In this Lexicon attempt has been made to collect and produce a compact source of readily available and upto date information for unider-graduate and post-graduate students and scientists in plant science. This Lexicon deals with technical terms, definitions, techniques and annexures with Hall of fame, Multinational companies involved in Agri business, Cultivated economic species with recent botanical classification. We hope that the students, teachers, researchers and all of those interested in breeding at Molecular level will be benefitted by many of the terms commonly encountered in the subject and allied fields defined in this book and that it will encourage the development of a vocabulary which will aid them in pursuing further studies in the fascinating science. This lexicon contains about 5000 defintions and terms from Plant breeding, Genetics, Biotechnology, Biochemistry, Cell biology, Tissue culture, Molecular biology, Microbiology, Horticulture, Pathology, Entomology, Sericulture and Forestry. The relative terms which are coming under a common subject are cross referenced then and there, with due indication so that comparatively the meaninings could be understood. This can provide the reader with an insight into similarities and differences between closely related terms.