Prof. S. Venkat Ratnam had his basic training in Plant Cytogenetics. Later he had advanced training in plant Biosystematics under the supervision of Prof. V H Heywood (DSc), DM Moore (PhD) and Prof. JB Harborne (FRS) . He submitted his thesis on “Experimental Taxonomy of section Iris of old world” and published several research papers on various aspects. He obtained his PhD on Experimental Taxonomy (Biosystematics) of section Iris . He had been teaching Plant Biosystematics to MSc student as an elective course. He is also the author and editor of six botany books and co-author of plant taxonomy book along with three other authors. He guided many MPhil and PhD students. He has been supervising many students in Plant Ecology, Plant Cytogenetic and Biosystematics for their Doctoral degrees