Apples started their journey in the Hindu Kush region and have been brought west by traders on the Silk Road and selected for flavour and “eatablity”. The largest city in that region is called Almaty – the etymology of which has a few disputed translations, but all involve Apples. The name may mean “full of apples”, “apple mountain” or “Grandfather of apples”. The city and region around it have archaeological history dating back to around 1000 BC, so the apples were around long before human settlement. Each apple tree has its own unique taste as apples have multiple chromosome that mingle each time a flower is fertilised by pollen from another.
Prior to human intervention however the history of apples is interesting. European fossil beds, such as the Messel Pit in Germany, illustrate the presence of members of the Rosaceae family restricted to low-growing plants with small fruits across Asia and Europe of early and mid-Eocene period. Most have small fruits and seed is distributed by birds. However some living on the edges of woods switched to large animal dispersal to achieve better dispersal in these clearings Malus species included. While larger fruits are energetically more costly than their smaller counterparts, they were selected for on the late Miocene landscape of Eurasia, allowing trees to respond faster to climate change and environmental stressors.
Glaciation then broke up the range into isolated enclaves and further genetic divergence occurred. Megafauna species decreased and now mainly bears and deer fulfill this role. Separate species developed including M sylvestris in Europe, M sieversii in the Kindu Kush area, M orientalis in the Caucasus, and M baccata in Asia. The modern domesticated apple M pumila/domestica shows traces of all 4 apple species , with the last hybridisation occurring on the westward trajectory along the Silk Road by humans.
4 malus species hybridization into M pumila and subsequent grafting of clones of human preference.
There is already evidence of the previously thought genetically ‘pure’ M sieversii in the Tian Shan Mountains showing genes from M pumila as seed dispersal along the trade routes operates in both directions.
It is interesting that apples, the most commonly grown fruit is not domesticated like cereals or rice. The clones are maintained by grafting as each seed showing marked genetic diversity.
Crown cleft grafting