B chromosomes of Secale cereale L. and S. montanum Guss. from Turkey.

To investigate the cytological variation of the species of the genus Secale in eastern Turkey, said to be one of the most probable places for the origin of cultivated rye, we determined the frequency and cytogenetical characteristics of B chromosomes (Bs) of the two species, S. cereale L. and its wild related S. mantanum GUSS., from Turkey. Cytological observation was carried out on 15 Turkish populations (a total of 861 individuals) of S. celleale. Two Turkish populations had plants with two Bs, but the other populations had no plants with Bs. The frequency of plants with Bs varied from 0% to 2.2%. Therefore, we concluded that the Bs frequency in Turkey is low. The Bs detected in this study did not pair with autosomes (As). They were considered to undergo the directed nondisjunction at the first pollen mitosis and the first embryo-sac mitosis, and to be the standard type for their morphology, which are features common to cereale's Bs from various regions of the world. This supports the monophyletic origin of cereale's Bs. Furthermore, no plants with Bs were found among the four Turkish populations (a total of 45 individuals) in S. montanum cytologically analyzed.