Bland tomatoes don’t have tasty genes

It’s no secret that heirloom tomatoes taste superior to their supermarket equivalents. Now research shows certain genes responsible for that intense flavour have been bred out.

Denise Tieman at the Chinese Academy of Agricultural Sciences in Shenzhen and colleagues conducted detailed analyses on tomatoes to identify the cause of the taste discrepancy.

Their work, published in the journal Science, emphasises the need to focus on re-flavouring one of the world’s highest-value fruits – a product which, according to the paper, is “a major cause of consumer complaint”.

To find the genetic root of the tasteless tomato problem, the team sequenced genomes of almost 400 modern, heirloom and wild tomatoes, tracking the sugars, acids and volatile chemicals that potentially contribute to flavour.

Heirloom and wild tomatoes were used as a baseline example of a tomato’s chemical composition in times before human intervention.

The results show that certain purpose-grown species developed by humans do not rate well on taste, even at peak ripeness, and that post-harvest techniques such as refrigeration can also damage flavour.

The team also asked a group of participants to rate the taste of 101 different varieties of tomato.

This data comparison helped the researchers tease out which genes have the most effect on taste, contributing to the beginnings of a roadmap to recovering the lost flavour.

Data pointed to 33 chemicals linked to overall consumer liking, and 37 that significantly correlated with “flavour intensity”. Smaller tomatoes were found to have higher sugar content, thus a sweeter flavour.

The researchers also uncovered 13 flavour-associated volatile chemicals that were significantly reduced in modern varieties and used their genomic data to identify the corresponding genes that had been lost.

The findings could kickstart a taste recovery in modern tomatoes – and also apply to other crops.