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The roots and the tubers grow suspended in the air, without touching the soil. Growing potatoes in mid-air, in a new technique called aeroponics, is showing great promise. The technique consists of cultivating potato seedlings on specially adapted frames so that the roots, and the tubers, grow suspended in the air, without touching the soil.

This avoids the need to disinfect the soil with harmful chemicals and keeps the tubers healthy as well. The frames are covered with black plastic to keep out the light and the plants are sprayed with a solution of nutrients to allow them to grow.

The International Potato Center (CIP) is using the technique to improve production and reduce the cost of producing seed potatoes. The method is up to ten times more effective than with the conventional techniques. Another advantage is that the little tubers can be harvested at any size seed user wants, from 5 to 30 grams. Spraying fertilizers directly on to the roots makes it possible for the growth phase to continue for more than 180 days without interruption, which does not happen with conventional techniques.

First results have been very successful. For example, 67 seed tubers were obtained per plant with the variety Yungay; with Canchán INIA, 70 tubers and with Perricholi, 69. With conventional techniques, the average is from 5 to 10 tubers per plant.

Seed potatoes are very important for potato producers because the success of the harvest will depend on the quality of seed tubers used. Virologists from CIP’s Integrated Crop Management division are working with the Experimental Station of Santa Ana in Huancayo, where the Germplasm Acquisition and Distribution Unit is producing optimal seed tubers of first class sanitary quality for researchers who require them.

Growing potatoes in mid-air, with a technique called aeroponics, is showing great promise for the production of seed potatoes. Seed potatoes are very important for potato producers because the success of the subsequent harvest depends on the quality of the seed tubers used.

The technique consists of cultivating potato seedlings on specially adapted frames so that the roots, and the tubers, grow suspended in the air, without touching the soil. This avoids the need to disinfect the soil with harmful chemicals and also keeps the tubers healthy. Plantlets with roots are pushed through the top of a table-like structure. The frames are covered with black plastic to keep out the light and the roots are sprayed with a recirculated solution of nutrients to allow them to grow.

“In the greenhouse, seed potatoes were traditionally grown in soil that had been sterilized with methyl bromide, because it was cheap, effective in killing pathogens and weed seeds but it did not alter the characteristics of the substrate,” said Victor Otazú, the chief of CIP’s experimental station of Santa Ana in Huancayo. However, bromine is 60 times more destructive to the ozone layer than chlorine, so methyl bromide was put on the the list of banned ozone-depleting substances of theUnited Nations Montreal Protocol.

Sterilizing the soil with heat is also expensive, so CIP is using looking at aeroponics to improve production and reduce costs. The method is up to ten times more effective than conventional techniques. “First results have been very successful,” said Victor Otazú. For example, 67 seed tubers were obtained per plant with the variety Yungay; with Canchán INIA, 70 tubers and with Perricholi, 69. With conventional techniques in pots, we get 5 to 10 tubers per plant.”

Another advantage is that the little tubers can be harvested at any size the seed user wants, from 5 to 30 grams. The process also allows stepped harvests. Spraying fertilizers directly on to the roots makes it possible for the growth phase to continue for more than 180 days without interruption, which does not happen with conventional techniques. There is a small investment in equipment needed, but still the tubers work out significantly cheaper.

“The technology is novel in the sense that very few people are aware of it or its potential,” said CIP virologist and seed system specialist Ian Barker, “but it has been used in China and Korea for some time.” Even NASA's long range plans for a visit to Mars reveal that the surface crew will spend 60% of their time farming to sustain themselves. Aeroponics is considered the agricultural system of choice because of its low water and power inputs and high volume of food output per sq meter.

CIP’s Germplasm Acquisition and Distribution Unit is already using the technique to produce optimal seed tubers of first class sanitary quality for researchers. Further work in Huancayo will look at the suitability of the technique for a wide range of genotypes including native varieties.

There has also been a lot of demand already for information and training. The Peruvian national research program INIEA is interested and researchers in Ecuador want to install a unit in that country. CIP’s Paul Demo sees much promise for southern Africa.