The chief minister is appointed by the governor. The other ministers are appointed by the governor on the advice of the chief minister. This means that the governor can appoint only those persons as ministers who are recommended by the chief minister.
But, there should be a tribal welfare minister in Chhattisgarh, Jharkhand, Madhya Pradesh and Odisha. Originally, this provision was applicable to Bihar, Madhya Pradesh and Odisha. The 94th Amendment Act of 2006 freed Bihar from the obligation of having a tribal welfare minister as there are no Scheduled Areas in Bihar now and the fraction of population of the Scheduled Tribes is very small. The same Amendment also extended the above provision to the newly formed states of Chhattisgarh and Jharkhand.
Usually, the members of the state legislature, either the legislative assembly or the legislative council, are appointed as ministers. A person who is not a member of either House of the state legislature can also be appointed as a minister. But, within six months, he must become a member (either by election or by nomination) of either House of the state legislature, otherwise, he ceases to be a minister.
A minister who is a member of one House of the state legislature has the right to speak and to take part in the proceedings of the other House. But, he can vote only in the House of which he is a member.