Interspecific hybridization between B. oleracea inbred lines of head cabbage, Brussels sprouts, kale and B. taurica and inbred lines of rapeseed (B. napus L.) were performed aiming at the development of the new sources of genetic variability of vegetable Brassicas. Using conventional crossings and the embryo-rescue techniques the following interspecific hybrids were developed: 11 genotypes of F₁ generation, 18 genotypes of F₂ and F₁ × F₂ generations (produced after self- and cross-pollination of interspecific F₁ hybrids), 10 plants of the BC₁ generation (resulted from crossing head cabbage cytoplasmic male-sterile lines with interspecific hybrids of the F₂ and F₁ generations) and 8 plants of BC₁ × (F₁ × F₂). No viable seeds of the BC₂ generation (B. oleracea) were obtained due to the strong incompatibility and high mortality of embryos. The morphological characteristics during the vegetative and generative stages, pollen characteristics, seed development and propagation, nuclear DNA contents and genome compositions of interspecific hybrids were analyzed. All the interspecific F₁ hybrids were male-fertile with a majority of undeveloped and malformed pollen grains. They showed intermediate values for morphological traits and nuclear DNA contents and had nearly triploid chromosomal numbers (27 to 29) compared with parental lines. The F₂ generation had a doubled nuclear DNA content, with 52 and 56 chromosomes, indicating their allohexaploid nature. F₂ hybrids were characterized by a high heterosis of morphological characteristics, viable pollen and good seed development. F₁ × F₂ hybrids were male-fertile with a diversified DNA content and intermediate pollen viability. BC₁ plants were male-sterile with an intermediate nuclear DNA content between the F₂ and head cabbage, having 28 to 38 chromosomes. Plants of the BC₁ × (F₁ × F₂) generation were in majority male-fertile with 38–46 chromosomes, high seed set, high heterosis and intermediate values for morphological traits. The obtained interspecific hybrids are valuable as new germplasm for improving Brassica-breeding programs.

The strains of bacteria Paenibacillus glucanolyticus, Curtobacterium pusillum and Methylobacterium extorquens were isolated as non-deleterious contaminations from hosta or raspberry tissue cultures. Microshoots of chrysanthemum, gerbera, hosta and rose were inoculated with these bacteria and their influence on shoot multiplication and rooting was evaluated. None of the investigated bacteria caused symptoms of hypersensitivity or vitropathy on the shoot explants at rooting and shoots multiplication. C. pusillum stimulated axillary shoot formation in all studied plant genotypes. Length and number of rose roots and their length were higher but number of roots and their length in chrysanthemum were lower in inoculated than in controls. The number and the length of shoots and roots in gerbera and hosta and the number of shoots in chrysanthemum inoculated with M. extorquens were higher but shoot length of chrysanthemum and rose, and root length of rose were lower as compared with controls. P. glucanolyticus influenced higher number and length of chrysanthemum shoots and root length of chrysanthemum and gerbera than noninoculated control but the number of gerbera and hosta roots was lower and root length of rose was as low as 0.2 cm. All assessed bacteria were able to assimilate atmospheric nitrogen and M. extorquens and P. glucanolyticus were able to produce IAA.

Among the numerous protocols that describe the extraction of DNA, those relating to the isolation of DNA from infected plants, are rare. This study describes a rapid and reliable method of extracting a high quality and quantity of DNA from rhododendron leaves artificially infected with Phytophthora cactorum, P. cambivora, P. cinnamomi, P. citrophthora, and P. plurivora. The use of the modified Doyle and Doyle protocol (1987) allowed us to obtain high quantity and quality DNA (18.26 μg from 100 mg of the fresh weight of infected leaves at the ratios of A260/280 and A260/230 - 1.83 and 1.72, respectively), suitable for conventional polymerase chain reaction (PCR) and real-time PCR amplifications

P. lacustris sp. nov. (formerly known as Phytophthora taxon Salixsoil) was first isolated in 1972 in the UK and then in many other European countries, including Poland. The aim of this work was a morphological, physiological, and genetic characterization of the P. lacustris isolates by means of the daily growth rate, mycelium morphology, and generative and vegetative structures, depending on the temperature of incubation and growth media. In addition, the ability to colonize willow shoots and leaves was estimated. Out of 114 isolates of P. lacustris obtained from water habitats located near plant nurseries in central and southeastern Poland in 2007-10 that were identified on the basis of molecular tests which showed high diversity in colony growth patterns and daily growth rates, 10 groups were separated by means of Duncan’s test. Representatives of these 10 groups together with three reference isolates – P. lacustris P245 as the holotype, P. gonapodyides CBS 117380 as a specimen most closely related phenotypically to P. lacustris, and P. cactorum as a positive control of forest trees’ pathogen – were researched. Great heterogeneity in the growth rates and morphology of mycelium, as well as in the structure of zoosporangia and hyphal swellings, were observed. Moreover, the isolates differed in their ability to colonize the willow leaves and shoots in the in vitro tests. Some correlation may be found between the daily growth rates and colonizing abilities, and between the daily growth rate and the dimension of the sporangia. Also, a large genotypic variation between the isolates based on the fingerprint patterns generated by molecular techniques (RAPD and ISSR) was obtained.

ISHS VI International Symposium on Production and Establishment of Micropropagated Plants Burkholderia phytofirmans PsJN promotes in vitro rooting and acclimatization of Helleborus