COLUMN ONE : Debut for the Hairy Potato : With its unmatched potential for feeding the world’s hungry, scientists are laboring mightily to make a better spud. That requires outwitting some ever-resourceful insects.
K. V. Raman placed a “hairy potato” leaf under a microscope rigged with a television camera, then sprinkled a few tiny aphids on the leaf’s dark surface. Suddenly, on a nearby video monitor, it was the giant aphids vs. the hairy potato.
Live and in color. Hungry aliens advancing over the magnified leafscape. Getting gummed up and bogged down in a forest of sticky stalks. Struggling mightily. Then weakly.
Finally, the aphids were still. Raman, an entomologist from India, smiled triumphantly. The hairy potato had prevailed.
“It’s something like flypaper, yeah,” Raman said. But it’s much more than that.
The hairy potato is a new, hybrid potato plant with tiny, goo-tipped “hairs” on its leaves and stems that keep aphids, beetles and other bugs from eating at humanity’s expense. The hybrid helps increase crop yields and reduces the need for costly and toxic insecticides.
It is one of many innovations the Peru-based International Potato Center is harvesting in a major effort to stem the advances of world hunger and environmental contamination.
Potatoes, first domesticated many centuries ago here in the Andean region, offer unmatched potential for feeding the Earth’s increasingly crowded population, expected to reach 6 billion by the end of the century. As the International Potato Center likes to point out, the potato can produce “more nutritious food faster and on less land than any other food crop.”
It’s also extraordinarily adaptable, according to Gregory J. Scott, an economist at the center (and a grandson of the late Los Angeles philanthropist Joseph Scott). Potatoes are grown in 140 countries, surviving at altitudes ranging from below sea level to more than 14,000 feet, in deserts and in the humid tropics and as far north as the Arctic Circle.
While the Soviet Union is by far the world’s biggest producer, potatoes are also the main staple in such countries as Peru, Bolivia and Colombia. Potato production is on the rise throughout much of the Third World, doubling, for example, in billion-strong China since 1960.
Also, developing countries have enormous potential for increasing production further, Scott noted. Average Third World yields range from 12 to 30 metric tons per acre, compared with 75 to 85 tons in the United States and a potential 170 tons an acre for some of today’s improved varieties.
In terms of value, potatoes already are the world’s No. 4 food crop, after rice, wheat and corn. But the few potato varieties grown commercially in most countries are vulnerable to devastating plagues and blights. As a result, farmers use more chemical pesticides on potatoes than any other crop except cotton.
One of the main priorities of the International Potato Center--known by its Spanish initials as CIP--is to reduce the need for those chemicals, which increase farmers’ costs, contaminate rural environments and sometimes endanger the health of consumers.
Hence the hairy potato.
Developed in a joint project by the CIP and Cornell University, hairy potatoes currently are being tested by commercial farmers in the United States. They have been successfully grown on an experimental basis without insecticides in Peru and the Philippines, said Raman.
“We are not saying we are going to zero application of these insecticides,” he said. “But we can cut them back 80% or so.”
While the hybrid’s resistance to insects has been proven, Raman said, the CIP is still working on “improving the quality of the tuber and maybe pushing the yields more.”
The tuber is the potato plant’s edible end--technically an underground stem rather than a root. The “eyes” of a potato tuber are really buds, and when they are planted, they sprout and produce new potato plants.
Tubers come in myriad sizes and shapes. Breeders hope that the hairy potato tuber eventually will be as big as your basic Idaho potato. Hairy potatoes now being tested yield up to 1.8 pounds of tubers per plant, while hairless commercial varieties, with heavy use of insecticide, can yield more than 2.2 pounds per plant.
The hairy potato has been proven resistant to the Colorado potato beetle, a feared pest in the United States, the Soviet Union and Eastern Europe. Most insecticides used against the Colorado beetle have been withdrawn from the U.S. market because they contaminate ground water.
Other insects stymied by the hairy potato include the potato tuber moth, the leaf miner fly, thrips, mites and aphids--all major threats to potato crops in developing countries.
Hubert Zandstra, director general of the CIP, predicted that hairy potatoes will be in widespread commercial use “three to five years from now--with a lot of luck, two years.”
Obviously, the hairy potato did not materialize overnight. Nor did any potato, for that matter.
As long as 2,000 years ago, Andean farmers began cultivating domesticated varieties derived from wild potato species. After the Spanish conquest in the 16th Century, the potato reached Spain and began to spread through Europe.
It was the main staple in some European countries by 1845, when a fungus called late blight wiped out the tuber in Ireland and caused the infamous Potato Famine. Nearly 1 million people died, and up to 2 million emigrated, many to the United States.
Ireland’s potatoes died out because all of them were the genetic descendants of only a few varieties brought from the new world, and all were vulnerable to late blight. Scientists say more diverse genetic material might have provided resistant varieties.
Today, four varieties account for three-fourths of all potatoes grown in the United States--but it needn’t be that way. More than 5,000 domesticated and wild potato varieties are alive and well at the CIP headquarters in the Lima suburb of La Molina.
The CIP is one of 13 centers in the Consultative Group on International Agricultural Research (CGIAR), a worldwide consortium supported by official and private donors. Many of the centers work to preserve bio-diversity and put it to use in agriculture.
Pioneering work in the so-called Green Revolution of high-production varieties of super-seeds was conducted by the CGIAR’s International Rice Research Institute, based in the Philippines, and its International Center for the Improvement of Corn and Wheat in Mexico.
The CIP, founded in 1971, has an annual budget of $20 million and a staff of 600, most of them working outside the headquarters in several countries. The core of the organization is a “genetic bank” that preserves living samples of all known potato varieties.
One section of the genetic bank is a white, vault-like chamber where the temperature is kept at 42 degrees and pinkish fluorescent light washes over high rows of metal shelves neatly packed with test tubes. The sterile tubes contain small potato plants that will stay alive up to four years, their development arrested by the low temperature.
All of the known varieties of the potato are packed into a space the size of a living room, safer and far more compact than open fields for keeping the genetic material of one of the world’s most important foods. “You have exactly the same material here as you have in five hectares,” said John Dodds, a British biochemist, as he peered into the chill brightness. A hectare equals about 2 1/2 acres.
Every two to four years, plants are rotated out of the cold room to a warmer “multiplication room.” There they are given hormone treatments and light variations that make them produce tiny potato tubers whose eyes can be used for planting and normal propagation.
“We take some of the material back to the field and plant it to take another look at it,” Dodds said.
Zosimo Huaman, a Peruvian with a British Ph.D., is in charge of maintaining the CIP genetic bank. He said it contains about 1,500 wild potato varieties and 3,500 native American domesticated ones.
Through centuries of painstaking breeding and selection, Andean Indians developed potatoes with a multitude of virtues. Huaman said some grow at extremely high altitudes and are frost resistant; others grow in coastal desert areas, drawing their moisture from the sea mist.
“Some have flesh that is completely red or purple,” he said. “They used these to dye cloth. Other potatoes, for example, are very tasty and are selected to be eaten only roasted.”
Of hundreds of varieties still eaten in Peru’s highlands, Huaman said his favorite is a potato with deep yellow flesh. “This in my opinion is the tastiest potato. In the Lima market it reaches the highest prices.”
The CIP’s treasury of genetic material is being used to breed potatoes suitable for widely varying growing conditions and tastes around the globe. And just as the center has sent samples of desert potato plants to Israel and frost-resistant plants to the Soviet Union, Huaman said, it could send different potatoes to the United States to give consumers there a wider variety of tastes and textures.
One of the CIP’s main projects has been to collect wild and domesticated varieties from throughout Latin America so that diversity useful for breeding new varieties will not be lost. But some wild varieties, previously classified by botanists, already have become extinct.
“We went to look for these potatoes, and unfortunately many of these can no longer be found because they were lost forever,” Huaman said. Such “genetic erosion,” in potatoes as well as other species, irreversibly limits man’s possibilities for making the best use of the planet’s natural life forms.
Huaman observed that without wild varieties with sticky little “hairs,” called glandular trichomes, the hairy potato would not have been possible.
“We are just beginning to see what is the potential of these wild potato species,” he said.
Technicians at the CIP and Cornell developed the hairy potato through a long process of plant cross-breeding, mixing the hereditary material, or germ plasma, of selected wild potatoes and commercial varieties from the United States and Europe. “Back-crosses” and “recurrent selection” through successive generations of plants finally produced the one with the desired characteristics.
The CIP has used the same conventional techniques to breed new potato varieties that look and taste better, grow faster under different conditions and contain more nutrients. Now the center also is using high-tech genetic engineering to improve potatoes by implanting synthetic or “designer” genes, bypassing the long breeding process.
Dodds, the biochemist who heads the CIP genetic resources department, and Jesse Jaynes of Louisiana State University are using a bacterium as a vector for transferring synthetic protein genes into potato cells to enrich the nutritional value of tubers. Dodds also hopes to endow potatoes with designer genes that will prevent the multiplication of viruses and provide resistance to bacteria.
In one project, Dodds and Jaynes have put anti-bacterial genes from a giant silk moth into potato cells. A CIP spokesman said the moth genes have proven effective in giving potatoes greater resistance to disease.
But such genetically engineered material is confined to the laboratory because of “bio-safety” concerns such as unpredictable propagation and a lack of legal framework for using it in the field, a CIP spokesman said.
“It’s tested under very controlled conditions, and absolutely none goes into the field because we simply don’t have guidelines,” the spokesman said. “Science is ahead of regulations.”
Fortunately, that is no problem for varieties improved by conventional breeding methods, including the hairy potato.
