Berry fruit species are, in many countries, considered biologically and economically valuable and important species of small fruits. The aim of this work was to examine the influence of either decreased or increased mesos concentrations (MgSO₄, CaCl₂, and KH₂PO₄) on shoot multiplication of five cultivars of three small fruit species (Amelanchier alnifolia var. cusickii, Rubus fruticosus ‘Black Satin’ and ‘Loch Ness’, and Vaccinium corymbosum ‘Brigitta Blue’ and ‘Toro’). Mesos nutrients were manipulated from half to four times their base concentration. The results indicate that mesos manipulation significantly influences the number and length of shoots in most of the studied cultivars. The greatest multiplication rate for A. alnifolia was achieved with tripled mesos, whereas ‘Black Satin’ and ‘Loch Ness’ reacted positively to a lower (1–2x) concentration of mesos. Decreasing the concentration of mesos to half led to worse quality in both blackberry and Saskatoon shoots. ‘Brigitta Blue’ was more sensitive to greater mesos concentrations compared to ‘Toro’. Optimizing the mineral nutrition of plants cultivated in vitro enhances their multiplication rate and contributes to a higher production of good quality plantlets.

The aim of this work was to develop protocols for micropropagation of selected Rubus cultivars – ‘Tulameen’ and ‘Black Jewel’ (Rubus idaeus L.), ‘Bl...

The aim of this work was to evaluate shoot multiplication of two blackberry (Rubus fruticosus L.) cultivars ‘Black Satin’ and ‘Loch Ness’ on two culture media: Murashige & Skoog (MS) and its modification Murashige & Skoog Van der Salm medium (MS VDS) which differ only in iron source (FeNaEDTA, FeEDDHA, respectively). Statistical analyses showed no significant difference in shoot multiplication between different iron sources for both tested cultivars. For ‘Black Satin’ it was shown that double concentration of chelates FeNaEDTA and FeEDDHA in culture media negatively affected on shoot growth and multiplication. These results can be very useful for further optimization of micropropagation process for different Rubus cultivars.

The purpose of this work was to apply V and D cryo-plate methods for cryopreservation of Vaccinium corymbosum ʻToroʼ, Fragaria × ananassa ʻCleryʼ, and Amelanchier alnifolia (Nutt.) M. Roem. and to monitor the multiplication capacity of shoots regenerated from cryopreserved explants. Shoot tips pre-cultured for 1 d at 23°C in the dark on medium containing 0.3 M sucrose were used as explants. Loading was performed in a solution containing 2 M glycerol and 0.8 M sucrose (30 min at room temperature). In the V cryo-plate, dehydration was carried out at room temperature (20 to 50 min) using the following plant vitrification solutions: original PVS2, 90% PVS2 solution, and PVS3. Regarding the D cryo-plate, dehydration was performed in closed glass containers over silica gel for 2, 2.5, or 3 h. In both protocols, rewarming was carried out in a 1.0 M sucrose solution (15 min at 25°C). Regenerated shoots were multiplied and multiplication parameters were monitored after the second subculture. Using the V cryo-plate method, the highest regrowth in highbush blueberry was obtained following 50-min treatment with all three VSs (61.7 to 80.9%). The D cryo-plate method was even more suitable with maximum regrowth of 89.4% achieved after 2.5 h of desiccation. For strawberry, 62.5% was the highest regrowth recorded using PVS3-based V cryo-plate method while 83.3% of regrowth was observed using D cryo-plate protocol. Regrowth of saskatoon reached a maximum of 50% after 50-min treatment with PVS3 while it did not exceed 40% in other treatments. By the second subculture, shoots regenerated from cryopreserved explants regained and even exceeded the multiplication capacity of shoots regenerated from non-cryopreserved explants. This study is the first to present the successful application of the V cryo-plate method in highbush blueberry, as well as the utilization of both V and D cryo-plate methods in saskatoon.

BACKGROUND: Amelanchier alnifolia is an attractive small fruit difficult to propagate by traditional methods. Moreover, this species can be susceptible to dormancy after transplanting to the soil. OBJECTIVE: The aim of this work was to evaluate factors that contribute to effective in vitro rooting and acclimatization of micropropagated shoots of Amelanchier alnifolia. METHODS: Different auxins, media concentrations, and sprays containing plant growth regulators were tested. The experimental data were treated by analysis of variance. RESULTS: 1-naphthalene acetic acid (NAA) was superior for rooting compared to indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA). Cultivation of shoots on Murashige & Skoog (MS) medium with a half-strength concentration ( ¹ / ₂ MS) led to higher rooting frequencies than on full-strength MS medium. Addition of 1.5 mg l ^–1 spermidine to cultivation medium did not significantly improve rooting. Gibberellic acid (GA ₄₊₇ ) alone or in combination with 6-benzylaminopurine (BAP) did not effectively break post-rooting dormancy. CONCLUSION: The greatest number of actively growing plants was recorded after rooting the shoots on ¹ / ₂ MS medium with 1 mg l ^–1 NAA followed by a spray treatment with 1 mg l ^–1 BAP. These results are directly applicable for improving rooting efficiency and acclimatization of micropropagated Amelanchier spp. plantlets.