In botany and horticulture, parthenocarpy (literally meaning virgin fruit) is the natural or artificially induced production of fruit without fertilization of ovules. The fruit is therefore seedless. Parthenocarpy occasionally occurs as a mutation in nature, but it is usually considered a defect, as the plant can no longer sexually reproduce, but may propagate by asexual means. However, parthenocarpy of some fruits on a plant may be of value. Seedlessness is a very desirable trait in edible fruit with hard seeds such as pineapple, banana, orange and grapefruit. Parthenocarpy is also desirable in fruit crops that may be difficult to pollinate or fertilize, such as tomato and summer squash. In dioecious species, such as persimmon, parthenocarpy increases fruit production because staminate trees do not need to be planted to provide pollen. Parthencarpy is undesirable in nut crops, such as pistachio, where the seed is the edible part.