From which branches do PSUs usually recruit and what is the eligibility criteria of PSUs ?

PSU's recruit from all branches. as far as the eligilbility criteria is concerned, it differes from company to company. for eg, few companies may prefer toppers, while few have age as a criteria. You may want to visit the website of your preferred PSUs to look at their recruitment details.

The PSUs are generally recruiting for your areas of specialisation, namely marketing finance and also for support and analytical functions. A first class with an age bar of 27 for general candidates is usually the criteria