A global corn price decline is behind the four-year contraction of Hawaii’s seed farming industry, according to a report commissioned by the industry’s trade association.

The report from the Hawaii Crop Improvement Association released Monday said a collapse in corn prices reduced farmer demand for corn seeds that in turn curtailed spending on seed research, development and production in Hawaii, where five companies make up the industry.

“The seed industry has scaled down to reflect the reality of corn and other price declines in recent years,” said the report produced by local economist Paul Brewbaker for the trade association. “Hawaii’s five modern seed industry companies are now repositioning in the new global commodity pricing reality.”

Much of the report is based on data collected by the U.S. Department of Agriculture, which issued its own report last month that said the value of Hawaii’s seed crop industry ticked up 7 percent to $151 million in the recently ended 2015-16 season from $141 million in the prior season. Still, the recent value remained 38 percent below a $242 million peak in the 2011-12 season.

The USDA report said shipments of seeds produced in Hawaii fell to 7.4 million pounds last season from 8.6 million pounds in the prior season, compared with a record 12 million pounds in the 2009-10 season. But no reason for the decline was given.

Brewbaker’s analysis said corn prices fell from $7 a bushel in 2012 to $3.50 a bushel during much of the early part of this year, and that this decline caused Hawaii seed companies to pull back on their work producing new seed varieties for farmers.

“Falling global demand for these and other global commodities as inputs — from bio-fuels in energy production to uses as oils, sugars, and other carbohydrates in food consumption — all reduced corn grain prices and farmers’ demand for corn seed as a use of it,” the report said. “As a result, Hawaii’s corn seed industry has shrunk.”

The report said 97 percent of the seeds produced in Hawaii are corn.

Despite being down almost $100 million, seeds still rank as Hawaii’s biggest crop.

Other top crops include sugar cane, at about $70 million to $80 million in annual sales; coffee and ranching, at about $50 million each a year; and macadamia nuts, at about $40 million a year. Pineapple also remains big, but industry value is no longer reported to avoid disclosing sales revenue of individual private companies.

Seeds have been Hawaii’s most valuable crop since 2006, based on USDA estimates that value seed crops using the cost of production because the companies that grow seeds here produce plants with desired traits, often using genetic manipulation, and send the seeds to the mainland for mass reproduction and sale to farmers.

Brewbaker’s report said Hawaii’s five seed companies — BASF, Dow AgroSciences, DuPont Pioneer, Monsanto and Syngenta — contribute $323 million to the local economy when factoring in jobs and spending that are supported by the companies, which operate 10 farms on Oahu, Maui, Molokai and Kauai.

This contribution breaks down to $116 million for Oahu, $105 million on Kauai and $102 million on Maui and Molokai, the report said. The industry also supported $15.7 million in state tax revenue, the report added.

One hard-to-explain item in the report involves how many workers the industry employs. The report said the five companies directly employ about 1,800 workers, including 1,102 full-time and 734 part-time or seasonal workers. A similar report in 2013 produced by Thomas Loudat, a local economist, and Prahlad Kasturi, an economics professor at Radford University in Virginia, said 1,397 people then worked in Hawaii’s seed industry. This suggests that employment rose as industry spending fell dramatically.

Brewbaker said this topic should be explored more, but that it could have to do with a possible shift in where the industry directed spending in recent years. His report said 55 percent of industry spending was on research and development while the other 45 percent was for reproducing seeds for export.

Brewbaker said it is hard to tell where Hawaii’s seed industry may be headed. One upcoming change could be the sale of Syngenta’s Hawaii operations. The company announced last month a plan to sell all its Hawaii assets.

Syngenta, which has 105 full-time employees and an unspecified number of seasonal and part-time workers, said it wants to continue procuring seeds here from a buyer as part of a sale targeted for completion by June.