Genomics of Commercially Important Traits in Date Palm (Phoenix dactylifera)

Lisa S. Mathew, Sweety Mathew, Karsten Suhre and Joel A. Malek

Weill Cornell Medicine in Qatar, Doha, Qatar

The Date Palm is a fruit tree of high importance to the region between North Africa and India. Recent efforts have produced draft genome assemblies, identified regions associated with the sex of a tree and color of the fruit. Despite this progress, few efforts have utilized genome-wide association studies (GWAS) to identify other commercially important traits. This is in part due to the fact that the vast majority of date palms are clonally propagated either by the traditional offshoots or, more recently, by tissue culture methods. Indeed, most date palm growing countries have just a few extremely popular cultivars that make up the majority of their crop. To support GWAS studies in date palm we have begun assembling a dates fruit biobank from more than 250 genetically distinct date palms. These originate from more than 12 countries and include many of the most popular date cultivars in the world. We have documented numerous features of the fruit including physical and chemical attributes. Additionally we have collected fruit from over 50 seed propagated date palms for use as a validation population. Genotype data from whole genome sequencing (200 samples) and genotyping-by-sequencing (50 samples) of the date fruit biobank samples have been assembled. Here we show the results of GWAS for commercially important traits of date palm fruit. It is expected that these results will assist in the development and breeding of improved date palm cultivars.