Hi Ganga,
Sorry for the confusion, actually the proposed solution is for lookup main and for tuple field.
You can achieve this by using keyword search, you may be noticed there is field available that is keyword where you can give the values of those fields whose keyword is "Stemmer".
So choose stemmer for the lookup field in the main table and copy the lookup field value and paste in the keyord field of free form serach after this you will be getting the relevant result.
For more information refer Data Manger Refrence Guide.
Regards
Rahul