The value of seed crops in Hawaii managed a slight rise to a record this past season, according to a new government report, though the industry appears to have plateaued after rapid growth over much of the past decade.

The National Agricultural Statistics Service estimates that Hawaii’s seed crop industry value rose 1.5 percent last season to a record $243 million from $239.4 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.

The leveling off had been expected as company operations matured after big land acquisitions and farm expansions in recent years.

Seeds — primarily seed corn — have been Hawaii’s "largest" crop by value since overtaking pineapple in 2006, according to the Statistics Service. However, other crops are still bigger in terms of sales and their contribution to the local food supply.

The difference has to do with how the Statistics Service calculates industry value for seeds.

Seed production in Hawaii primarily involves studying plant genes and properties, breeding plants with desired genes both traditionally and using biotechnology, testing the resulting plants and growing large quantities of favorable plants to produce parent seed. The parent seed is sent to the mainland for mass reproduction and sale to farmers.

Because the seeds produced in Hawaii aren’t sold, the Statistics Service, which is a unit of the U.S. Department of Agriculture, calculates industry value based on operating expenses excluding land purchases.

The seed industry has attracted criticism for its work genetically modifying plants, but is supported by many in the agriculture industry for keeping farmland in farming and being a major employer in the sector.

Seed companies like Hawaii because of its relative isolation and because corn can be planted and raised to maturity three or four times in one year compared with only once on the mainland, thereby allowing faster advancement of research.

Hawaii seed crops are grown year-round, though the main season is from November to June. The recent report covers the 2011-12 season.

Five seed companies — BASF, Dow AgroSciences, Monsanto, Pioneer Hi-Bred International and Syngenta — have seed farm operations in the state. They operated 10 farms using about 5,600 acres last season, which was down from 6,200 acres the year before.

The report said the farms shipped 12.5 million pounds of seeds last season, up from 10.2 million pounds the season before.

Spending on seed corn was flat at $230 million in each of the past two seasons, the report said. The industry gain in value was from spending on other types of seed crops that totaled $13 million last season compared with $9.5 million the season before.

Other types of seeds grown in Hawaii include soybean, wheat, sunflower, rice, rapeseed and sorghum.