The board shall consist of the State Commissioner of Agriculture and Commerce, who shall be a member and ex officio chairman thereof, and four other members to be appointed by the Governor, one of whom shall be from each highway commissioner’s district and the fourth member from the state at large, all of whom shall be qualified electors of the State of Mississippi, one of whom shall be a wholesale groceryman dealing in fruits and vegetables, one a retail groceryman dealing in fruits and vegetables, one a farmer growing fruits and/or vegetables, and one a farmer producing poultry and eggs. In making the first appointments, the term of office of the farmer producing poultry and eggs shall be appointed for one year, the retail groceryman dealing in fruits and vegetables shall be appointed for two years, the farmer growing fruits and/or vegetables shall be appointed for three years, and the wholesale groceryman dealing in fruits and vegetables shall be for four years, and each of the successors shall thereafter be appointed for a term of four years. Vacancies on the board shall be filled by the Governor for the unexpired term.