Cytogenetics of Sorghum

Abstract

Sorghum is an interesting genus having a large number of well-recognized species taxonomically classified into five subgenera. Cytogenetic analysis led to the understanding of the nature of chromosomal variations, origins, and probable relationships based on chromosome morphology. Progress in the science of conventional and molecular cytogenetics, and genomic research provide a detailed insight into the genome organization of an individual or species, leading to enhanced utilization of genetic and physical information towards improvement of the crop. The integration of genetic, physical, and cytomolecular maps of the Sorghum genus is useful to scientists working on genomics of grass species. Large-scale molecular karyotyping of grass genomes would facilitate alignment of related chromosomal regions among different grass species and also facilitate genetic and cytogenetic studies of chromosome organization and evolution. As compared to other crop species little is known about the karyomorphology in sorghum mainly due to the small size of its chromosomes. In this chapter efforts have been made to collate the scattered information on karyotype studies, cytotaxonomy, phylogenic relation, numerical and structural variations, genome architecture, and wide introgression in sorghum. Implications of the information on sorghum improvement are discussed.