Editing Cucumber (section)

=== Flowering and pollination ===
[[File:Cucumis sativus 0002.JPG|thumb|left|150px|''Cucumis sativus'' flower]]

{{Infobox genome
| image = <!-- Karyotype, for instance -->
| caption =
| taxId = 1639
| ploidy = diploid
| chromosomes = <!-- number of pairs -->
| size = 323.99 Mb
| year =
| organelle = mitochondrion
| organelle-size = 244.82 Mb
| organelle-year = 2011
}}

Most cucumber cultivars are seeded and require pollination. For this purpose, thousands of [[Honey bee|honey]] [[beehive]]s are annually carried to cucumber fields just before bloom. Cucumbers may also be pollinated via [[bumblebee]]s and several other bee species. Most cucumbers that require pollination are [[Self incompatibility in plants|self-incompatible]], thus requiring the [[pollen]] of another plant in order to form [[seed]]s and fruit.<ref name="Nonnecke">{{cite book |author=Nonnecke, I.L. |year=1989  |title=Vegetable Production |publisher=Springer  |isbn=9780442267216 |url=https://books.google.com/books?id=H7i8QJw8BJsC }}</ref> Some self-compatible cultivars exist that are related to the 'Lemon cucumber' cultivar.<ref name="Nonnecke" />

A few [[cultivar]]s of cucumber are [[Parthenocarpy|parthenocarpic]], the [[blossom]]s of which create [[seedless fruit]] without [[pollination]], which degrades the eating quality of these cultivar. In the [[Agriculture in the United States|United States]], these are usually grown in [[greenhouse]]s, where [[bee]]s are excluded. In [[Europe]], they are grown outdoors in some regions, where bees are likewise excluded.{{Citation needed|date=February 2021}}

Traditional cultivars produce male blossoms first, then female, in about equivalent numbers. Newer [[gynoecious]] hybrid cultivars produce almost all female blossoms. They may have a [[pollenizer]] cultivar interplanted, and the number of beehives per unit area is increased, but temperature changes induce male flowers even on these plants, which may be sufficient for pollination to occur.<ref name="Nonnecke" />

In 2009, an international team of researchers announced they had sequenced the cucumber [[genome]].<ref>{{Cite journal|last1=Huang|first1=S.|last2=Li|first2=R.|last3=Zhang|first3=Z.|last4=Li|first4=L.|last5=Gu|first5=X.|last6=Fan|first6=W.|last7=Lucas|first7=W.|last8=Wang|first8=X.|last9=Xie|first9=B.|last10=Ni|first10=P.|last11=Ren|first11=Y.|display-authors=4|year=2009|title=The genome of the cucumber, ''Cucumis sativus'' L|journal=Nature Genetics|volume=41|issue=12|pages=1275–81|doi=10.1038/ng.475|pmid=19881527|doi-access=free|first28=J.|first26=G.|last27=Lu|first27=Y.|last28=Ruan|first12=H.|last29=Qian|first29=W.|last30=Wang|first30=M.|first25=Y.|last26=Tian|last25=Ren|last13=Li|first18=J.|first13=J.|last14=Lin|first14=K.|last15=Jin|first15=W.|last16=Fei|first16=Z.|last17=Li|first17=G.|last18=Staub|last12=Zhu|first24=Z.|first19=A.|last20=Van Der Vossen|first20=E. A. G.|last21=Wu|first21=Y.|last22=Guo|first22=J.|last23=He|first23=J.|last24=Jia|last19=Kilian}}</ref>

A study of [[genetic recombination]] during [[meiosis]] in cucumber provided a high resolution landscape of meiotic [[DNA damage (naturally occurring)|DNA double strand-breaks]] and [[chromosomal crossover|genetic crossovers]].<ref name = Wang2023>{{cite journal |vauthors=Wang Y, Dong Z, Ma Y, Zheng Y, Huang S, Yang X |title=Comprehensive dissection of meiotic DNA double-strand breaks and crossovers in cucumber |journal=Plant Physiol |volume=193 |issue=3 |pages=1913–1932 |date=October 2023 |pmid=37530486 |pmc=10602612 |doi=10.1093/plphys/kiad432 |url=}}</ref>  The average number of crossovers per chromosome per meiosis was 0.92 to 0.99.<ref name = Wang2023/>