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.

Diseases of agricultural crops are the main reason for decreased yield and quality of product. Blast (causative agent: Pyricularia oryzae Cav.) is the most harmful disease on rice fields. Economic damage caused by the pathogen is significant in all areas of the world’s rice cultivation. The most effective, economically justified and environmentally friendly strategy for combating it is development of resistant varieties. The application of DNA markers linked to loci of resistance to blast is relevant in this area. This makes it possible to significantly shorten the breeding process and promptly develop disease-resistant rice forms. In this regard, the aim of the work was to develop source material for breeding as well as highly productive rice varieties and lines with genes of resistance to blast based on the use of molecular marking method. To achieve this goal, we have launched a program since 2007 aimed at introduction of the blast resistance Pi-ta gene, effective for the south of Russia, into the domestic rice cultivar Flagman. After a number of recurrent crosses, the breeding material was obtained, which was studied for economically valuable traits in breeding nurseries. As a result of evaluation and rigorous discarding as well as according to the results of a phytopathological test for blast resistance, several lines were identified that have high indicators of milled rice quality, resistance to blast, yield and economically valuable traits. Rice accession KP-171-14 with the Pi-ta gene, adapted to growing conditions in the south of Russia, resistant to the Krasnodar population of P. oryzae, and having high yield and grain quality, in 2017 was submitted for State Variety Trials (SVT) under the name Alyans. Accessions KP-30 and KP-23 are tested for economically valuable traits and disease resistance in competitive variety trials. The best accession will be submitted to SVT. The introduction and cultivation of such varieties will reduce the use of chemical protection products, obtain environmentally friendly agricultural products and avoid contamination of grain ecosystems

Taxonomic relationship between Fragaria L. and Potentilla L. representatives is actively discussed today in the context of phylogenetic analysis by molecular markers and hybridization results. According to the data published, crosses between F. х ananassa Duch. (8x) х P anserina L. (4x) produce haploids, parthenogenetic seedlings (8x) and aneuploids. No viable progenies have been obtained. Our long-standing research in F. х ananassa х P anserina hybridization was targeted at obtaining 8x agamospermic progenies and studying their genetic variability. In one of the experiments, when P. anserina pollen was used in crosses, along with 2n = 56 matromorphous seedlings, an absolutely sterile seedling No. 89-3 was produced, which insignificantly differed from F. х ananassa by its phenotype, thus matching the Fragaria type. Chromosome number in root apical meristem cells appeared to be 2n = 6x = 42, being intermediate between the crossed parental forms. The absence of any morphological traits of the pollen parent (P. anserine) showed the need to make molecular genetic analysis in order to prove its hybrid origin. Methods. To trace its origin, the techniques of Polygalacturonase Inhibitor Proteins (PGIPs) PCR and Amplified Fragment Length Polymorphism (AFLP) PCR analysis of internal transcribed spacer (ITS) were applied to F. х ananassa х P anserina seedlings. The study showed that seedling No. 89-3 and the parthenogenetic progenies are identical and correspond to the mother form (F. х ananassa). Hence, eliminating 14 chromosomes of F. х ananassa and 14 chromosomes of P. anserina during the first divisions of a zygote (2n = 70) should be considered as the most likely scenario for the 2n = 42 chromosome number development in the studied No. 89-3, so the genetic material of P. anserina was absent in the embryo’s somatic cells. Development of aneuploids and parthenogenetic seedlings (8x) in the crosses of F. х ananassa х P anserina makes it possible to study additional mechanisms of variability appearing in the Fragaria genus. Reproductive isolation of an aneuploid, due to its complete sterility, limits its use solely to a cover plant’s role. In addition, its herbage biomass may be used for making fermented tea.

Tetraploid maize attracts breeders because of its large kernel and cob sizes, high nutrient content, and higher yield of herbage mass than diploid maize. Hence, it is important to study its biochemical composition and nutritional value in order to develop original source material for breeding. Accessions of tetraploid sweet corn from VIR’s genebank were used to analyze biochemical composition of the grain. The main task of the work was to identify differences among the accessions at the level of the metabolite spectra. A comparison of the values in the content of total sugars in kernels homozygous for the su2 gene did not reveal significant differences between diploid and tetraploid genotypes, while the fractions of sugars revealed some differences. Studies have shown that in diploid grains deviations from the reference for the total sugars content are -8.2 mg/100g, and in tetraploid ones, -2.9 mg/100g, although the overall ratio of dominant and recessive alleles (1AA:2AA) remains the same in both genotypes. Tetraploid sweet corn showed greater variability of the coefficient of variation (CV) in the grain protein content (CV = 6.80%), starch (CV = 8.27%) and oil (CV = 13.3%) compared with the diploid one. Potential donors of high protein, starch and oil contents in the kernel of tetraploid sweet corn were identified. A new cultivar of tetraploid sweet corn, ‘Baksanskaya Sakharnaya’, was developed, with a yield up to 16 t/ha of cobs in a marketable milky ripeness state and representing predominantly the double-cob type. This cultivar has high flavor qualities due to the fact that its kernels contain 16.3% of protein, 63.2% of starch, and 7.5% of oil. Moreover, the cultivar is resistant to biotic environmental factors. The tetraploid genome provides greater variability of the kernel’s biochemical composition and other economically valuable traits due to its greater genetic capacity, compared with the diploid genome. Development of new high-yielding hybrids of sweet corn based on VIR’s holdings will allow breeders to significantly broaden the genetic polymorphism and assortment of modern breeding achievements, and contribute to providing high-quality raw materials for food and canning industry.

Great damage to potato production is caused by cyst nematodes, which include two species: Globodera pallida (Stone) Behrens, the object of external quarantine, and Globodera rostochiensis (Wollenweber) Behrens, the object of internal quarantine in the Russian Federation. The breeding of varieties resistant to the G. rostochiensis has long been one of the priorities of Russian potato breeding, while a targeted search for sources of resistance to G. pallida in our country until recently was not actually carried out, since this pathogen was not detected in Russia, although it was traced in neighboring countries. The possibilities of selection of G. pallida-resistant genotypes using traditional phytopathological methods are extremely limited, so the information about the presence of markers of resistance genes to this pathogen in the domestic breeding gene pool is of particular importance.

Here we present the results of molecular screening of 160 varieties bred in Russia and in adjacent countries from the collection of VIR for the presence of markers of Gpa2 gene, which provides resistance of potato varieties to G. pallida (Pa2/Pa3 pathotypes).

It is shown that among 160 varieties of the analyzed subset 19 have a di­agnostic fragment of the allele-specific marker of the Gpa2 gene - Gpa2-2. These 19 varieties isolated in molecular screening simultaneously con­tained allele-specific markers of the Rxl gene controlling resistance to potato virus X (PVX).

Genome editing using the CRISPR/Cas system is a breakthrough tech­nology in plant genetics and breeding. The most large-scale application of this new technology on crop species is observed for rice. This fact is explained not only by the significance of this crop, but also by the relatively high transformation amenability. Although the end result of genome editing is a non-transgenic plant with desired mutation (muta­tions), an unavoidable step in the process of creating such a new mutant is the use of genetic engineering methods. To date, the CRISPR/Cas sys­tem has been tested on dozens of rice target genes, of which mutations in more than 30 genes have led to the desired improvement of economically important traits. The remaining experiments are related mainly to the verification of the genes’ functions, and belong to the field of reverse genetics. Improvement or acquisition of new properties is associated with mutations in the genes that affect productivity, grain fragrance and chemical composition, flowering time, the resistance to biotic and abiotic stress factors, and herbicides, as well as pollination control needed in hybrid breeding. These achievements are reviewed in the current article. It is important to note that about fifty different genotypes are already involved in improving rice varieties with the help of genome editing. This creates the prerequisites for a wide practical application of genome editing technologies in rice breeding programs