potatoes, we love them, particularly at this time of year. Thanksgiving is close, and it just would not be the same without those creamy mashed potatoes to accompany your turkey and cranberries. Did you know that Wisconsin ranks 3rd in US potato production?  Did you know that the potatoes you are enjoying actually began life anywhere from 5-8 years before they got to your plate?  Probably not, but during the next few blog posts we would like to introduce you the exciting journey that your potato takes from a lab in Madison, to isolated farms in pristine Northwest Wisconsin and even a trip to Hawaii for a lucky few. This is the process needed to produce the disease-free seed tubers that potato growers must plant to meet all your culinary potato needs.  We hope these next blog posts will help illuminate this fascinating journey.

Potatoes are not grown from actual seeds, but come from daughter tubers (seed pieces) that carry all the traits of the mother plant. To be certain that plants are disease-free, true to variety and carry only the traits such as color, texture and taste that consumers desire, the journey starts in labs on the University of Wisconsin-Madison campus.  The Wisconsin Seed Potato Improvement Program, the first of its kind in the US, is funded by Wisconsin potato growers and directed  by Dr. Amy Charkowski of the UW-Department of Plant Pathology. Here, disease-free potato plants representing hundreds of varieties and characteristics are maintained. In the winter, tiny tissue slivers are grown into small plants in sterile test tubes. These tiny plants, the forerunners of your favorite baked or mashed potato, are then cut into even smaller pieces and grown into plantlets that have roots and leaves of their own.  Every spring, thousands of these plantlets are driven from Madison to an isolated UW Elite Seed farm in northern Wisconsin, close to Rhinelander. Once there, they are placed in protected hydroponic greenhouses, where they can grow over the summer and produce hundreds of pea to marble-sized mini-tubers, which represent the future of the potato industry. Over 400,000 mini-tubers are produced in Wisconsin using this method every year.   (more…)

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