Somatic embryogenesis of the banana hybrid cultivar FHIA-18 (AAAB) in liquid medium and scaled-up in a bioreactor

The development of somatic embryos in liquid culture medium has a number of advantages for large-scale propagation of plants. This paper describes an improved system for the mass propagation via somatic embryogenesis of the banana hybrid cultivar FHIA-18 (AAAB). Explants from immature male flowers were used to form high frequency embryogenic tissue, this tissue was then used to establish embryogenic cell suspensions in a basic MS medium plus 1.0 mg l^–1 biotin, 100 mg l^–1 glutamine, 100 mg l^–1 malt extract (Sigma), 1.0 mg l^–1 2,4-D and 45 g l^–1 sucrose. Secondary multiplication of somatic embryos was achieved in liquid media in rotary shaker and in bioreactors. The number of embryos per litre obtained with 80.0% DO₂ and effects of pH were also studied. A high regeneration percentage of plants were obtained (89.3%) in only 1 month of culture, somatic embryos were then placed to germinate in temporary immersion systems and field testing of somaclonal variation.     

Complete germination of papaya (<Emphasis Type="Italic">Carica papaya</Emphasis> L. cv. `Maradol Roja´) somatic embryos using temporary immersion system type RITA® and phloroglucinol in semi-solid culture medium

A critical factor in somatic embryogenesis protocols in papaya (Carica papaya L.) has been incomplete germination of somatic embryos due to formation of a basal callus, which prevents the emission of the radicle. This work aims to achieve complete germination of somatic embryos in liquid and semi-solid culture media. The effect of the culture conditions on germination of somatic embryos using the RITA® temporary immersion system were evaluated as well as the effect of phloroglucinol on germination of somatic embryos in semi-solid culture medium. The results of using the RITA® culture medium with a combination of 0.02 μM BAP and 2.90 μM gibberellic acid had a good response for total germination (100%) but somatic embryos had only partial germination with 400 mg fresh mass. However, the optimum inoculum density was 200 mg fresh mass of somatic embryos which produced 100% total germination and 95% somatic embryos with complete germination. Also, it was possible to achieve complete germination of somatic embryos with low callus formation (13%) using phloroglucinol at a concentration of 475.8 μM on semi-solid culture medium. This is the first report of two biotechnological strategies for complete germination of plants from somatic embryos in the papaya cultivar `Maradol Roja´.