The specialized book "Crossability studies in Cajanus cajan (L) Millsp." offers a comprehensive investigation into the interspecific hybridization of Cajanus cajan, also known as Pigeon Pea, with various wild species. The research aims to develop methods for producing interspecific hybrids by expanding genetic diversity through the use of wild relatives. The study analyzes the crossability between two Pigeon Pea cultivars and three wild species, with pollen germination and pollen tube growth serving as key parameters. The results indicate that most crosses exhibit prezygotic barriers, while only one cross shows postzygotic barriers. Additionally, various treatment methods to enhance fertilization are explored, highlighting the need for combined approaches to overcome crossability obstacles. This book is a valuable resource for researchers and practitioners in the fields of plant breeding and genetics.