Pure or applied you can try for teaching job in any field . It is not like if you want to teach biotech then you can't do after it masters . Most of the colleges ask botany as one subject in graduation for master in botany . Feel free to ask further question . Take this example of Kerala university
Bio-Chemistry: BSc with Bio-Chemistry or Chemistry as optional Main subject and any two of the following as subsidiary subjects viz. (i) Mathematics (ii) Physics (iii) Botany and (iv) Zoology under Part III securing not less than 55% marks for that part / BSc Industrial Fish and Fisheries (Vocational) / BSc Biological Techniques and Specimen Preparation (Vocational) / BSc Biochemistry and Industrial Microbiology (restructured). Subject combinations with Bio-Chemistry or Chemistry (Vocational) are also eligible. 25% seats will be reserved for candidates with BSc Biochemistry.
Biotechnology: Bachelor’s Degree with 55% marks in Part III excluding language in Botany, Zoology, Life Sciences, Microbiology, Biochemistry, BSc Agriculture, BE / BTech in Chemical Environment, MBBS, BVSc, BSc MLT, BSc Biotechnology( Voc.), BSc Botany & Biotechnology ( restructured).
Bioinformatics: Graduate in any branch of Life Sciences (Botany, Zoology, Microbiology, Biotechnology, Bioinformatics, Biochemistry, Medicinal Chemistry or any other degree recognized as equivalent by the University of Kerala) with not less than 55% marks in qualifying examination.
Botany: BSc with Botany as optional Main subject under Part III with not less than 55% marks for that part / BSc Clinical Nutrition and Dietetics (Vocational) (If Botany is one of the main subjects)/BSc Industrial Microbiology (Vocational) (If Botany is one of the main subjects) / BSc Biotechnology (Vocational) (If Botany is one of the main subjects) / BSc Botany and Biotechnology (restructured). BSc Vocational course with the subject combinations Biotechnology, Chemistry, Zoology/Botany are also eligible.