Genomic guides for date sex

High-throughput DNA sequencing has identified a region of the date palm genome that is linked to gender. The finding, reported online this week in Nature Biotechnology, may have important implications for production of this staple food in many Middle Eastern and North African nations.

Date palm (Phoenix dactylifera L.) is one of the three most economically important woody palms ― the two others being the oil and coconut palms. Approximately 100 million date palm trees throughout the world produce 15 million metric tons of fruit annually. Unlike most plants, date palms are either male of female. However, breeders need to wait at least five years before the plants reach maturity to discover whether a plant is a fruit-bearing female, or a barren male.

Joel Malek and colleagues assembled a draft of the date palm genome, the first of its kind for a member of the palm family. Comparisons of the genomic sequences from male and female date palms belonging to nine different varieties reveal sequences linked to gender. Thee authors also propose that date palm uses an XY-type system of gender inheritance, similar to that seen in humans. The authors 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.