Banana (genus Musa) diversity is high with genetics indicating multiple
origins centred in south East Asia. This giant herbaceses plant grows up to 3m
in height and is distributed mainly along rainforest margins. There are
approximately 50 species (as seen below) including plantains all that are monocotyledonous,
sterile and parthenocarpic; so the fruit develops without seed development or
pollination and fertilization.
They came into cultivation
by farmer’s collection of cultivators from the wild who spontaneously exhibited
a parthenocarpic fruit production mutation which has now led to a production of
100 million tons annually, with banana being a staple food across the Asian,
African and American tropics. About 85% of banana production is eaten as a
staple food in the country of production and banana export remains a
significant part of the economy of many developing countries. Successful
cultivation is due to the production of ‘suckers’, a vegetative copy of the parent
plant that grows at the base of the mother. They are removed and planted separately
allowing rapid vegetative propagation and multiplication.
However banana production
faces major challenges from biotic and abiotic stresses. Due to its difficult
to trace genetics and the sterility of the crop, attempts at hybridization,
mutation or transformation to create new varieties has so far been unsuccessful.
There are several devastating diseases and virulent strains affecting Musa
varieties such as Black sigatoka leaf spot, Mycosphaerella fijiensis; a fungal disease leading to 50% crop
losses. Currently controls to stop disease spread include the development and
application of chemical controls, and the search for genetically resistant
cultivars.
Within the gene pool of cultivars
and wild species there are genetic resistances to many stresses with potential
for exploitation. Genomic approaches are now rapidly advancing in Musa and have
the prospect of helping enable banana to maintain and increase its importance
as a staple food and cash crop. To
create better food security through greater yields and more efficient
production, greater yield stability, better use of water, less and less toxic
chemical input, and higher quality further genetic research into Musa crops is
needed to allow for targeted breeding, transformation and efficient use of Musa biodiversity
in the future (Heslop-Harrison &
Schwarzacher, 2007).
