Development
of highland banana cell suspension system: A critical stage in genetic
improvement of the banana
P. Namanya,
G. Mutumba, S.M. Magambo, W. Tushemereirwe
The East African highland banana, the most important
staple food in Uganda, is susceptible to a range of pests and diseases.
This has been attributed to a limited genetic variation of the banana
group. Development of resistant genotypes using a genetic transformation
approach has been identified as a potential option to explore. The
initial objective was to establish a system to generate embryogenic cell
suspensions for East African highland bananas. Cell suspensions are the
material of choice for genetic transformation of banana because of their
regeneration capacity through somatic embryogenesis. Immature male
flowers were used as explant source.
Embryogenic callus with somatic embryos and friable tissue was
obtained after a culture period of 4 months on callus induction medium
designated M1. Subsequent
cell suspensions were initiated and maintained in liquid medium MA2
(Cote et al., 1996). The cells
in suspension were embryogenic and a cell growth rate of 1.5-2.0 scv per
month was observed. The embryogenic cell suspension stage is critical
for introduction of genes of resistance into the bananas. Regeneration produced up to 2.18x102 embryos per
0.05-0.1ml scv. Germination of these embryos was observed at 2.78% and
3.27% for two cell suspension lines. Plantlet recovery was 60-100%, all
being normal, plants with root and shoot at weaning. This study clears
the key hurdle to application of genetic improvement of East African
highland bananas using genetic transformation approaches.
|
