The Domestication of the Apple Gift from Central Asia

The domestic apple (Malus domestica Borkh and sometimes known as M. pumila) is one of the most important fruit crops grown in temperate regions worldwide, used for cooking, eating fresh, and cider production. There are 35 species in the genus Malus, part of the Rosaceae family which includes several temperate fruit trees. Apples are one of the most widely distributed of any perennial crop and one of the top 20 most productive crops in the world. A total of 80.8 million tons of apples are produced annually worldwide. The apples domestication history starts in the Tien Shan mountains of Central Asia, at least 4,000 years ago, and probably closer to 10,000. Domestication History Modern apples were domesticated from wild apples, called crabapples. The Old English word crabbe means bitter or sharp-tasting, and that certainly describes them. There were likely three main stages in the use of apples and their eventual domestication, widely separated in time: cider production, domestication and spread, and apple breeding. Crabapple seed remains likely from cider production have been found in numerous Neolithic and Bronze age sites across Eurasia. Apples were first domesticated from the crabapple Malus sieversii Roem somewhere in the Tien Shan mountains of Central Asia (most likely Kazakhstan) between 4,000–10,000 years ago. M. sieversii grows at intermediate elevations between 900–1,600 meters above sea level (3,000–5,200 feet) and is variable in growth habit, height, fruit quality, and fruit size. Domesticated Characteristics There are thousands of apple cultivars today with a wide range of fruit sizes and flavors. The small, sour crabapple was turned into large and sweet apples, as humans selected for large fruits, firm flesh texture, longer shelf life, better post-harvest disease resistance, and reduced bruising during harvest and transportation. Flavor in apples is created by a balance between sugars and acids, both of which have been altered depending on the variety. The domestic apple also has a comparatively lengthy juvenile phase (it takes 5–7 years for apples to begin producing fruit), and the fruit hangs longer on the tree. Unlike crabapples, domesticated apples are self-incompatible, that is to say, they cant self-fertilize, so if you plant the seeds from an apple the resulting tree frequently does not resemble the parent tree. Instead, apples are propagated by grafting rootstocks. The use of dwarfed apple trees as rootstocks allows for the selection and propagation of superior genotypes. Crossing into Europe Apples were spread outside of central Asia by steppe society nomads, who traveled in caravans along ancient trade routes predating the Silk Road. Wild stands along the route were created by seed germination in horse droppings. According to several sources, a 3,800-year-old cuneiform tablet in Mesopotamia illustrates grapevine grafting, and it may well be that grafting technology helped to spread apples into Europe. The tablet itself has not yet been published. As the traders moved the apples outside of central Asia, the apples were crossed with local crabapples such as Malus baccata in Siberia; M. orientalis in the Caucasus, and M. sylvestris in Europe. Evidence of that westward movement from central Asia includes isolated patches of large sweet apples in the Caucasus mountains, Afghanistan, Turkey, Iran, and the Kursk region of European Russia. The earliest evidence for M. domestica in Europe is from the Sammardenchia-Cueis site in northeastern Italy. There a fruit from M. domestica was recovered from a context dated between 6570–5684 RCYBP (cited in Rottoli and Pessina listed below). A 3,000-year-old apple at Navan Fort in Ireland may also be evidence of early apple seedling imports from central Asia. Sweet apple production—grafting, cultivation, harvesting, storage, and the use of dwarf apple trees—is reported in ancient Greece by the 9th century BCE. The Romans learned about apples from the Greeks and then spread the new fruit throughout their empire. Modern Apple Breeding The last step in apple domestication took place only in the last few hundred years when apple breeding became popular. Current apple production worldwide is limited to a few dozen ornamental and edible cultivars, which are treated with high levels of chemical inputs: however, there are many thousands of named domestic apple varieties. Modern breeding practices start with the small set of cultivars and then create new varieties by selecting for a range of qualities: fruit quality (including flavor, taste, and texture), higher productivity, how well they keep over the winter, shorter growing seasons and synchronicity in blooming or fruit ripening, length of cold requirement and cold tolerance, drought tolerance, fruit tenacity, and disease resistance. Apples occupy a central position in folklore, culture, and art in several myths from many western societies (Johnny Appleseed, fairytales featuring witches and poisoned apples, and of course the stories of untrustworthy snakes). Unlike many other crops, new apple types are released and embraced by the marketplace—Zestar and Honeycrisp are a couple of new and successful varieties. In comparison, new grape cultivars are very rare and typically fail to gain new markets. Crabapples Crabapples are still important as sources of variation for apple breeding and food for wildlife and as hedges in agricultural landscapes. There are four extant crabapple species in the old world: M. sieversii in the Tien Shan forests; M. baccata in Siberia; M. orientalis in the Caucasus, and M. sylvestris in Europe. These four wild apple species are distributed across temperate zones in Europe, usually in small low-density patches. Only M. sieversii grows in large forests. Native North American crabapples include M. fusca, M. coronaria, M. angustifolia, and M. ioensis. All of the extant crabapples are edible and were likely used before the spread of cultivated apple, but compared with sweet apples, their fruit are tiny and sour. M. sylvestris fruit are between 1-3 centimeters (.25-1 inches) in diameter; M. baccata are 1 cm, M. orientalis are 2-4 cm (.5-1.5 in). 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