Murashige and Skoog medium (MS) and modified Anderson's Rhododendron medium (mAN) were compared for in vitro shoot multiplication of three highbush blueberries ‘Berkeley’, ‘Bluecrop’ and ‘Goldtraube’. All media contained 0.5 mg l ⁻¹ zeatin applied either alone or combined with 0.1, 1 and 5 mg l ⁻¹ IBA. In vitro rooting was induced using mAN medium supplemented with 0.8 mg l ⁻¹ IBA and 4 g l ⁻¹ activated charcoal. The results obtained showed that mAN medium is more suitable for in vitro multiplication of the selected highbush blueberry cultivars than MS medium. Low concentration of IBA (≤1 mg l ⁻¹ ) added in zeatin-supplemented mAN medium increases shoot multiplication efficiency of highbush blueberries in vitro and can be recommended for large-scale propagation of high-quality plants. MS medium induced partial or full necrosis of stems and leaves, which was more pronounced on media containing zeatin combined with increasing concentration of IBA. Rooting capacity of shoots varied widely among the tested blueberry cultivars. The highest rooting and acclimatization rates were achieved in ‘Goldtraube’ (82.8% and 91.8% respectively), and the lowest (10% and 66.7% respectively) were in ‘Berkeley’.

Three types of callus tissues established from anther culture of eleven doubled haploid (DH) lines of wheat (Triticum aestivum L.) were evaluated for their ability in enhancing friable embryogenic (Type II) culture differentiation and genetic transformation. Differences between types of callus inocula were highly significant (P<0.001), suggesting that the quality of the initial callus explant is of profound importance in encouraging the proliferation of Type II cultures. Other factors found to be crucial included weekly subculture of friable embryogenic callus tissues on a maintenance medium containing 30 μM dicamba and a predominance of amino‐acid nitrogen supplement. Transfer and integration of the β‐glucuronidase gene was also affected by the type of inoculum when suitable embryogenic cell cultures were transformed using silicon carbide whiskers and high velocity microprojectiles. Expression of the hygromycin phosphotransferase selectable marker gene sequence was confirmed in all the stably transformed cell lines maintained on selection media containing lethal levels of hygromycin. Comparatively, there were differences in the frequency of regenerable, transgenic clonal segments between whisker‐treated and microprojectile bombarded tissues mainly as a result of the fact that cultures vortexed with whiskers were more capable of post‐treatment cell proliferation and embryo differentiation than those bombarded with cDNA‐coated microprojectiles. Conditions for obtaining these results are outlined and discussed in relation to the suitability of the two transformation strategies for producing transgenic cell aggregates of wheat.

Somatic embryogenesis was initiated from immature zygotic embryos of intraspecific cross ofAbies alba and interspecific combination ofAbies alba x Abies nordmanniana. The most responsive explants for induction of embryogenic calli were zygotic embryos in precotyledonary stage of development. Biochemically the compared embryogenic lines were uniform irrespective of their morphology or embryogenic potential. The flow cytometric analysis of single embryogenic lines suggests that no changes in ploidy levels occur during induction and culture of embryogenic callus inAbies alba what confirms the convenience of this system for propagation of valuable seed material.

Maturation and germination of somatic embryos of hybrids A. alba × A. alba and A. alba × A. nordmanniana were followed by protein analysis of single embryogenic -suspensor masses (ESM) and analysis...