Experiments were carried out to establish optimum culture condition and to identify the most responsive hypocotyls segments to regenerate shoots in the presence of slight callus for the local cabbage cultivar, Brassica oleracea L. var capitata subvar. kkcross. Results of the study showed that only the upper segment of the hypocotyls (1 cm and 2 cm from both shoot apex) excised from in vitro seedlings, regenerate shoots while the segment nearest to the apex (1 cm) regenerate both shoots and roots. Optimum regeneration was obtained when the seedlings' age were 3 weeks old as compared to younger or older explants. Types of culture vessels did not exhibit any significant effect on the hypocotyls culture. Multiple shoots with the presence of slight healthy callus (0.5 - 2.0mm diameter) were successfully regenerated at a frequency of 42 and 50% respectively from hypocotyls sections cultured on a basal Murashige and Skoog (MS) medium supplemented with 3-lndole acetic acid (1AA) [1 µg/L (w/v)], kinetin [2 µg/L(w/v)] and casein hydrolysate [500 µg/L(w/ v)] (designated as Ms1 medium) and B5 medium supplemented with adenine sulphate [40 mg/L(w/v)], glutamine (6mM) and 2, 4,5-trichlorophenoxyacetic acid [2,4,5- T (0.1 mg/L( w/v)] (designated as cs23 medium). Clonal propagation from axillary buds was induced on a basal MS medium supplemented with low concentration of kinetin [0.05-0.2mg/L(w/v)]. Plantlets with complete roots were successfully transferred into a mixture of soil and vermiculate (1: 1) and grown into normal mature cabbage plants in the glasshouse.
Protocorm-like bodies (PLBs) of an orchid (Oncidium lanceanum) were irradiated using 220 MeV 12 C 5+ ions, accelerated by AVF cyclotron at JAEA, Japan in 2005. Five different doses were applied to the PLBs; 0, 1.0, 2.0, 6.0 and 12.0 Gy. Following irradiation, these PLBs were maintained in cultures for germination and multiplication. Irradiation effects on growth and seedling regeneration patterns as well as molecular characteristics of the in vitro cultures were monitored and recorded. In general, average fresh weights of the irradiated PLBs increased progressively by irradiating the explants at 1.0, 2.0 and reached the maximum at 6.0 Gy. The figure however dropped when the explants were irradiated at 12 Gy. Surprisingly, although the highest average fresh weight was recorded on PLBs irradiated at 6.0 Gy, most of these PLBs were not able to regenerate into complete shoots. On average, after 4 months of irradiation, only 21 seedlings were successfully regenerated from each gram of these PLBs. The highest shoot regeneration was recorded on cultures irradiated at 2.0 Gy in which 102 seedlings were obtained from one gram of the PLBs. Some morphological changes were seen on in vitro plantlets derived from PLBs irradiated at doses of 1.0 and 2.0 Gy. Most of the regenerated seedlings have been transferred to glasshouse for further morphological selection. Molecular analysis showed the presence of DNA polymorphisms among the seedlings from different doses of irradiation.