Abstract
Inter simple sequence repeats (ISSR) analysis was used to determine the genetic diversity among 15 genotypes of sorghum [Sorghum bicolor (L.) Moench] growing in some parts of Saudi Arabia and Yemen. A total of 92 alleles were amplified, with an average of 13 ISSR alleles per primer. Cluster analysis divided the 15 genotypes into two main groups. Group A consisted of five genotypes with white grains from Jazan and Abha with a similarity coefficient range of 0.527 to 0.818. Group B was comprised of 10 genotypes; two genotypes from Al-Qassim were clearly delimited from the remaining eight samples with a coefficient range from 0.709 to 0.490. The eight genotypes were divided into two clusters; one was comprised of landraces with dark grains from Abha in Saudi Arabia and Ab in Yemen, with a similarity coefficient range between 0.563 and 0.781, and the other cluster was differentiated into three white-colored-grain genotypes and one colored-grain genotype; all samples from North Yemen had a similarity coefficient range from 0.454 to 0.800. The current results encourage further collection and authentication of sorghum landraces in the gene banks of Saudi Arabia.