Which are seedless fruits

Why do some grapes have no seeds?

In nature there have always been grapes that are seedless. Biologists speak of parthenocarpy or virgin fruitiness when plants develop fruit without fertilization between male and female parts of the plant having taken place beforehand. There are some grape varieties that have a higher percentage of such seedless grapes than others. The property "seedlessness" could be improved further and further through breeding.

Sultanas and currants

Well-known seedless grape varieties are z. B. "Sultana" (also known as "Thompson Seedless") and "Korinthiaki". They are used to make the dried grapes known as "sultanas" or "currants", which are commercially available under the collective term "raisins". The ‘Thompson Seedless‘ variety is the world's most important seedless table grape for fresh consumption.

Almost seedless is also possible ...

In addition to the completely seedless berries, there are also those that only form very small and soft seeds that are barely noticeable when eating. Here biology speaks of sham parthenocarpy. In the trade, such grapes are usually offered as "seedless".

Seedless and large: only with hormone treatment

All "seedless" grape varieties have in common that they usually only develop relatively small berries without special treatment by the grower. This is because they lack a plant hormone that is required for berry growth, which is produced in the seeds.

If the vintner now wants his seedless grape varieties to develop large berries that can keep up with the large-fruited specimens in the trade, he can spray them with artificially produced plant hormones, usually gibberellins and auxins, during the growth phase. These plant hormones also occur naturally in the plant and are essential for the plant physiological processes. The two plant hormone groups mentioned are mainly involved in the growth processes of plants.

An additional effect of hormone treatment on table grapes is that the stems grow stronger. As a result, the berries do not hang so closely together and are less likely to be attacked by fungal diseases.

Hormone treatment is safe

The hormone treatment of grapes need not worry you. The applied plant hormones are not harmful to human health. In addition, the use by the user must be planned so that the active ingredient is completely degraded at the time of harvest.