AWA: Academic Writing at Auckland

The domesticated sweet apple, Malus domestica, has a complex history that is still largely unknown and understudied. However, it is generally accepted that it originated in Central Asia, where wild apples still grow today (Pollan 2001:11). A long history of collection and hybridisation preceded proper cultivation and domestication. Apples spread with the Persian, Greek and Roman civilisations throughout Europe, then to America and eventually every continent except Antarctica (Luby 2003: 7). Morphological changes are reflected in the apple’s selection primarily for taste and size, resulting in homogeneity both morphologically and genetically. Lastly, the apple has changed in its significance and importance to economies, from being a luxury item in early Persian feasts to its status as an international commodity today (Morgan and Richards 1993: 13,131).

Much is still unknown about the exact time and place where the apple plant originated (Zohary and Hopf 1988: 153), but it is generally agreed that the centre of diversity amongst wild apples today is probably the place where they first evolved: in the temperate mountain forests of Central Asia, specifically in the Tien Shan mountain region of Kazakhstan. The apple blossom evolved to attract bees and birds as pollinators (Harris 2002: 426). However, apple trees began to be selected for through another agent: mammals, including large ones such as bears. Selecting the tasty fruits, apples began to disperse in the guts of mammals, thereby beginning selection for the fruits of the apple tree rather than the flowers, a process carried to its extreme by humans (Harris 2002: 426). The ancestry of the domestic apple is difficult to deduce, as apples hybridise very easily (Pollan 2001: 11). The genetic makeup of Malus domestica shows contributions from many different wild apple types from distinct geographic regions, east and west (Zohary and Hopf 1988: 153); it is therefore a complex interspecific hybrid. The basal genetic stock is generally agreed to be Malus sieversii, the Central Asian wild apple (Luby 2003:1).  However, one genetic study argues that the European crab apple (Malus sylvestris) could be the primary progenitor of the domestic apple (Coart et al. 2006: 2180). The early roots of the apple are therefore still open for debate, but the story leading to the domestication of apples by humans is more well known.

Archaeological evidence shows apples were under selection by humans thousands of years before they were domesticated. Tiny apple remains found in Anatolia date back to 6500 B.C, (Luby 2003: 7) and apple remains from the Bronze Age already showed an increase in size from the Neolithic apple remains (Hyams 1971: 125). Trade routes through the Tien Shan region began the dispersal of M. sieversii and its hybrids, either through the guts of the domesticated horse, or by humans transporting them. (Luby 2003: 7; Harris 2002: 427). The first evidence of cultivation comes from apple remains being discovered on the Sinai peninsula around the 10^th century B.C, far south of where they occurred naturally (Zohary and Hopf: 153). The delay between initial selection by humans and domestication can be explained by the ‘extreme heterozygosity’ of apple trees, remedied only with the technique of grafting, introduced around 2000 B.C in China (Pollan 2001: 12), and spreading to Mesopotamia (Harris 2002: 427). Apple trees grown through seeds do not necessarily resemble their parents, instead they vary wildly (Juniper and Mabberley 2006: 92-93). To cultivate apples with any degree of homogeneity, they needed to be ‘vegetatively propagated’ rather than allowed to sexually reproduce (Zohary 2004: 6). The invention of grafting facilitated this: cuttings of a tree are transplanted onto another and the tree takes on the cutting’s genetic code; it is essentially cloning. Zohary (2004:6) states that this allows the genotypes of “exceptional individuals” to become fixed and clonally propagated for long periods of time; the cultivars of M. domestica that we see today are therefore not so much genetic ‘races’ as they are many copies of a few favoured trees. Grafting allowed what was essentially the “instant domestication” of the apple to take place (Juniper and Mabberley 2006: 93).

Cultivation of the early domesticated apple was perfected in the Persian Empire, and Alexander the Great took apples to Greece around 300 B.C (Luby 2003:7). It was through the Romans, however, that the apple spread far and wide. Apple orchard economies were perfected and spread throughout Western Europe and Britain (Morgan and Richards 1993:14), where they hybridised with crab apples (Luby 2002: 8). Roman records show at least 23 known types were cultivated (Pollan 2001: 12). Fruit growing had a special place in both Christian and Islamic tradition through the Middle Ages; apple orchards were maintained in monastery gardens and the same was true of Koranic tradition (Luby 2003:7-8). This association of apple growing with religion was key in its spread worldwide with the rise of Protestantism- apples were designated God’s ‘special fruit’ and taken across the Atlantic to America (Luby 2003:8). Here, helped along almost single-handedly by the legendary Johnny ‘Appleseed’ Chapman, apples went wild again (Pollan 2001:13). Chapman did not believe in cloning, and in any case, the few grafted trees brought over died, unsuited to the climate. Allowing domesticated apples to ‘remake’ themselves through seed planting allowed North American apples to become distinct from the European stock, creating ever more varieties which were re-domesticated through grafting and are cultivated en masse today (Pollan 2001: 42).

The domesticated apple, through its selection by humans, has undergone many morphological changes. Domesticated apples differ greatly from the wild apples of Central Asia; apples there show an astonishing variety of colours, sizes, tastes, shapes and textures (Juniper and Mabberley 2006: 47). The domesticated, and therefore clonally propagated apple is by definition morphologically and genetically homogenous (Gladieux 2000: 659). Domestication has meant some apples have mutated towards ‘parthenocarpy’: development of the fruit without pollination or even seed production, as humans through grafting have taken over their reproduction, rendering seeds unnecessary (Zohary 2004: 9). One study (Archetti 2009) shows that domesticated apple trees have largely lost their autumn colours, which are thought to have evolved as a mechanism to avoid parasites. Apple trees are selected for based almost entirely on the productivity and taste of their fruit; this combined with lack of genetic diversity has resulted in apple trees needing more pesticide than any other crop (Pollan 2001: 52). While genetic manipulation has allowed introduction of genes that, for instance, resist fireblight (Eaton 2002), ultimately the manipulation of the apple genome still only results in morphological changes that humans select for. Michael Pollan (2001:52) argues that “the domestication of the apple has gone too far” resulting in domesticated apple trees being “less fit” as a plant, as well as vulnerable to disease and dependent on human-driven propagation. The Irish potato famine showed the dangers of selecting away variation in favour of only a few morphological characteristics (Pollan 2001: 56). Additionally, the habitat of the Central Asian apple has been reduced to the point where there is a danger of losing the genetic potential it holds to reinvigorate the domesticated apple genome (Juniper and Mabberley 2006: 59).

The change in the morphology of apples is intertwined with its importance and significance to economies over time. The apple gained a significant food production role in classical times, and remained an important fruit crop for centuries afterward (Zohary and Hopf 1988: 153). However, to early economies: “Apples were something people drank (Pollan 2001: 9).” Cider was a crucial alternative to wine in regions that couldn’t support the fickle grape; fermented apples were in fact often a more sanitary and safe option than water (Pollan 2001:22). Apples were also thought the cure a number of ailments, this belief in its value as a healthy food (Morgan and Richards 1993:16-17) has been combined with modern day health awareness and the socially constructed value of fresh produce (Jarosz and Qazi 2000).  Apples have therefore shifted in importance to economies through time, from a fruit used mainly for cider to a fruit valued most when consumed fresh (Pollan 2001: 22). This has changed the face of its domestication; morphological homogeneity is more prized. Indeed, the domesticated apple was cut down to only a fraction of the Malus gene pool when the industry decided to mass cultivate only a few brand name, well known varieties in the interests of economics and global distribution:  varieties such as the Red Delicious and the Gala (Pollan 2001: 51). Apples are an international- rather than a local- commodity, and local variation has little economic value (Morgan and Richards 1993: 131). Annual production now exceeds 60 million tons (Gladieux 2000: 660). The apple has become the most important fruit crop in temperate regions across the globe (Zohary and Hopf 1988: 151).

The domesticated apple, Malus domestica, is generally accepted to have originated in Central Asia, from the wild species Malus sieversii, though it is a complex hybrid of many genes (Luby 2003: 1). Millennia of collection, dispersal and hybridisation preceded proper cultivation and domestication; the invention of grafting was key in this delay (Pollan 2001: 154).  Apples spread with the Persian, Greek and Roman civilisations throughout Europe, then was allowed to return to wild propagation in America, eventually reaching every continent except Antarctica (Luby 2003: 7). Morphological changes are reflected in the apple’s selection primarily for taste and size, resulting in loss of variation both morphologically and genetically (Zohary, 2004: 6). Lastly, the apple has changed in its significance and importance to economies, from being a fruit primarily fermented for cider to its status as an international fresh produce commodity today (Morgan and Richards 1993: 13,131).

References

Archetti, M. 2009. Evidence from the domestication of apple for the maintenance of autumn colours by coevolution. Proceedings: Biological Sciences Vol. 276 (1667): 2575-2580

Coart, E., Van Glabeke, S., De Loose, M., Larsen, A. S and Roldán-Ruiz, I. 2006. Chloroplast diversity in the genus Malus: new insights into the relationship between the European wild apple (Malus sylvestris (L.) Mill.) and the domesticated apple (Malus domestica Borkh.) Molecular Ecology Vol 15 (8): 2171-2182

Eaton, Joe. 2002. Review of The Botany of Desire: A Plant's-Eye View of the World, by Michael Pollan. Whole Earth, Spring: 81

Gladieux, P. 2000. Evolution of the population structure of Venturia inaequalis, the apple scab fungus, associated with the domestication of its host. Molecular Ecology Vol 19 (4): 658-674

Harris, SA., Robinson, J.P., Juniper, B.E.  2002. Genetic Clues to the Origin of the Apple. Trends in Genetics Vol 18 (8): 426-430

Hyams, E. 1971. Plants in the service of man: 10,000 years of domestication. London: Dent

Jarosz, L., Qazi, J. 2000. The geography of washington’s world apple: global expressions in a local landscape. Journal of Rural Studies Vol 16 (1): 1-11 [PDF Format, no page numbers]

Juniper, B., Mabberley, D. 2006. The Story of the Apple. Oregon: Timber Press Inc.

Luby, J.L. 2003. Taxonomic Classification and Brief History, in Apples: Botany, Production and Uses, ed D.C Feree and I.J Warrington. 1-14. Wallingford: CABI.

Morgan, J; Richards, A. 1993. The Book of Apples. United Kingdom: Ebury Press Ltd.

Pollan, M. 2001. The Botany of Desire: A Plant’s Eye-View of the World. New York: Random House.

Zohary, D. 2004. Unconscious Selection and the Evolution of Domesticated Plants. Economic Botany Vol 58 (1): 5-10

Zohary, D., Hopf, M. 1988. Domestication of plants in the old world : the origin and spread of cultivated plants in west Asia, Europe, and the Nile Valley. Oxford: Clarendon Press; New York : Oxford University Press.