Breeding better strawberries? Scientists uncover genetic roadmap of cultivated strawberry

26 Feb 2019 --- An international team of scientists led by the University of California, Davis,(UC Davis) and Michigan State University have sequenced and analyzed the genome of the cultivated strawberry, which will provide a genetic roadmap to help more precisely select desired traits.

Consumers want strawberries to be sweet, ripe and juicy, like those picked fresh from a garden. Suppliers want them to be easy to handle and ship and commercial strawberry growers need their crops to be high-yielding and disease-resistant. This step may now allow breeders to grow a strawberry to satisfy all those needs.

The study was published yesterday in the journal Nature Genetics.

“Without the genome, we were flying blind,” says Steven Knapp, Professor of Plant Sciences and Director of the UC Davis Strawberry Breeding Program. “It was like having a library of books, but all the books’ pages were blank.”

Protecting strawberries from disease
The US is the world's largest producer of strawberries, and almost 90 percent of them are grown in the cool, coastal climates of California. Growers are continually struggling to fight off diseases like Fusarium wilt, Verticillium wilt and Macrophomina without having to use fumigants. The assembled genome will allow scientists to identify specific genes that can protect the plant against diseases. Strawberries can also develop diseases that may involve several different genes, similar to complex diseases in humans. Sequencing the genome will help unravel that complexity.

“The genome sequence is powerful because it provides scientists with barcodes for nearly all the genes in strawberry. We can use that information to identify genes that play an important role in traits of agricultural importance,” notes Knapp.

Similarly, scientists may also be able to find genes in the strawberry that lead to increased flavor or aroma for the consumer, while maintaining the firmness and shelf life for producers.

Origins of the strawberry
Patrick Edger, co-corresponding author with Michigan State University, and his team also deciphered the complex evolutionary history of the cultivated strawberry. While humans are diploid species, meaning each cell contains two complete sets of chromosomes, one from each parent, the cultivated strawberry is an octoploid. Each cell in a strawberry plant contains eight complete sets of chromosomes, so untangling its evolution is a feat.

“The strawberry has a rich history that spans the globe, ultimately culminating in the fruit we enjoy today,” he says.