Somatic embryogenesis and plant regeneration in suspension cultures of dessert (AA and AAA) and cooking (ABB) bananas (Musa spp.)

Proembryogenic calli were initiated from basal leaf sheaths and rhizome tissue on modified Schenk and Hildebrandt (SH) medium with 30 μM 3,6–dichloro–2–meth–oxybenzoic acid (Dicamba). Cell suspensions were maintained in half–strength Murashige and Skoog (MS) medium supplemented with 20 μM Dicamba. The development of somatic embryos was promoted in cell suspensions 3–4 weeks after subculture in liquid modified MS medium with 5 μM zeatin. Characteristic stages of embryonic development were recapitulated and histological examination confirmed bipolar organization of somatic embryos. Conversion into plantlets took place in double layer media system composed of solid half strength MS medium with 5 μM zeatin and 1 g/l charcoal and liquid, hormone–free, half strength MS medium. In four Musa genotypes several hundred plantlets were regenerated and transferred into soil where they continued to grow. Somatic embryogenesis represents a significant step in developing a new breeding strategy for apomictic banana and plantain species.