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Botrytis cinerea Pers.: Fr is an important strawberry disease-causing pathogen with a broad host range. Classical B. cinerea identification is complicated due to the lack of morphological polymorphism between species. The use of molecular tools helps to identify pathogens fast and accurately. This study aimed to determine Botrytis spp. isolates and evaluate the genetic diversity of grey mould population in Lithuania. During June-August of 2012-2014, 273 isolates were sampled from 12 different areas of Lithuania. All samples were isolated from infected fruits, and single-spore isolates were extracted. B. cinerea isolates were identified using B. cinerea species-specific primers Bc108The polymerase chain reaction (PCR) showed two bands characteristic of two specific DNA fragments of B. cinerea -upper and lower band of 360 and 480 bp, respectively. These two bands reflect pathogen genotype differentiation and could be used for cryptic species detection. The cryptic species analysis revealed that resistant group I accounted for 16.95% and sensitive group II for 83.05% of the Lithuanian collection of B. cinerea isolates. The precise identification of the B. cinerea cryptic species is important for the species-specific fungicide resistance and aggressiveness. Four microsatellite markers used in this study revealed genetic diversity of B. cinerea. The 158 isolates were identified as B. cinerea. The most polymorphic microsatellite marker was BC6 (0.88) and the least polymorphic -BC7 (0.79). The isolates clustered into three genetic groups. The first group consisted of 45 strains, the second group of 15 and the third group of 4 isolates. Our data show genetic diversity within the Lithuanian population of B. cinerea. One of the management tools is recognition and identification of the pathogen which leads to optimal and efficient disease management.

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Winter hardiness is one of the main traits affecting survival, productivity and cultivar choice for important horticultural plants in a temperate climatic zone. Given the complexity of the trait and the often fluctuating winter weather, extensive field testing over many years would be required to gain reliable results. Testing for cold tolerance under controlled conditions to grade genotypes has been used in several plant breeding programs to identify superior genotypes of different species. The aim of the present study was to investigate cold tolerance of microshoots of different genotypes of the genera Prunus and Fragaria after 7, 14, 28 and 56 days of cold acclimation, by measuring ion leakage and evaluating the critical temperature (CT50) after freezing in vitro. Genotypes of Rosacea family demonstrated distinct patterns of CT50 change during cold acclimation. Cold acclimation for 56 days decreased the CT50 value by 1.3-2.0°C for Prunus microshots and by 0.8-2.1°C for Fragaria microshoots in comparison to nonacclimated plants. The results of cold acclimation and freezing treatments of Rosacea family plants in vitro show that for maximal cold hardiness, acclimation for 56 days or longer is required. Sour cherry (Prunus cerasus) cv. 'Orkolija', garden strawberry (Fragaria × ananassa) cv. 'Melody', Virginia strawberry (F. virginiana) and musk strawberry (F. moschata) were the most winterhardy after 56 days' cold acclimation. The data obtained in the study can be used to improve breeding and cryopreservation technologies of Rosacea plants, and lay the foundation for identification of genes responsible for efficient cold acclimation and low temperature tolerance.

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The present study evaluated genetic diversity of Lithuanian populations of Lythrum salicaria in relation to parameters of riparian environment. Growing along Nemunas, Seaside and Lielupė river basins, 15 populations were examined using amplified fragment length polymorphism markers. Molecular data were related to the river basins, type of land use and cover, natural vice versa regulated fragments of the rivers. Population mean genetic diversity parameters were as follows: percentage of polymorphic loci (57.2), expected heterozygosity (0.183), polymorphismc information content (0.218). Mantel test revealed correlation (R2 = 0.0986, p = 0.01) between genetic and geographic distance of populations. Greater genetic diversity within, rather than among populations (ΦPT = 0.213) was observed. According to the Bayesian clustering, studied populations are admixtures of two gene pools. Analysis of molecular variance revealed significant differentiation between populations belonging to distinct river basins, between populations from natural vs. regulated fragments of the rivers.