Final answer:
Growing trees from seeds of store-bought fruit may result in less desirable fruits due to genetic variability from sexual reproduction. Asexual reproduction techniques like grafting are used to produce consistent quality fruit by combining desirable fruit properties with vigorous and disease-resistant rootstocks. Parthenocarpy, the development of fruit without seeds, may also play a role when dealing with seedlessness as a selected trait in breeding programs.
Step-by-step explanation:
When you grow trees from the seeds of fruits bought at grocery stores, the resulting fruit may not taste as good or may not bear fruit at all due to the genetic variability inherent in sexual reproduction. Most woody plants do not 'breed true' from seeds, which means a seed from a desirable plant, when grown, likely won't produce a tree with the same desirable traits. This is a result of the genetic mixing that occurs during sexual reproduction, resulting in offspring that are genetically distinct from their parents. Instead, commercial fruit producers use asexual reproduction techniques such as grafting, where the shoot of a plant with desirable fruit is attached to the rootstock of another plant that offers vigor and disease resistance.
Grafting allows for the preservation of the fruit's quality because the genetic material that codes for the fruit's desirable traits is directly transferred without the variation introduced by sexual reproduction. For example, the European grapevine, which produces high-quality wine grapes, has been successfully grafted onto North American species that are resistant to the insect pest Phylloxera. In contrast, sexual reproduction generates variability and while this can be beneficial for long-term evolution and adaptation, it often leads to less desirable traits for fruit production in the short term.
Seed grown trees may also not produce fruits due to the development of methods like parthenocarpy, where fruits develop without seeds, an adaptation that may not be favored in naturally propagated plants but might be intentionally selected for by agriculturalists. Breeding programs have used this to create varieties like seedless watermelons and seedless grapes, often through selective breeding and manipulation of the plant's genetics.