Crop physiology is concerned with the processes and functions of the crops at cellular, sub-cellular and whole plant levels in response to environmental variables and growth. In short, physiology is the study of functional aspects of crop plants. This book is published for the purpose of competitive examination preparation like JRF, SRF, M.Sc. and Ph.D. Entrance and ICAR examination.This Book contains five chapters starting from plant water relations, Nutrio physiology, Carbon fixation, Growth Physiology and Stress physiology.