Every person, firm, association, or corporation subject to the provisions of sections 81-2,149 to 81-2,154 shall observe, perform, and comply with all rules, regulations, and requirements fixed, established, or specified by the University of Nebraska Institute of Agriculture and Natural Resources as to what crops grown or to be grown in Nebraska shall be eligible for certification, either by the institute directly or by agents or agencies authorized by it for the purpose, and as to standards, requirements, and forms of and for certification under such sections, except that not more than one such agent or agency for certification shall be designated for any one specified crop. No certification, within the provisions of such sections, shall be made or authorized except by or through the institute.