Musa acuminata Colla (AA genomes) and Musa balbisiana Colla (BB genomes) are the wild progenitors of the cultivated banana, they are highly variable in Thailand. The genetic system is relatively unknown and complicated due to interspecific hybridization, heterozygosity and polyploidy, which are common in most clones. These factors make identification of closely related banana cultivars difficult, especially when sterile. The high annealing temperature-random amplified polymorphic DNA (RAPD) technique was used to estimate the genetic relationship between 22 selected banana cultivars, utilizing 14 random primers. Phylogenetic relationship was determined by unweighted pair group method with arithmetical averages cluster analysis. The dendrogram constructed from the similarity data showed that all the 22 cultivars analysed were closely related with a narrow genetic base. There were sufficient RAPD polymorphisms that were collectively useful in distinguishing the cultivars. The dendrogram grouped all the AA, BB, AAA, AAB and ABB genomes into a major cluster. Several subgroups are recognized within the major clade. As expected, Ensete glauca Roxb. (Musaceae) and Strelitzia reginae Banks (Strelitziaceae) were clearly differentiated from the analysed edible bananas. Our study showed that RAPD markers are sufficiently abundant to classify and readily dissect genetic differences between the closely related Musa germplasm and provide a basis for the selection of parents for improvement of this germplasm.Keywords Banana Á Molecular phylogeny Á Musa Á HAT-RAPD Á Thailand Abbreviations HAT-RAPD High annealing temperaturerandom amplified polymorphic DNA BpBase pair(s) UPGMA Unweighted pair group method with arithmetical averages

Tetraploid plants were induced successfully from diploid bananas Musa acuminata (AA genome) 'Kluai Leb Mu Nang' and 'Kluai Sa' (2n = 2x = 22) with in vitro oryzalin treatment. Calluses from in vitro-grown shoot tips of both cultivars were treated with oryzalin at concentrations of 1.5 or 3 mg l -1 for 24, 48 and 72 h, respectively. The oryzalin treatments produced tetraploids at a frequency of 15.6% in 'Kluai Leb Mu Nang' and 16.7% in 'Kluai Sa' as detected by flow cytometry. Chromosome counting showed that the tetraploid plant chromosome number was (2n = 4x = 44). The selected tetraploid plants were transplanted in the field and variations in the morphological characteristic of leaf shape and fruit bunch compared to normal diploid plants were found under the same growing condition even after 3 years of cultivation.

A protocol for the regeneration of Gypsophila paniculata L. using nodal explants from 2-month-old field grown plants was established. The induction of multiple shoots was best obtained on Murashige and Skoog (MS) medium supplemented with 13.3 μM BA. Callus growth was observed on MS medium containing 44.3 μM BA. Calluses were transferred to MS medium supplemented with 2, 4-D (4.5, 13.5, 22.6 μM), NAA (5.3, 16.1, 26.8 μM) or BA (4.4, 13.3, 22.1 μM) for 2 months to induce shoot formation. After 6 weeks of initial culture, multiple shoots were regenerated from calluses cultured on MS medium supplemented with 13.3 μM BA. All regenerated shoots produced roots on 16.1 μM NAA containing MS medium within 4 weeks. Rooted plantlets were hardened and established in pots at 100% survival. For induction of in vitro flowering, regenerated shoots could be induced to flower efficiently when cultured on MS medium containing 13.3 μM BA and 50 g/l sucrose.

Experiments were carried out on four cell types: Chlorella sp., Tetraselmis sp., and mesophyll protoplasts of Dendrobium and Lilium longiflorum. The speed of cell translation in between a pair of cylindrical electrodes was measured at different solution conductivities (σ s ). For each field frequency, the speed was plotted against the gradient of electric field squared to obtain the real part Re[f(ω)] of complex permittivity. Conductivity (σ) and permittivity (ε) of the cytoplasm and cell membrane were obtained by iterative method using a spherical single shell model. It was found that membrane permittivity (ε m ) of plankton cells was fairly large compared to that of mesophyll protoplasts, whereas the reverse was true for membrane conductivity (σ m ). The permittivity of cytoplasm (ε c ) varied from 105ε o to 150ε o for plankton and from 83ε o to 105ε o for the protoplasts. The estimated values for σ c ranged from 8 to 40 mS.m -1 for plankton and from 1 to 20 mS.m -1 for the protoplasts. The cytoplasmic conductivity (σ c ) of the latter was the same as that of the external medium implying that these mesophyll protoplasts behave like lossy dielectric at σ s between 1 mS.m -1 to 20 mS.m -1 . Possible specific membrane capacitance (C m ) varied from 6 to 12 mF.m -2 for plankton and from 2 to 31 mF.m -2 for the protoplasts.

Plant regeneration of Anubias barteri var. Nana was achieved through organogenesis in shoot tip cultures. Multiple shoots were induced from cultured shoot tips on a modified MS (Murashige and Skoog, 1962) medium supplemented with BA and kinetin. The maximum green shoot numbers were best obtained on MS medium containing 3 mg/L BA with 5 shoots. Rooting in all regenerated shoots was promoted on MS medium devoid of plant growth regulators or kinetin singly. Acclimatization and survival when transferred to field conditions were shown to be 100% in the regenerated plants. Cytological and flow cytometric analyses of the mother plants and in vitro grown plants derived from 5 years old cultures showed no differences in ploidy level, they were all diploid (2n = 2x = 48) with a 2C peak indicating that ploidy alteration did not occur.