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In Search of Spuds

TO COLLECT WILD potatoes from around the planet, David Spooner has touched down on mountain peak landing strips, scaled potato-coddling trees in old growth rainforests and endured double vision while hiking over a 17,000-foot mountain pass between Bolivia and Peru. A CALS horticulture professor and researcher with the U.S. Department of Agriculture, Spooner made these trips to give plant breeders the raw materials they need to better protect cultivated potatoes from disease. But a few years ago, he abruptly stopped. Grow recently sat down with Spooner to ask why.

How different are wild potatoes from our cultivated varieties?

Very different. Wild tubers, for instance, are often tiny and mildly poisonous. Most of them have long stolons—their underground stems. And actually, the tuber that we eat is just a swollen stolon. So with wild potatoes, it’s often an Easter egg hunt to try to find the tubers. One thing people breed for with potatoes is short stolon. Obviously, you don’t want to put a potato plant in the ground and then have to harvest the potatoes 20 feet away.

How about good traits? Why is it important to preserve the biological diversity of this species?

So that plant breeders have access to the genetic diversity needed to improve our cultivated potato. Wild potatoes are an enormous reservoir of beneficial traits, including disease resistance, nutritional qualities and a whole range of agronomic traits. By agronomic traits, I just mean how (a potato) grows, how it processes, what it looks like and those types of things.

Wild potatoes are an enormous reservoir of beneficial traits, including disease resistance, nutritional qualities and a whole range of agronomic traits.

With all of the agricultural tools available to farmers in America today, are our potatoes really at risk for disease?

Many diseases can be avoided through chemical control, and in the United States, we can afford the pesticides, insecticides and fungicides needed for that. However, there are certain diseases that can’t be controlled very well. So yes, disease is still a big problem here, and people are constantly trying to better the potato’s resistance to those particular diseases.

Is there any chance that we could face another devastating crop failure on the scale of the Irish Potato Famine?

During the Irish Potato Famine, a major disease almost completely wiped out the potato crop (in Europe) because potatoes didn’t have resistance to that disease. It was a classic case of an emerging disease, an example of something we are constantly concerned about. In fact, disease resistance is one of many reasons why we collect and preserve (wild potato) germplasm —in order to try to breed crops that have resistance to diseases that we think might be a problem.

So really, collecting and storing this germ-plasm is about preserving biodiversity.

Yes—but I wouldn’t say I’ve always thought of it that way. As a formally trained botanist, I knew about biodiversity, but I only thought about it in the sense of preserving plants and animals in their natural environment, like in the rainforest. I didn’t think about it in the context of plant breeding, because that wasn’t my training. This idea wasn’t obvious to me until I joined a community that uses biodiversity in an applied sense, instead of in the usual “green” sense. Now it’s clear to me that biodiversity can be viewed in an ecological context, as well as in more of an applied agricultural context.