Parthenocarpy

Parthenocarpy, a term coined by the botanist Noll in 1902, is the phenomenon in which a fruit develops without the ovary having undergone fertilization at all. It occurs naturally in certain varieties of pineapple, banana, and papaya. In these plants, the placental tissue inside the unfertilized ovary itself produces the plant hormone auxin (specifically indole-3-acetic acid, IAA), and it is this auxin, rather than any signal from a developing embryo/seed, that drives the enlargement of the ovary into a fruit. The resulting fruit closely resembles a normally, sexually produced fruit in size and appearance, but, because no fertilization and hence no seed development ever took place, it is seedless.

Beyond the varieties in which it occurs naturally, parthenocarpy can also be induced artificially in otherwise seed-bearing crops, using techniques such as spraying the flower with gibberellins, deliberately delaying pollination, or dusting the stigma with pollen from a different (incompatible) species purely to trigger the hormonal cascade without achieving true fertilization. This artificial induction is of direct commercial value, since it is one of the standard ways seedless fruit varieties are produced for the market.