The purpose of this research by the way of investigating the molecular genetic structure of a highly variable fungal phytopathogen Pyricularia oryzae Cav., to determine effective genes for the development of a strategy for immunogenetic protection against rice blast in conditions of epiphytotic development of the disease in the south of Russia, which would combine high efficacy with both environmental friendliness and resource and energy saving, to ensure country's food security. The knowledge of local pathotype diversity of Pyricularia oryzae Cav. and the (a)virulence genes in rice-growing regions of Russia may allow the prediction of new races and its interaction in local agro-ecology. The identification of virulence gene may become an indispensable theoretical basis for the development of genetic sources with long-lasting resistance to rice blast. Based on molecular and genetic approaches, the genetic structure and biodiversity of the phytopathogenic fungus Pyricularia oryzae Cav. in the south of Russia were considered. The monitoring was studied and it isolated 57 strains of the pathogen from the damaged herbal material collected from the fields in eight agro-ecological rice-growing regions of the Krasnodar Region (Russian Federation): Krasnoarmeysky, Kalininsky, Krymsky, Abinsky, Temryuksky, Seversky, Slavyansky districts, Krasnodar, Rostov Region (Russian Federation)-Proletarsky district and the Republic of Adygea (Russian Federation). A multiplex PCR technique was applied on the basis of fragment analysis to identify the virulent fungal isolates. 33 fungal genotypes with unique genetic profiles were identified among the studied races of Pyricularia oryzae Cav. Their DNA profiles were created. The studied isolates of the pathogen of rice blast were classified using morphological and microbiology cultural features. Based on the phytopathological test using differentiation rice varieties, the quantitative and qualitative composition of (a)virulence genes in fungal races was established. Effective genes for pathogen resistance, which are recommended for breeding programs for the development of rice varieties resistant to rice blast, were identified in the south of Russia.

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Grain productivity of rice is significantly reduced by dangerous disease – blast. Therefore, the development of resistant high yielding rice varieties with the Pi group of genes is important. Use of molecular markers linked with the loci of resistance significantly optimizes the breeding process. The purpose of the research is to develop rice lines combining 2-6 loci of resistance to blast: Pi-1, Pi-2, Pi-33, Pi-ta, Pi-b, Pi-40 by molecular marking. Materials and Methods. As donors of resistance genes foreign samples were used, recipient – Russian varieties. In the studies we used micro-satellites markers and PCR analysis. Results. In the first stage of the research as a result of hybridization domestic lines with genes Pi-l, Pi-2, Pi-33 were obtained. At the second stage – hybrids with all 3 genes were developed. In the third stage genes Pi-b and Pi-ta and on the fourth – Pi-40 were introduced. Conclusion. As a result, rice genotypes, combining 6 loci of blast resistance were developed with use of marker assisted selection.

Selection done using molecular markers has spread to all types of agricultural plants and animals. Marker assisted selection (MAS) is safe for ecology and food products consumed. The purpose of the study is to develop Sub1A gene (which determines tolerance to prolonged flooding) in the Russian rice varieties using DNA-markers and Polymerase chain reaction (PCR) analysis. A large volume of prebreeding rice material (F2-F4, BC2F2) was created with tolerance genes for prolonged flooding, to control weed in rice agrophytocenosis. The forms with 120-130-day vegetation period were selected. An analysis of the co-inheritance of simple sequence repeat (SSR) markers Sub1Aq, Sub1C173, Sub1A203 with the Sub1 gene was carried out. It revealed the codominance of the selected microsatellites. They can be used to identify and visualize the allelic state of a given target gene in the breeding material. The recurrent parental rice forms, donors of the gene Sub 1 and the hybrids of F2 and ВС2F1 population were tested on tolerance to prolonged flooding. The gene is effective in ensuring resistance to this stress factor within 2 to 3 weeks and it can be recommended for the breeding programs to develop modern genetic resources of rice tolerant to prolonged and deep flooding for weed control on rice fields.

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