Summer 2008

Living Science

The quest for the perfect potato has kept David Spooner on the move for most of two decades.

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.

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.

When you come across a new kind of potato, what do you do with it?

Typically, we send some of its seeds to the U.S. Potato Gene Bank in Sturgeon Bay, Wis., where they catalogue and store the species.

And the gene bank receives samples from all over the world?

Yes. However, that has changed tremendously in the last 10 years. The whole system of collection, storage and distribution of germplasm started in the 1970s, when the paradigm was “common heritage of mankind.” This means that, at the time, everybody saw germplasm as common property. But then, through a number of developments—including changing intellectual-property rights practices, national legislation on access to genetic resources and sharing the benefits from their use, and the Convention on Biological Diversity—some nations began to restrict access to their genetic resources.

I collected 14 years in a row, from 1987 up until 2000. My last expedition was to Panama in 2000. Since then I haven’t been given permission to collect. It’s very frustrating.

What potential problems do these restrictions pose for U.S. breeders?

When you look at the major native crops that originated in the United States, we’ve got blueberries, sunflowers and strawberries. It would be hard to feed a family on that. We also have what the Native Americans ate, such as corn and beans. But even those items may have been brought up from the south. In short, the United States is relatively germplasm-poor. Fortunately, we have one of the richest collections of crop germplasm in the world. And we share it widely, because all nations depend at least to some extent on germplasm from elsewhere in the world.

How do you continue your work under the new restrictions?

Now I study potatoes abroad a few months out of every year. The Peruvians don’t mind you studying their potatoes in their country. It’s to their benefit. In fact, two of my graduate students recently did a big project looking at Peruvian germplasm. To do this study, we imported germplasm from the United States to Peru.

And luckily, the world seems to be reconsidering the current system. People are starting to realize that when they put a wall around their own country, not only do they keep stuff in, but they’re keeping good stuff out as well. The policy is so restrictive that some of the good exchanges have been stopped.

If the restrictions loosen, would you return to collecting samples?

I hope I can in the future. One of the things that I’m doing to create a better climate is training graduate students from Latin America. In fact, almost all of my students in the last 10 years have been from Latin America. In this way, I’m also helping to address the desire for reciprocity.

You must have some great stories from the years you spent collecting specimens.

For 14 years, I collected from every country from Mexico to Chile. It was a great opportunity to develop as a scientist, meet people and establish collaborations. One time, I spent six weeks on a boat in Chile just going from island to island collecting potatoes. That was fun. Also, I love Peru because it’s just so full of biodiversity and I’ve made many friends there. These aren’t really stories, just fond memories of something I dearly miss doing. I would love to get back into the field again.

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