Seedless grapes are in fact as natural and as healthy as grapes with seeds, and unlike popular conjecture, they are not genetically modified organisms. Seedless grapes are used in the production of raisins, jelly, jam, juice, and wine, and are preferred over seeded grapes for reason of edibility.

Grapes have been cultivated for thousands of years. Vitis Vinifera  was domesticated from the wild grape, V. Vinifera Sylvestris, but still bears close morphological and genealogical characteristics. In fact wild grapes can interbreed with domesticated grapes when they encounter each other, however they flower at different times which reduces the likelihood of gene transfer through pollination. Wild grapes are sometimes reintroduced into commercial grape breeding programs, but mutations occur frequently in grape cultivars leading to a diverse genetic pool Seedlessness is the result of a natural mutation that occurred in some cultivated grapes. This natural phenomenon was exploited by vineyards to improve the desirability of grapes by making them easier to grow and consume. Most seedless grapes are bred from the Sultania (Thompson seedless) landrace (traditional isolated cultivars), but also the Black Monukka, Malta, Beauty Seedless, and others.

Seedless grapes are either a result of parthenocarpy –which is also how banana’s and many other fruits and vegetables reproduce, or stenospermocarpy. Parthenocarpy is a naturally occurring type of vegetative reproduction in crops that does not require fertilization, and results in seedless offspring. In stenospermocarpy, fertilization does occur, but development stops at the rudimentary stage, resulting in “aborted” seeds that are largely imperceptible. However, seedless grapes do contain traces of seeds.

Most commercial seedless grapes are stenospermocarpically cultivated through traditional hybrid breeding and embryo rescue. In hybrid breeding, as the name suggests, seeded grapes are cross-bred with seedless grapes. Seeded grapes are used as the female parent, while seedless grapes are employed as the pollen parent. Traditional hybridization results in a low yield of seedless grapes. However, another method of cultivation known as embryo rescue yields over 80% seedless grapes. In embryo rescue, both parent grapes are of the seedless variety.

Seedlessness is just one characteristic amongst many that was selectively bred in grapes to increase desirability. Domestication and breeding of grape cultivars has also increased the quality, size, sugar content, and edibility of the fruit. Grapes are a good course of fiber, vitamins, and antioxidants. When a study on the antioxidant potency of 13 different varieties of grapes was conducted,  both seedless and seeded grapes were found to have potent antioxidant activity. Two out of the top three most potent were indeed seedless, and in addition skin color didn’t matter. It was determined that antioxidant potency was dependent upon the chemical composition of polyphenols and flavonoids within the grape. grape. Seedlessness does not change the nutritional value of the crop. Nutrient content however, is dependent on species-type, cultivar, soil, regional climate, pathogen invasion, and vineyard.

Domestication and cultivation of crops has greatly improved the quality and quantity of foods that we eat. Agricultural breeding practices select for specific desirable characteristics to propagate fresh produce. These traditional practices date back to ancient times, in regard to grape vineyards, and are useful for maintaining consistency in yield, quality, and appearance.  Human selection as well as natural mutations have resulted in different varieties, such as seedless cultivars, but seedless grapes are not produced through genetic modification (which involves the insertion of genes from other organisms) and are no less nutritious or healthy than seeded grapes.

References

Li, Z., Li, T., Wang, Y., & Xu, Y. (2015). Breeding new seedless grapes using in ovulo embryo rescue and marker-assisted selection. In Vitro Cellular & Developmental Biology, 51(3), 241-248. doi:http://dx.doi.org/10.1007/s11627-015-9677-x

Clark, J. R. (2010). Eastern united states table grape breeding. Journal of the American Pomological Society, 64(2), 72-77. Retrieved from

Kedage, V. V., Tilak, J. C., Dixit, G. B., Devasagayam, T. P. A., & Mhatre, M. (2007). A study of antioxidant properties of some varieties of grapes (vitis vinifera L.). Critical Reviews in Food Science and Nutrition, 47(2), 175-85.

ARADHYA, M. K., DANGL, G. S., PRINS, B. H., BOURSIQUOT, J., WALKER, M. A., MEREDITH, C. P., & SIMON, C. J. (2003). Genetic structure and differentiation in cultivated grape, vitis vinifera L. Genetical Research, 81(3), 179-92

Cain, D. (2010). New diversity in table grapes: A commercial perspective. Journal of the American Pomological Society, 64(2), 83-85.

Patrice This, Thierry Lacombe, Mark R. Thomas (2006). Historical origins and genetic diversity of wine grapes. Trends in Genetics, 22(9), 511-519.