SSAP method was used to study the genetic diversity of 22 Linum species from sections Linum, Adenolinum, Dasylinum, Stellerolinum, and 46 flax cultivars. All the studied flax varieties were distinguished using SSAP for retrotransposons FL9 and FL11. Suzuki diagnostic system software. Thus, the validity of SSAP method was demonstrated for flax marking, identification of accessions in genebank collections, and control during propagation of flax varieties. Polymorphism of Fl1a, Fl1b, and Cassandra insertions were very low in flax varieties, but these retrotransposons were successfully used for the investigation of Linum species. Species clusterization based on SSAP markers was in concordance with their taxonomic division into sections Dasylinum, Stellerolinum, Adenolinum, and Linum. All species of sect. Adenolinum clustered apart from species of sect.

SSAP method was used to study the genetic diversity of 22 Linum species from sections Linum, Adenolinum, Dasylinum, Stellerolinum, and 46 flax cultivars. All the studied flax varieties were.

The data confirmed the accuracy of the separation in these sections. Members of section Linum are not as closely related as members of other sections, so taxonomic revision of this section is desirable.

Usitatissimum accessions genetically distant from modern flax cultivars were revealed in our work. These accessions are of utmost interest for flax breeding and introduction of new useful traits into flax cultivars. The chromosome localization of Cassandra retrotransposon in Linum species was determined. Introduction The genus Linum comprises about 200 species which are distributed throughout the temperate and subtropical regions of the world. The genus is subdivided by Ockendon and Walters into five sections: Linum, Dasylinum (Planch.) Juz., Linastrum (Planchon), Bentham, Syllinum Griseb., and Cathartolinum (Reichenb.) Griseb. Some taxonomists classified the members of the L. Perenne group from section Linum to an independent section Adenolinum (Reichenb.) Juz.

The species L. Stelleroides (Planch.), distributed in Far East and China, was classified by Yuzepchuk [] to a monotype section Stellerolinum Juz. The phylogenetic analyses based on chloroplast ( ndhF, trnL-F, and trnK 3′ intron) and nuclear ITS (internal transcribed spacer) DNA sequences revealed that genus Linum was not monophyletic. It contains two major lineages: a yellow-flowered clade (sections Linopsis, Syllinum, and Cathartolinum) and a blue-flowered clade (sections Linum, Dasylinum, and Stellerolinum) []. The cultivated flax ( L. Usitatissimum L.) belongs to sec. Linum from a blue-flowered clade.

Usitatissimum is believed to have originated as a result of domestication of wild species L. Angustifolium Huds. Approximately 8000 years ago [–]. For a long time flax has been cultivating as a dual-purpose crop grown for its fiber and linseed oil.

According to morphological and qualitative traits, cultivated flax was divided into five main types: (1) fiber flax ( L. Usitatissimum subsp. Usitatissimum); (2) oil flax ( L. Usitatissimum L. Humile Czernom.); (3) dual-purpose flax ( L.

Usitatissimum L. Intermedium Czemom.) that was an intermediate form between the first two ones cultivated for fiber and oil; (4) large seeded flax ( L. Usitatissimum L. Latifolium Snankev.) which is characterized by a set of specific morphological features and cultivated for oil in the Mediterranean region and North Africa; (5) winter flax ( L. Usitatissimum L. Snankev.) cultivated for fiber and oil in the Caucasus, Turkey, Balkans, and some other south regions of Europe [, ]. In addition, collections of flax germplasm maintain accessions of primitive flax forms with dehiscent capsules ( L.

Usitatissimum convar. Crepitans [Boenningh.] Kulpa et Danert) []. The taxonomy of the genus cannot be considered as finally established one because the phylogenetic linkages between the individual taxa have not been sufficiently investigated. The phylogeny of species of the genus Linum was previously studied by the use of molecular and cytogenetic approaches [, –], but there are problems that still remain to be solved.