There shall be an adjutant general who shall be appointed by the governor and shall hold office during the pleasure of the governor and his commission shall expire with the term of the governor appointing him. The adjutant general shall be the commanding general of the military forces of the state and in addition to the duties delegated to him by law, he shall perform such other duties as prescribed by the governor as commander-in-chief. The adjutant general shall be commissioned in the national guard with the rank of not less than brigadier general. No person is eligible for appointment as adjutant general unless he is a federally recognized member of the national guard with current service of not less than six (6) years as a commissioned officer in the national guard of Idaho and has attained the rank of colonel or above.