Use the passport that is valid at the time.
Alexus P. Sham firstname.lastname@example.org (917) 498-9009. The above information is only general in nature and does not constitute legal advice. It does not create an attorney-client relationship.
I agree with my colleagues, you would fill out the form based upon the name listed on the currently valid passport at that time. For interview, your wife should bring both the current and prior passports as well as all other standard evidence required for visa issuance.
This information is provided as a courtesy based upon the limited information provided in your post and does not constitute an attorney-client relationship.
Use the passport you plan to present at the interview for the visa.
The above is intended only as general information, and does not constitute legal advice. You must speak with an attorney to discuss your individual case.