Karyotype Analysis in Fourteen Species and Varieties of the Genus Bromus L. (Poaceae)

抄録

Karyotypic analyses were performed in twenty populations of fourteen Bromus species and varieties from three sections of Bromus L., Genea Dum., and Pnigma Dumort., growing in Iran for the first time. The chromosome numbers of B. stenostachyus, B. tomentosus and B. kopetdaghensis are new and new polyploidy level has been reported for B. cappadocicus, B. erectus, B. variegatus and B. tomentosus. The ANOVA and LSD tests revealed a significant differences (p<0.01) in the size of chromosomes as well as chromosome arms among the populations of each species, among species with similar somatic chromosome numbers in each section and also among the three sections studied, indicting the role of the chromatin change in the species diversification in the genus Bromus. PCA analysis showed that the mean chromatin length of the chromosomes is one of the most variable karyotypic features among the Bromus species studied. Pearson correlation determined among the karyotypic features showed that the increase in the mean chromatin length has been accompanied with an increase in the size of both short and long arms of the chromosomes. The increase in the mean chromatin length showed a significant correlation with the TF percentage therefore increasing the level of karyotype symmetry.