Date sex – XY marks the spot

Dates, the sticky, sweet fruits of the date palm (Phoenix dactylifera), are the product of sexual reproduction in that plant and borne on the female plants of this dioecious species. Globally, about 15 million metric tonnes of dates are produced annually from 100 million date palm trees and represent a staple food in many Middle Eastern and North African nations. Given this economic importance it is important to know if an individual tree is male or female. Up to now breeders have had to wait for 5 years before they could tell the sex of a tree. That process is likely to be speeded up dramatically with the discovery by Eman Al-Dous et al. (Nature Biotechnology; doi:10.1038/nbt.1860) of sequences of the genome that are linked to gender. The work, which represents the first genome sequence of a member of the palm family (Arecaceae) – and, indeed, of the higher taxonomic ranking, the order Arecales – has also identified genetic markers likely to facilitate breeding of traits such as superior fruit quality and more convenient ripening times into the best current cultivars. The group also propose that the date palm employs an XY system of gender inheritance, similar to that used by humans. In case you were wondering, parthenocarpy is known in this species, but the seedless fruit is smaller and of lower quality than the sexually produced product (http://en.wikipedia.org/wiki/Date_%28fruit%29#Food_uses).