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The aim of the study was to evaluate phenotypically and genetically, 15 gooseberry genotypes plants propagated in vitro and ex vitro by cuttings grown in the second year in field conditions. The outcome of this was that in vitro propagated shrubs were shown to grew more strongly. Their height and the number of shoots were significantly higher for the 11 genotypes and a width of 12 genotypes for gooseberry. However, fruit abundance was greater in much more traditionally multiplied plants. Beyond the aforementioned, Genetic stability analysis of clones derived from in vitro cultures of five gooseberry varieties was performed. Herein, 13-15 plants with in vitro and mother plants were analyzed. The number of products generated by the AFLP primer pairs ranged from 33 to 108. The highest total number of amplification products was obtained as a result of the AFLP reaction for the plants ‚Hinnonmaki Rot’ (300), and the lowest for the varieties ‚Hinsel’ and ‚Resika’ (262). Genetic variability in gooseberry in vitro plants ranged from 1.03% for ‚Captivator’, to 10.3% for ‚Hinsel’. Genetic stability was also assessed using ISSR markers. Plants of five genotypes derived from conventional and in vitro reproduction were used. Accordingly, a total of 2294 amplification products were obtained, of which 2.8% were polymorphic. The size of the obtained products was from 250 to 2900 bp, depending on the starter and variety. ISSR-PCR analysis showed different degrees of polymorphism - from 0 for the ‘Hinnonmaki Rot’ and ‘Resica’ to 11.6% for the ‚Hinsel’ variety.

Polyploids of many species of horticultural plants are widely used in breeding programs since they are characterized by vigorous growth, larger organs, and greater resistance to biotic and abiotic stress. Saskatoon berry (Amelanchier alnifolia Nutt.) is in a form of diploid (2n = 2x = 34) and tetraploid. So far, no reports on induction of polyploidy in this species have been found. The aim of the study was to obtain Saskatoon berry octoploids with the use of in vitro shoot cultures. Shoots of the tetraploid of Canadian cultivars ‘Martin’ and ‘Smoky’ derived from in vitro cultures were used for induction of chromosome doubling. The shoot explants were incubated in a multiplication medium with the addition of one of the following antimitotics: colchicine, trifluralin, oryzalin or amiprophos methyl (APM) for two weeks (six days in the darkness and then eight days under a 16-h photoperiod). Then, the shoots were transferred to the multiplication medium without antimitotics and propagated in vitro by two subcultures. Octoploids were selected based on flow cytometry. Trifluralin showed the most phytotoxic effect. Six octoploids were obtained, four for ‘Martin’ after treatment with 250 mg L−1 of colchicine and two for ‘Smoky’ following the treatment with 5 mg L−1 of APM. All obtained octoploid individuals were multiplied and the level of ploidy was re-examined by flow cytometry and chromosome counting, which confirmed their octoploid genotype (2n = 8x = 136). They are probably the first octoploids of the genus Amelanchier in the world. The newly obtained octoploids were rooted in vitro, acclimatized to ex vitro conditions and grown in a greenhouse. Octoploids grew very slowly and showed a tendency to premature dormancy, which was manifested by inhibition of growth. In octoploid plants, the stomata were significantly larger and the number of stomata per 1 mm2 of leaf area was lower, compared to the tetraploid counterparts.

The sour cherry is known to exhibit the phenomenon of gametophytic self-incompatibility which prevents self-fertilization. In sour cherry, besides self-incompatible cultivars, there often occur self-compatible cultivars. This is due to the occurrence of natural mutations of the S-RNase or SFB genes and, consequently, loss of functionality of S-alleles. Here we present the results of the identification of S-haplotypes of 21 cultivars of sour cherry from various regions of Europe. The analyses were performed using methods based on the amplification of intron I and intron II of the S-RNase gene and fragments specific to the individual alleles of the S-RNase or SFB genes. The tested cultivars were found to contain 15 S-haplotypes: S1, S1ʹ, S4, S6, S6m, S6m2, S9, S12, S13, S13ʹ, S26, S35, S36a, S36b, and S36b2. The most frequently occurring S-haplotypes were S13ʹ (61.9%), S36a (57.1%), and S26 (47.6%). On the basis of the results, 17 of the 21 cultivars were deduced to be self-compatible. The results w...

We examined the effects of cooling applied for 4 to 20 weeks on donor cultures of four dwarfing apple rootstocks (P16, P22, P59 and M26). Our aim includes increasing their competence for in vitro adventitious shoot regeneration from the leaves. Donor cultures were maintained on a shoot multiplication medium at 4°C in the dark for 4 months, followed by subculture on a fresh medium for 4 weeks. The cooling of the cultures caused an increase in the adventitious shoot number and a decrease in the starch content and an increase in the soluble sugar content (monosaccharides, raffinose and stachyose). The accumulation of stachyose in response to cold is a new observation, and it suggests that raffinose and stachyose play important role in the acclimation of dwarf apple rootstocks to low temperatures.

The goal of this study was to evaluate whether Rubus genotypes could be selected in vitro for tolerance to drought stress. Drought conditions were simulated by introducing polyethylene glycol 6000 (PEG) into proliferation or growth regulator free media. The ability to produce axillary shoots, dry weight and proline content were used for evaluation of the stress reaction. All the cultivars reacted to PEG in the medium with a decrease in the axillary shoot number and an increase in proline content. The reaction differed in strength depending on the concentration of the stressor in the medium, the length of the stress period, and the genotype. To yield a practical value for breeding, the results obtained in vitro will be compared with results from in vivo experiments which are underway.

Rose genotypes can be recalcitrant in in vitro regeneration. A lack of competence for regeneration results in unsatisfactory numbers of adventitious shoots, which diminishes achievements in use of genetic engineering in rose modern breeding. Among the factors which can partially overcome this problem is the use of thidiazuron (TDZ) in the induction phase of regeneration. We studied the use of TDZ in concentrations 0.05 and 1.0 mg l−1, in the medium for the culture of donor shoots with the aim of increasing the regeneration competence of five rose cultivars differing in their regeneration ability. All the tested genotypes increased their regeneration potential when the donor shoots were cultured on TDZ media for 15 or 30 days. The strongest effect, doubling to quadrupling the number of shoots, was obtained in the cultivars characterized by the lowest regeneration potential. This enhanced regeneration ability was maintained through two or three subsequent 4-week long regeneration passages.

Shoots of Codiaeum variegatum 'Excellent' produced in vitro on defoliated explants were rooted on the MS medium with I mg 1 -1 indole-3-butyric acid (IBA). Almost all shoots, even the smallest one (5 mm long) rooted and doubled their length in the course of 4 weeks. In order to stimulate more shoot elongation during in vitro rooting, we decreased the IBA concentration to 0.5 mg 1 -1 , excluded IBA from the medium with 3 g 1 -1 activated charcoal (AC) or supplemented AC medium with gibberellic acid (GA 3 ). GA 3 incresed shoot length insignificantly but also decreased the number of rooted shoots. Diluting the MS medium by half stimulated root growth when combined with 2 mg 1 -1 Gelrite instead of 7 g 1 -1 agar.

The removal of all developed leaves from 1 to 1.5 cm shoots of Codiaeum variegatum Blume var. pictum Muell. Arg. ‘Excellent’, cultured on the Murashige–Skoog medium containing 4.4 μM (1 mg l−1) 6-benzylamino-purine (BAP) and 5.8 μM (2 mg l−1) gibberellic acid (GA3), doubled the number of axillary shoots in comparison to non-defoliated controls. An additional increase in shoot numbers was achieved when the shoots were placed on the medium horizontally or vertically in an inverted position with the shoot tip down. Shoot tip removal slightly improved axillary branching, and additional defoliation strengthened this effect. Exogenous indole-3-acetic acid (IAA) decreased shoot numbers, and 2,3,5-triiodobenzoic acid (TIBA) did not replace defoliation nor diminish the size of callus formed at the base of the shoots. Almost all the shoots obtained were able to root on the medium with 4.9 μM (1 mg l−1) indole-3-butyric acid (IBA), and acclimatize in the greenhouse.

An effective system for in vitro regeneration of adventitious shoots from callus for the transformation or mutation of gerbera was developed. Callus was produced from petioles of the youngest 3–4 leaves detached from auxillary shoots produced in vitro. Induction medium, on which leaves were incubated over 3 or 6 days, contained 2.3 μM thidiazuron and 0.53 μM α-naphthaleneacetic acid. Explants were than transferred to one of three regeneration media with lower levels of growth regulators. Regeneration was quantified over four (4-weeks each) passages at the time of explant transfer to fresh medium. Direct shoot regeneration occurred during the first 4 weeks, and after these shoots were discarded a semi-compact organogenic callus was produced. Effectiveness of shoot regeneration depended on four criteria: the cultivar (three cultivars were tested), the sequence of passage on regeneration medium, the growth regulators in regeneration medium and the duration of the induction period. Regeneration potential from calli of all cultivars increased from the first to the fourth passage. Duration of the incubation period on induction medium (3 or 6 days) influenced regeneration to varying degrees, depending on the cultivar used and the regeneration medium contents. There were no differences between two of the regeneration media – B, containing 2.2 μM 6-benzyladenine and 0.3 μM indole-3-acetic acid and C, containing 4.4 μM 6-benzyladenine, 4.6 μM zeatin and 0.6 μM indole-3-acetic acid. Cultivar Mariola was the most productive and regenerated more than seven shoots per callus in the fourth passage. Regeneration on medium B was further evaluated on four additional gerbera cultivars.

The pattern of regeneration from tissues of Paeonia mlokosewitschii and P. tenuifolia cultured in vitro in the same chemical conditions depended on the initial explant. Direct shoot regeneration was obtained from the bases of petioles and petals, and leaf veins. Vegetative initial buds and regenerated in vitro shoots produced on their bases slowly growing nodular callus which was very productive in repetitive shoot regeneration. The tops of stems, flower bases, sepals, petals and ovary walls produced small callus which regenerated white and red spherical structures within 1.5 years. After that time also from those cultures arised nodular, shoot regenerating callus developed.