Spending by seed crop companies in Hawaii has continued to grow, albeit at a slower pace, in recent years, but the number of jobs in the single biggest sector of local agriculture has declined.

That’s one of the conclusions in a new economic impact study on the industry commissioned by the Hawaii Farm Bureau Federation.

The report also said seed companies in Hawaii forecast spending $250 million over the next 10 years, down from $423 million over the past 10 years.

Thomas Loudat, a local economist, and Prahlad Kasturi, an economics professor at Radford University in Virginia, authored the study, which updates a similar report issued in 2009. The study was paid for by the Hawaii Crop Improvement Association, a trade group representing seed companies.

Much of the study is based on data collected by the U.S. Department of Agriculture’s National Agricultural Statistics Service, which in November reported that the value of Hawaii’s seed crop industry rose 1.5 percent last season to a record $243 million from $239 million the season before.

Last season’s gain was the second year of near-flat growth after what had been annual increases of roughly between 20 percent and 40 percent for most of the prior decade.

Even with overall industry spending staying positive, the number of jobs has decreased. The report said 1,397 people were employed in the industry, down from 1,863 counted in the 2009 report.

The industry includes 10 farms on Oahu, Kauai, Molokai and Maui cultivating primarily seed corn but also soybean, wheat, sunflower, rice, rapeseed and sorghum on about 5,600 acres last season, which was down from 6,200 acres the year before.

Five seed companies — BASF, Dow AgroSciences, Monsanto, DuPont Pioneer and Syngenta — have seed farm operations in the state and are members of the industry association.

Seed growers in Hawaii generally study plant genes and properties, breed plants with desired genes both traditionally and using genetic engineering, test the resulting plants and then grow large quantities of favorable plants to produce parent seed. The parent seed is sent to the mainland for mass reproduction and sale to farmers worldwide.

Because the seeds produced in Hawaii aren’t sold, the Statistics Service calculates industry value based on operating expenses excluding land purchases. That compares with crop sales for other crops.

The genetic engineering aspect of the industry — which is used to manage resistance to pests, drought, disease and herbicides, among other things — does attract criticism and opposition.

The state Legislature heard a bill this year that proposes requiring public hearings and a permit to develop a new species of genetically engineered organism.

"Monsanto has been banned in numerous countries around the world because their biotech products and pesticide use is a menace to all life," wrote Carl York in testimony supporting the bill. "They should not be allowed to operate on the planet, definitely not in Hawaii with its unique climate and amazing diversity."

The bill, House Bill 97, stalled.

The seed industry association has invited mainland farmers to share personal stories with local government and community leaders about positive values of genetically engineered crops.

"Unfortunately, attempts by anti-GMO activists, with philosophical and religious opposition to science-based industries, are creating a hostile climate for the future of agriculture in our state and putting Hawaii’s seed industry and all its benefits in jeopardy," the association said in a brochure promoting the effort.

The study said seed growers play an integral part in sustaining agriculture in Hawaii, where a little more than 20 years ago farming contributed 2 percent of the state gross product but in recent years fell to less than 1 percent even as the seed industry grew rapidly.

"While seed crop industry growth and job creation may be leveling as the industry matures, it yet remains the most significant contributor as an individual crop to the agricultural sector of Hawaii," the report said. "The Hawaii seed industry has mitigated the downward trend of agriculture as a contributor to Hawaii economic activity maintaining this source of statewide as well as per county economic diversification."

The report noted that seed industry jobs pay 36 percent higher on average than Hawaii farm labor jobs and 11 percent higher than the state average for all jobs.

The industry also is a significant contributor to taxes. The study said companies linked to seed growers in Hawaii paid $29.4 million in state taxes, which was more than double the $13.8 million reported in the 2009 study.

The study said that including indirect and induced economic benefits — such as revenue received by a restaurant patronized by a seed company worker — the industry produces a ripple effect of about $286 million on top of about $264 million in direct spending including land purchases, for a total of $551 million.