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- Author or Editor: Adriana C. de M. Dantas x
- HortScience x
This work was carried out in the Tissue Culture Laboratory of Embrapa Temperate Climate aiming to maximize the protocol for in vitro culture of potato cv. Baronesa. The treatments consisted of multiplication of microcuttings with one, two, or three buds with/without leaves and originated from different regions of the shoot: apical, middle, or basal. Each treatment was repeated five times with each replication composed of five explants that were inoculated in 250-ml flasks with 40 ml of the medium containing MS salts and vitamins added to: sucrose (30 g·L-1), myo-inositol (100 mg·L-1), agar (6 g·L-1). The pH was adjusted to 5.6 before autoclaving. After inoculation, the flasks remained in a growth room at 25 ± 2 °C, 16-h photoperiod, and 19 μmol·m-2·s-1 light intensity provided by cool-white fluorescents lamps. Observations were done every 5 days. Final evaluation was performed after 30 days. It was observed that basal microcuttings provided longer shoots and that microcuttings with leaves bore the best ones. This kind of explant also favored a higher number of shoots, axilary buds, and better multiplication rate. The presence of leaves in the microcutting is important when basal explants are used once it can improve the number of axillary buds and the rate of multiplication. The higher the number of buds in the microcutting the lower the rate of multiplication. The in vitro multiplication of potato could be improved by using one-leaf bud basal microcutting.
Three different leaf segments (apical, basal, and middle) were treated in combination with aluminum at 0, 5, 10, 15 and 20 mg·L-1. Three kinds of leaf segments were inoculated in flasks in 12 replicates, with the adaxial surface touching the medium composed by basic macro- and micronutrient and MS vitamins added to 2,4-D (1.0 mg·L-1); BAP (5.0 mg·L-1); sucrose (30.0 g·L-1); myo-inositol (100.0 mg·L-1) and agar (6.0 g·L-1). The pH was adjusted to 4.0 before autoclaving. After inoculation, the explants were incubated in a dark growth room for 21 days and then, placed during 80 days, at 25 ± 2 °C, 16-h photoperiod provided by white fluorescent lamps under 19 μE·m-2·s-1 radiation. At the end of this period, the explants were evaluated. It was observed that basal leaf explants provided greener callus and that the heavier ones came from the middle leaf explants. Absence of Al or high Al concentrations favored the number of adventitious buds, whereas intermediate concentrations inhibited them. The absence of Al favored basal explants to form adventitious shoots, while lower concentrations favored apical and basal segments. High Al concentration appear to stimulate adventitious shoots in the basal and middle explants. Although it was evident that callus intensities were lower in higher Al concentration, Al is not so harmful to callogenesis and organogenesis.
This work aims to verify the effect of BAP (6-benzyladenine purine) and CPPU (forchlofenuron) on the in vitro shoot proliferation of apple rootstock cultivars M.111 and M.7 under different concentrations. The experiment was carried out in the tissue culture laboratory at Embrapa Temperate Climate in Pelotas, RS, Brazil. As initial explants, microcuttings were used from in vitro culture. The treatments consisted of the combination of two cultivars with cytokinins and six differents concentrations (0.0, 1.5, 3.0, 4.5, and 6.0 μMol). The explants were inoculated in 250-mL flasks with 40 mL MS medium with agar (7.0 g·L-1), myo-inositol (100.0 g·L-1), NAA (0.005 mg·L-1), and sucrose (40.0 g·L-1). The pH was adjusted to 5.9 before autoclaving. After inoculations the culture was kept for 50 days under 25 ± 2 °C, 16-h photoperiod, and 19 μMol·m-2·s-1 radiation. CPPU performed better than BAP for cultivar M.111 and it had similar response for cultivar M.7 as bud and shoot multiplication and multiplication rate is concerned. The BAP increased the number of shoots with higher length and with no callus formation in the shoot base, contrary to CPPU. The most efficient concentrations were 4.7 and 5.5 μMol for CPPU and BAP, respectively.
This work aimed to evaluate apple rootstock somaclones by characterizing the genetic variability among them. The isoenzymatic systems were used for analyzing variability as follows: FAC (acid phosphatase), PRX (peroxidase), and 6-PGD (6-phosphogluconate dehydrogenase). The migration were performed by applying a potential difference around 10 volt/linear cm. A data matrix was built so that the genotypes were placed in the lines and the bands in the columns. The scores were attributed as follows: band present (1) and band not present (0). By the gel analyses in relation to the presence/absence and band intensity, we observed marked differences among the somaclones and within somaclones as well. In the peroxidase system a higher band polyimorphism was detected with 18 enzymatic patterns. The group analyses for the 73 apple somaclones revealed a large variability through the enzymes (18 peroxidases, 8 FAC, and 6 6-PGD), which were classified into two groups. Group I was represented by M.7 somaclones with seven subgroups with 43% similarity among the clones. Differences among M.9 and M.111 cultivars and two clones referred to as M9b and M925 were fitted within somaclones M.111. The remaining somaclones of cultivar M.9 showed a higher variability bearing 43 subgroups. Clones M929, M930 and M932 presented 100% similarity.