Perfecting the Pineapple

A team of researchers is working to solve a trio of troubles afflicting Hawaii’s

January, 2004

The lush portrait of green-on-red pineapple fields under blue skies on Oahu and Maui belies a more difficult truth. Namely, that growing pineapple in Hawaii is increasingly difficult and all too often unprofitable. The only remaining kamaaina grower, Maui Pineapple Co. (AMEX: MLP), has struggled for nearly a decade to stay in the black. The other major growers here, Fresh Del Monte and Dole Fresh Foods, have similarly struggled against low world-pineapple prices and increasing competition from places where land and labor are cheaper – namely, Central America and Asia.

In 1995, a team of researchers from the University of Hawaii, the Hawaii Agricultural Research Center (HARC) and the three big growers launched a coordinated effort to build a better pineapple. Armed with a wide variety of expertise in plant physiology, virology, entomology and molecular biology, among other disciplines, the group has worked to create a pineapple cultivar that will resist nematodes, mealybug-associated wilt virus and spontaneous flowering, the three scourges of Hawaii’s pineapple industry. Over the past four years, the group has received $1.1 million in federal funding.

The high-tech attack could level the playing field and make the state’s $100-million pineapple industry competitive with lower-cost international competitors. “It could be huge for the industry. The areas they are working on are very costly and risky to deal with,” says Doug Schenk, president of Maui Land & Pineapple and the Pineapple Growers Association of Hawaii. At stake are roughly 1,300 jobs and decades of pride.

Hawaii pineapple growers bear some costs unique to the Islands. Nematodes – tiny worms that attach themselves to the roots of pineapple plants and ruin them – are Hawaii’s worst pineapple problem. However, nematodes are not a pineapple problem in Costa Rica, Hawaii’s top competitor for branded fresh pineapple. Schenk says Hawaii growers must spend several hundred dollars per acre to fumigate their fields against nematodes. Even that option will disappear when a ban on the preferred pineapple chemical fumigant proscribes its use in the United States and abroad starting in 2006.

To fight the nematode, the research group decided to focus on a protein naturally produced in pineapple and rice plants, among others, that gums up the digestive tract of the worm and prevents it from reproducing. The protein does not occur in sufficient quantities in pineapple root to do this, but the team figured if it could increase the concentration in the roots a nematode-resistant pineapple might result. David Christopher, a molecular biologist with the University of Hawaii’s College of Tropical Agriculture and Human Resources (CTAHR), found the gene on the pineapple genome that governs root development.

Then researchers at HARC inserted the gene sequence responsible for anti-nematode protein in rice into the pineapple root development gene. The HARC and UH researchers are waiting for U.S. Department of Agriculture approval to start field tests with the transgenic pineapples. Christopher is also examining how he might be able to augment protein production by manipulating the pineapple’s own genes, a course that might raise less controversy than inserting genes from other plants.

Any genetic manipulation will likely raise vehement protests. But according to Christopher, who says genetically tested crops are very rigorously tested by the U.S. Food and Drug Administration, “It would eliminate a lot of pesticides from our environment and make it much safer to grow pineapple here.” An added bonus is that the same protein might be commercially useful in the enzymatic processing of protein-rich drinks or possibly even as a blood-coagulation promoter, says Christopher. Growing it in pineapple could prove a viable way to achieve mass production.

Pineapples that flower spontaneously represent another big problem. Although growers spray a hormone to induce flowering uniformly across a field, sometimes a percentage of those pineapples bloom and subsequently ripen out of synch with the others. Thus, they can’t be harvested with the rest of the crop. This costs money in lost pineapples or increased labor to harvest the rogue pineapples. Robert Paull, chair of the Department of Tropical Plant and Soil Sciences at CTAHR, is looking at ways to alter pineapple genes to suppress spontaneous flowering, while leaving the plant open to induced flowering from the spray. Paull is also looking at ways to make spray-induced flowering more uniform.

UH researchers are also tackling mealybugs. The insects feed on pineapple plants. They also transmit a virus. The two problems together cause pineapple plants to wilt and sometimes die. Mealybug wilt is a serious problem for pineapple growers worldwide. However, spraying to stop mealybugs is costly and environmentally undesirable. That’s where CTAHR plant virology expert John Hu comes in. Hu, who is also studying how to stop the banana bunchy-top virus, hopes to develop transgenic pineapple plants that resist mealybug wilt. This would be part of an integrated pest-management strategy to minimize pest damage and limit spraying pesticides.

Unlike past pineapple research, which has ended up benefiting Costa Rica as much as Hawaii, these efforts will be hard to replicate elsewhere, according to Paull. He says, “Much of what is developed here is designed for Hawaii and would require considerable research to apply elsewhere. The research means that the industry has the best technology possible to utilize in their production.”

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