[Cytogenetic monitoring of the Usmansky and Hrenovskoy autochtonic pine stands].

The data on the cytogenetic monitoring of the Usmansky and Khrenovskoy autochthonic pine stands (Voronezh Region) allow their status to be rated satisfactory. The indices of the mitotic and nucleolar activity as well as of abnormal mitosis were within the normal variation range for Scotch pine. However, the occurrence of micronuclei (less than 1%) points to pathological processes starting in the stands, which necessitates urgent measures for the conservation of the Usmansky and Khrenovskoy Forests as valuable gene sources.