The present Plant Biology and Biotechnology Department with a Post graduate and Research Centre had its beginning in 1927 with an intermediate Botany programme. Botany has been offered as an Ancillary subject since 1960. Later, in 1970 the Department started offering B.Sc. Botany and in 1983 the PG programme was started.
By the concerted efforts of the teachers from the period of its establishment the Department has grown to the present status and it was upgraded as a Research Department in 1993. Since then several major and minor research projects supported by agencies such as UGC, DOEn, DBT, DST, CISR, TNSCST have been completed. 31 scholars have completed their Ph.D., from the Department. At present seven members of the Dept are guiding a number of Ph.D. scholars.
The Department of Science & Technology of the Govt. of India has chosen this Department as one of the centers for "Fund of improvement of Science and Technology Infrastructure in University and Higher Education Institutes" (FIST). The contributions of this Department played a role in getting for St.Xavier's the "College with Potential for Excellence status" to the college. It has become a fully fledged research centre to offer research programs in any area of Plant Science.
The Department under its new nomenclature as approved by the Government of Tamil Nadu has been offering the choice based credit system at the UG and PG levels since 2002. The UG programme has been vocationalized with the financial assistance of UGC.
Apart from the core curriculum the Department also offers a number of extra-Departmental courses such as Photomicrography, Food Technology, Mushrooom Cultivation, Bioethics, Ecotourism and Forest Resource Management, Etc.,