Grower members and their respective alternates for each district shall be selected by the Secretary from nominees elected by the growers in such district. Handler members and their respective alternates for each district shall be selected by the Secretary from nominees elected by the handlers in such district. Processor members and their respective alternates shall be selected by the Secretary from nominees elected by the processors. Public members for each committee shall be nominated by the Fresh Pear Committee and the Processed Pear Committee, each independently, and selected by the Secretary. The Fresh Pear Committee and the Processed Pear Committee may, each independently, prescribe such additional qualifications, administrative rules and procedures for selection for each candidate as it deems necessary and as the Secretary approves.