/ 27 June 2008

Success will be sweet in latest genome hunt

The cacao plant is to become the latest organism to have its complete genetic code sequenced, but it is no idle exercise to generate tastier products for chocoholics.

The five-year project is expected to help crop scientists identify genes in different varieties of cacao trees that make them resilient to drought and resistant to pests and diseases.

By using the information to direct crop breeding programmes, scientists believe they will be able to grow hybrid cacao trees that are more robust and produce higher yields than existing varieties.

In the past 15 years, three funguses called witches’ broom, frosty pod and black pod have devastated the global cocoa crop, costing growers an estimated $694-million a year. The losses, exacerbated by political unrest in Africa where much of the crop is grown, have contributed to a 50% rise in cocoa prices in the past year.

Understanding more about the tree’s genetic make-up could give scientists clues on how best to protect crops against water shortages and diseases which may emerge as climate change takes hold.

An estimated 500-million pairs of letters make up the cocoa genome, which will be analysed by IBM’s Blue Gene computer, the second fastest in the world. The computer firm is joining forces in the $10-million Chocolate Genome Project with the US department of agriculture and the confectionery company Mars.

”Once we have the whole genome, they’ll be able to go in and look at all the genes they’re interested in,” said Ray Schnell, a geneticist at the United States agriculture department’s subtropical horticulture research station in Florida. ”They’ll all be interested in flavour genes.” When the project is finished, the complete set of genes will be made public.

Researchers have begun field trials of cacao trees in West Africa, Papua New Guinea, and South and Central America. – guardian.co.uk