Any female can become a mother plant, no matter how old. She can be grown from seed or be a clone of a clone. The important thing to remember when taking clones from a mother is never to let the mother bloom and then revert back to vegetative growth. Clones taken from a rejuvenated female tend to be less potent and weaker.
Several mother plants that are always kept in vegetative stage are a good source of cloning stock. Strong mothers produce strong healthy clones. Start new mothers from seed every year. Clones have a better chance of being strong and healthy when mothers are not stressed.

Mother plants must have at least eighteen hour days to retain a strong and accurate set of genetic characteristics. Each time a mother is forced from vegetative growth to flowering and back again, her genetic integrity diminishes. An easy analogy would be to make a photocopy of an original page and then photocopy the photocopy. The original is always more clear. By the time the photocopy is photocopied twice in a row, it is a totally different document. (I hope that makes sense) Degradation takes place over years through stress and through the stress of flowing and rejuvenation, which causes plants to loose their integrity. Mothers that are forced to flower and revert back to vegetative growth, not only yield less, they are stressed and confused.