Sunday, June 30, 2013

Peach

          The peach, Prunus persica, is a deciduous tree, native to China, South Asia and North America. It bears an edible juicy fruit also called a peach. The species name persica refers to its widespread cultivation in Persia, whence it was transplanted to Europe. It belongs to the genus Prunus which includes the cherry and plum, in the family Rosaceae. The peach is classified with the almond in the subgenus Amygdalus, distinguished from the other subgenera by the corrugated seed shell.
          Peaches and nectarines are the same species, even though they are regarded commercially as different fruits. Nectarines have an orange center and faint fuzz, while peaches have white centers and very fuzzy skin; genetic studies suggest nectarines are produced due to a recessive allele, whereas peaches are produced from dominant allele for fuzzy skin.
          China is the world's largest producer of peaches and nectarines.

          Prunus persica grows to 4–10 m (13–33 ft) tall and 6 in. in diameter. The leaves are lanceolate, 7–16 cm (2.8–6.3 in) long, 2–3 cm (0.79–1.2 in) broad, pinnately veined. The flowers are
produced in early spring before the leaves; they are solitary or paired, 2.5–3 cm diameter, pink, with five petals. The fruit has yellow or whitish flesh,
a delicate aroma, and a skin that is either velvety ( peaches ) or smooth ( nectarines ) in different cultivars. The flesh is very delicate and easily bruised in some cultivars, but is fairly firm in some commercial varieties, especially when green.  The single, large seed is red-brown, oval shaped, approximately 1.3–2 cm long, and is surrounded by a wood-like husk. Peaches, along with cherries, plums and apricots, are stone fruits ( drupes ). There are various heirloom varieties, including the Indian peach, which arrives in the latter part of the summer.
          The scientific name persica, along with the word "peach" itself and its cognates in many European languages, derives from an early European belief that peaches were native to Persia. The Ancient Romans referred to the peach as malum persicum "Persian apple", later becoming French pêche , hence the English "peach".

          Cultivated peaches are divided into clingstones and freestones, depending on whether the flesh sticks to the stone or not; both can have either white or yellow flesh. Peaches with white flesh typically are very sweet with little acidity, while yellow-fleshed peaches typically have an acidic tang coupled with sweetness, though this also varies greatly. Both colours often have some red on their skin. Low-acid white-fleshed peaches are the most popular kinds in China, Japan, and neighbouring Asian countries, while Europeans and North Americans have historically favoured the acidic, yellow-fleshed kinds.
          Although its botanical name Prunus persica refers to Persia (present Iran) from where it came to Europe, genetic studies suggest peaches originated in China, where they have been cultivated since the early days of Chinese culture, circa 2000 BCE. Peaches were mentioned in Chinese writings as far back as the 10th century BCE and were a favoured fruit of kings and emperors. As of late, the history of cultivation of peaches in China has been extensively reviewed citing numerous original manuscripts dating back to 1100 BCE.
          The peach was brought to India and Western Asia in ancient times. Peach cultivation also went from China, through Persia, and reached Greece by 300 BCE. Alexander the Great introduced the fruit into Europe after he conquered the Persians. Peaches were well known to the Romans in first century AD, and was cultivated widely in Emilia-Romagna. Peach tree is portrayed in the domuswall paintings of the towns destroyed by the Vesuvius eruption of 79 AD, with the oldest artistic representations of peach fruit, discovered so far, are in the two fragments of wall paintings, dated back to the 1st century AD, in Herculaneum, now preserved in the National Archaeological Museum in Naples.

          It is a popular theory that the peach was brought to the Americas by Spanish explorers in the 16th century, and eventually made it to England and France in the 17th century, where it was a prized and expensive treat. The horticulturist George Minifie supposedly brought the first peaches from England to its North American colonies in the early 17th century, planting them at his Estate of Buckland in Virginia. Although Thomas Jefferson had peach trees at Monticello, United States farmers did not begin commercial production until the 19th century in Maryland, Delaware, Georgia and finally Virginia.
          It is little known however that there is proof of the peach being grown in Native American orchards prior to colonization with numerous varieties of peach being grown by Indigenous American people as well as a wild variety. It is thought to have grown as far north as the Aleutian Islands, where there in a cave a specific type of bowl used in the "peach pit game" was found which is several thousands of years old. The "peach pit game" known by many names and many Indigenous American cultures is an ancient game which is still played to this day.
          In April 2010, an International Consortium, The International Peach Genome Initiative (IPGI), that include researchers from USA, Italy, Chile, Spain and France announced they had sequenced the peach tree genome (doubled haploid Lovell).
          Peaches grow very well in a fairly limited range, since they have a chilling requirement that low altitude tropical areas cannot satisfy. In tropical and equatorial latitudes, such as Ecuador, Colombia, Ethiopia, India and Nepal, they grow at higher altitudes that can satisfy the chilling requirement. The trees themselves can usually tolerate temperatures to around -26 to -30 °C (-15 to -22 °F), although the following season's flower buds are usually killed at these temperatures, leading to no crop that summer. Flower bud kill begins to occur between -15 and -25 °C (5 and -13 °F), depending on the cultivar (some are more cold-tolerant than others) and the timing of the cold, with the buds becoming less cold tolerant in late winter.

          Typical peach cultivars begin bearing fruit in their third year and have a lifespan of about 12 years. Most cultivars require between 600 and 1,000 hours of chilling; cultivars with chilling requirements of 250 hours (10 days) or less have been developed enabling peach production in warmer climates. During the chilling period, key chemical reactions occur before the plant begins to grow again. Once the chilling period is met, the plant enters the so-called quiescence period, the second type of dormancy. During quiescence, buds break and grow when sufficient warm weather favorable to growth is accumulated. Quiescence is the phase of dormancy between satisfaction of the chilling requirement and the beginning of growth.
          Certain cultivars are more tender, and others can tolerate a few degrees colder. In addition, intense summer heat is required to mature the crop, with mean temperatures of the hottest month between 20 and 30 °C (68 and 86 °F). Another problematic issue in many peach-growing areas is spring frost. The trees tend to flower fairly early in spring. The blooms often can be damaged or killed by freezes; typically, if temperatures drop below about −4 °C (25 °F), most flowers will be killed. However, if the flowers are not fully open, they can tolerate a few degrees colder. (From Wikipedia)


Juice of fruit same kind
- Peach juice

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