Studies on DNA polymorphism are of great relevance in plant breeding since they give a deeper insight into genetic diversity. DNA profiles of individual plants of red clover varieties produced using the simple-sequence repeat primers UBC825, UBC827, UBC857, 77H, 78H, 104H and GO4 were assessed in this work. In the DNA profiles, in total 39–43 fragments were amplified, of which 52.5–60.4% were polymorphic. The highest number of fragments was amplified by the UBC827 primer, moreover, these fragments were found to be most polymorphic (90.5%). Slightly fewer polymorphic fragments were generated by the primers 77H and 78H. The primers 104H and GO4, when used in PCR, produced in the DNA profiles only one fragment each, which was identical for all individuals. Comparison of the varieties revealed the lowest number of fragments in the individuals of the variety ‘Vyliai’ (39), of which 57.4% were polymorphic. In the DNA profiles of the individuals of the varieties ‘Liepsna’ and ‘Arimaičiai’ 43 fragments were identified.

Research on the intravarietal genetic diversity suggests that plants of the variety ‘Liepsna’ are characterised by the greatest polymorphism (0.313), while ‘Arimaičiai’ has been found to be the most homogeneous variety (0.241).

The genetic distance between the varieties varied from 0.010 to 0.458. According to Nei’s coefficient value, the greatest genetic distance was noted between the varieties ‘Vyliai’ and ‘Arimaičiai’ (0.177) and between ‘Liepsna’ and ‘Arimaičiai’ (0.181). Variety-specific DNA fragments were identified in some red clover varieties. Amplification done with the primer 78H produced a fragment of 1400 bp which is variety-specific to ‘Arimaičiai’. The 800 bp fragment, generated by the UBC857 primer, was specific to individuals of the varieties ‘Liepsna’ and ‘Vyliai’.

Keywords: red clover, varieties, DNA, ISSR fingerprinting