Editing Date palm (section)

== Description ==

Date palms reach up to {{convert|30|m|ft|-1|abbr=off}} 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.<ref name="Hodel" /> The roots have [[pneumatode]]s.<ref name="Halli-Mangenot-1986">{{cite journal |last1=Belarbi-Halli |first1=R. |last2=Mangenot |first2=F. |date=1986-08-01 |title=Bayoud disease of date palm: ultrastructure of root infection through pneumatodes |journal=Canadian Journal of Botany |volume=64 |issue=8 |pages=1703–1711 |doi=10.1139/b86-228 |bibcode=1986CaJB...64.1703B |issn=0008-4026}}</ref> The [[leaves]] are {{convert|4|-|6|m|ft|abbr=on}} long, with spines on the [[petiole (botany)|petiole]], and [[pinnate]], with about 150 leaflets. The leaflets are {{convert|30|cm|in|0|abbr=off}} long and {{convert|2|cm|in|0|abbr=on}} wide. The full span of the crown ranges from {{convert|6|-|10|m|ft|abbr=on}}.

The date palm is [[dioecious]], having separate male and female plants. Like all members of genus Phoenix, sex determination occurs through an [[XY sex-determination system]], where three genes that are conserved in all males and absent in all females have been identified.<ref>[https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.634901/full Evidence of Recombination Suppression Blocks on the Y Chromosome of Date Palm (Phoenix dactylifera)]</ref> 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 [[Cutting (plant)|cuttings]] of heavily cropping cultivars. Plants grown from cuttings will fruit 2–3 years earlier than seedling plants.

[[File:דקל תמר מצוי חתך גזע דמוי עץ (3).jpg|thumb|''Phoenix dactylifera'' trunk section. As with other members of the [[Arecaceae|palm family]], date palms do not produce annual [[tree rings]].]]
[[File:Phoenix dactylifera 0zz.jpg|thumb|Leaves of the date palm]]
Dates are naturally wind-[[pollination|pollinated]], but in traditional oasis horticulture and modern commercial orchards, they are entirely [[Hand-pollination|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 maintain 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 {{lang|ar|تبلية}} in Arabic) to keep him attached to the trunk while climbing.{{citation needed|date=May 2024}}

Date fruits are oval-cylindrical, {{convert|3|-|7|cm|abbr=on|in|frac=2}} long, and {{convert|2|-|3|cm|in|frac=4|abbr=on}} diameter, and when ripe, range from bright red to bright yellow in colour, depending on variety. Dates contain a single [[Drupe|stone]] (seed) about {{convert|2|-|2.5|cm|in|frac=8|abbr=on}} long and {{convert|6|-|8|mm|in|abbr=on|frac=32}} thick. Three main [[cultivar group]]s exist: ''soft'' (e.g., [[Medjool]]); ''semi-dry'' (e.g., [[Deglet Noor]]), and ''dry'' (e.g., [[Thoory]]).{{citation needed|date=May 2024}}

=== Genome ===
[[File:Germination of Date Palm.jpg|thumb|right|Germination of date palm]]

A draft genome of ''P. dactylifera'' ([[Khalas (date)|Khalas variety]]) was published in 2011<ref>{{Cite journal |last1=Al-Dous |first1=Eman K. |last2=George |first2=Binu |last3=Al-Mahmoud |first3=Maryam E. |last4=Al-Jaber |first4=Moneera Y. |last5=Wang |first5=Hao |last6=Salameh |first6=Yasmeen M. |last7=Al-Azwani |first7=Eman K. |last8=Chaluvadi |first8=Srinivasa |last9=Pontaroli |first9=Ana C. |last10=DeBarry |first10=Jeremy |last11=Arondel |first11=Vincent |last12=Ohlrogge |first12=John |last13=Saie |first13=Imad J. |last14=Suliman-Elmeer |first14=Khaled M. |last15=Bennetzen |first15=Jeffrey L. |date=June 2011 |title=De novo genome sequencing and comparative genomics of date palm (Phoenix dactylifera) |journal=Nature Biotechnology |language=en |publication-date=2011 |volume=29 |issue=6 |pages=521–527 |doi=10.1038/nbt.1860 |issn=1546-1696|doi-access=free |pmid=21623354 }}</ref> followed by more complete genome assemblies in 2013<ref>{{Cite journal |last1=Al-Mssallem |first1=Ibrahim S. |last2=Hu |first2=Songnian |last3=Zhang |first3=Xiaowei |last4=Lin |first4=Qiang |last5=Liu |first5=Wanfei |last6=Tan |first6=Jun |last7=Yu |first7=Xiaoguang |last8=Liu |first8=Jiucheng |last9=Pan |first9=Linlin |last10=Zhang |first10=Tongwu |last11=Yin |first11=Yuxin |last12=Xin |first12=Chengqi |last13=Wu |first13=Hao |last14=Zhang |first14=Guangyu |last15=Ba Abdullah |first15=Mohammed M. |date=2013-08-06 |title=Genome sequence of the date palm Phoenix dactylifera L |journal=Nature Communications |language=en |volume=4 |issue=1 |pages=2274 |doi=10.1038/ncomms3274 |issn=2041-1723 |pmc=3741641 |pmid=23917264|bibcode=2013NatCo...4.2274A }}</ref> and 2019.<ref name="Hazzouri-2019" /> The later study used long-read sequencing technology. With the release of this improved genome assembly, the researchers were able to map genes for fruit color and sugar content.<ref name="Hazzouri-2019">{{cite journal | doi=10.1038/s41467-019-12604-9 | title=Genome-wide association mapping of date palm fruit traits | year=2019 | last1=Hazzouri | first1=Khaled M. | last2=Gros-Balthazard | first2=Muriel | last3=Flowers | first3=Jonathan M. | last4=Copetti | first4=Dario | last5=Lemansour | first5=Alain | last6=Lebrun | first6=Marc | last7=Masmoudi | first7=Khaled | last8=Ferrand | first8=Sylvie | last9=Dhar | first9=Michael I. | last10=Fresquez | first10=Zoë A. | last11=Rosas | first11=Ulises | last12=Zhang | first12=Jianwei | last13=Talag | first13=Jayson | last14=Lee | first14=Seunghee | last15=Kudrna | first15=David | last16=Powell | first16=Robyn F. | last17=Leitch | first17=Ilia J. | last18=Krueger | first18=Robert R. | last19=Wing | first19=Rod A. | last20=Amiri | first20=Khaled M. A. | last21=Purugganan | first21=Michael D. | journal=Nature Communications | volume=10 | issue=1 | page=4680 | pmid=31615981 | pmc=6794320 | bibcode=2019NatCo..10.4680H }}</ref> The [[New York University Abu Dhabi|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.<ref>{{cite journal | doi=10.1038/ncomms9824 | title=Whole genome re-sequencing of date palms yields insights into diversification of a fruit tree crop | year=2015 | last1=Hazzouri | first1=Khaled M. | last2=Flowers | first2=Jonathan M. | last3=Visser | first3=Hendrik J. | last4=Khierallah | first4=Hussam S. M. | last5=Rosas | first5=Ulises | last6=Pham | first6=Gina M. | last7=Meyer | first7=Rachel S. | last8=Johansen | first8=Caryn K. | last9=Fresquez | first9=Zoë A. | last10=Masmoudi | first10=Khaled | last11=Haider | first11=Nadia | last12=El Kadri | first12=Nabila | last13=Idaghdour | first13=Youssef | last14=Malek | first14=Joel A. | last15=Thirkhill | first15=Deborah | last16=Markhand | first16=Ghulam S. | last17=Krueger | first17=Robert R. | last18=Zaid | first18=Abdelouahhab | last19=Purugganan | first19=Michael D. | journal=Nature Communications | volume=6 | page=8824 | pmid=26549859 | pmc=4667612 | bibcode=2015NatCo...6.8824H }}</ref>