The two have absolutely nothing at all to do with one another.

You do not need a codeshare to sell flights. You do not need a codeshare to sell through fares. You do not need a codeshare to set pricing in conjunction with another airline -- although it's possible that such an arrangement would need approval from Indian anti-trust regulators if it included Indian cities; I don't know Indian anti-trust law.

While it is natural to codeshare on JV routes, it is not a prerequisite to having a JV, and it would be trivial to design a JV in a world without codeshares.