Vicia faba

• 1. Introduction

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  Vicia faba carries 13 GB of DNA in its cells, one of the largest genomes among diploid field crops, with a predicted 34,221 protein-coding genes. That is a heavy genetic load for a plant that looks like an ordinary garden bean. Vicia faba goes by several names, including broad bean, fava bean and faba bean, and it belongs to the pea and bean family. People grow it to eat, and they also grow it to feed the soil. Its seeds appear on breakfast tables, in street food and in the rituals of many cultures. For some people, though, the same seeds are a medical hazard. This documentary asks where the plant came from and why such a tough crop still needs defending. It also asks how one humble seed came to carry so much meaning.

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• 2. Ancient Fields

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  At the el-Wad Terrace, a Natufian site, archaeologists found charred legumes that may belong to a wild ancestor of the broad bean. Nobody has identified that ancestor for certain, and the true origin of the crop remains unknown.

  The firmer evidence comes from three neighbouring Neolithic sites in Israel's Lower Galilee: Yiftah'el, Ahi'hud and Nahal Zippori. Each yielded carbonised remains of domestic faba beans. Radiocarbon dating of those remains leads scientists to believe that domestication may have begun as early as 8250 BCE.

  The qualities that made the plant useful then still make it useful now. As a legume, it fixes nitrogen in the soil, and it can survive the winter. Farmers still sow it as a cover crop to hold soil against erosion.

  Toughness is a large part of its appeal. The broad bean copes with harsh and cold climates. Unlike most legumes, it tolerates salty soil and heavy clay, although it prefers rich loam.

  The name depends on where the speaker lives. In the United Kingdom, Canada, Australia and New Zealand, the common name is broad bean. In the United States, the usual term is fava bean, borrowing the Italian word for the bean.

  In English-speaking countries, the name also tracks the seed type. Large-seeded cultivars grown for people are broad beans. Smaller, harder-seeded types resembling the wild plant are called horse bean, field bean, tic bean or tick bean, and they mostly feed animals. Even so, their stronger flavour is prized in some human recipes, including falafel.

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• 3. Anatomy of a Bean Plant

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  A broad bean plant stands stiffly upright as an annual, with two to four stems that are square in cross-section. Its leaves are pinnate, carrying between two and seven leaflets, and they have a grey-green bloom. Unlike most other vetches, the leaves have no tendrils, so the plant never climbs over its neighbours.

  The flowers have five petals, and the white wing petals each carry a black spot. Botanists note that this spot is true black rather than the deep purple or blue seen in many so-called black markings. Crimson-flowered broad beans also exist, and they were recently saved from extinction. A strong, sweet scent draws in bees and other pollinators.

  The pod is broad and leathery, and it turns from green to a dark blackish-brown as it ripens. Its surface is densely downy. Each pod holds three to eight seeds.

  Wild plants and food cultivars differ sharply in size. A wild pod is about 1 cm in diameter, while many modern food cultivars produce pods 2-3 cm thick. Wild seeds measure 5-10 mm across. Food cultivars have flattened seeds up to 20-25 mm long and 15 mm broad.

  Inside each cell, the plant has a diploid chromosome number of 12, arranged as six homologous pairs. Five of the pairs are acrocentric and one is metacentric.

  Those chromosomes made the broad bean a laboratory star. In 1957, researchers used V. faba root cells to give the first experimental demonstration that eukaryotic chromosomes replicate semiconservatively, the scheme Watson and Crick had proposed in 1953.

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• 4. Danger on the Plate

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  Phytohaemagglutinin is a lectin found in beans generally, and V. faba holds it only in relatively low concentrations. Boiling the beans for 10 minutes destroys most of it.

  A second chemical concern is levodopa, which broad beans contain in abundance. People taking irreversible monoamine oxidase inhibitors should avoid the beans, to prevent a pressor response.

  The best-known danger is favism, a hemolytic response linked to a metabolic disorder called G6PDD. The beans contain vicine, an alkaloid glycoside that may set off a hemolytic crisis. Sufferers must avoid broad beans entirely.

  Greece offers a striking example of how widespread the condition can be. Favism is quite common there because malaria was endemic in previous centuries. People affected by it simply do not eat broad beans.

  Plant breeders have found a way around the problem. In the 1980s, they identified a faba bean line low in vicine and convicine, and the trait has since entered several modern cultivars. These low-content beans are safe for G6PD-deficient people. As of 2019, a molecular marker can guide marker-assisted breeding to lower these compounds further.

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• 5. Enemies of the Crop

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  In mainland Europe and North Africa, a parasitic plant called Orobanche crenata, the carnation-scented broomrape, can devastate broad bean yields. It is one of several threats, and fungi supply most of the others.

  The chocolate spot fungus, Botrytis fabae, is among the worst diseases of the crop. It damages the leaves, reduces photosynthesis and cuts the harvest. The fungus switches from a quiet phase to aggressive attack when temperature and humidity rise together. Low soil potassium and phosphorus, and dense seeding, make matters worse. The quiet phase shows only as small red-brown lesions on leaves, and sometimes on stems and pods.

  Prevention beats treatment. Early planting avoids the hot, humid stretch from late spring into early summer. Thinning seedlings or sowing less seed also helps, as does a foliar fungicide. Growers can also plant rows running west to east, which lets the sun dry the crop more. Transplanting instead of direct seeding lowers the risk further.

  Other fungi leave their own signatures. Powdery mildew species such as Erysiphe baeumleri can be held back with resistant cultivars, overhead irrigation or sulfur fungicides. Fusarium solani lives in the soil and causes stunting, yellowing and streaky root lesions in brown, red or black. Faba bean rust, caused by Uromyces viciae-fabae, speckles mature leaves with orange dots ringed in yellow, which can merge into an orange lawn. Two Sclerotinia species cause stem rot, and the researcher Lithourgidis and colleagues published field work on them in 1989-2005 and 2007.

  Bacteria also attack the plant. Xanthomonas campestris and X. axonopodis travel on contaminated seed and overwinter in crop residue, leaving lesions that make the plant look burned. Copper bactericides, clean seed and resistant cultivars help. Pseudomonas syringae also overwinters on residue, so rotation and clearing residue are the main defences. A virus, faba bean necrotic yellows virus, is shared with other Vicia species.

  The black bean aphid, Aphis fabae, is the major insect pest. Early summer infestations typically begin at the tip of the plant and can cover large sections of it. They also discolour the pods, lowering their saleable value. High-pressure water can wash aphids off an established plant, and reflective plastic mulch may deter them. Because V. faba tolerates low and medium infestations, insecticide is needed only when the aphids become heavy.

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• 6. Breakfast Across Borders

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  Raw mature broad beans are 11% water, 58% carbohydrates, 26% protein and 2% fat. A 100-gram portion supplies 1425 kJ of food energy. It also supplies 26% of the Daily Value of folate, and 52-77% for minerals such as manganese, phosphorus, magnesium and iron.

  Among popular pulses, including chickpea, pea and lentil, the broad bean has the highest protein-to-carbohydrate ratio. Eating it alongside cereals is recommended, because the two foods together supply all the essential amino acids.

  In Egypt, the broad bean is a staple eaten by rich and poor alike. Cooks simmer dried beans on very low heat for several hours, then partly mash them and add oil, salt and cumin. The result is ful medames, traditionally eaten with bread at breakfast and counted among Egypt's national dishes. Egyptian-style falafel also uses broad beans as its main ingredient, where the Levantine version uses chickpeas.

  Sudan follows a similar path. For most Sudanese, especially city dwellers, broad beans form the main dish at breakfast, which is called fatoor. Cooks add salt, chili pepper and cumin, then finish the dish with sesame oil and a sprinkling of jibna cheese. Mixed with bread, the dish is called fatta, and the cooking liquid, known as boash, is often eaten the same way.

  In Iraq, one popular breakfast is Bagilla Bil-Dihin, also called Tishreeb Bagilla. Bread is soaked in the water the beans boiled in, then topped with the beans, melted ghee and often a boiled or fried egg. Fool, a mash of broad beans, is another common breakfast across Iraq and other Arab countries. At the lunch table, Timmen Bagilla is rice cooked with broad beans and dill.

  Syria cooks the bean for breakfast, lunch or dinner. Its ful medames is not mashed, and it adds tomato, parsley, onion and olive oil. Another version adds tahini, garlic and lemon. For lunch, foulieh combines broad beans with meat, garlic, lemon juice and cilantro, served beside rice. Syrian Christians prepare the same recipe without meat during Lent.

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• 7. Regional Kitchens

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  In Ethiopia, the broad bean is called baqella, and it is one of the most popular legumes in the country. Cooks use it in place of peas to make a flour called shiro, the base of shiro wot stew. During fasting periods in the Ethiopian Orthodox Church tradition, cooks make two uncooked dishes from broad bean flour. Hilibet is a thin white paste with onion, green pepper and garlic, and siljo is a fermented, sour, spicy yellow paste. On the Thursday before Good Friday, people eat gulban, made from peeled half-beans cooked with wheat, peas and chickpeas.

  In Sichuan, China, broad beans are fermented with soybeans and chili peppers to make a spicy paste called doubanjiang. In south Algeria, they become besarah and doubara, and doubara is popular in the city of Biskra.

  In Iran, the city of Kashan is known for the highest production of broad beans, called baghalee, with excellent taste and colour. The fresh season lasts only about two weeks in the middle of spring. Dried beans cooked with rice make baghalee polo, one of the most famous dishes of Gilan in the north.

  Japan calls the bean soramame, meaning sky bean. A roasted or fried snack called ikarimame takes its name from the word for anchor. In Finland the word härkäpapu means ox bean, and the bean is used in a meat substitute called Härkis.

  Greece offers a puzzle of words. The Greek fáva does not mean the broad bean but yellow split pea, and broad beans are koukiá. Cooks stew them with artichokes while still fresh in the pod. On Crete, shelled fresh beans accompany the local drink tsikoudia.

  Italy alone has a long list of broad bean dishes. In Sardinia, they are cooked with lard, bacon or minced pork. Roman cooks pair them with guanciale or artichokes, and Sicily makes a soup called maccu. Apulia serves a purée with wild chicory. In Liguria, people eat them raw as the first garden product of early spring, sometimes with salami from Sant'Olcese. In central Italy, the bagiana soup was once popular and has recently been rediscovered.

  Elsewhere in Europe, Luxembourg names smoked collar of pork with broad beans, Judd mat Gaardebounen, as its national dish. Malta makes the vegetable soup kusksu with pasta beads, and Serbia sets a pureed bean aspic with garlic in a mould. Portugal's favada is a stew with onion and pork, and in Alentejo cooks add a lot of coriander. Turkey simmers young pods with onions in olive oil to make the dish called bakla.

  In Nepal, the bean is called bakulla. Dried beans are mixed with other legumes into a blend called qwati, which is cooked as a soup for the festival of Janai Purnima. People there believe it reinvigorates the body after the monsoon paddy season.

  In the Netherlands, cooks serve broad beans with fresh savory and melted butter. According to folk belief there, rubbing the velvety inside of a pod on a wart is a remedy.

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• 8. Ballots, Omens and Kings

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  In ancient Greece and Rome, a white bean cast a yes vote and a black bean cast a no. Even today, the Greek word koukia is used unofficially for votes. Beans were also food for the dead, as at the annual Lemuria festival.

  The ancient Roman family name Fabius comes from the bean, and so does the modern political term Fabian. Porphyry and Iamblichus both report that Pythagoras once persuaded a bull not to eat beans.

  In Ubykh culture, people practised favomancy, throwing beans on the ground and reading the pattern in which they fell. The Ubykh word for bean-thrower grew into a general term for seers and soothsayers. In English, the expression not worth a hill of beans points to the bean's cheapness and its place in the peasant diet.

  Italy holds the richest traditions. Broad beans are sown on the 2nd of November, All Souls Day, and small cakes shaped like beans are called fave dei morti, or beans of the dead. Tradition says that Sicily once lost every crop except the beans, which kept people from starving, and thanks went to Saint Joseph. Broad beans have since become traditional on Saint Joseph's Day altars in many Italian communities.

  Some Italians carry a single broad bean for luck, believing it will keep them from ever lacking the essentials of life. On the 1st of May, Roman families traditionally eat fresh beans with Pecorino Romano on an excursion into the Campagna. Northern Italy takes the opposite view, because the beans there are traditionally animal feed, and elderly people may frown on eating them.

  Portugal and Spain bake a broad bean into their Christmas King's cake, called bolo Rei and roscón de reyes. Whoever gets the slice with the bean is supposed to buy next year's cake. France has a similar custom with the galette des rois. The bean there, now often a small china or metal trinket, is called the fève. The finder becomes king or queen of the meal and is often expected to serve drinks to the others.

  The ancient writer Pliny claimed the bean acted as a laxative, and European folklore says that planting beans on Good Friday, or at night, brings good luck. The beans even reached the courts. In Frederick E Rose (London) Ltd v William H Pim Junior and Co Ltd, in 1953, both sides mistook feveroles for ordinary horse beans.

  The city of Groningen in the Netherlands treats roasted or fried broad beans as a local delicacy, called molleboon. Until the 1800s, the city council used mollebonen for voting, sometimes real beans and sometimes stones or clay ones. The word molleboon became a nickname for the people of Groningen.

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