We have a Basset too!
My opinion is, so long as the Basset is not with the Yorkies when it is time for them to breed, I wouldn't think that it would deter them from 'being interested.'
If you suspect your female is coming into heat, then I would try to keep them separated as much as possible. But not just from the Basset, from each other as well. They should only be allowed to tie under your close, watchful eye. I have to actually hold my female in place during the tie because she wants to either take off, or turn on the male. You don't want either of them to be injured during the process.