Recommended books for Paper I of UPSC Botany Optional subject

1. Cell Biology and Genetics:
- Molecular Biology of the Cell by Bruce Alberts, Alexander Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, and Peter Walter.
- Cell and Molecular Biology by Gerald Karp.

2. Plant Anatomy:
- Plant Anatomy by B.P. Pandey.
- Plant Anatomy by Katherine Esau.

3. Plant Embryology and Reproduction Biology:
- Plant Embryology by B.M. Johri.
- Plant Reproduction by S.K. Jain.

4. Plant Physiology:
- Plant Physiology by Lincoln Taiz and Eduardo Zeiger.
- Plant Physiology by Frank B. Salisbury and Cleon Ross.

5. Plant Systematics:
- Plant Systematics: A Phylogenetic Approach by Walter S. Judd, Christopher S. Campbell, Elizabeth A. Kellogg, and Peter F. Stevens.
- Plant Taxonomy by O.P. Sharma.

6. Plant Breeding and Economic Botany:
- Plant Breeding: Principles and Methods by B.D. Singh.
- Economic Botany by S.L. Kochhar.

7. Ecology and Plant Geography:
- Ecology by Eugene P. Odum.
- Ecology and Environment by P.D. Sharma.

8. Biotechnology:
- Biotechnology: Expanding Horizons by B.D. Singh.
- Introduction to Biotechnology by William J. Thieman and Michael A. Palladino.

9. Plant Pathology:
- Plant Pathology by George N. Agrios.
- Introduction to Plant Pathology by P.D. Sharma.

10. Genetics and Plant Breeding:
- Genetics by Benjamin A. Pierce.
- Principles of Plant Breeding by B.D. Singh.

These books cover the major topics of Paper I of the UPSC Botany Optional subject. It is advisable to refer to multiple books for a comprehensive understanding of the subject. Additionally, candidates should also refer to previous year question papers and study materials provided by coaching institutes to get a better idea of the exam pattern and to practice solving questions.