There are hundreds of varieties of breadfruit (Image: Douglas Peebles/Corbis)
It’s a protein-packed fruit that can grow in the ever-saltier soils climate change is bringing – could breadfruit feed the world? One determined woman says yes
IN APRIL 1789, Lieutenant William Bligh set off from the Pacific island of Tahiti to sail halfway round the world to Jamaica. Twenty-three days into the voyage, his crew mutinied. They set him adrift in the Bounty’s launch, along with 18 men who were loyal to him, and dumped the ship’s cargo overboard. That cargo included 1000 breadfruit plants destined for the Jamaican sugar plantations, whose owners were clamouring for a cheap and reliable source of food for their slaves.
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But Bligh was a stubborn man. In 1792, by now promoted to captain, he set out again from Tahiti and successfully shipped 2000 breadfruit plants to Jamaica, 678 of which bore fruit. The slaves initially turned their noses up at the green, lumpy fruit with its potato-like flesh, but within 50 years Artocarpus altilis had become a staple on the island.
There are no more slaves in the West Indies but there is, once again, a problem of food insecurity, and global warming is aggravating it. Breadfruit fell out of favour long ago, eclipsed by cheap imports based on wheat, rice and maize. Today Jamaica imports more than half its food – including, ironically, sugar. Now, with the island facing the prospect of rising seas and rising debt, the government has embarked on a campaign to cut its crippling food bill by encouraging local production. Once again, breadfruit is being touted as the solution – but not the varieties Bligh introduced. This time, the plants are being carefully selected to suit Jamaica’s needs and tastes. And they are not coming by boat but by FedEx.
A resurgence of interest in breadfruit, not just in Jamaica but around the world, is thanks in large part to one woman, Diane Ragone of the (NTBG) in Hawaii. When she began studying the plant in the early 1980s, even basics such as where it originated and the identity of its ancestor were unknown. The majority of Bligh’s 678 plants belonged to just two varieties or cultivars, known in the Caribbean as white and yellow breadfruit. They are dense, starchy and, some might say, bland-tasting. But there are hundreds of varieties in the Pacific islands, with differing flavours, textures and fruiting seasons. Ragone spent the 1980s collecting and documenting more than 200 of these, and has propagated 125 varieties from 34 countries.
By the early 2000s, Ragone was working with Nyree Zerega of Northwestern University in Chicago to tease out the history of the plant. Their first task was to identify the common ancestor of all today’s breadfruit varieties. The plant had undergone so many changes on different Pacific islands at different times, with growers selecting for traits according to local conditions and tastes, that the tracks leading back to the breadfruit “Eve” had become confused. One broad pattern was immediately clear, however: the further east you go, the more the genetic diversity of cultivars shrinks, and the less likely they are to have seeds.
A sterile plant cannot reproduce without human intervention, and by virtue of that intervention humans must have transformed a fertile ancestor into the sterile breadfruit. To find that ancestor, Zerega needed a powerful forensic tool. She found it in DNA fingerprinting. Analysing the DNA of all the cultivars in the collection, she found that most included fingerprints of a seeded plant called the breadnut that grows on New Guinea. .
Her discovery fit with what was emerging from archaeological work at the time about how the Pacific was colonised. It was thought that Austronesians, who make up the populations of islands across the Pacific, originated in Taiwan, reaching New Guinea about 4000 years ago. From there they island-hopped eastward, through Melanesia to Polynesia – with a sidestep north to Micronesia – until they reached Tahiti. En route they fanned out north to Hawaii and south to New Zealand, both of which they reached about 1500 years ago (see map). Now it seems the expansion may have happened even faster than this. Based on radiocarbon dating of bone from burial sites and finds of an Austronesian style of pottery known as Lapita, archaeologist Matthew Spriggs of the Australian National University in Canberra concludes that these expert seafarers didn’t arrive in New Guinea until closer to 3000 years ago. From there they reached Tonga – nearly 5000 kilometres to the south-east, and over halfway to Tahiti – within a couple of generations.
Tracing the roots
Each time they colonised a new island, the Austronesians took provisions with them: dogs, chickens, rats, yams. It has even been suggested that they “pre-seeded” the next island with edible crops before settling there permanently. In doing so, they may have copied farming techniques they had seen practised by the indigenous people of New Guinea who, it appears from work by Spriggs’s colleague Tim Denham, were .
When it came to transporting breadfruit, the Austronesians would not have been able to take seeds. That’s because seeds in the few varieties that still bear them and in the breadnut do not survive being stored so wouldn’t have lasted a long voyage. Instead, the Pacific pioneers probably took roots. A simple nick to the root of a breadfruit causes it to produce a shoot – an asexual form of reproduction called vegetative propagation. “If you vegetatively propagate something generation after generation after generation, mutations accumulate that may have led to the seedless type,” says Zerega.
So it would appear that breadfruit has seen humanity through periods of hunger for millennia. It may have fallen out of favour in Jamaica, but throughout the Pacific islands it remains a staple, and it’s not hard to see why. It outstrips rice, wheat and maize in terms of production per hectare. As yet unpublished research indicates that the average production of 24 of Ragone’s cultivars is 320 kilograms of fruit per tree per year. One 3-kilogram fruit easily provides the carbohydrate portion of a meal for a family of five. Trees start bearing fruit between three and five years of age, depending on the cultivar, and require very little care. And they provide much needed shade. “Traditionally in Polynesia you would plant a breadfruit when a child was born, because that would guarantee food throughout that child’s life,” says Zerega.
In 1996, Ragone saw a photograph of a centuries-old, managed, diverse breadfruit agroforest in Micronesia and thought, “Why couldn’t this be done elsewhere?” That’s when she realised that her collection was not simply an archive but a valuable practical resource. In 2003 she created the , the centrepiece of which is a supersized orchard planted in serried ranks on the wild eastern coast of the island of Maui in Hawaii. Today, some of the trees are 20 metres tall, and the institute is working with an initiative called the Alliance to End Hunger, with the aim of distributing breadfruit to food-insecure countries worldwide.
It makes sense. Breadfruit trees thrive in the tropics, a region corresponding with some of the world’s greatest food insecurity. The fruit, which can be used in both sweet and savoury recipes and ground into flour, is versatile and surprisingly nutritious. . What’s more, breadfruit protein has a higher proportion of essential amino acids – that is, better quality protein – than soy. Nevertheless, Ragone and her colleagues know that if breadfruit is to be eaten more widely, they cannot simply foist it on people, as Bligh did. They need to identify varieties that best suit the environment, climate and tastes in different countries.
Research at the Breadfruit Institute is revealing how varieties compare when it comes to things like yield, fruiting season and protein and mineral content. The work to identify desirable traits is ongoing. For instance, first indications are that some cultivars may be highly salt-tolerant – important in Caribbean islands whose soils are set to get saltier as sea levels rise.
There are also hints that the more highly domesticated varieties from the eastern Pacific are less robust. Miranda Hart at the University of British Columbia in Kelowna, Canada, studies the symbiotic fungi that live in the roots of the breadfruit tree, helping it to capture nutrients from the soil. She has found that . “Why ‘pay’ fungi to protect you from pathogens or provide you with phosphorus when you are living a relatively safe life in someone’s garden?” she says. This could influence the choice of cultivars sent to countries where growing conditions are poor.
The other practical problem is how to propagate and transport the plants. Root propagation, as practised by the Pacific island colonisers, produces only a few new shoots a year per tree, meaning it is not suited to large-scale production. Plus the roots would never be allowed across borders today, teeming as they are with tropical microbes. So in 2003, Ragone contacted plant chemist Susan Murch at the University of British Columbia, who set to work adapting tissue culture methods – already in use for many commercial food and flower crops – to the breadfruit.
Tissue culture is faster than root propagation because it uses shoot material from the branches, meaning more can be taken from a single plant. This must then be induced to grow in specially adapted media. Getting the media right for breadfruit was tricky, Murch says, not least because the plant produces a sticky white sap containing latex and phenols that, if left in the medium, causes the tissue to rot.
It has been a slow process with a low success rate, and for some cultivars it hasn’t worked at all. “We’ve been doing this for more than a decade and at this point we have 48 varieties at different stages of production,” says Murch. Her lab is the bottleneck, she says, but once the trees are through it, the advantages of tissue culture become clear. The trees are disease-free and start bearing fruit sooner – as early as two years of age. In 2008, Murch and Ragone brought in specialist private partners to help them propagate the tissue-cultured saplings on a commercial scale. From the varieties Murch has successfully propagated, 35,000 trees have now been sent to 26 countries.
Funding to import breadfruit to Jamaica and Haiti has come from a US-based charity called , founded by Mary McLaughlin and her husband Michael. The first variety they introduced, Ma’afala, is native to Samoa and has a different fruiting season to the varieties already in those islands, extending the period in which fresh breadfruit is available. It is also a shorter tree, making it more hurricane-proof. The Ma’afala saplings are grown on government-sponsored research stations until they are robust enough to be planted out. In Jamaica Ragone’s team is also testing other varieties to see how they behave under local conditions. With the first trees imported to Jamaica in 2009 now bearing fruit, Puerto Rico and Costa Rica have asked to join the programme. Eventually, McLaughlin hopes to see breadfruit agroforests throughout the Caribbean. First, though, local people have to reacquire a taste for it.
Recipes for success
That Jamaicans took 50 years to incorporate breadfruit into their diet the first time around is normal, says Murch. She points out that tomatoes were not accepted in England for decades following their introduction in the 16th century, because they were thought to be poisonous. It takes two generations, she says: “It has to be something your grandmother cooked.” McLaughlin wants to accelerate that process by teaching people new ways to cook and eat breadfruit. She offers her favourite recipe: “A third of a cup of breadfruit flour, a third of a cup of orange juice, one egg, cinnamon, nutmeg, vanilla and a teaspoon of oil. That makes pancakes for three people.”
Efforts are also afoot to extend the fruit’s shelf life. Breadfruit pasta and crisps are being developed, says Zerega. And the McLaughlins have come up with a “factory-in-a-box” that consists of a shredder and a grinder. Shredded when fresh, the fruit can then be dried and stored until needed, when it can be ground and used as flour.
The breadfruit, like that better-known staple the banana, is in many ways a human creation. The two share history and, as a result, biology – both are propagated vegetatively or clonally rather than by seeds. However, the main commercial banana variety, the Cavendish, is currently threatened with extinction by a fungus called black sigatoka, and stopping the rot is proving difficult partly because its wild ancestors remain unknown. By contrast, breadfruit may be in the ascendancy. The most widely eaten varieties outside the Pacific islands are too bland and starchy for many western tastes, but Ragone and her collaborators can change that. By selection and hybridisation, they could come up with varieties that are not just resistant to disease and climate change, but also taste delicious. If so, breadfruit’s popularity could spread far beyond Jamaica and the tropics. Once again, its future hangs in the balance, just as it did more than two centuries ago, when William Bligh stood in his launch and watched his precious cargo vanish beneath the waves.
“The breadfruit, like the banana, is in many ways a human creation”
Find out how it tastes: “Recipes for an unexpected tropical wonder food“
This article appeared in print under the headline “Wonder food”
