Cultivation of the date palm (Phoenix dactylifera L) began with the Spanish missionaries in the 1700's but commercial production did not begin until the introduction in the late 1800's and early 1900's of clonal materials from the Middle East and North Africab y the United States Department of Agriculture (USDA). Efforts to develop date palm cultivation under US conditions lead to the introduction of many different varieties from various countries. These materials were used in a breeding program conducted between 1948 and 1983. The objectives of the breeding program were to develop superior female varieties and backcrossed males to use for breeding purposes. Organized date palm research in the US was terminated in 1983. Date palm varieties deemed to be the best suited for production in the US as well as specific breeding lines and hybrids were incorporated into the germplasm holdings of the National Clonal Germplasm Repository for Citrus & Dates (NCGRCD). These genetic resources are maintained for use in scientific investigations and are available to qualified researchers around the world. Researchers in California and other countries have used NCGRCD holdings to investigate genetic relationships between varieties, develop molecular markers, and develop genomic information. Genome sequencing by the Qatar group has utilized some NCGRCD holdings and has coincidentally validated the identity of some NCGRCD accessions and backcrossed males. Currently, mapping populations are being generated for cooperative use.