Rent of joint property

The share is to be decided by both of you. If it is not mentioned in figures in sale deed it may be deemed as equal i.e.50%.

The one that pays Loan/EMI may have tax benefit on loan.

The share of rent income could be according to % of ownership……………………..and/or as decided amongst owners.

Discuss with your own counsel specializing in Tax matters/CA at your own location.

You have three options

One_-- file return of income of your wife disclosing income of rent.  Since she is house wife then tax liability is nil.  You also file return showing your regular income only.  But deduction u/s 24 and deduction u/s 80C is not allowable to you. 

Two_- You can file your return showing income from regular source plus full rental income fully and claim deduction u/s 24 for payemnt of interest on borrowed capital.  you can also claim dedcution u/s 80C for repalyemnt of principal of house loan.  No need to file retun of wife, 

three_- You can divide the rent equally same and disclose each portion of rental income along with regular income.  Since EMI is paid by you, only you can claim deduction u/s 24 and deduction u/s 80C.  Your wife can not claim the same in her income.

Finally logic is that income from rent should come to tax net. 

                                 It is beneficial to you if option three choose.