ROME, Oct 14 (Reuters) - Italy"s Treasury is considering extending by six months tax breaks for corporate mergers it first introduced to entice a buyer for troubled state-owned bank Monte dei Paschi di Siena (MPS) (BMPS.MI), two sources close to the matter said. The scheme applies to all companies but it benefits mostly banks and it is a key plank of an incentive package the Treasury has tabled to sell MPS to stronger rival UniCredit (CRDI.MI).