Since travelling across the border (to Queensland) I have been trying to get my hands on a banana plant to have in our yard. Like many mothers I’m sure, I spend half my week in and out of grocery stores picking up kilos of the bright yellow fruit, so I fancy the idea of growing my own.
You would think that in sunny Queensland it wouldn’t be too hard to get your hands on one, would you, but with the ever popular Cavendish variety of banana highly susceptible to a fungus referred to as Panama Tropical Race 4, authorities are now highly controlled in how and where you can buy your banana plants from. On July 1st 2016 the regulations did change however, and you are no longer require to get a permit to grow banana plants in Queensland, provided they are plants that have been grow from tissue culture and purchased from a QBAN accredited nursery. This means you can not simply take a ‘sucker’ from your neighbours plant and give it a go in your yard. Similarly, plants purchased for growth in Queensland cannot be sent to NSW due to strict quarantine practices, and vice versa.
Just last year, the TR4 fungus spread through one entire property in North Queensland, which threatened the State’s $600 million industry. Yikes!
Panama Tropical Race 4 has spread throughout Asia, Africa and the Middle East, and scientists all around the qlobe are scrambling to breed new varieties of Cavendish which may be TR4-resistant.
The Cavendish banana is the most popular variety of banana, and accounts for some 90% of, not only Australia’s banana market, but also the total global banana export trade. There have been some discoveries of some varieties of banana which are more tolerant of TR4, however none yet have been found to be truly resistant. The more tolerant varieties of the popular fruit tend to be smaller, thinner skinned varietes, which come from plants which are not as productive, and therefore could not fill the production levels required. Unfortunately, the TR4 fungus infects the fruit and makes the banana unfit for human consumption (as seen below).
At this point, the Queensland Department of Agriculuture is attempting to fast track the development of new varieties that will be resistant to TR4 through a process called ‘mutant breeding’. It is not genetic modification as there is no change to the plant DNA, and there is nothing being added. The process involves the plant instead being exposed to radiation and placing the plant in a state of stress in order to create a “mutant” with a particular trait.
It is not only a problem for Queensland either, many years ago, from about 1996, the Northern Territory’s banana supplies were found to be infected by TR4 as well. After mutation breeding is complete in Queensland, the plants will be sent to the NT’s Coastal Plains Horticulture Research Station for testing. The NT are currently interested in the Honduran bred Goldfinger which is highly resistant to the TR4 disease, however the fruit is not commercially acceptable; in flavour, bunch quality and production capabilities.
This isn’t the first time we have been staring down barrel of a life without bananas. Some 60 years ago, Big Mike (a.k.a Gros Michel), the variety favoured at the time, was wiped out by a version of the very same fungus. The problem with bananas (and the way we grow them) is that they are sterile clones. Ever wondered why bananas don’t have any seeds? Unlike an apple tree for example, the banana plant is the largest herbaceous flowering plant. After the banana plant has produced its fruit, the plant stem dies. The suckers (small bulbs) which grow out of the plant’s underground rhizome (called the corn) are then replanted, and new plants grow. Bananas are therefore propagated vegetatively; sure the quality is consistent because they’re all genetically identical, but this also means that they are prone to disease as they are unable to evolve and adapt, and resistance cannot be bred into them. The fungus however can continue to change, and whilst Cavendish were once resistant, they are no longer.
It’s a tough spot to be in as the yellow fellows are Australia’s most popular fruit and lord knows when prices sky rocketed after Cyclone Larry in 2006, people literally went bananas!
(Lady) fingers crossed for some breakthroughs soon!