Go to R3AC3 TCode and Enhance the "MATERIAL" Adaptor object Tables/Structures within object tab with Tables MARC and MARC_KEY tables and save. then Download the "MATERIAL" Again then go to COMMPR01 go to Relationships and you will find the Location Tab open it you can see the Plants which are assigned to the Material.
Note : before Downloading the MATERIAL you should Download "DNL_PLANT" First.
Thanks and Regards,
Arun