Persica

a genus of trees of the family Rosaceae. There are five species: the peach (P. vulgaris), P. kansuensis, P. dawidiana, P. potanini, and P. mira. Persica is native to central and northern China, where it grows wild. All cultivated varieties, that is, fruit varieties, are descended basically from the peach. Other species are used mainly as ornamentals or stocks for cultivated varieties.

The peach reaches a height of 8 m. The leaves are alternate and broad- or oblong-lanceolate. The bisexual flowers are large and roselike in some varieties and small and campanulate in others. The fruit is a juicy drupe weighing from 20 to 600 g and ranging in shape from flat (napiform) to elongate (ovate or oval). The fruit, depending on the variety, has skin ranging in color from greenish white to orangish yellow; the skin has a light or carmine flush and is usually fuzzy. The flesh may be yellow or white, mealy or somewhat crunchy, and sweet or sour. The fruits may have freestones or clingstones.

The peach is native to mountain regions. Its range of cultivation is from 50° N lat. to 35°-45° S lat. The most extensive plantings are in the United States, France, Italy, Japan, Spain, Turkey, Bulgaria, Hungary, and Rumania. In the USSR the principal commercial plantings are in the republics of Middle Asia and Transcaucasia, in the Moldavian SSR, in the Dagestan ASSR, on the Black Sea coast of the Northern Caucasus, and in the Crimea. Peaches are relatively thermophile and tolerate heat well. The trees first bear fruit in the second or third year; fruiting continues until the trees are ten to 15 years old.

The fruits, also called peaches, contain 80-90 percent water, 6-14 percent sugar (5-10 percent sucrose), 0.5-1.2 percent pectins, 0.08-1.02 percent acids (mainly malic and tartaric acids), 9.4-20 mg percent vitamin C, and 0.6-1.0 mg percent carotene. The seeds (dry matter) contain 20-60 percent fatty oil and 0.7-0.4 percent essential and bitter almond oils. The fruits are eaten fresh, dried, or processed into compote, jam, or juice. The yield of fruit is up to 20-40 tons per hectare.

In the USSR more than 50 varieties have been regionalized. The most common include Aromatnyi, Ak-Sheftali 1 and 2, Zolotoi Iubilei, Kievskii rannii, Konservnyi rannii, Kremlevskii, Molozani, Narindzhi, Sochnyi, Sovetskii, and Uspekh. All peaches are divided into the following three groups: true peaches (with fuzzy fruits), nectarines (with smooth fruits), and napiform Persica (with flattened fruits). These groups include table varieties (with fibrous fruits) and canning varieties (with crunchy fruit). Ornamental peach varieties are noted for their pyramidal or “weeping” habit, their intensely dark leaves, and their double flowers.

Persica is propagated by seed or grafting. Seedlings of semicul-tivated Persica, bitter almond, wild myrobalan, blackthorn, and, less frequently, apricot are used as stocks. For good fruit production, the trees should be pruned and thinned out each year. The trees are damaged by the peach aphid and the peach borer. Diseases include leaf curl, mottle, and downy mildew.