Source: Digest - Crop & Food Research's quarterly newsletter - Issue 54

A single gene has been identified as critical to both the sweetness and storability of onions

In collaboration with international colleagues, Crop & Food Research vegetable geneticist John McCallum has been able to identify that a gene, Frc on chromosome 8, is responsible for sugar content in onions.

It’s a discovery that could have significant implications for onion growers the world over.

“The information could make it possible in the future to consistently produce sweet-eating or better storing onions,”  Dr McCallum says. “Given that onions currently vary widely in terms of bulb size, taste and processing qualities, this research is likely to be highly sought-after by growers interested in consistent characteristics.”

Dr McCallum says there is a relationship between sweetness and dry matter level, which is important for onion storability. The more frequently the sweetness gene occurs, the sweeter the onion. The less often it occurs, the less sweet, but the harder the onion is, making it good for storage or export.

The research, which took five years, was funded by the Foundation for Research, Science and Technology. International collaboration with researchers in Japan, the Netherlands and the USA allowed access to plant and genome data that helped clinch the story.

“This research is one of the first major practical applications of the onion gene map,” Dr McCallum says.