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  • Author or Editor: Marisa de F. Oliveira x
  • HortScience x
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Asparagus is a vegetable that presents an increase in yield when propagated by meristem culture. On the order hand, the rooting phase in asparagus is greatly affected by the previous phase, i.e,. multiplication. This species presents a better rooting performance when callus is formed at the shoot base. So, the aim of this work was to evaluate treatments during the multiplication phase, which also leads to callus formation at the shoot base. The initial explants came from shoots being cultivated in vitro. It was tested kinetin at: (0.0, 0.5, 1.0, 1.5, and 2.0) μM; ancymidol at (0.0 and 0.5) μM and NAA at (0.0 and 0.5) μM for both genotypes, which were cultured in a MS medium added to sucrose (30 g·L–1), agar (6.0 g·L–1) and myo-inositol (100.0 m g·L–1). Shoots bearing two buds were inoculated in 10-ml test tubes and placed in a growth room for 30 days when they were evaluated. The addition of kinetin significantly improved the number of buds and at 1.3 μM this growth substance presented the best results as number of shoots is concerned. NAA application promoted a negative effect on spear bearing. The addition of ancymidol in this phase did not improve the bud multiplication. It was shown that clone M14 performed better than the hybrid cv. Deco as multiplication is concerned.

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The potato cultivar Cristal recently released by the CPACT/EMBRAPA Breeding Program has high dry matter and low reduce sugars. These are desirable characteristics as industry processing is concerned. Nevertheless, this is a recalcitrant cultivar. The meristem culture is difficult to establish along with a very low multiplication rate. The aim of this work was to improve the multiplication rate for this cultivar. Two-bud microcuttings derived from apical, mid, and basal regions were inoculated in test tubes with 10 ml MS culture media and vitamins as follows; myo-inositol (100 mg·L–1); sucrose (10 g·L–1). No growth regulator was added. All treatments were placed in a growth room in a 16-hour photoperiod; 25 ± 2°C and 2000 lux. One month later, although it was observed that the final growth was more pronounced for basal microcuttings, no difference could be detected for number of shoots and multiplication rate. It was concluded that it makes no difference whatsoever kind of microcutting is used to start the micropropagation process.

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The potato cultivar Cristal has recently been released by the CPACT/EMBRAPA Breeding Program. Such cultivar was selected for having high dry matter and low sugar content, which makes it desirable for the chip industry. However, this is a recalcitrant cultivar as far as in vitro multiplication is concerned. The aim of this work was to improve the rate of multiplication for this cultivar when it was submitted to different MS salt and sucrose concentrations in the culture media. Two-bud microcuttings were inoculated in test tubes (20 × 150) mm with 10 ml MS media at 3/4-, 1/2-, and full-strength and MS vitamins added to: myo-inositol (100 mg·L–1), agar (7.0 g·L–1) and sucrose as follows: 10, 20 and 30 g·L-1. Each treatment was repeated eight times and each replicate had eight explants. After inoculation the whole material was kept in a growth room at 25 ± 2°C, 16-hr photoperiod and 2000 lux. The evaluation was done 35 days later. It was found and increase in the number of buds as the sucrose concentration in the media decreased. As far as MS salts are concerned no difference in bud number was observed. The rate of multiplication was slightly higher for MS media at full strength and sucrose at low concentration (10 g·L–1). This treatment could be recommended for this cultivar.

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The apple crop in Brazil is established in acid soils with low pH. This condition leads to high aluminum levels in the soil. The aim of this work was to evaluate the callogenesis and organogenesis of apple rootstock somatic material under aluminum and different auxins concentrations. Internodes of apple rootstock cv. Marubakaido were inoculated in a MS medium containing aluminum (10 mg·L–1), BAP (5.0 mg·L–1), MS vitamins, myo-inositol (100 mg·L–1), sucrose (30 g·L–1), and agar (6.0 g·L–1). Picloram and NAA were tested at (0, 0.5, 1.0, 1.5, and 2.0 μM. Internodes were inoculated in test tubes and the whole material remained in dark for 3 weeks and then to 16-h photoperiod, 25 ± 2°C and 2000 lux. NAA-treated explants performed better than picloram ones. Callus intensity was maximized at 0.5 μM NAA. Although the higher percentage of callus formed (91%) occurred for NAA at 1.0 μM and 82% for picloram at the same concentration. NAA-treated explants responded for 62% of regenerated callus, while picloram presented only 6%. NAA also increased the mean number of shoots (3.54) and buds (11.52) as compared to picloram, which presented 1.40 and 2.78, respectively.

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