New technique to boost taste of tomatoes

Scientists have identified the important factors responsible for loss of flavour in tomato, an advance that can make the supermarket tomatoes taste noticeably better.
Numerous genes responsible for the flavour of tomatoes have been lost, as food producers selected the fruit for other qualities, such as size and firmness.
Now, researchers at University of Florida (UF) in the US have unveiled the lost genes associated with the original flavour.
"We're just fixing what has been damaged over the last half century to push them back to where they were a century ago, taste-wise," said Harry Klee, a professor of horticultural sciences with UF.

"We can make the supermarket tomato taste noticeably better," he said, adding the technique involves classical genetics, not genetic modification.
In the study, step one was to find out which of the hundreds of chemicals in a tomato contribute the most to taste.

Modern tomatoes lack sufficient sugars and volatile chemicals critical to better flavour, Klee said.
Those traits have been lost during the past 50 years because breeders have not had the tools to routinely screen for flavour, he said.
To help, researchers studied what they call "alleles," the versions of DNA in a tomato gene that give it its specific traits.

Klee likened the concept to DNA in humans. Everyone has the same number of genes in their DNA, but a particular version of each gene determines traits such as height, weight and hair colour.
"We wanted to identify why modern tomato varieties are deficient in those flavour chemicals. It's because they have lost the more desirable alleles of a number of genes," Klee said.
Scientists then identified the locations of the good alleles in the tomato genome, he said. That required what is called a genome-wide assessment study.
The scientists mapped genes that control synthesis of all the important chemicals. Once they found them, they used genetic analysis to replace bad alleles in modern tomato varieties with the good alleles, Klee said.

Because breeding takes time, and the scientists are studying five or more genes, Klee said the genetic traits from his latest study may take three to four years to produce in new tomato varieties.
The study was published in the journal Science.