Papayas may not be Hawaii's sole source of genetically modified (GM) produce, but the crop has borne much of the brunt in the public debate on GM foods.

An attack on J and L Papaya Farm in late September destroyed around 100 genetically modified papaya trees on the Big Island, where the great majority of Hawaiian papaya production is located, newspaper Honolulu Civil Beat reported.

The act is reminiscent of earlier attacks targeting GM papayas on the island, including the destruction of 10 acres of the crop in 2011 and the destruction of 8,500 trees the year before.

The most recent attack comes hot on the heels of a controversial debate over GM production in Hawaii. Two bills to restrict biotechnology are currently being debated by local government. One bill would require all GM papaya trees to be cut down and would fine GM growers, according to the newspaper.

In a conversation with www.freshfruitportal.com, University of Hawaii researcher Dr. Richard Manshardt explained how the now controversial, genetically modified Rainbow variety came to prominence and took over the once struggling Hawaiian industry.

Manshardt worked on the development of the variety at a time when Kapoho Solo papaya production in Hawaii tinkered on the verge of collapse as a result of the ringspot virus. The variety, introduced to Hawaii in 1910, was first hit by the pathogenic virus in the 1940s and continued to experience ups and downs until researchers turned to genetic development in the 1990s.

"There were attempts with conventional breeding, trying to find papaya types around the world that were resistant to the virus. While there are some that are tolerant, which means they can get the disease but they can still produce some crop, there is nothing that is really resistant and high quality that can be used for breeding purposes," Manshardt said of earlier attempts to prevent ringspot.

"When I first got here [30 years ago], I tried to cross papaya with wild relatives that had disease resistance from the mountains in the Andes but the crosses were sterile. To make a long-story short, we couldn’t use that approach. Even though we had the virus resistance, they weren't fertile. They were like mules, so we couldn’t breed them."

Around 1987, university researchers began playing with the creation of a genetically modified variety to solve the production barriers that had not yet been addressed through breeding and management alone.

"A lot of things were tried but nothing worked very well, not in an economic sense to try to control this disease. So it’s not something we just cooked up overnight and decided that genetic engineering was the way to go. It was the last in a series of things," he said.

By 1998, the team had the genetically modified Rainbow variety - a target of recent farm attacks - ready for commercialization.

"Growers picked it up very quickly because it worked. The cultivar was a hybrid, an F1 hybrid. It had many of the characteristics of the Kapoho commercial line, the one they had always exported. It was actually a higher yielding variety," he said.

Today, Manshardt said an estimated 75% to 80% of papayas grown in Hawaii are genetically modified. GM options on the islands have also expanded, including varieties like SunUp and Laie Gold.

"There are growers that still grow the old susceptible varieties and the virus is still around. But we can say the inoculum level, the amount of virus, is lower," the researcher said.

Heightened competition

In the meantime, as Hawaii worked to recover its industry, other global players stepped up their game and made competition more difficult.

"After the Rainbow was released, volume did get back up but it never got to the level it was at before ringspot came in. If you take a look at imports into the mainland U.S. over that period from the early 90s to early 2000s, Hawaii imports drop. At the beginning of the decade we had about three quarters of the imports but by the end of the decade we were way down to less than 25%," he said.

During this time, Mexico increased its presence on the U.S. market, as did Belize and Brazil.

"Our real competitors were from Belize and Brazil that exported into the U.S. the same kind of Solo papayas. They just took up the slack that was dropped when the production dropped in Hawaii due to the virus and became a very tough competition situation for Hawaii in the mainland U.S.," he said.

"At the same time, with our exports to Japan, which were very lucrative – growers made much more money selling in Japan – we lost a lot of that market because we weren’t able to supply fruit and also because when the Rainbow was released, Japan didn’t accept genetically engineered fruit."

On the local market, Manshardt said that most have been open to eating GM fruit but that much of the debate has been complicated by the entrance of larger corporate interests dedicated to genetic seed development on the islands.

"It's a volatile issue and papaya hasn't had much to do with that because it wasn't produced through corporate interests. It was through University of Hawaii, Cornell University, USDA," he said, explaining that most GM research is funded privately.

"Almost all GMO is corporate because they have the money. The only public image is papaya because it’s the only publically developed GMO crop. People equate GMO with corporate interests and all that goes on with that.

"It’s a technology with tremendous promise. It’s not going to replace conventional or organic but it’s a tool we should have. We are being denied it [through funding] because of unreasonable fears and special interests."

Among the noise of GM debate, Manshardt encouraged co-existence by allowing the farmer to choose which production option is most appropriate.

"The grower organizations, people actually doing the farming and universities, they all espouse co-existence. There are all of these different ways of growing things: organic, GMO, conventional. They can all co-exist."

Photo: Rainbow papaya by Hawaii Grown Papayas

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