Wetenschap - 15 januari 2015


Rob Ramaker

Eleven billion genetic letters analysed. Onion genome is five times bigger than human genome. Plant scientists at Wageningen have deciphered the genetic material
of the onion, as became clear from a presentation of provisional results at a conference in San Diegoin early January.

The onion is not the first crop to have its genome mapped: the bulb crop was preceded by the tomato and the potato. Even so, mapping such a large genome is still quite a feat, for the onion genome contains about 16 billion ‘genetic letters’, five times as many as the human genome. Now almost 11 billion of those 16 billion ‘genetic letters’ have been decoded, says Richard Finkers, a DLO researcher at Plant Research International. He hopes to be able to add many more before the final version is published. ‘The more information you have, the more questions you can answer about the evolution of the onion.’ Plant breeding companies can

use genetic information to develop new onion varieties more quickly onion plants that are disease resistant, for example, or that produce better quality onions. The new genetic information could also solve the problem of daylight requirements. Because onions grow all over the world, their ideal day length ranges from 11 to 16 hours of light. Cross-breeding often unintentionally changes the daylight requirement, says Finkers. Researchers now hope to find out which genes determine daylight preferences. That is why part of the funding for the Plant Breeding department’s top-sector project comes from the plant breeding company Bejo seeds.

 Photo: Colin