Potato plants produce the highest yields at moderate temperatures, i.e., about 21 degrees Celsius at day and 18 degrees Celsius at night.

"At such temperatures and at the correct length of the day a protein SP6A, which causes the formation of tubers, to prepare the plant to cooler periods", explained German scientists.

Heat, however, causes plants to switch to growing more green shoots and leaves, but the potato turns out almost no tubers. Scientists have tested this empirically, by placing the plants in a greenhouse where the temperature was 29 degrees during the day and 27 degrees at night. They found that even a few of the formed tubers contain less starch and germinated faster, so they were less nutritious and pretty soon rotted.

"Until now, the mechanism that prevents such changes in the potato plants at high temperatures, were not known," says Professor Uwe Sonnewald, head of the Department of biochemistry at the University of Erlangen-Nuremberg, who led the research team.

But now his team found out that ribonucleic acid (RNA), consisting of 19 nucleotides, regulate the formation of tubers in the plant and responds to temperature changes. It is inactive at low temperatures, but begins to work higher.

Deactivating this small RNA in genetically engineered potato plants, the researchers were able to ensure that the potatoes continued to produce tubers of high quality and in hot conditions, thereby achieving progress in the protection of the potato industry, even in the face of global warming.

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