Seedless Maple
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A seedless fruit is a fruit developed to possess no mature seeds. Since eating seedless fruits is generally easier and more convenient, they are considered commercially valuable. Most commercially produced seedless fruits have been developed from plants whose fruits normally contain numerous relatively large hard seeds distributed throughout the flesh of the fruit.


Varieties

Common varieties of seedless fruits include watermelons, tomatoes, grapes (such as
Termarina rossa Termarina rossa is a red Italian wine grape variety that is grown in the Emilia-Romagna region of northern Italy. The grape is unique among ''Vitis vinifera'' varieties in that it is naturally seedless. Historically Termarina rossa was grown in the ...
). Additionally, there are numerous seedless citrus fruits, such as oranges, lemons and limes. A recent development over the last twenty years has been that of seedless
sweet peppers The bell pepper (also known as paprika, sweet pepper, pepper, or capsicum ) is the fruit of plants in the Grossum Group of the species ''Capsicum annuum''. Cultivars of the plant produce fruits in different colors, including red, yellow, orange ...
( Capsicum annuum). The seedless plant combines male sterility in the pepper plant (commonly occurring) with the ability to set seedless fruits (a natural fruit-setting without fertilization
WO/2008/152134
In male sterile plants, the
parthenocarpy In botany and horticulture, parthenocarpy is the natural or artificially induced production of fruit without fertilisation of ovules, which makes the fruit seedless. Stenospermocarpy may also produce apparently seedless fruit, but the seeds are ac ...
expresses itself only sporadically on the plant with deformed fruits. It has been reported that plant hormone provided by the ovary seed such as auxin and /or Gibberellin promotes fruit set and growth to produce seedless fruits. The innovation has been to develop Pepper plant, producing seedless marketable fruits from bottom to top of the plant. An end-product of sweet, crunchy, seedless fruit was achieved not by genetic manipulation, but by intelligent selection. Initially, without seeds in the fruit, vegetative propagation was essential. However, now – as with seedless watermelon – seedless peppers can be grown from seeds. The term "seedless fruit" is biologically somewhat contradictory, since fruits are usually defined botanically as mature ovaries containing seeds. Seedless fruits can develop in one of two ways: either the fruit develops without fertilization (
parthenocarpy In botany and horticulture, parthenocarpy is the natural or artificially induced production of fruit without fertilisation of ovules, which makes the fruit seedless. Stenospermocarpy may also produce apparently seedless fruit, but the seeds are ac ...
), or pollination triggers fruit development, but the ovules or embryos abort without producing mature seeds (
stenospermocarpy Stenospermocarpy is the biological mechanism that produces parthenocarpy (seedlessness) in some fruits, notably many table grapes. In stenospermocarpic fruits, normal pollination and fertilization are still required to ensure that the fruit 'sets', ...
). Seedless banana and watermelon fruits are produced on triploid plants, whose three sets of chromosomes make it very unlikely for meiosis to successfully produce
spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...
s and gametophytes. This is because one of the three copies of each chromosome can't pair with another appropriate chromosome before separating into daughter cells, so these extra third copies end up randomly distributed between the two daughter cells from
meiosis 1 Meiosis (; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately res ...
, resulting in the (usually) swiftly lethal aneuploidy condition. Such plants can arise by spontaneous mutation or by hybridization between
diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...
and tetraploid individuals of the same or different species. Some species, such as tomato, pineapple, and
cucumber Cucumber (''Cucumis sativus'') is a widely-cultivated Vine#Horticultural climbing plants, creeping vine plant in the Cucurbitaceae family that bears usually cylindrical Fruit, fruits, which are used as culinary vegetables.
, produce fruit in which there is no seed to be found if not pollinated but will produce seeded fruit if pollination occurs. Lacking seeds, and thus the capacity to propagate via the fruit, the plants are generally propagated vegetatively from cuttings, by
grafting Grafting or graftage is a horticultural technique whereby tissues of plants are joined so as to continue their growth together. The upper part of the combined plant is called the scion () while the lower part is called the rootstock. The succ ...
, or in the case of bananas, from "pups" (
offset Offset or Off-Set may refer to: Arts, entertainment, and media * "Off-Set", a song by T.I. and Young Thug from the '' Furious 7: Original Motion Picture Soundtrack'' * ''Offset'' (EP), a 2018 EP by singer Kim Chung-ha * ''Offset'' (film), a 200 ...
s). In such cases, the resulting plants are genetically identical
clone Clone or Clones or Cloning or Cloned or The Clone may refer to: Places * Clones, County Fermanagh * Clones, County Monaghan, a town in Ireland Biology * Clone (B-cell), a lymphocyte clone, the massive presence of which may indicate a pathologi ...
s. By contrast, seedless watermelons are grown from seeds. These seeds are produced by crossing diploid and tetraploid lines of watermelon, with the resulting seeds producing sterile triploid plants. Fruit development is triggered by pollination, so these plants must be grown alongside a diploid strain to provide pollen. Triploid plants with seedless fruits can also be produced using
endosperm The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the embryo and ...
culture for the regeneration of triploid plantlets from endosperm tissue via somatic embryogenesis. One disadvantage of most seedless crops is a significant reduction in the amount of
genetic diversity Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is dis ...
in the species. As genetically identical clones, a pest or disease that affects one individual is likely capable of affecting each of its clones. For example, the vast majority of commercially produced bananas are cloned from a single source, the '' Cavendish'' cultivar, and those plants are currently threatened worldwide by a newly discovered fungal disease to which they are highly susceptible.


References

{{reflist Edible fruits Fruit morphology