dates (fruit)

''Phoenix dactylifera'', commonly known as date or date palm, is a flowering plant species in the palm family, Arecaceae, cultivated for its edible sweet fruit called dates. The species is widely cultivated across northern Africa, the Middle East, and South Asia, and is naturalized in many tropical and subtropical regions worldwide. ''P. dactylifera'' is the type species of genus ''Phoenix'', which contains 12–19 species of wild date palms.

Date trees reach up to in height, growing singly or forming a clump with several stems from a single root system. Slow-growing, they can reach over 100 years of age when maintained properly. Date fruits (dates) are oval-cylindrical, long, and about in diameter, with colour ranging from dark brown to bright red or yellow, depending on variety. Containing 61–68 percent sugar by mass when dried, dates are very sweet and are enjoyed as desserts on their own or within confections.

Dates have been cultivated in the Middle East and the Indus Valley for thousands of years. There is archaeological evidence of date cultivation in Arabia from the 6th millennium BCE. The total annual world production of dates amounts to 8.5 million metric tons, countries of the Middle East and North Africa being the largest producers and consumers. Dates are “emblematic of oasis agriculture and highly symbolic in Muslim, Christian, and Jewish religions.”

Description

Date trees reach up to in height, growing singly or forming a clump with several stems from a single root system. Slow-growing, they can reach over 100 years of age when maintained properly. The roots have pneumatodes. The leaves are long, with spines on the petiole, and pinnate, with about 150 leaflets. The leaflets are long and wide. The full span of the crown ranges from .

The date palm is dioecious, having separate male and female plants. They can be easily grown from seed, but only 50% of seedlings will be female and hence fruit-bearing, and dates from seedling plants are often smaller and of poorer quality. Most commercial plantations thus use cuttings of heavily cropping cultivars. Plants grown from cuttings will fruit 2–3 years earlier than seedling plants.

Dates are naturally wind- pollinated, but in traditional oasis horticulture and modern commercial orchards they are entirely hand-pollinated. Natural pollination occurs with about an equal number of male and female plants. With assistance, one male can pollinate up to 100 females. Since the males are of value only as pollinators, they are usually pruned in favor of fruit-producing female plants. Some growers do not even maintain any male plants, as male flowers become available at local markets at pollination time. Manual pollination is done by skilled labourers on ladders, or by use of a wind machine. In some areas such as Iraq the pollinator climbs the tree using a special climbing tool that wraps around the tree trunk and the climber's back (called in Arabic) to keep him attached to the trunk while climbing.

Date fruits are oval-cylindrical, long, and diameter, and when ripe, range from bright red to bright yellow in colour, depending on variety. Dates contain a single stone about long and thick. Three main cultivar groups exist: soft (e.g. 'Barhee', 'Halawy', 'Khadrawy', 'Medjool'); semi-dry (e.g. 'Dayri', ' Deglet Nour', 'Zahdi'), and dry (e.g. 'Thoory').

Genome

In 2009, a team of researchers at the Weill Cornell Medical College in Qatar published a draft version of the date palm genome (Khalas variety). The draft genome sequence was improved in 2019 with the release of a more complete genome sequence using small molecule real-time sequencing technology by a team from the New York University Abu Dhabi Center for Genomics and Systems Biology and the UAE University Khalifa Center for Genetic Engineering and Biotechnology in the United Arab Emirates. With the release of this improved genome assembly, the UAE researchers were able to map genes for fruit color and sugar content. The NYU Abu Dhabi researchers had also re-sequenced the genomes of several date varieties to develop the first single nucleotide polymorphism map of the date palm genome in 2015.

Etymology

The species name ''dactylifera'' 'date-bearing' is Latin, and is formed with the loanword in Latin from Greek (), which means 'date' (also 'finger'), and with the native Latin , which means 'to bear'. The fruit is known as a date. The fruit's English name (through Old French, through Latin) comes from the Greek word for 'finger', , because of the fruit's elongated shape.

Distribution

The place of origin of the date palm is uncertain because of long cultivation. According to some sources it probably originated from the Fertile Crescent region straddling Egypt and Mesopotamia while others state that they are native to the Persian Gulf area or even western India. Fossil records show that the date palm has existed for at least 50 million years.

Ecology

A major palm pest, the red palm beetle (''Rhynchophorus ferrugineus''), currently poses a significant threat to date production in parts of the Middle East as well as to iconic landscape specimens throughout the Mediterranean world. Pinhas et al. 2008 uses piezoelectric sensors and speech recognition technology to detect ''R. ferrugineus''. They achieved a 98% detection ratio on young ''P. dactylifera'' in very controlled laboratory conditions. Another significant insect pest is '' Ommatissus lybicus'', sometimes called the "dubas bug", whose sap sucking results in sooty mould formation.

In the 1920s, eleven healthy Medjool palms were transferred from Morocco to the United States where they were tended by members of the Chemehuevi

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