14 February 2019
Crete’s contribution to North African date palms
Published online 15 January 2019
New research sheds light on the evolutionary origins of the North African date palm.
North African date palms are a hybrid between cultivated date palms from the Middle East and a wild species of palm that grows on the island of Crete and in parts of southern Turkey, new research shows.
The research sheds light on the evolutionary history of one of the oldest tree crop species in the world, which remains a major fruit crop of arid regions of the Middle East and North Africa.
Researchers from New York University’s Abu Dhabi’s Center for Genomics and Systems Biology sequenced the genomes of 71 cultivated date palm varieties from the Middle East, North Africa and South Asia, and multiple genomes from each of its five closest relatives.
They found that hybridization between P. dactlifera date palms and P. theophrasti — a species endemic to the Eastern Mediterranean — is the source of mixed ancestry and genetic distinction of North African date palms.
The analysis found that up to 18 percent of the genome of North African varieties could be traced to P. theophrasti. Researchers say hybridization has not only led to increased genetic diversity in North African date palms compared to date palms from the Middle East, but may also lead to new genes being introduced to cultivated date palms that could improve yields and disease resistance.
“Our results continue a trend that we are seeing: that the movement of many fruit tree crops are accompanied by hybridization with local wild species,” says NYUAD biologist Michael Purugganan. “[We want] to continue to highlight the importance that between-species hybridization has on crop adaptation.”
Flowers, J. M. et al. Cross-species hybridization and the origin of North African date palms. PNAS http://dx.doi.org/10.1073/pnas.1817453116 (2019).