Are Seedless Grapes Genetically Modified? A Full Analysis of Tasty Varieties and Breeding Methods

Grapes are quite rich in potassium and excellent in quality and taste; they can be eaten fresh, dried into raisins, or squeezed for juice and made into wine, making them a fine fruit.So what varieties of seedless grapes are there? Are they genetically modified? How are they bred?It is understood that seedless grapes are not genetically modified. There are two kinds of seedless grapes, and neither is genetically modified. One is naturally seedless, triploid grapes, such as Summer Black and Wuhe Zaohong (8611); the other is obtained by treatment with growth hormones, such as using gibberellin to dip the flower clusters at full bloom, which can also yield seedless Kyoho grapes.

What varieties of seedless grapes are there?

Seedless grape varieties include Early Summer Seedless, Ruby, Flame Seedless, Horse Teat, Crimson Seedless, Red Globe Seedless, 8612, and Bixiang. These are naturally seedless. There are also some other varieties that can be treated to become seedless. Seedless green grapes cost 5 yuan/jin. There is also a very small but very sweet grape that costs around 10 yuan/jin.

How are seedless grapes bred?

So how can the seeds be prevented from developing while still providing the fruit with enough hormones to promote fruit development? There are the following methods:

1. Apply a certain concentration of plant hormones to the fruit, inhibiting seed development while promoting fruit development;

2. Through hybridization, make the seeds unable to develop normally, while giving a certain stimulus so that the fruit itself can produce enough plant hormones for its development;

3. Produce seedless grapes by seeking mutant individuals that naturally produce sterile seeds but can produce plant hormones themselves.

We know that after the pistil is pollinated, during the process in which the ovules develop into seeds, the developing seeds synthesize a large amount of auxin. Only under the action of this auxin can the ovary develop into fruit. So how do the ovaries of these seedless fruits develop into fruit? This is because these varieties synthesize more auxin in the ovary after flowering, and can develop directly into seedless fruit without the need for exogenous auxin or pollen stimulation. Although this characteristic of natural seedless fruit is controlled by genetic genes, it is also affected by the environment, especially temperature.

For example, frost damage can cause the formation of seedless pears; low temperature and high light intensity can induce seedless tomatoes; short-day conditions and lower night temperatures can cause melons to produce seedless fruit. This may be because low temperature and frost damage inhibit the normal fertilization and development of the ovules. Because seedless fruit does not form seeds, seedless grapes can only be propagated by vegetative means such as cuttings and grafting. Besides grapes, many other fruits are also obtained as seedless fruits by this method, such as bananas, mandarins, and pineapples.

Appendix: How to choose seedless grapes

1. Fresh grapes have a layer of white bloom on the surface, which comes off when touched by hand; grapes without white bloom may be the leftovers after being picked over, with all the bloom rubbed off.

2. Fresh grapes have firm stems, and the stems and berries are fairly firmly attached, while ordinary grapes that have been stored for a long time have berries that wobble as soon as the stem is lifted, so it is advisable not to buy them.