India won't be able to contribute anything to the program as most of the development is already completed, but India could purchase a significant amount. If you include the Air force along with the Navy India could have the largest F-35 fleet outside the US. But then again maintaining 3 5-Gen fighters is going to be a nightmare (assuming the AMCA works out). India's Navy is going to need a 5-gen fighter as PAK-FA is way to big for Indian Carriers at this point.
Frankly i dont see IAF ordering F35 , unless AMCA is delayed beyond 2030 and IAF decides that it would need another aircraft to replace 110 odd Mirage 2000 and Jaguar Darin III which will stay in service till 2030
IAF Su30MKI will begin retiring in 2035 , While mmrca will remain in service till 2050
While India has projected a requirement of 500 Fifth Gen Fighters
Out of which 250-300 will comprise of PAKFA/FGFA ,rest could be AMCA or F35A if AMCA is delayed
I can only see navy acquiring F35C in near future
that too becoz it will be last naval fighter purchase for atleast 20 yrs
However Naval order is not expected to be more than 40-50 Aircraft , with deliveries beginning by 2018
Navy could place a follow on order however it will depend on whether or not GOI approves the IAC3
Thats coz govt has till now only approved 3 AC comprising Vikramaditya , Vikrant , IAC2