Mars has started to unwrap the DNA of chocolate, a scientific milestone it claims will improve cocoa quality for 6.5 million farmers who depend on the crop.

The preliminary cacao genome sequence was unveiled three years ahead of target this week. It is the product of a multimillion-dollar joint research project launched two years ago by Mars, the US Department of Agriculture's Research Service and IBM to create a more sustainable world ­cocoa supply.

The complete genome has yet to be decoded, but Mars claimed the initial findings would be enough to help farmers breed more robust, higher yielding, drought and disease-resistant cocoa trees. The data will be publicly available for free with no patent.

Mars estimated farmers suffered £400m to 500m in damages to cocoa last year and said West Africa stood to benefit most from the findings as it represented 70% of global production.

Similar research has been undertaken on corn, rice and wheat but Mars global director of plant science Howard-Yana Shapiro said cocoa has been an "orphan crop" in terms of genome sequencing.

"Though cocoa is one of the top 10 traded commodities, it is grown in regions where governments don't have a lot of funding for science and research so there hasn't been anyone to support it," he said. "So we decided to take matters into our own hands."

Shapiro wouldn't comment on whether the research would result in GM chocolate entering Mars products but stressed that the focus was to equip farmers with better tools to accelerate traditional breeding methods.