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Scientists from the University of Otago in New Zealand have found the location of one of the earliest securely dated sites of sweet potato cultivation in Polynesia, New Zealand’s South Island.
They found evidence of microscopic sweet potato starch granules alongside Asia-Pacific taro (a root vegetable) and Pacific yam (uwhi) at Triangle Flat in Golden Bay (Mohua) on South Island. The cultivation was dated to as early as AD 1290-1385.
“These early dates correspond with the period during which settlement of Aotearoa New Zealand began and provide the first pre-1400 evidence for kumara (sweet potato) cultivation in Te Waipounamu — as early as anywhere else in Polynesia — and for the southernmost world attempt to grow uwhi,” a statement by the University of Otago noted.
New Zealand, called Aotearoa in the language of its indigenous Maori people, is divided into two main islands. The more populated North Island and the more scenic and larger in size South Island. The latter is known as Te Waipounamou or ‘Island of the greenstone’ in Maori.
The Polynesians were born out of a synthesis of Asian and Papuan cultures (as is now well-known from analysis of mitochondrial DNA) between roughly 1800 BC and 700 AD.
Between 700 and 1595, they colonised most of their traditional homeland of Polynesia or the islands of the Pacific Ocean. Polynesia is roughly defined as a ‘triangle’ whose three corners are Hawaii, New Zealand and Easter Island.
Armed with just their famous double-hulled, outrigger canoes (something similar to the Tamil catamarans) and with a knowledge of stellar and marine animal movements, the Polynesians colonised these islands, isles and atolls, farming, developing kitchen gardens, developing distinct art forms today famous globally like tattoos and the Haka dance and also fighting (and sometimes cannibalising) each other in brutal tribal warfare.
“They travelled in huge double-hulled canoes carrying all the supplies needed for a successful new colony: stone tools, animals (pig, chicken and dog) and, most importantly, the seeds of the crops on which they survived,” an article on the BBC notes.
A few crops that survived in the gardens across Polynesia became the main part of Polynesians’ diet. These were coconut, yam, taro, banana, breadfruit, and sweet potato.
While the other plants have a Southeast Asian origin (given the Lapita Theory which posits that Polynesians descended from Taiwanese Aborigines), the sweet potato is an oddity. It evolved in the Peruvian portion of South America’s Andes mountain range.
This has led to hypotheses that indigenous Americans in the pre-Columbian (before Columbus) Americas were in Polynesia or in contact with the Polynesians.
In 1947, Norwegian explorer Thor Heyerdahl had famously voyaged from Peru in South America to the Tuamotu islands in the Pacific on a raft made of balsa wood called the Kon-Tiki to prove that ancient South Americans had settled in Polynesia.
“Despite its importance to Polynesian life both in the past and today, little is known about the timing and circumstances of the sweet potato’s initial spread across Oceania. Some botanists propose it drifted naturally into Polynesia thousands of years ago, but many anthropologists infer undated human mediation instead, especially since the Māori name kūmara is a variation on pre-Columbian American sweet potato names,” the Otago statement said.
“Given these uncertainties and intriguing possibilities, scholars have debated exactly when, and even if, sweet potato became important in early Polynesian colonisation, Professor Barber says,” it added. Ian Barber, from Otago’s Archaeology Programme, is the lead author of the study.
Polynesian peoples include indigenous Hawaiians, Easter Islanders, Tongans, Tahitians, Samoans, Marquesans and of course, the Maori of New Zealand.
Kupe, the semi-legendary Polynesian explorer, is said to have discovered Aoetearoa in 925 CE following which the Maori settled and colonised the country, much before the coming of Anglo-Celtic white Europeans (Pakeha to the Maori).
Scientists have, for long, wondered as to what could have fed the Maori once they arrived in New Zealand.
“Existing views have assumed the first settlers turned instead to forage for the flightless moa, other birds and marine animals, with kūmara only becoming important later, especially in warmer areas central to northern Aotearoa New Zealand where pā earthworks proliferated,” the statement noted.
The Giant Moa, a huge, flightless bird, became extinct within a century of Maori arrival.
But the Otago researchers noted that their findings prove that the first Polynesian arrivals to New Zealand were farming sweet potato as well.
The team found that the first Aotearoa gardeners developed sophisticated planting pit and shell mulch technologies in local environments and soils, which helped secure kūmara horticulture in a marginal climate.
According to Barber, the findings from the study will help inform current horticulture efforts. The sweet potato is currently the world’s fifth most important edible crop. But it is under threat of climate and other environmental change in many parts of the world, according to him.
“New knowledge from the past as well as the present may yet support food security science targeting sweet potato production. Archaeological knowledge of these ancient technologies might yet inform modern efforts to improve natural hardiness and nutrition in sweet potato.”
