Agriculture Reference
In-Depth Information
Potatoes
Potatoes are the essence of bland stolidity. They adapt to almost any cooking technique you
can imagine and are happy being paired with almost any ingredient. Accounting for almost
one third by weight of all the vegetables eaten in America and available year-round, they
are so common we might well take them for granted. But that's all a facade. Dig just below
the surface, and you'll find that these seemingly placid vegetables are among the strangest
members of the plant kingdom.
Potatoes are members of the Solanaceae family, relatives of tomatoes, eggplants, chiles
and the (really) deadly nightshade. They are tubers, which are part of the root system. But
whereas true roots reach out through the soil to collect nutrients, tubers swell up to store
the food the plant has collected. Tubers reproduce asexually. As every elementary school
science student has learned, if you cut a potato into pieces and sow them in the ground,
each piece will grow a plant exactly like the one you started with (they are true clones).
Potatoes can also reproduce sexually - they have pretty white flowers that when pollinated
will develop a fruit that looks like a teeny, very seedy tomato. But successful pollination
occurs only very rarely, and the results are genetically haphazard - plant a potato seed, and
who knows what might happen.
Potatoes are extremely demanding about their growing conditions, too. They need rich
earth and are among the most nutrienthungry of all food plants. The soil must be deep and
fine; any clods will deform the spuds, so farmers are careful not to walk where potatoes are
growing for fear of compacting the dirt. Potatoes also need a lot of water - about an inch per
week is perfect - but the land must be well drained; soggy earth encourages rot and all kinds
of fungal nastiness. Potatoes are susceptible to an amazing array of pests and diseases: early
and late blights, potato beetles, mosaic virus, leafhoppers, aphids and various wilts and rots
that can destroy entire fields within days. It was late blight, Phytophthora infestans, that
devastated the Irish potato harvest in the late 1840s, killing more than a million people and
creating a wholesale redistribution of population around the world. (A new, fungicide-res-
istant mutation of P infestans has cropped up in several American growing areas.)
To help fight off this onslaught of pests and diseases, potatoes have developed their own
system of self-defense. When the plant feels weak and threatened, it begins to pump up pro-
