SCIENCE

Are there spuds on Mars?

Joint US-Peruvian project suggests the humble potato could be cultivated on the red planet

A seedling manages to grow under Martian conditions.CIP | EPV

Peruvian and US scientists say they have passed the first test toward growing potatoes on Mars. After successfully using some of the most arid and saline soil on Earth, the next step is now to submit plants to atmospheric conditions similar to those on the Red Planet.

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Potatoes on Mars, a joint project launched in January 2016 between the Lima, Peru-based International Potato Center (CIP) and NASA’s Ames Research Center (ARC), has two main objectives: to establish whether it would be possible to grow potatoes on a future colony on the Red Planet, while at the same time, the experiment aims to take advantage of the knowledge acquired in carrying it out to establish the best tubercular variety to grow on hostile environments on Earth.

There is a third objective as well: to ready humankind for the impact of climate change on the fourth-most cultivated foodstuff that we eat.

The second phase of Potatoes on Mars can be watched online

“We selected 65 varieties that could deal with the stress produced by aridity,” says Walter Amorós, a CIP researcher. The potatoes were then planted in the La Joya desert in the south of Peru.

“These are the most Mars-like soils on Earth,” says an ARC press note, noting that the salinity in particular is similar to that on Mars. “They have 20 times more salt, particularly sodium and boron,” adds Amorós.

The soil conditions chosen for the experiment were so demanding that no other plant of use to humans – from wheat and quinoa to beans – passed the test. Not that the potatoes found it easy. They had to be helped with water rich in nutrients to help them put down roots. Only one of the native varieties and four genetically modified types actually did so and then tuberized – the botanical process by which roots or the lower stems of some plants become tubercular.

“We now have to carry out further research into how to produce larger amounts under stable conditions,” explains Amorós, highlighting that the results so far are only part of a very early phase in the project and that it is still to be seen how the species that have survived deal with the other problems associated with Martian soil, particularly the presence of oxidants such as perchlorates.

There are many other factors to be taken into account, says Julio Valdivia, a former NASA researcher, of Lima’s UTEC university: “Atmospheric pressure of six millibars compared to Earth’s one bar; an atmosphere made up almost entirely of CO2, 95% compared to 0.03% on Earth; very high levels of ultraviolet light; an average temperature of -20ºC; and gravity of a third of that on Earth…”

Only one of the native varieties and four genetically modified types put down roots 

The second phase of Potatoes on Mars, which can be observed online, will use CubeSats, miniature satellites used for space research. But instead of being put into orbit, they will recreate the conditions on Mars. “They will help us find the most-resistant potatoes. This phase two will attempt to find the limits of the potato by approximating Martian conditions,” says Valdivia.

There is still a long way to go, and the project requires further funding, which is scarce. Even if any of the plants survive the CubeSat test, biotechnology will be required to increase production, the first seedlings would have to taken to Mars from Earth and then tested on the red planet itself.

And if they don’t, as Amorós points out: “They will at least be of use on Earth.”

English version by Nick Lyne.

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