Russell Kokubun, the director of the state Department of Agriculture, is retiring at the end of the year.

Gov. Neil Abercrombie had tapped Kokubun, a former Big Island state senator and Hawaii County Councilman, to lead to the department shortly after the governor was elected in 2010.

“I wish to extend my aloha and appreciation to Chair Kokubun, who has informed me of his decision to retire at the end of the year and return to his family farm in Volcano on Hawaii Island,” Abercrombie said in a statement.

“As a former legislator and farmer, Russell brought a unique perspective to the position and has helped to move Hawaii’s agriculture and sustainability initiatives forward. This has included support for farmers and new farm innovation, promoting locally grown food, and investing in a solid agricultural infrastructure. I wish Russell the very best as he follows his heart home to the Big Island to work the land and provide for his family and community.”

Kokubun is an ally of U.S. Rep. Colleen Hanabusa and will likely help her with her Democratic primary campaign for U.S. Senate, according to sources close to Hanabusa.

Kokubun is not expected to take a paid role with the campaign, but could help with organization on the Big Island, sources say.

Kokubun was state Senate vice president when Hanabusa served as state Senate president.

Hanabusa is challenging U.S. Sen. Brian Schatz in the primary to fill out the rest of the late U.S. Sen. Daniel Inouye’s six-year term, which runs through 2016.

Abercrombie appointed Schatz over Hanabusa to replace Inouye after the senator died last December.