This text is divided into four parts. The first part discusses Mendellian genetics, covering: the basic principles of Genetics-Mendel's laws; linkage and crossing over; chromosome mapping; sex linked inheritance; sex determination; population genetics; and extrachromosomal inheritance and human genetics. The chapters of the first part all include problems with examples of solutions. The second part deals with molecular genetics which includes modern discoveries on DNA and gene action, and it discusses topics such as: the structure of DNA; replication of DNA; protein synthesis; RNA structure; genetic code; fine structure of gene; microbial genetics; mutations; gene regulation; molecular genetics; and genetic engineering. The third part covers cytogenics, discussing such topics as: cell cycle; mitosis and meiosis; structure of eukaryotic chromosome; polypoidy; and chromosomal abnormalities. The fourth section discusses techniques and applications of plant breeding, covering such topics as: mutation; breeding; polypoidy; male sterility; self incompatibility; heterosis; plant introduction; and selection in plant breeding.