ISHS Acta Horticulturae 829: VI International Symposium on In Vitro Culture and Horticultural Breeding
SECONDARY SOMATIC EMBRYOGENESIS IN BANANA CIEN-BTA-03 (MUSA SP. AAAA) AND REGENERATION OF PLANTS |
| Authors: | M. Ramírez-Villalobos, E. de García |
| Keywords: | somatic embryos, scalps, shoot apexes, embryo conversion |
| Abstract:
Cavendish is the most widely cultivated banana in the world. Since cultivated bananas are propagated using conventional vegetative reproduction, plants are genetically identical and cannot evolve disease resistance. It has been necessary to employ biotechnology tools to induce mutation, namely, somaclonal variation, gene transfer, and somatic embryo induction. The latter provides the best vegetative material for in vitro genetic improvement programs. In the present investigation we established an efficient protocol to obtain somatic embryos and regenerate plants through secondary somatic embryogenesis from scalps of the somaclone CIEN-BTA-03 (AAAA), which is resistant to black Sigatoka. This clone was obtained by in vitro somaclonal variation of cv. ‘Williams’ Cavendish (AAA), which is susceptible to black Sigatoka. Vegetative shoots (8 mm high by 1.5 mm diameter) were taken from in vitro plants and incubated in media (MS salts plus four treatments of BA and IAA). The best results (46 scalps per cm2 of the tissue mass) were obtained in the treatment containing BA 25 mg/L, IAA 0.217 mg/L, when incubated for four months in temporary immersion, followed by two months in a similar though solid medium. The scalps were excised and cultured in embryogenesis induction medium Zs (one half MS salts, 1 mg/L 2,4-D, 0.219 mg/L zeatin and 1.8 g/L Phytagel). Embryogenic callus and primary embryos were obtained from the scalps after 3.5 months. Primary embryos were isolated and transferred to multiplication medium (Zs without Phytagel) and placed in an orbital shaker in darkness for two months to produce embryogenic cell suspensions (CS). Subsequently, aliquots of sediment of the CS were transferred to maturation medium MM (Zs without growth regulators), to produce mature embryos. After four months they were transferred to conversion medium (Zs plus 0.2 mg/L BA and 2 g/L Phytagel) to produce plants. This system is very effective and highly repeatable. | |
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