The term of office of all members of the commission, except any ex officio member, shall be two years from the date of their election and until their successors are qualified. However, of the first members of the commission, one-half of the producers or grower-handlers and shippers shall serve for one year, and one-half of the producers or grower-handlers and shippers shall serve for two years, with the determination of term of each such member to be made by lot at the time of election. Terms of office of each commissioner shall be limited to four consecutive terms, except that any member selected for a one-year term may serve not more than five consecutive terms.