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Stenospermocarpy

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**Stenospermocarpy:**

Stenospermocarpy leads to seedlessness in fruits like table grapes.
– Normal pollination and fertilization are needed for fruit development.
– Gibberellin is used in commercial seedless grapes to increase fruit size.
Grape breeders use the embryo rescue technique to develop new seedless grape cultivars.
– Two types of seedlessness in grapes are true seedlessness and commercial seedlessness.

**Stenospermocarpy Seeds:**

– Stenospermocarpic seeds vary in size and development.
– Larger seeds are called rudimentary seeds, while smaller ones are seed traces.
– Different types of seeds are visible in stenospermocarpic grapes.
– A scientific article shows photos of ovules and seeds in grape cultivars.
– The degree of development of seed coat and endosperm varies in stenospermocarpic seeds.

**Seedless Grape Cultivars:**

– Seedless grapes are categorized into white, red, and black types based on fruit color.
– Popular white seedless grapes include Thompson Seedless and Perlette.
– Flame Seedless is a popular red seedless grape cultivar.
– Black Beauty and Concord Seedless are examples of black seedless grape cultivars.
– Various seedless grape cultivars are cultivated worldwide.

**External Links:**

– Herrera (2002) provides guidance on improving size and quality of seedless grapes.
– The link to the Wikipedia page on Stenospermocarpy offers more information.
– New Mexico State University’s Guide H-311 discusses seedless grape cultivation.
– The external links section contains resources related to plant reproduction.
– The Wikipedia page on Stenospermocarpy falls under hidden categories on the site.

**References:**

– Ramming (1999) discusses new grape cultivars.
Wood (1997) highlights mouth-watering new fruits in agricultural research.
– Stout (1936) delves into seedlessness in grapes in a technical bulletin.
– Striem et al. (1992) explore the development of seed-coat and endosperm in grapes.
– Costantini et al. (2021) present somatic variants for seed and fruit set in grapevine.

Stenospermocarpy (Wikipedia)

Stenospermocarpy is the biological mechanism that produces parthenocarpy (seedlessness) in some fruits, notably many table grapes.

Undeveloped seeds in 'Crimson Seedless' grapes

In stenospermocarpic fruits, normal pollination and fertilization are still required to ensure that the fruit 'sets', i.e. continues to develop on the plant; however subsequent abortion of the embryo 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 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 cultivars by using the embryo rescue technique. Before the tiny embryo aborts, it is removed from the developing fruit and grown in tissue culture 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 significant 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. A scientific article with many photos of ovules, aborted and normal seeds of the parthenocarpic, stenospermocarpic and seeded cultivars.

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