Sweet success for scientists

The cacao bean - from the cacao tree - is the key ingredient of chocolate, but blight frequently wipes out entire crops, costing growers more than $700m each year.

However, by mapping the genes of the cacao tree, scientists hope to identify key traits in its DNA that will allow them to breed or engineer high-yielding plants with greater disease resistance.

With the chocolate business already generating $50bn a year, such an achievement would come with big financial rewards for farmers and chocolate makers.

Al Jazeera's Tarek Bazely reports.