Cavendish was a great success, saving the banana industry and spreading it around the globe for the next five decades. 99% of exports and almost half the total production in the world are Cavendish varieties. This strength is now the biggest vulnerability for the banana industry. Panama disease is back, and the Cavendish banana is no longer resistant.
It is only a matter of time before the disease returns to the vast plantations in the Caribbean and Central America. The last outbreak of Panama Disease may provide some insight into how to resolve this latest crisis. An unlikely source provided the answer. The answer came not from the jungles in South-East Asia where bananas were native but rather from Chatsworth House. This was the former home of William Cavendish, the Sixth Duchess of Devonshire, a politician and keen gardener.
The Duke and the Gardener
Cavendish hired a young farmer’s child as his head gardener in 1826. Joseph Paxton was the young farmer’s son Cavendish hired as his head gardener in 1826. He used the skills he gained from building experimental greenhouses in Chatsworth to design the Crystal Palace, a famous London landmark.
John Williams, who was a missionary in the Pacific Islands, received Cavendish plants for his ministry. The first specimens of this plant were planted in Samoa back in 1838. From there, the plant spread throughout the world, including to Tonga and Fiji. It also reached Australia and Hawaii, as well as the origin of the banana – New Guinea. Williams was not able to see it, as he had been eaten by New Hebrides islanders in 1839. They were unenthusiastic towards his message.
The Massacre of John Williams National Library of New Zealand
Nicolas Baudin, a French privateer and cartographer, brought the Gros Michel varieties from Myanmar to St Pierre botanical gardens in Martinique at the beginning of the 19th century. The botanist Jean Francois Pouyat took it to Jamaica in 1835. These specimens were probably used to create the banana export industry at the beginning of the 20th century.
The distribution of banana plants in every place on earth that is hot enough to allow them to grow has been surprising. They are sterile. Wild Bananas contain large, hard seeds that make them difficult to eat. Modern bananas are unable to produce seeds. This genetic quirk has not hindered the spread of bananas. It is the very thing that makes them so desirable. What has made them so vulnerable?
They cannot reproduce sexually because their chromosomes can’t be equally divided to create a sex cell, as happens in “diploid” organisms (such as humans, most animals, and many plants) that have two copies of each chromosome. They cannot reproduce sexually because their chromosomes can’t be divided equally to make a sex-cell, like “diploids, which have two copies of each of the chromosomes (such as human beings, many animals, and most plants).
This type of triploid can occur when the formation of sex cells in diploid organisms is not completed properly. Sometimes, cells with two copies of a chromosome are formed instead of just one. These cells can fuse with normal sex cells, but the resultant plant will have two chromosomes from one parent and a chromosome from the other. This prevents it from producing viable sex cells. The banana plant can still produce fruit, but it cannot make seeds.
This may seem like a problem at first, but plants do not rely solely on sexual reproduction. New plants can be grown by cuttings. And new banana trees, also known as suckers, are often produced from existing plants.
They could not have known about chromosome numbers. Most of the varieties they grew were triploid. They must have learned to keep an eye out for these lucky accidents and grow them instead of their wild and weedy relatives.
It has both positive and negative consequences. Cuttings produce identical plants, with the exception of a few mutations. This eliminates chance and variety from the equation. We only take cuttings from trees that have fruit and are vigorous. All of the new plants will look similar to the original tree.
It is also great for any disease that infects them because if it gets a foothold, those nearby will be vulnerable as well. It is, unfortunately, also good for any disease which infects the bananas. If it gains a foothold, it will spread to all of the trees in that area. This is exactly what’s happening.
In 1874, the first case of Panama disease was discovered in Australia. The banana leaves stopped growing first. They began to curl up and wilt. The trees eventually dried up and died. The disease first appeared in 1890 in the country that bears its name. It spread over the next thirty years to the Caribbean and Central American nations.
In 1910, the cause was finally identified as Fusarium oxysporum Cubense, or simply “Foc.” The channels that carried water and minerals to the leaves from the roots became blocked. The fungus was thought to have clogged these channels, but now we know that the plants themselves plug them in an attempt to prevent the fungus from spreading.