Peach

The peach (Prunus persica) is a deciduous tree native to the region of Northwest China between the Tarim Basin and the north slopes of the Kunlun Shan mountains, where it was first domesticated and cultivated. It bears an edible juicy fruit called a peach or a nectarine.

The specific epithet persica refers to its widespread cultivation in Persia, whence it was transplanted to Europe. It belongs to the genus Prunus which includes the cherry, apricot, almond and plum, in the rose family. The peach is classified with the almond in the subgenus Amygdalus, distinguished from the other subgenera by the corrugated seed shell. Peach and nectarines are the same species, even though they are regarded commercially as different fruits. In contrast to peaches, whose fruits present the characteristic fuzz on the skin, nectarines are characterized by the absence of fruit-skin trichomes (fuzz-less fruit); genetic studies suggest nectarines are produced due to a recessive allele, whereas peaches are produced from a dominant allele for fuzzy skin.

Peaches grow in a fairly limited range in dry, continental or temperate climates, since the trees have a chilling requirement that tropical or subtropical areas generally cannot satisfy except at high altitudes (for example in parts of Ecuador, Colombia, Ethiopia, India and Nepal). Most cultivars require 500 hours of chilling around 0 to 10 °C (32 to 50 °F). During the chilling period, key chemical reactions occur but the plant appears dormant. Once the chilling period is fulfilled, the plant enters a second type of dormancy, the quiescence period. During quiescence, buds break and grow when sufficient warm weather favorable to growth is accumulated.

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