Tamed

by Alice Roberts

  Vavilov wrote, ‘All around the city, one could see a vast expanse of wild apples covering the foothills and forming forests.’ He was struck by the similarity of the fruit of some of the wild-apple trees there to cultivated varieties. These wild apples were not like the small and sour-tasting European wild crabapples, but plump fruit, bursting with flavour. ‘Some trees are so good in the quality and size of their fruits that they could be transplanted straight into a garden,’ he enthused. This was quite astonishing – especially given how different domesticates usually are from their wild precursors. Just think about the difference between maize and teosinte, or even domesticated and wild wheat. Identifying a wild progenitor usually takes a fair bit of detective work – but not so with the apple. It seemed blindingly obvious that this wild central Asian species was extremely closely related to, and shared an ancestry with, the tamed fruit trees of orchards. Vavilov was sure that the region around Almaty must be the geographic birthplace of this fruit – the centre of domestication. ‘I could see with my own eyes,’ he wrote, ‘that this beautiful place was the origin of the cultivated apple.’

  And yet, towards the end of the twentieth century, some botanists were still focusing on the European crabapple, Malus sylvestris, as the likely progenitor for domesticated apples. Others weren’t so sure. In 1993, horticulturalist Phil Forsline, from the US Department of Agriculture, returned to the forests of south-eastern Kazakhstan. Joining forces with local scientists, he embarked on a botanical survey – which included tasting fruits, finding flavours which varied from nutty to aniseed-like, sour to sweet. He was also keen to collect seeds from as many varieties as possible, to create an archive of ‘germplasm’ which could potentially be used to improve crops in the future. In the end, he and his team returned to the States with more than 18,000 apple seeds.

  Like Vavilov and Sievers before him, Forsline was struck by how similar some of the wild apples were to domesticated varieties. But there was another reason to believe that this region around Almaty represented the original homeland of apples, and that was the dazzling variety of the apple trees growing there. Vavilov had realised that diversity could provide an important clue to geographic origins. As we’ve seen, species do tend to be most diverse close to their origin, where they’ve had the longest time to accumulate differences. And large-fruited apple trees seem to have been growing and evolving in the forests of the Tian Shan for at least 3 million years.

  Malus sieversii is a strange fruit tree in many ways. Other species of wild apple, also known collectively as crabapples, tend to have small, sour fruit. The origin of the name ‘crabapple’ is debated – its Scottish form, scrabbe, suggests that it might have come from a Norse word, simply meaning ‘wild apple’, but ‘crab’ may also have meant ‘sour’. Crabapples tend to occur on their own, or in small groups. None form dense forests like Malus sieversii on the Tian Shan. Another bizarre feature of this species is its prodigious variation – in the size of individual trees, colour of flowers, and shape, size and flavour of fruit. A key to that diversity may be the depth of time that this species has had to develop there, in the Kazakh forests, but it also tends to rejoice in variety in a way that other Malus species just don’t. Crabapples are extremely conservative in comparison.

  The large-fruited central Asian wild apple seems to have evolved from earlier, small-fruited predecessors, which may have spread across Asia before the Tian Shan Mountains began to thrust up into the sky. And when they did, they formed an island of suitable habitat – a unique physical environment – for an isolated population of apple trees, surrounded by inhospitable deserts. The repeated Ice Ages of the Pleistocene, creating fluctuations in climate across the globe, may have driven plants into fragmented pockets of habitat, over and over again. Perhaps the tendency for wild apples to vary so much – and particularly for offspring to differ widely from their parents – developed as a useful adaptation to environmental variability.

  The central Asian wild apple is closely related to the Siberian crabapple, Malus baccata, which has small, red fruits that are eaten by birds, who then do the job of dispersing the seeds – after the pips pass through their guts. It’s likely that the ancestor of Malus sieversii was also a bird-dispersed apple. But then it diversified. Large fruits strongly suggest that a very different sort of animal – a mammal – has been seduced into helping with seed dispersal. It seems that apples originally grew larger fruit to grab the attention and satisfy the tastebuds and appetite of bears. (Of course, that formulation is a shortcut: the mechanism that has led to the appearance of larger-fruited apples is the mechanism that lies at the heart of evolution – natural selection. Presented with a variety of fruits, bears preferred those that were larger, and the trees bearing them would have had an evolutionary advantage, passing more of their genes on to the next generation of apple trees.) Over time, one lineage of originally small-fruited trees changes into a new species, with large apples that bears just couldn’t resist. Small apples would have been less attractive, but also less likely to germinate successfully, if they passed through the guts and emerged relatively unscathed. Apple pips stuck inside apples don’t germinate. That seems unnecessarily contrary, but it prevents new apple plants from springing up underneath the parent plant to compete with it. Crunching up larger apples exposes the seeds – an essential step towards germination. If an apple pip escapes being crushed by teeth, it will then pass through the gut intact. When it emerges at the other end, it has a chance of becoming a new tree, perhaps miles away from its parent. Emerging from the back end of a bear, the pip would land in a pile of fertile manure on the forest floor. But being dumped on to the forest floor – even with the bear fertiliser factored in – isn’t an ideal position from which to start growing. Luckily, there are other large forest mammals that can help to bury apple seeds: wild boar do a great job of turning and churning soil, increasing the chances of successful germination.

  Nevertheless, whilst brown bears (and boars) undoubtedly did an excellent job of spreading apple pips through the forests of central Asia, it would take humans – and their horses – to unleash a diaspora of this fruit across Asia, Europe, and eventually the whole world.

  The archaeology of apples

  The ancient hunting and gathering nomads of central Asia left scarce, faint traces of themselves behind. Fragments of animal bones from a handful of sites record their presence – so that we know they were mainly hunting horse, ass and aurochs. In the Tian Shan Mountains themselves, there are hints of human presence both before and after the peak of the last Ice Age. As the world warmed up, there was a change in technology. Hunting techniques changed – judging by stone artefacts, dating to around 12,000 years ago, which include tiny ‘micro’-blades that must surely have been stuck into the shafts of darts or harpoons to be of any use at all. Then there was that shift from hunting to mobile herding – with the arrival of cattle and the domestication of horses – around 7,000 years ago, close to the start of the Copper Age. By almost 5,000 years ago, in the third millennium BCE, the Bronze Age had reached the Eurasian Steppe, and recent research has revealed that cereal crops were being grown in eastern Kazakhstan at this time. The grains included wheat and barley from the west, and millet from the east. The people growing these cereals in the mountains were still mobile herders – but they were clearly returning to the same seasonal camps, to sow, harvest and thresh their crops. A chain of Bronze Age sites, from the Yellow River in the east, through the Tian Shan to the Hindu Kush, stand testament to a healthy flow of ideas between east and west way back in prehistory, along what’s been named the ‘Inner Asian Mountain Corridor’. By the second millennium BCE, pastoralists had moved into the highland valleys of the Tian Shan, bringing their sheep, goats and horses, wheat and barley with them.

  The pastoral lifestyle that had taken root in the Tian Shan – and the Altai Mountains to the north-east – may well have been introduced by the Yamnaya. Whether that was by cultural diffusion – a transfer of ideas from one so
ciety to another – or by an actual migration of pastoralists to the east, is a hot topic of debate. The first evidence of human settlement at Almaty goes back to the Bronze Age, 4,000 years ago (2000 BCE). Like the Yamnaya, the Bronze Age people of Almaty built kurgans for their dead. Right in the centre of that Inner Asian Mountain Corridor, Almaty quickly became an important stopping-place on the east–west trade routes that connected central China to the Danube – which would later become known as the Silk Road.

  Wheat and barley arrived in central Asia from the west, millet from the east. But now it was time for central Asia to offer up its own gift to the rest of the world. People and horses travelling along the proto-Silk Road, which passed through the wild-apple forests, helped to spread apples beyond their homeland, as travellers stuffed the fruit into their saddlebags – or devoured the apples. After all, the fruit of the apple tree had evolved as a means of spreading seeds. It’s no accident that apples are delicious – that’s part of the way they encourage us to help them spread. Humans – and horses – love eating apples just as much as bears do. And horses could do the job of both bear and boar – splitting the flesh of the apple away from its seeds and depositing those pips in a pile of manure, as well as driving pips down into the sod with their hooves.

  And so apples began their diaspora, as freely pollinated, naturally sown seedlings – still essentially wild things, but with new two-legged and four-legged friends to help them on their way. As this fruit spread, it needed a name. Indo-European languages contain two different formulations of a word for apple, one sounding a bit like ‘abol’ and the other ‘malo’, but it’s possible that both of these words come from an original, Proto-Indo-European word – samlu. The Bronze Age and Iron Age riders on the Eurasian Steppe may have spoken of apples as amarna or amalna. It’s easy to hear this changing into the ancient Greek melon, and the Latin malum. But, as it travelled west, the word changed again – with the ‘m’ becoming ‘b’. (This is not such a weird transition as it looks when written down. Make the sound ‘mmm’, then give me a ‘mmmb’, then just a ‘b’ – see? When you perform them, these sounds are all very similar – ‘m’, ‘b’, ‘p’ are all produced by the lips coming together or parting.) The ancient apple word continued splintering into separate languages and dialects, but still the Ukrainian yabluko, Polish jablko and Russian jabloko retain a faint affinity with German apfel, Welsh avall and Cornish avel. The mythical Isle of Avalon was the Isle of Apples. Whatever the tortuous routes by which this word has reached us today, in all its varieties, it hints at an origin in central Asia, just like apples themselves – and the horses that bore them on their original journeys.

  Words for apples can be quite misleading. The most famous apple of them all, the mythical apple in the Garden of Eden, may not have been an apple at all. That sounds like an odd thing to say of something mythical, a storytelling device. But the original story didn’t refer to an apple. The forbidden fruit growing in the Garden, which the serpent encouraged the woman to eat, was tappuah. This Hebrew word doesn’t mean apple. In fact, it’s only very recently that apple varieties have been developed which will actually grow in the hot, dry climate of Palestine, where the stories probably originate. Scholars debate what was actually meant by that word tappuah. It could have been an orange, pomelo, apricot or pomegranate – but it almost certainly wasn’t an apple.

  Homer’s Odyssey, probably written in the ninth century BCE, apparently contains a reference to apples, growing in the orchard of King Alcinous, on the mythical Isle of Scheria:

  Here luxuriant trees are always in their prime,

  pomegranates and pears, and apples glowing red,

  succulent figs and olives swelling sleek and dark.

  But these ‘apples’ – along with others in Greek myth, such as the one given by Paris to Aphrodite, or those growing in the garden of the Hesperides – could actually have been any round fruit. The Greek word melon, despite its shared roots with other Indo-European words for apple, is not specific – it could mean any plump, round fruit (including melons!).

  It’s not just the early words for apples that are tricky. Reaching Mesopotamia, the apple itself was discovered to be a bit of a trickster. By 4,000 years ago, when a type of apple close to our domesticated apples first appears in the Near East, people in this area had been farmers for thousands of years. They understood the ways of nature, and could control them … but not when it came to fruit trees. It wasn’t as though fruits and nuts hadn’t been an important part of the diets of ancient people – these types of plants were just very hard to domesticate. Unlike the cereals and pulses, woody plants have more built-in genetic variability. Apples have two sets of chromosomes – like us. And they will not self-pollinate. They’re described as ‘highly heterozygous’ – it’s unusual to find the same version of a particular gene repeated on the other chromosome in the pair. In this way, they’re also a bit like humans. Our heterozygosity (what a deliciously poetic mouthful of a word) means that children tend to differ from their parents. Similarly, fruit trees – and in particular, apples – don’t stay ‘true to type’ – an annoying trick if you’re a horticulturalist trying to breed trees which all retain a particular, desirable trait. The seedling progeny of a beautifully sweet-fruited apple tree will almost inevitably be too sour to eat – as the naturalist Henry David Thoreau wrote: ‘sour enough to set a squirrel’s teeth on edge’. But ancient apple orchardists eventually discovered how to make the apple stay true. They found a way of capturing the qualities of a prized apple tree and passing on those traits to other trees. In the fourth millennium BCE, gardeners invented cloning.

  Some plants lend themselves to cloning – they do it naturally. Any plant that spreads by sending out runners over or under the ground, to grow a new bit of itself, some distance away from the parent plant, is essentially cloning itself. You can divide the roots between the two of them and the youngster will carry on growing by itself, quite happily. My Rosa rugosa hedge is extremely good at cloning itself in this way. I have no doubt that, left to its own devices, it would propagate itself all over the place with its offshoots, and turn my whole garden into a thicket. I have to keep it in check by cutting back its runners and the brave new shoots attached to them. But if I wanted more Rosa rugosa, I could keep those shoots and shove them in the ground elsewhere – and they would take root and grow. Early agriculturalists were able to use this natural tendency of some plants to reproduce asexually to their advantage. They found that they could cultivate clones of figs, grapes, pomegranates and olives from cuttings, and that date palm would grow successfully from divided offshoots. But pears, plums and apples were much less malleable. They wouldn’t stay true to type when grown from seed, and it was very hard to get cuttings to take root – especially in the dry lowlands of the Near East. There’s plenty of evidence for wild and feral apples spreading by vegetative propagation, sending out suckers from roots, or sprouting anew from branches which have become covered with soil on the ground, but it seems more difficult to get domesticated apples to reproduce in this way.

  Someone must have noticed, however, that trees can join together. This could have been an extremely ancient discovery. You can make a shelter from slender, living trees, bending them into a basic yurt-like frame. Even if you cut withies to make such a structure, they may take root and grow – especially if you’re using willow or fig – and over time, the withies will merge and meld with each other where they cross. Having noticed that, perhaps having seen two wild trees growing too close and merging with one another, it’s not too much of a leap of faith to ask: if I cut this tree and attach it to this other tree, could it grow? And it worked. Millennia before the transplant of a heart from one human being to another, our ancestors discovered that they could transplant fruiting limbs from one plant on to the rooted limb of another.

  Grafting means that you can clone hundreds of apple trees from a single ‘parent’ (it’s not a parent in the strict sense, but an identical sibling). It bri
ngs other advantages, too. If you plant a seed, you must wait years for it to grow and start flowering and fruiting. But if you graft a mature limb, or scion, even on to a juvenile rootstock, it will quickly start bearing fruit – you leapfrog right over the immature stage. You can add new cultivars to your rooted tree at any time. By choosing your rootstock carefully, you can affect the size of the tree too, making a dwarf out of a cultivar that would be a giant on its own. Some rootstocks bring advantages with them, which the variety you want to grow doesn’t possess, such as pest or drought resistance. Grafting can also be used in another way – to save an ailing tree. If the roots have been attacked by pathogens, or the bark of the trunk has split, you can plant seedlings around your traumatised tree and encourage them to fuse with the trunk higher up, to carry essential water and nutrients up to the branches, from the soil, like a bypass graft.

  Grafting seems like an astonishingly advanced technological development, and yet there’s a hint it may have already been carried out on other plants by the time apples arrived in the Near East, in the early second millennium BCE. The clue comes from a snippet of cuneiform script on a fragment of a Sumerian clay tablet, dating to around 1800 BCE, discovered during excavations of the palace of Mari, in modern-day Syria. This ancient text referred to grapevine shoots being brought to the palace to be replanted. It’s been widely interpreted as referring to grafting – but it’s actually not clear whether those grapevine shoots were simply going to be used as cuttings: pushed straight into the ground. Vines do root easily, so perhaps that’s a more likely scenario. Nevertheless, other clay tablets from Mari refer explicitly to apples being shipped in to the palace. The kings of Mari certainly knew the taste of apples, even if they weren’t growing them or grafting them for themselves yet.