In this book, attempts have been made to give simple, concise and updated information about the aspects relevant to agricultural sciences. The main objective of this book is to help the reader to quickly grasp the facts comprehensively and systematically from various branches of agriculture. The text in 23rd edition of the book has been made more comprehensive, updated and thoroughly revised, duly incorporating the latest findings, data and technologies. We believe that this book will also be useful for fellow teachers, researchers, development officers for references and easy answering of many complicated questions. The book has been designed particularly for the aspirants of various competitive examinations like NTA AIEEA-ICAR-JRF/NTS(PGs), Senior Research Fellowship (SRF), NTA ICAR-National Eligibility Test (NTA ICAR- NET) & Agricultural Research Services (ARS) and will also be useful to seek admission in Ph.D. through entrance examinations of SAU's, various institutions and get through screening tests conducted by various states for jobs in Agricultural Sciences, Civil Services, Agricultural Officers, Bank P.O. (Agriculture), ADO and allied agricultural examinations.