Freestone cultivars, those with fruits that break away easily from the stone or seed, are much more popular for the fresh market than the clingstone type in which the flesh of the fruit is firmly attached to the stone. The freestone 'Elberta' cv. has been the most popular of all cultivars, but it is being replaced by firmer, more attractive cultivars. The highly perishable fruit must be harvested at a precise stage of ripening. Following fertilization, only one ovule normally develops at the expense of the other, leading to the development of a one- seeded stone. The peach ovary is covered with a dense coat of hairs.
Most cultivars produce pollen at the time the stigma is receptive.
Nectar is secreted at the base of the corolla. The fact that only one ovule must be fertilized for a peach fruit to set as compared to hundreds of ovules in other fruit such as melons or papayas, enormously simplifies the pollination of the peach. Normally, the flowers are fully closed at 6 a.m., but most of them are open by 10 a.m., and all are open by noon. Considering the economic importance of the peach crop, surprisingly little has been done about its pollination requirements. Many self- sterile cultivars have been largely or completely eliminated from the market, regardless of their other good qualities, because interplanting of cultivars and insect pollination are necessary in their production.