Even if the supermarket shelf is hard to believe – there are hundreds of varieties of potatoes.
What the farmer doesn't know, he doesn't eat! When Prussian King Frederick II had seed potatoes distributed in 1744/45 to prevent famine, many later ended up in the garbage – the farmers had eaten the poisonous berries out of ignorance. Despite the royal "potato decree" of 1756, cultivation got off to a slow start. But Old Fritz allegedly had soldiers stationed in the fields and thus demonstrated: These tubers are valuable.
Today, Solanum tuberosum, as it is called, is part of the fixed repertoire of German cuisine. On average, Germans consume around seventy kilograms a year. The German Society for Nutrition recommends the potato as part of the basic diet, because the starchy tubers not only fill you up and can be prepared in a variety of ways. They also provide important minerals and trace elements, especially potassium, but also calcium, magnesium, phosphorus, iron and zinc. The tuber also contains various B vitamins such as thiamine (B1), riboflavin (B2), pantothenic acid (B3), niacin (B5) and pyridoxine (B6), without which almost no biochemical process in the body can take place. With a vitamin C content of around 17 milligrams (mg) per 100 grams, it is well behind kiwi (100 mg) or lemon (53 mg), but can easily keep up with apple (12 mg) and pear (5 mg).
The reddish to bluish-black coloring of some potatoes is also due to anthocyanins, plant pigments from the flavonoid group, which are very effective at eliminating free radicals. Some anthocyanins also improve vision, inhibit inflammation, slow down blood clotting or protect blood vessels, for example by they reduce the permeability of the vein wall or ensure relaxation of the arteries and coronary vessels, thereby lowering blood pressure. The potato that ends up on our plate is neither fruit nor root, but the thickened end of an underground shoot. Botanists speak of a tuber. This serves the plant for vegetative – i.e. asexual – propagation. As soon as there is no more threat of frost, the farmer sticks them in the ground. In the field, the potato sprouts from small depressions, the so-called eyes. These form new shoots above and below ground and new tubers by the time they are harvested - in our case from May to October, depending on the variety.
Because they only thrive below the surface, the soil around the plant is usually mounded. It is also important to hoe the soil regularly and to aerate it. To avoid the transmission of potato diseases, a distance of around 62.6 to 75 centimeters between and 30 to 40 centimeters within the rows is recommended. For the same reason, no leftover potatoes from the previous year should be left on the field and tools used to trim the plants should always be disinfected. Unfortunately, the potato beetle, which was thought to have disappeared, is benefiting from the fact that many farmers are now doing without harsh insecticides.
By the way: Sieglinde and Co come in far greater variety than the vegetable shelves in the supermarket would suggest: At the Federal Plant Variety Office - a kind of "TÜV test center" for useful plants - 206 varieties are currently approved for the trade in seeds and plant parts and listed according to criteria such as pathogen resistance, ripening time, yield, flower color, tuber shape and type of cooking.
Variety does not only ensure a varied taste experience. It also plays a major role in ensuring crop yields. If only a few varieties are cultivated, the risk of epidemics increases, as it did in the mid-19th century: A fungal disease, late blight, destroyed a large part of the harvest, because even then, farmers had committed themselves to just a few varieties. The greater the variety of crops and thus the gene pool, the more likely it is that some varieties will prove to be resistant. That is why there are 2,834 varieties and breeding lines stored in the potato gene bank in Groß Lüsewitz near Rostock, a branch of the Gatersleben Institute for Plant Genetics and Crop Plant Research. In addition, there are 150 wild and cultivated species from South America, of which the gene bank registers more than 3000 different genetic variants - technically genotypes.
Did you know?
- The salad potato Linda is about to end. Shortly before the end of the 30-year plant variety protection – a kind of patent on seeds – the marketer Europlant withdrew the approval. Now the Lower Saxony organic farmer Karsten Ellenberg wants to apply for a new license. But then Linda would be treated like a new breed and tested again for two years.
- One hundred grams of boiled potatoes have only 57.1 kilocalories. The same amount of French fries has 124 kilocalories, with chips it is even 535. Because frying forms small pores through which water vapor escapes. If you take the "fries" out of the hot fat, the tubes cool down and a vacuum is created, which sucks in the fat.
- Anyone who would like to try their hand at growing unusual potatoes and has no commercial intentions can order free samples from the potato gene bank in Groß Lüsewitz
The Heidelberger Verlag Spektrum der Wissenschaft is the operator of this portal. Its online and print magazines, including "Spektrum der Wissenschaft", "Gehirn&Geist" and "Spektrum – Die Woche", report on current research findings.