Yes, We Have No Bananas – The Demise of the Cavendish

Whether sliced into a bowl of cereal, split in two and served with ice cream, or peeled and eaten, the banana is a common part of the American diet. Americans eat more bananas annually than oranges and apples combined. Bananas are an excellent source of vitamins, including B6 and C, magnesium, potassium, and fiber. While Americans typically view bananas as a snack food, in other parts of the world, they hold a much more important nutritional role. In some areas of Africa, where more than 200 species of the fruit are grown, bananas account for 80% of consumed calories. However, the banana that you know and love a variety called the Cavendish is in danger of being wiped out by a catastrophic disease currently spreading across the globe.

bananas

The Cavendish variety accounts for nearly 100% of the bananas imported around the world.(Photo credit: Muellek Josef/Shutterstock)

But just how did this far-grown fruit become such a popular snack in America? More importantly can anything be done to prevent the demise of the Cavendish variety from the spread of this disease?

While you might think that bananas grow on trees, the banana plant is actually the worlds largest herb. The banana part that we eat grow from a long stalk that extends out of a stem covered in flowers. The female flowers grow into fruit at the base of the stalk, while the male flowers grow at the tip of the stalk. A group of bananas is called a hand; a single banana is called a finger. Nearly all banana plants lack seeds, which means that the plants do not reproduce sexually. Instead, new plants emerge from an existing plants root system. In order to bear fruit, a banana plant must have at least 14 consecutive months of frost-free weather; this explains why most bananas are grown in tropical regions around the world.

The cultivation of bananas began in Southeast Asia around 10,000 years ago. Of the thousands of banana species that are native to Asia, only about 10 to 15 were brought to Africa. Because banana plants mutate easily, today Africa boasts around 200 species. But because they are all genetically similar, these varieties are susceptible to the same disease and parasites.

Bananas were first introduced to America in the 1870s by Cape Cod fishing captain Lorenzo Dow Baker, when he imported nearly 200 bunches into Jersey City, New Jersey. The American public was introduced to the yellow fruit at the Philadelphia Centennial Exhibition in 1876. By the early 1900s, Americans were devouring 15 million bananas a year. A decade later, that number would swell to 40 million a year. The number would continue to increase, culminating in today’s whopping 30 billion pounds of bananas consumed in America each year.

The United Fruit Company (now Chiquita), co-founded by Baker, played a key role in popularizing bananas in the United States. While Americans readily took to the exotic delicacy, getting bananas to the United States from Central America was no simple feat. Transporting bananas thousands of miles required clearing rain forests, building railroads and communication networks, and developing refrigeration techniques to keep the produce fresh. The political turmoil brought to that region of the world by the banana industry also complicated matters. Governments were established and overthrown, corruption was rife, and working conditions for plantation workers were dismal for much of the industry’s formative years..

While today the Cavendish banana accounts for nearly 100% of the bananas imported into the U.S., prior to the 1950s the Gros Michel variety held the top spot. By all accounts, the Gros Michel was superior to the Cavendish in almost every way it was tastier, it was larger in size, and it was easier to transport. However, beginning the 1900s, a plant disease called Tropical Race 1 began to wipe out Gros Michel crops around the world. By the 1950s, the Gros Michel was virtually extinct. The Cavendish variety originally native to China and resistant to Tropical Race 1 was introduced by Standard Fruit Company (now Dole) as a replacement. The United Fruit Company adopted the variety soon after.

Now it appears that history is repeating itself as a new strain of the plant disease is threatening banana crops around the world. Called Tropical Race 4, this disease is caused by strains of soil bacteria called Fusarium oxysporum f. sp. cubense or Foc. It first appeared in Asia in the late 1980s/early 1990s and spread throughout Taiwan, Indonesia, Malaysia, the Philippines, China, Jordan, Mozambique, and northern Australia. Experts expect the disease to reach the Caribbean and Central America where 80% of imported bananas are grown within the next 5-10 years. Though plant scientists originally thought the disease functioned by injecting toxins into the plants, new research indicates that the disease actually works by turning on a mechanism in the banana plants that causes programmed cell death. Because the disease is spread by contaminated soil or the importation of infected rhizomes, it is hard to control the disease once it has been discovered in an area.

Currently, an antidote to Tropical Race 4 does not exist. Researchers have had little success in developing a banana resistant to the disease. Separate research groups are employing classical breeding and genetic engineering techniques to come up with a solution. For example, scientists at the Laboratory of Tropical Crop Improvement located at the Catholic University of Leuven in Belgium are working to insert genes from a radish which is resistant to a fungus similar to Tropical Race 4 into the Cavendish banana. Though the research is promising, much more needs to be done before DNA manipulation could be considered a viable solution.

More to Explore

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Bananas: The Uncertain Future of a Favorite Fruit
Yes, We Do Have Bananas, For Now
Fungus Threatens Top Banana
Yes, We Will Have No Bananas

 

This article was originally published on BioZine in March 2014.

Comments

  1. Bananas are good. Almost good.

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