Whose income in case of death of assesee

I want to know when an assessee dies and proprietorship bus is taken by his wife, and we are filing two return for the period from begining of FY to the death of assessee and from the date of assets & liabilities taken over by his wife to closing of F.Y what will be the treatment of income gained for the period begining of FY to the death of assessee. Where it will be taxable?