A seedless fruit is a fruit developed to possess no mature seeds. Since eating seedless fruits is generally easier and more convenient, they are considered commercially valuable. Most commercially produced seedless fruits have been developed from plants whose fruits normally contain numerous relatively large hard seeds distributed throughout the flesh of the fruit. Varieties Common varieties of seedless fruits include watermelons, tomatoes, and grapes (such as Termarina rossa). Additionally, there are numerous seedless citrus fruits, such as oranges, lemons and limes. A recent development over the last twenty years has been that of seedless sweet peppers (Capsicum annuum). The seedless plant combines male sterility in the pepper plant (commonly occurring) with the ability to set seedless fruits (a natural fruit-setting without fertilization). In male sterile plants, the parthenocarpy expresses itself only sporadically on the plant with deformed fruits. It has been reported that plant hormones provided by the ovary seed (such as auxins and gibberellins) promote fruit set and growth to produce seedless fruits. Initially, without seeds in the fruit, vegetative propagation was essential. However, now – as with seedless watermelon – seedless peppers can be grown from seeds. Biological description Seedless fruits can develop in one of two ways: either the fruit develops without fertilization (parthenocarpy), or pollination triggers fruit development, but the ovules or embryos abort without producing mature seeds (stenospermocarpy). Seedless banana and watermelon fruits are produced on triploid plants, whose three sets of chromosomes make it very unlikely for meiosis to successfully produce spores and gametophytes. This is because one of the three copies of each chromosome cannot pair with another appropriate chromosome before separating into daughter cells, so these extra third copies end up randomly distributed between the two daughter cells from meiosis 1, resulting in the (usually) swiftly lethal aneuploidy condition. Such plants can arise by spontaneous mutation or by hybridization between diploid and tetraploid individuals of the same or different species. Some species, such as tomato, pineapple, and cucumber, produce fruit in which there is no seed to be found if not pollinated but will produce seeded fruit if pollination occurs. Lacking seeds, and thus the capacity to propagate via the fruit, the plants are generally propagated vegetatively from cuttings, by grafting, or in the case of bananas, from "pups" (offsets). In such cases, the resulting plants are genetically identical clones. By contrast, seedless watermelons are grown from seeds. These seeds are produced