Hi Umesh,
I am not sure what do you mean with "feed Open POs, PRs, stock on hand , Stock in transit and Production Plan in ECC".
In ECC you can create Production Orders and Requisitions manually. You can also make stock movements, but this will generate an accounting posting.
In general, APO is only used for planning. Execution is commonly done in ECC. So in APO you could create orders, but stock movements will be done in ECC.
Kind Regards,
Mariano