nakhil

phoenix dactylifera

Description

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 the genus Phoenix, which contains 12–19 species of wild date palms.

Date trees reach up to 30 meters (100 feet) 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 4–6 m (13–20 ft) long, with spines on the petiole, and pinnate, with about 150 leaflets. The leaflets are 30 centimeters (12 inches) long and 2 cm (1 in) wide. The full span of the crown ranges from 6–10 m (20–33 ft).

Date fruits (dates) are oval-cylindrical, 3 to 7 centimeters (1 to 3 inches) long, and about 2.5 cm (1 in) in diameter, with colors ranging from dark brown to bright red or yellow, depending on the variety. Dates contain a single stone about 2–2.5 cm (3⁄4–1 in) long and 6–8 mm (1⁄4–5⁄16 in) 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’). 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.

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.

As with other members of the palm family, date palms do not produce tree rings.

Dates are naturally wind-pollinated, but in both traditional oasis horticulture and in modern commercial orchards they are entirely pollinated manually. Natural pollination occurs with about an equal number of male and female plants. However, 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 laborers 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 تبلية in Arabic) to keep him attached to the trunk while climbing.

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, UAE researchers were able to map genes for fruit color and sugar content. The NYU Abu Dhabi researchers 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 dactylus in Latin from Greek daktylos (δάκτυλος), which means ‘date’ (also ‘finger’), and with the native Latin fero, 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’, δάκτυλος, because of the fruit’s elongated shape.

Distribution

The place of origin of the date palm is uncertain because of its 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.

Gallery