CHROMATIN CHARACTERIZATION BY BANDING TECHNIQUES, IN-SITU HYBRIDIZATION, AND NUCLEAR-DNA CONTENT IN CICER L (LEGUMINOSAE)

The karyotypes of three accessions, one each from three annual species of the genus Cicer, namely Cicer arietinum, Cicer reticulatum, and Ci cer echinospermum, were examined and compared using C-banding, the flu orochromes chromomycin A(3), DAPI, and Hoechst 33258, in situ hybridiz ation of the 18S-5.8S-25S and 5S rDNA sequences, and silver staining. The nuclear DNA content of the three species and the amount of heteroc hromatin were also determined. The results suggest an evolutionary pat hway in which C. reticulatum is the ancestral species from which both C. arietinum and C. echinospermum are derived with the loss of one pai r of satellites; subsequently, C. echinospermum further differentiated by the accumulation of chromosomal rearrangement(s) that gave rise to a hybrid sterility barrier.