Analysis of genetic relationships among rice cultivars from different ecogeographic groups using SSR markers

Microsatellite DNA markers are widely used in genetic research on rice: for studying the genetic diversity of genetic resources collections, iden-tifying microevolutionary processes within the genus Oryza L. and analyzing genetic relationships of gene pools from different regions of the world, as well as in gene mapping and performing marker-assisted selection in breeding. Given the size of the collection held by the All-Russian Rice Research Institute, which has a total of about 7,000 accessions, it is important to analyze its genetic structure and study genetic diversity, including the use of molecular genetic methods. The aim of the work was to clarify the genetic relationships among modern Russian rice varieties and varieties from different regions of Asia (Central Asia or East Asia) representing various ecogeographic groups using microsatellite DNA markers. The material of the study was 32 rice cultivars representing three different ecogeographic groups: Eastern, Central Asian and European. We used 10 SSR markers, which showed a level of polymorphism from 2 (RM11, RM316, RM19) to 8 alleles (RM1). For a total of ten loci, 46 alleles were identified. The average PIC was 0.45. The results of the Bayesian analysis and clustering using the UPGMA method made it possible to make a conclusion about the complex genetic structure of the set of the studied cultivars, which is consistent with the presence of cultivars from different ecogeographic groups (EGG). A number of cultivars that occupy an intermediate position between ecogeographic groups were identified, which obviously is a consequence of the active use of crosses between cultivars belonging to different EGGs in the process of breeding. Russian cultivars, which according to their morphological characteristics belong to the European ecogeographic group, were attributed to the group which also included some varieties from Central Asia and from the Eastern EGG. It was a consequence of the use of cultivars belonging to different ecogeographic groups in domestic breeding programs.