The regular term of office of each producer member shall be three (3) years. The first commission members shall be appointed by the governor, and their terms shall terminate as follows:
(1) District I, IV & VII on July 1, 1970;
(2) District II, V & VIII on July 1, 1971;
(3) District III, VI & IX on July 1, 1972.
All other commission members shall be elected as provided in section 25-3107 and their respective terms shall end on July first of each third year thereafter.
Any vacancies that occur on the commission shall be filled by appointment by the other members of the commission, and such appointee shall hold office for the remainder of the term for which he is appointed.