hi,

see this year for the first time Eligibility criteria to appear for GATE-2021  is relaxed from the minimum 10+2+4 (ongoing) to minimum 10+2+3 (ongoing), so thats why b.sc candidates of three years course were also eligible for gate exam.  however m.sc admission in most of the colleges was based on graduation score or entrance test by the respective university which includes banaras hindu university, jadavpur university, jawharlal nehru university etc. so we do not have any previous years cutoff for m.sc admission based on gate score. since gate 2021 eligibility criteria has changed, their might possibility that the universities  would have include release  some provision of admission related with gate score. so just check for the colleges website which offers m.sc course. In case you are interested for integrated phd you may apply for iiser, indian association of cultivation science etc.