Posts Tagged ‘crabapples in mastodon dung’

Pleistocene Apples (Malus sp.)

August 26, 2015

The ancestor of all domesticated apples (Malus domestica) still grows in montane forests located in Kazkhstan, Kyrgyztan, and western China.  A genetic study shows that all modern cultivated apples descend from Malus sieversii, a species that reaches 60 feet in height and grows among pine and oak trees as a co-dominant.  Traders brought seeds of M. sieversii to Europe where it readily crossed with the European crabapple, M. sylvestris.

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The mountains of Kazakhstan are where the ancestors of modern apples grow wild.

Photo of apples hanging from a tree.

Malus sieversii, 1 of the ancestors of the domesticated apple (Malus domestica).

Scientists believe the first apple trees evolved 10 million years ago and originally were a small sour fruit spread by defecating birds.  Elephants and bears favored larger sweeter mutations of this fruit, and they helped shape the evolution of a food that was more palatable to humans by also spreading the seeds in their dung.  Humans began cultivating apples 4000 years ago, and there are 3000 known varieties.  Just .03% of these varieties equals 70% of the world’s production.

There are an estimated 30-55 species of apples and crabapples in the Malus genus.  Scientists disagree over species status of some populations, and the propensity of species in this genus to crossbreed adds to the confusion.  Some species of crabapples are native to North America.  Mastodon dung excavated from the Aucilla River in Florida contained some crabapple.  None of America’s native crabapples, however, are comparable in quality to M. sieversii.  American crabapples rarely become a co-dominant tree like M. sieversii does in the mountains of southwest Asia.  Instead, they grow as an occasional tree in early stages of forest succession.

Apple trees descended from orchards planted by Europeans do occur throughout North America.  Circa 1974, I saw an apple tree that produced good quality green apples in an oak-dominated woods in Niles, Ohio.  The quality of most wild apples growing from seed reportedly varies.  Euell Gibbons wrote that most are not worth cultivating for fresh eating, but they do make good cooking apples.  All apples sold in grocery stores are the progeny of rare mutations.  Horticulturalists graft branches of the high quality mutations (known as scions) on rootstocks of uncultivated apple trees.  Trees are available with as many as 5 different varieties grafted on to them, but they are expensive.  Think hard before buying one of these 5 on 1 trees–insect pest can kill the tree thereby wasting money.

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