NZ helps peel off potato's genome

The potato is the world's third-most-important food crop after wheat and rice. Photo / Supplied

New Zealand researchers have helped to map the potato's genetic blueprint for the first time, in a breakthrough that could revolutionise potato breeding and food security.

Plant & Food Research scientists played an instrumental role in decoding the potato's DNA sequence, a key step in discovering how the crop grows and reproduces. The results of the five-year study were published in the journal Nature.

By establishing the genetic makeup of the crop, the Potato Genome Sequencing Consortium (PGSC) expects to help potato breeders to improve the yield, quality, nutritional value and disease resistance of potato varieties more quickly.

Plant & Food researcher Jeanne Jacobs said the development was highly significant because the potato was the world's third-most-important food crop.

"It's after wheat and rice. More tonnes of maize are produced but this mainly goes to animal feed. [Potato] is very important in terms of sustaining the population, and because it grows in such a wide range of environments, altitudes and latitudes - it's increasingly replacing other crops in marginal lands."

Every organism has a genome, a chemical "instruction book" that shows how all the genes should be put together. Sequencing the genome involves pulling apart the building blocks of the organism and reassembling them.

This enabled the consortium to locate the potato genes that held particular traits. The scientists could then target these genes in breeding, which sped up the process.

Dr Jacobs said the potato genome sequence permitted potato breeders to reduce the 10-12 years needed to create new varieties.

"I'd love to say we'll knock three or four years off, but that's very difficult to predict. You still have to test it out in the field.

"On the other hand, it increases efficiency. Rather than start off with a huge number [of genes] and have to carry it on for a number of years, we can much more readily target and say 'this is the lot we want to chase, forget the rest'."

Researchers found 39,000 genes in the potato genome. These would be used as a baseline for identifying the key genes of interest to the potato industry - high health, yield, pest and disease resistance.

"The baseline is enormously helpful in the next jigsaw we are trying to piece together. You'll sometimes find new genes, and that could well be the difference between having a resistance to a disease and not having resistance."

By 2020 it is estimated that more than two billion people worldwide will depend on potatoes for food, feed or income. The crop has a worldwide production of about 309 million tonnes, but around $5.1 billion of crops are lost every year to disease.