The pear tree is a species of the genus Pyrus L. in the family Rosaceae, bearing the pomaceous fruit. Several species of pear are valued for their edible fruit and juices while others are cultivated as trees. This book discusses the utilization of biochemical and molecular approaches for characterizing the genetic diversity and phylogenetic relationships of Pyrus L. germplasm in order to provide developed technologies for crop improvement. This book is of interest to plant geneticists, plant breeders, researchers, and scientists.