Hummus in Danger: Why Climate Change Could Spell the End for a Beloved Middle Eastern Dip

The extreme genetic bottleneck could doom the domesticated chickpea, unless a wild variant from Turkey rides in to save the day

Hummus in danger: the chickpea turns out to suffer from an extreme genetic bottleneck, but possibly hybridizing with wild varieties could restore the genetic diversity needed to weather climate change.
Mike Regan

Hummus, the beloved Middle Eastern dip, is in danger. Chickpeas are going the way of the cheetah.

For rather different reasons, both plant and cat are suffering from genetic bottlenecks that reduce their ability to cope with change. And in a warming world, change is happening. In contrast to the cheetah, the domestic chickpea could still be saved by crossing with wild breeds that still exist, to restore lost genetic diversity, wrote Eric Bishop von Wettberg, a plant biologist at the University of Vermont, and others in Nature on Tuesday.

One snag is that the wild breeds that could save our passion for paste of the pea survive only in parts of Turkey and possibly Syria.

The cheetah population has been reduced to near-extinction and has become critically inbred. The chickpea suffered the other extreme. In fact the chickpea is the world's second biggest legume crop, second only to soybean. It was bred to the point that it too is experiencing "an extreme domestication-related genetic bottleneck," von Wettberg and the team wrote.

In other words, domestic chickpeas are too genetically alike. Change in circumstances could doom the lot.

Like meets like and they die together

To reduce ad absurdum, if all chickpea plants were identical, all could only survive in exactly the same range of conditions. If the conditions – temperature, water, whatever – exceed what they could survive, all would flop over and die.

If the chickpeas, also known as garbanzo beans, have genetic diversity, there is a probability that some will bear mutations that help them adapt and survive under increasingly onerous conditions.

Take an example from people: Those with darker skin are better suited to the intense ultraviolet radiation characterizing the tropics, while those with lighter skin are better suited to sunless climes. If all humans had the same characteristics, they would all be suited to only one clime and couldn't have survived in every corner and armpit of the world.

In other words, the chickpea that makes the hummus that Israelis eat by the ton is in danger from climate change.

Domestic chickpea in right hand, wild chickpea in left: University of Vermont plant biologist Eric Bishop von Wettberg led a team of scientists into remote regions of Turkey--hunting for ways to harness the diversity of agricultural plants' wild cousins.
Joshua Brown

The problem applies to the whole Middle East and Indian subcontinent, and Ethiopia for example, where the chickpea is a staple source of protein.

Perhaps ironically, salvation may come from the region where man possibly first domesticated plants: Anatolia. The scientists found wild chickpea varieties there that hold "great promise," von Wettberg says, as a source of new genes for traits like drought resistance, resistance to pod-boring beetles, and heat tolerance.

How long people have been farming anything, let alone the chickpea, is fiercely debated. Some argue that a gigantic prehistoric village in Israel dating to some 23,000 years ago couldn't have existed without agriculture. Genetic analysis indicates that staple grains, including wheat and barley, were domesticated that long ago. A more general consensus is that farming developed in Mesopotamia, part of the Fertile Crescent, and/or Israel around 12,000 years ago.

Not ashamed to ask for directions

The chickpea is thought to have been farmed for about 11,000 years: Charred chickpeas about that old were found in Asikli Hoyuk and a couple of other spots in Turkey.

And how did the scientists find the rare wild chickpea in today's southeast Turkey? They asked for directions.

"The way we found a lot of these populations was by driving around and asking shepherds on the side of the road, 'Yabani nohut?' which means 'wild chickpea," von Wettberg says, "then they would take us out in the fields and show us the plants."

Thusly they collected seeds from 371 plants at 21 sites, plus DNA from 839 plants. What they discovered was an extreme genetic bottleneck: at some point in time, more than 93 percent of the genetic variation in the wild plants was lost from the modern chickpea.

Note that as the heat rises, water fluctuates and the palette of pests and disease change, the conditions become less and less like those in which this founder crop was originally domesticated. Thus as the heat rises, etc., the domestic chickpea with its diminished diversity is in ever-mounting danger.

The same is true of the global banana crop, by the way, which is almost entirely based on clones of the Cavendish variety – which is susceptible to a pernicious fungal disease. Everybody grows the same banana because it tastes better than the hundreds of other banana species, but the world crop is threatened by the fungus.

Wonderfully, the wild Turkish chickpea proved to have striking resistance to insect pests, say the scientists. But science had better get a move on. The entire Mediterranean basin and Levant are heating faster than the rest of the globe as climate change advances, and face extreme desertification down the line, according to climate models. The wild chickpea itself will be in need of saving before it can save the chickpea crop and the hummus hounds of the world.