`Root' Solution for Hunger. Aided by international research, lowly potatoes may grow to feed the world. THIRD-WORLD AGRICULTURE

`WE'RE providing the weapons in the war against hunger and we have two excellent ones - the potato and the sweet potato,'' says Jos'e Valle Riestra, deputy director general of the International Potato Center (CIP) in Lima, Peru. The potato was first cultivated 8,000 years ago near Lake Titicaca and is still the country's staple. Dr. Valle Riestra's goal is to produce potatoes that can be cultivated in any climatic condition, elevation, or soil so that poor people in all areas can feed themselves.

The potato provides more calories and protein per unit of land and time than any other major food crop. Production is doubling every 10 to 15 years and is increasing faster than for any other crop. Three hundred million tons are grown yearly.

National potato research programs worldwide coordinate their activities with CIP headquarters in Lima and eight regional offices.

The potato center has a staff of 525 (including 45 foreign experts from 22 countries) and is one of 13 international agriculture research institutes. Some specialize in specific crops, like the International Rice Research Institute in the Philippines and the International Center for the Improvement of Corn and Wheat in Mexico. Others concentrate on specific areas, such as the Institute of Tropical Agriculture in Nigeria. All are supported by a $200 million budget contributed to by 42 donors worldwide and jointly administered by the United Nations Development Program (UNDP), the UN Food and Agriculture Organization, and the World Bank.

The potato, as well as other root crops, has an unearned reputation in some countries as an inferior food, or a poor person's staple. While roots are the main ingredient of the diet of half a billion people, the potato's nutritive content of protein, fiber, minerals, and vitamins B1, B2, and C hardly make it inferior. Medical researchers report that potatoes are even better than milk for malnourished children, who often can't digest milk. Potatoes provide a high-quality protein similar to that in dairy products. Unfortunately, the potato is still out of reach of a poor person's budget in many developing countries such as Indonesia and the Philippines.

Although the potato is normally grown in a cool climate, CIP is successfully breeding varieties that can be grown in various weather conditions and is focusing on the tropics, since that is where most of its research requests come from and where the need for a fast-growing, nutritious food is greatest.

Experiments are conducted in the potato center's sophisticated growth chambers, refrigerator-size boxes with glass windows through which one can see a potato plant in various conditions and growth stages. The chamber can be adjusted to create any type of climate in the world. CIP's breeding experiments also aim at producing potatoes that can best resist some 250 diseases and pests.

Only some of the tests are conducted in the laboratory. The Center has greenhouses and land next to the Lima headquarters, as well as three stations in other locations of Peru. In Huancayo, at an elevation of 3,200 meters (two miles), the station allows for research in a highland climate and also houses the World Potato Collection, containing 6,000 varieties. In San Ram'on, at 800 meters, CIP does its semitropical research at a mid-altitude in high jungle. And in Yurimaguas, at 180 meters, research is done on potatoes in hot and humid tropics.

CIP is quick to recognize that what is done in the laboratory can be declared a success only when its technology is realized by farmers and the resulting product is served to consumers. One such success has been confirmed by farmers in Sri Lanka, China, Western Samoa, Vietnam, the Philippines, and Bangladesh: the potato seed.

POTATOES are normally planted by placing tubers (chunks of potato that contain eyes) in the ground. But another way is planting seeds, of which 200 are contained in the berry that grows aboveground on the potato plant. Farmers have traditionally devoted a portion of their potato harvest to planting, because seeds usually produce different types of potatoes with various shapes, colors, growing time, and required cooking time. The center is developing seeds that will grow uniform potatoes.

The effort to train scientists, agricultural extensionists, and farmers brings research to consumers' plates all over the world. Worldwide potato-center training through national potato research programs is heavily supported by UNDP. Topics range from pest control to commercialization, with a current emphasis on training the trainees how to train.

``What they have in their heads is not as important as what they can put in someone else's head,'' notes Dr. Hern'an Rinc'on, communications support coordinator.

Another course focuses on diagnosis and teaches how to interview farmers, assess their needs, and incorporate them into the development of solutions.

``Technology in itself is not a response,'' explains Dr. Carmen Siri, information services coordinator. ``The extensionist first has to understand the farmer's needs. Otherwise, we can fall into the trap of developing technology that doesn't meet reality.''

Despite its central importance to world potato research and production, the center maintains a modest approach.

``We are not looking for a Green Revolution,'' says Valle Riestra. ``We just want to make food available to a larger number of people who want it and who cannot afford it.''