The Secret Garden : Research: A trail of intrigue winds from Israel to the Coachella Valley, where the folks who brought you the Seedless Watermelon plan to grow the world’s most popular fruit.

In the fall of 1988, the web of secrecy surrounding a multimillion-dollar experiment here began to unravel.

Word leaked out that research was being conducted at an obscure site in the Coachella Valley. Despite the protection offered by a private security firm, a guard dog and a 12-foot-high cyclone fence topped with razor-sharp barbed wire, important material began disappearing.

Later on, armed men entered the compound, shot and killed the guard dog and stole irreplaceable scientific data.

The most bizarre aspect of this incident is that the target was not priceless computer microchips, classified U.S. defense programs or the like. The bandits made off with a row of trees laden with fruit.

Fruit trees are not exactly rare in this rich agricultural area east of Palm Springs. These, however, were bearing the world’s most popular fruit at a season when they were unavailable anywhere else in the world.

The object of the research--and the uncharacteristically violent crop thefts--was the mango, that oblong tropical fruit with the smooth skin and seductively aromatic flesh. Mangoes are grown in India, the Philippines, Mexico, the Caribbean and other regions that fall between the Tropic of Cancer and the Tropic of Capricorn. (In this country, only Florida and Hawaii currently have any commercial mango production.)

This particular mango grove, covering just about 10 acres at the foot of the San Jacinto Mountains, was a major agricultural accomplishment. A fickle, tropical fruit that thrives in virtual 100% humidity was being successfully grown in Southern California’s dry, hot low desert.

But there’s more to the story than the extraordinary tropics-to-desert transplantation: The Coachella Valley mango trees are grafted, grown and nurtured to ripen during October and November, when all of the world’s major mango-growing regions are idle. The plan, in place since 1983, is to sell California mangoes, without competition, at ultra-premium prices.

The concept is the brainchild of Sun World International, Inc., which has developed and trademarked the Seedless Watermelon, the Le Rouge Royale pepper and the DiVine Ripe tomato.

Howard P. Marguleas, Sun World’s founder and CEO , had never tasted a mango until he took a trip to Singapore 10 years ago. “I began looking for them when I returned to the U.S. and had a hard time finding them in stores. And when I did find the fruit and began buying them, suddenly the season was over. So, I wanted to see if we could produce mangoes in a time of year when others didn’t have them,” he says.

In 1983, Marguleas visited an Israeli kibbutz on the shore of the Dead Sea where mangoes were growing in climatic conditions similar to those of the Coachella Valley. The Israeli researchers working on the project said there was no reason the method could not be transferred to the California desert.

Marguleas says the 1988 thefts of fruit and trees badly disrupted the mango research, as each tree was being closely monitored. At the same time, says Marguleas, “It was a great deal of encouragement to us that everyone was stealing our mangoes because we thought we must have something important. Nobody ever steals anything worthless.”

Although Sun World will not share its proprietary data, others have been sufficiently impressed with the results to consider emulating the firm. The University of California has purchased sizable Coachella Valley acreage in hopes of developing mango groves with state-financed technology that could then be shared with private industry.

The timing of the Coachella Valley harvest is crucial to the success of Sun World’s plan. The vast majority of the international mango crop comes to market between April and September.

“October and November are the only months that are without mangoes from some place in the world,” says Larry Nienkerk, owner and managing partner of Tavilla Sales Co. in Burlingame, Calif., the leading North American importer of mangoes. He says sales of the fruit have posted “major” gains over the past five years as the fruit has started appealing to a market wider than the traditional Asian and Hispanic customer. (A produce industry consultant estimates that between 50,000 and 60,000 metric tons of mangoes are sold each year in this country.)

“Mangoes have traditionally been an exotic fruit available mostly on the West Coast and, in particular, in Southern California,” says Bill Haines, of William David & Associates in Murrieta, Calif. “There is, however, quite an opportunity in marketing mangoes to the balance of the nation’s consumers. Once you have tasted a mango you can understand why they are the world’s most popular fruit.”

Nienkerk suggests that mangoes will become so popular in the United States that supermarkets will begin carrying different varieties. “There are,” he says, “more varieties of mangoes than apples.”

Sun World experimented with about 30 varieties, and chose the Keitt because it produces a very large fruit with a light green exterior and a rich, yellow flesh. The Keitt is not as fibrous or stringy as some of the more popular mangoes, and has a comparatively small stone or pit. The high sugar content gives the fruit excellent flavor.

The experimental plot went through a critical period last winter when an unusual freeze hit the Coachella Valley for four days in December. The company used a helicopter to circulate the cold and warm air and raise the overall temperature to prevent frost damage to the trees, which are extremely sensitive to cold weather.

Now the company is so pleased with the experimental plot, it has planted an additional 300 acres of mangoes in two Coachella Valley locations. (The exact spots remain a corporate secret.) Sun World estimates it will be two years before significant commercial production is achieved, but in five years, the firm hopes to grow a million cartons of mangoes annually.

There are also plans to double the current acreage. Even at that rate, though, the Sun World production will barely be a fraction of the Mexican crop. The timing of the Coachella harvest, however, should give the Valley an impact that belies its size.

In fact, Nienkerk says that the rarity of the California mangoes may make them too expensive for the domestic market.”I wouldn’t be surprised if the Japanese came in and bought most of them,” he says. “When there is an excellent-quality crop in short supply, the Japanese often offer a lot of money for it.”