Researchers have discovered the genetic region responsible for blackberries’ deploying of a type of pointy self-protection: thorns, which scratch pickers and damage fruit and make thornless blackberry varieties the preferred option in the U.S. market. Now, a team of researchers has pinpointed the genetic location behind them, paving the way for plant breeders to speed up development of thornless varieties.
Margaret Worthington, associate professor of fruit breeding and genetics for the Arkansas Agricultural Experiment Station said blackberry breeders have not had the necessary genetic information to identify why some plants lacked what are technically known as prickles but are commonly called thorns.
All fresh market blackberry varieties are tetraploids, meaning they have four copies of every chromosome as opposed to humans’ two copies. The higher number of copies makes genetic analysis more difficult. No one knew the genetic locus, or the location of a gene on a chromosome, for the prickly trait, making it “an obvious target to work on” in Worthington’s eyes.
The resulting study, titled “Genetic control of prickles in tetraploid blackberry,” was published in the G3: Genes, Genomes, Genetics journal in March.
Worthington said to her knowledge, the results reveal the “first diagnostic marker for any trait that’s been developed and published in blackberry.”
Ellen Thompson, co-author of the study and Global Rubus Breeding and Development Director for Hortifrut Genetics, also highlighted the significance of the work. “These are the world’s first publicly available markers developed for fresh-market and processing blackberries. Markers save time and money, allowing breeders to make decisions faster — before seedlings are planted in the field. Though Hortifrut Genetics blackberry breeding program is already 100 percent thornless, something many other companies are trying to achieve, using these markers to screen seedlings in a high-throughput manner allows us to incorporate diverse and rustic traits of thorny germplasm, study segregation ratios more quickly and identify the associated desirable prickle-free phenotypes at a very early stage,”
Worthington said she hopes future research can go beyond identifying the locus and pinpoint the thorny trait’s causal gene itself.
