Crimson Seedless berry and seed sections

Stenospermocarpy is the biological mechanism that produces

parthenocarpy In botany and horticulture, parthenocarpy is the natural or artificially induced production of fruit without fertilisation of ovules, which makes the fruit seedless. The phenomenon has been observed since ancient times but was first scientificall ...

(seedlessness) in some fruits, notably many

table grapes Table grapes are grapes intended for consumption as fresh fruit, as opposed to grapes grown for wine production, juice production, jelly and jam making, or for drying into raisins. ''Vitis vinifera'' table grapes can be in the form of either s ...

. In stenospermocarpic fruits, normal

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma (botany), stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or bu ...

and

fertilization Fertilisation or fertilization (see American and British English spelling differences#-ise, -ize (-isation, -ization), spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give ...

are still required to ensure that the fruit 'sets', i.e. continues to develop on the plant; however subsequent abortion of the

embryo An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sp ...

that began growing following fertilization leads to a near seedless condition. The remains of the undeveloped seed are visible in the fruit. Most commercial seedless grapes are sprayed with

gibberellin Gibberellins (GAs) are plant hormones that regulate various Biological process, developmental processes, including Plant stem, stem elongation, germination, dormancy, flowering, flower development, and leaf and fruit senescence. They are one of th ...

to increase the size of the fruit and also to make the fruit clusters less tightly packed. A new cultivar, 'Melissa', has naturally larger fruit so does not require gibberellin sprays. Grape breeders have developed some new seedless grape

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

s by using the embryo rescue technique. Before the tiny embryo aborts, it is removed from the developing fruit and grown in

tissue culture Tissue culture is the growth of tissue (biology), tissues or cell (biology), cells in an artificial medium separate from the parent organism. This technique is also called micropropagation. This is typically facilitated via use of a liquid, semi-s ...

until it is large enough to survive on its own. Embryo rescue allows the crossing of two seedless grape cultivars. There are two types of seedlessness in grapes: true seedlessness of parthenocarpic berries when only ovules may develop and commercial seedlessness of stenospermocarpic berries when aborted seeds go unnoticed when chewing. Stenospermocarpic seeds vary significantly in size and in the degree of development of the seed coat and the endosperm. Larger seeds of stenospermocarpic grapes are referred to as rudimentary seeds and smaller ones as seed traces.Costantini, L., Moreno-Sanz, P., Nwafor, C.C. et al. 2021. Somatic variants for seed and fruit set in grapevine ''BMC Plant Biology'' 21(135): 33.
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Seedless grape cultivars

Seedless grapes are divided into white, red and black types based roughly on fruit color. The most popular seedless grape is known in the United States as '

Thompson Seedless The sultana is a "white" (pale green), oval seedless grape variety also called the sultanina, Thompson Seedless (United States), Lady de Coverly (England), and oval-fruited Kishmish (Iraq, Iran, Palestine, Pakistan, Afghanistan, India). It is a ...

', but was originally known as 'Sultana'. It is believed to be of ancient origin. It is considered a white grape, but is actually a pale green. Other white cultivars are 'Perlette', 'Menindee Seedless', 'Interlaken', 'Himrod', 'Romulanus', 'Lakemont', 'Fayez', and 'Remaily Seedless.' The most popular red seedless in the U.S. is 'Flame Seedless'. Other red cultivars are 'Crimson Seedless', 'Ruby Seedless', 'Suffolk Red', 'Saturn' and 'Pink Reliance'. Some black cultivars are 'Black Beauty', 'Black Monukka', 'Concord Seedless', 'Glenora' and ' Thomcord.' Thompson Seedless berry and seed section 01.jpg, Thompson Seedless Sheegene 21 berry and seed section 01.jpg, Sheegene 21 Crimson Seedless berry and seed section 05.jpg, Crimson Seedless IFG Three berry and seed section 01.jpg, IFG Three Red seedless grape section 01.jpg, A red seedless IFG Seventeen berry and seed section 02.jpg, IFG Seventeen

References

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External links

Herrera, E. 2002. Improving size and quality of seedless grapes. Guide H-311. New Mexico State University
Plant reproduction

Seedless grape cultivars

See also

References

External links