Hello Aspirant,

There are different books which you can study for your theory as well as practicals and all of them are good.  Just choose the book with which you are comfortable. I am providing a drop down list for all the essential books:

1. Principles of Biochemistry by Lehninger
2. Textbook of Botany by Singh, Pande, Jain
3. Taxonomy of Angiosperms by Singh, Pande, Jain
4. Ecology and Environment by P.D.Sharma
5. Embryology of Angiosperms by Maheshwari
6. Plant Physiology by Taiz and Zeiger
7. Molecular Biology of the Gene by Watson

All the best!