The treatise is dedicated to one of the most important areas of modern biology i.e. plant molecular genetics. The science of genetics born to an Austrian monk Gregor Johann Mendel in the spring of 1865 was immediately consigned to the deep freeze for the next 35 years. It was rediscovered in 1900 by three scientists working independently. Since then the growth of the subject in terms of information generation has been phenomenal. The present book provides detailed information regarding the process of developing plants resistant to insect-pests, viruses, herbicides and cold stress using the modern techniques of genetics. It also discusses at length about heat-shock protein genes, defense response genes and photosynthetic genes of plants. The use of apomixis in crop genetic improvement has been thoroughly presented. The treatise has been prepared in simple language for easy understanding of the students, the complicated topics of plant molecular genetics. It would be of great interest to a very large group of readers undergraduate and postgraduate students of genetics, plant biotechnology, plant molecular biology, professional plant breeders and geneticists, research workers and candidates taking competitive examinations like NET, ARS and Civil services Examinations.