It has been rumoured for a while now that Tizen and Bada will merge. Well it looks like that bubble has now been popped as Hong Won-pyo, the president of Samsung's Media Solutions Center, says that:
Bada is not fit for today's modern smartphones and as a result Tizen will no longer merge with bada, but will merely "absorb" its best features.
Samsung plans to release a number of Tizen devices this year and as that begin, it will also mark the end of Bada. Technically Tizen smartphones will be able to run Bada applications but the reverse will not be true. Also there are lots of existing Bada users that would like to upgrade to Tizen but this upgrade path will not be provided.
Source The Verge