Chris Brown -- Back Off Groupies ... My Bus Is a No Ratchet Zone

Attention all Texas THOTS ... Chris Brown's got no room or time for you on his tour bus, because he's got baby Royalty on board, and that means some strict new rules for his homies.

Chris picked up his baby girl in Houston, and they're currently taking a 10+ hour ride to El Paso -- and our CB sources tell us Daddy is keeping things PG, telling his crew there will be:

- NO cursing
- NO smoking
- NO drinking
- and most importantly ... NO GROUPIES

It's not all bad ... we're told Chris is entertaining everyone with a Disney marathon of DVDs. Highlights include ... "Frozen," "Mickey Mouse Clubhouse," and the classic ... "Bebe's Kids."

One more thing -- we're told when Royalty naps ... it's lights out for everybody.

Someone's seriously wrapped around someone's little finger.