Characterization of asara tca isolates from Bulgaria with microsatellite markers

. osev1, I. Simeonov2, G. Djakova3, Ts. Hvarleva1*

1Agrobioinstitute, Agricultural Academy, 8 Dragan Tsankov, 1164 Sofia, Bulgaria 2Instiute of iticulture and Enology, Agricultural Academy, 5800 Pleven, Bulgaria 3Institute of Agriculture and Seed Science, Agricultural Academy, 7007 Rousse, Bulgaria

Abstract. The fungus Plasmopara viticola is the causal agent of downy mildew, one of the most severe grapevine diseases. The genetic diversity of this pathogen in Bulgaria has not yet been investigated. In order to assess the polymorphism among P. viticola isolates in Bulgaria six samples collected in different regions of the country were genotyped with 7 SSRs. The genetic polymorphism revealed by the used microsatelite markers allowed discrimination of P. viticola isolates originating from the different areas of Bulgaria. All samples were found to have a unique microsatellite profile. One sample was found to have a multiallelic profile at three out of seven loci and was excluded from the calculation of genetic diversity parameters. The number of alleles per locus varied between 2 and 6 with a mean value of 3.5 alleles per locus. The obtained values of observed heterozygosity ranged from 0.2 to 0.8 with an estimated average value of 0.46±0.13, which is a bit lower than the mean expected heterozygosity – 0.53±0.07. With this study the characterization of population structure of P. viticola pathogen in Bulgaria was initiated.

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Investigation on the resistance of doubled haploid sunflower lines to some biotic factors

M. Drumeva, P. Yankov, N. Nenova, P. Shindrova
Abstract. The investigation was carried out at the Laboratory facilities of Dobrudzha Agricultural Institute (DAI), General Toshevo, Bulgaria during 2010 – 2012, and involved 15 doubled haploid fertility restorer sunflower lines (R-lines). The lines were obtained by the gamma-induced parthenogenesis method under greenhouse conditions in 2007 from three hybrid combinations developed at DAI. The resistance of the plants to downy mildew – one of the main pathogens on sunflower, and to the parasite broomrape was followed. The breeding materials were infected with downy mildew (Plasmopara halstedii), race 731, and broomrape (Orobanche cumana Wallr.) under greenhouse conditions. The evaluation for resistance was done according to a scale from 0 % (susceptible genotype) to 100 % (resistant genotype). To determine the resistance to downy mildew, standard methodology was applied, adapted for work under the specific conditions of DAI; the methodology of Panchenko (1975) was used to determine the resistance to broomrape. Four lines demonstrated complex resistance to downy mildew and broomrape. Among the other eleven lines, three lines showed 100 % resistance to downy mildew race 731, and five lines were resistant to Orobanche (races A-F).

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Screening of plant protection products against downy mildew on cucumbers (Pseudoperonospora Cubensis (Berkeley & M. A. Curtis) Rostovzev) in cultivation facilities

S. Masheva, N. Velkov, N. Valchev, V. Yankova
Abstract. Screening of plant protection products (PPP) against downy mildew in cucumbers Pseudoperonospora cubensis (Berkeley & M. A. Curtis) Rostovzev was carried out during the period 2006-2011 in the “Maritsa” Vegetable Crops Research Institute, Plovdiv. Their toxicity to the imago of the bioagent Encarsia formosa Gah. were studied. High effectiveness (over 85.00 %) of the PPP with active ingredients: dimethomorph (Zampro SC, Acrobat paplus SC); symoxanil (Korsate Pro WG, Korsate R DF), strobilurins (Eclair 49 WG, Quadris 25 SC) was established. With the lowest effectiveness to the agent of downy mildew is Timorex 66 EC. All studied products are suitable for including in the systems for control of this disease. A non-toxic product to E. formosa is the botanical fungicide Timorex 66 EC, medium toxic products are those containing a.i. strobilurin and propamocarb-hydrochloride. The remaining PPP are slightly or medium toxic to the bioagent. Therefore E. fоrmosa could be applied parallel with slightly toxic fungicides against P. cubensis.
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