Leaf rust represents the major threat to wheat production in Russia and Ukraine. It has been present for many years and epidemics of the pathogen occur in different regions on both winter and spring wheat. In some regions there is evidence of more frequent epidemics, probably due to higher precipitation as a result of climate change. There is evidence that the virulence of the leaf rust population in Ukraine and European Russia and on winter wheat and spring wheat is similar. The pathogen population structure in Western Siberia is also similar to the European part, although there are some significant differences based on the genes employed in different regions. Ukrainian wheat breeders mostly rely on major resistance genes from wide crosses and have succeeded in developing resistant varieties. The North Caucasus winter wheat breeding programs apply the strategy of deploying varieties with different types of resistance and genes. This approach resulted in decreased leaf rust incidence in the region. Genes Lr23 and Lr19 deployed in spring wheat in the Volga region were rapidly overcome by the pathogen. There are continuing efforts to incorporate resistance from wild species. The first spring wheat leaf rust resistant varieties released in Western Siberia possessed gene LrTR which protected the crop for 10-15 years, but was eventually broken in 2007. Slow rusting is being utilized in several breeding programs in Russia and Ukraine, but has not become a major strategy.

Genetic organization of 52 Vibrio cholerae El Tor biotype preseventh and seventh pandemic strains isolated in various periods was studied by PCR assay and DNA-DNA hybridization. It was established that the genome of most ancient of analyzed strains isolated from a diarrhea patient in 1910 was devoid of CTX and RS1 prophages, vibrio pathogenicity islands (VPI and VPI-2), and pandemic islands (VSP-1 and VSP-2) that contain key virulence genes. The appearance of pathogenic properties in cholera vibrios for the first time causing a local outbreak of cholera in 1937 is connected with the acquisition of VPI and CTX that carried genes tcpA and ctxAB, respectively, which are responsible for the colonization of the small intestine and encode the production of cholera toxin. The appearance of the seventh pandemic agent for cholera was shown to correlate with the acquisition by its precursor of two additional blocks of genes VSP-1 and VSP-2. This finding strongly supports the involvement of these genes in formation of the pandemic potential in the strains. Molecular typing methods allowed elucidation of differences in the genetic organization between prepandemic and pandemic strains. The detected variability of the genome of contemporary virulent strains may be a reason for the occurrence of etiological agent of cholera with new properties.

The virulence frequency of 750 wheat powdery mildew isolates of wheat genotypes, carrying 23 Pm-genes and gene combinations, was studied over ten consecutive years from 2004 to 2013. Seventy-eight previously known and 39 new pathotypes were identified during this period. The results indicate that the majority of Pm-genes have high level of virulence. Sixty to ninety percent of the isolates were virulent to Pm6, Pm8, Pm8+11, Pm2+4b+8, Pm3g, Pm10+15, Pm10+14+15. The virulence frequency was variable for Pm1a, Pm2, Pm3a, Pm3b, Pm3c, Pm5, Pm7 genes and reached high level in certain years. The virulence frequency to genes Pm20, Pm37, Pm4a+ and to gene combination with Pm3c+5a+35 and breeding lines CN240/06, CN98/06 and CN158/06 ranged from 1 to 8%. Bread wheat lines CN240/06, CN98/06 and CN158/06, derived from interspecific crosses, proved to be highly resistant to powdery mildew.

Common bunt, caused by Tilletia caries (DC.) Tul., is widespread disease of wheat (Triticum aestivum L.) that causes serious yield reduction and loss of quality of this crop. Majority of Ukrainian wheat varieties are susceptible to bunt. It is necessary to search for sources of effective resistance genes.Aegilops cylindrica (2n = 28; genome CCDD) is a source of genes for some pest resistance in wheat Bochev et al. (1982). Ae. cylindrica carries resistance to leaf rust, stem rust, fusarium, septoria, powdery mildew and common bunt.The identification of DNA-markers linked to bunt resistance and susceptibility alleles would greatly facilitate the screening of wheat introgressive genotypes and accelerate the development of new resistant varieties. Microsatellites or simple sequence repeat (SSR) is widely used to search for molecular markers linked to many economic traits genes McIntosh et al. (2003).Present study reports markering and mapping with microsatellite markers of effective resistance gene to bunt in bread wheat introgressed from Ae. cylindrica. Bunt evaluation. Ae. cylindrica, recurrent parent wheat cv. Odesskaya polucarlikovaya and line Lutestens 23397, introgressive lines 5/55-91, 378/2000 and BC 3 F 2 -derived F 3 families were evaluated for resistance to bunt in field infection nursery. Bunt resistance in line 5/55-91 is controlled by a single dominant gene (Babayants et al. 2004). MATERIALS AND METHODS PlantMicrosatellite marker analysis. For SSR-analysis were used 95 pair primers to 107 microsatellite loci with known localization on chromosomes of wheat (Röder et al. 1998). For identification microsatellite markers linked to the resistance gene was used bulked segregation analysis (BSA) as described by Michelmore et al. (1991

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