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SCIENCE & POLICY: The beginning of the end for bananas?



                                  PART 1


------------------------------- GENET-news -------------------------------

TITLE:   THE BEGINNING OF THE END FOR BANANAS?

SOURCE:  The Scientist, USA

AUTHOR:  Dan Kloeppel

URL:     http://the-scientist.com/2011/07/22/the-beginning-of-the-end-for-bananas/

DATE:    22.07.2011

SUMMARY: "Our standard supermarket banana, a variety called Cavendish, may be at the brink of disaster. Chosen for its resistance to a fungal pathogen that wiped out its predecessor, the Gros Michel banana, the popular fruit has long battled a related fungus, which has all but devastated the banana industry in certain parts of the world. Now, it appears the Cavendish variety is facing a new threat?the very same fungal disease that drove Gros Michels off the market."

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THE BEGINNING OF THE END FOR BANANAS?

Already reeling from a 20-year losing battle with a devastating disease, the banana variety eaten in the United States is now threatened by a new?but old?enemy.

Our standard supermarket banana, a variety called Cavendish, may be at the brink of disaster. Chosen for its resistance to a fungal pathogen that wiped out its predecessor, the Gros Michel banana, the popular fruit has long battled a related fungus, which has all but devastated the banana industry in certain parts of the world. Now, it appears the Cavendish variety is facing a new threat?the very same fungal disease that drove Gros Michels off the market.

Cavendish bananas account for about 45 percent of the fruit?s global crop, with an annual export value of US$8.5 billion, according to the United Nations Food and Agriculture Organization. It was chosen to replace the original Gros Michel banana after a deadly fungal infection, known as Panama disease (Fusarium oxysporum f. sp. Cubense), wiped out much of the world?s banana crop in the first half of the 20th century.

Farmers adopted the Cavendish variety because it appeared to resist the blight, as well as about a dozen other banana diseases that also threaten the worldwide crop. But it wasn?t long before it too started suffering from disease. In the late 1980s, a mysterious malady began to wipe out Asian Cavendish plantations. Soil samples were sent to plant pathologist Randy Ploetz of the University of Florida?s Tropical Research and Education Center, who made the shocking identification: Panama disease was back, in the form of a new strain, which he dubbed Tropical Race 4.

Race 4 is just as virulent to Cavendish as Race 1 was to Gros Michel. The fungus enters the plant via its roots through infected soil or water and spreads via the plant?s vascular system. Once exposed, the plant yellows, and begins to look obviously sick?dried-out, sunken, and sagging. As the disease progresses, brown and purple stripes appear on the trunk, and the plant eventually dies. The disease, however, lives on, spreading via infected soil from plant to plant, plantation to plantation.

Today the disease has spread across Asia, into the Pacific, and to Australia, where it has devastated the island country?s banana industry. Though Race 4 has yet to hit Latin America, where bananas imported to the United States are grown, there?s little doubt it will, said Ploetz.

But it turns out that Race 4 is not the only threat to Cavendish bananas. As banana growers have fled from Race 4, replanting their Cavendish trees in areas only known to harbor Race 1, they quickly learned that Gros Michel?s old foe was now tormenting Cavendish bananas as well.

In 2010, scientists conducting a survey of plants infected in India, which grows and consumes more bananas than any other country in the world, were the first to conclusively identify the presence of Race 1 in the Cavendish banana. They published their findings in Plant Disease that November, and this March, Bioversity International?the global umbrella group for banana research?released a report confirming the finding: Race 1 had begun killing Cavendish plants in plantations around the Theni District of Tamil Nadu, India.

Banana scientists are still trying to determine why some Cavendish are no longer immune to Race 1. Altus Viljoenm, a researcher with the University of Stellenbosch in South Africa, speculates that this new strain of Race 1 may have evolved over time so that it could attack Cavendish.

Other researchers are skeptical of the finding. Ploetz notes that there have been rare cases in which Race 1 has killed individual Cavendish plants when they were already stressed?due to drought conditions, for example, or flooding. ?I suspect that this is the same thing,? he said.

But the authors of the Plant Disease paper reported that they had confirmed the finding with laboratory tests on sterile, potted Cavendish. ?To our knowledge,? the researchers wrote, ?this is the first report of [such] a virulent strain.?

Today, there are no cures, treatments, or even reliable molecular diagnostic tests for either Race, partly due to lack of detailed information on the banana genome, according to Bioversity. Currently, the best available strategy is containment. Ploetz has developed a plan to fight Race 4 if it appears in Latin American plantations, involving the use of strict quarantines on affected plantations to prevent, at least temporarily, the spread of the disease.

But isolating infected plantations is more a stopgap than a solution, Ploetz knows. ?It buys time,? he said, but barring any new discoveries, the spread of Panama disease remains inevitable. Ploetz said it?s important that similar agricultural practices be instituted in already affected countries to help prevent the spread to Latin America in the first place.

In the meantime, scientists are working to develop new approaches to quell disaster. Last year, for example, University of Queensland researcher James Dale began the first field tests of a genetically modified Cavendish, which he hopes will provide long-term resistance against Race 4.

Banana companies such as Chiquita and Dole are also reportedly working to develop new varieties. Though genetic modification has long been considered the only way to breed Cavendish, since the variety is completely sterile, recent research conducted in Honduras has revealed that a few Cavendish plants do produce viable seeds. Researchers at the Fundacíon Hondureña de Investigación Agrícola (FHIA) say these non-sterile fruit form the basis of a series of promising hybrids, that can be bred for resistance to the fungi. It will still be at least six years before the new breeds are ready to be brought to market, however, according to a source familiar with the project, or may never appear at all, now that the banana companies are no longer funding the research.

Most banana researchers agree that the real answer?as has been the case with crops like potatoes, apples, and grapes?is to abandon the monoculture that makes the emergence of a disease so devastating. A more diverse banana harvest would allow farmers to isolate susceptible bananas, surrounding them with more resistant varieties. If the solution ends up being a Cavendish stand-in that is resistant to both strains, on the other hand, the predicament of the banana monoculture?with its vulnerability to old, new, and yet-to-be discovered pathogens?would continue.

Dan Koeppel is the author of ?Banana: The Fate of the Fruit that Changed the World.? His account of a search, conducted in the Democratic Republic of Congo, for potentially diversifying banana breeds will appear in National Geographic in 2011.



                                  PART 2

------------------------------- GENET-news -------------------------------

TITLE:   YES, WE DO HAVE BANANAS, FOR NOW

SOURCE:  National Public Radio, USA (NPR)

AUTHOR:  Ira Flatow

URL:     http://www.npr.org/2011/07/22/138610585/yes-we-do-have-bananas-for-now

DATE:    22.07.2011

SUMMARY: "America?s most widely eaten banana type, the Cavendish, is threatened by a fungus that could wipe out U.S. banana supplies if it spreads to Latin America. Banana expert Dan Koeppel discusses the problem of banana monoculture, and why he says we should demand banana variety."

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YES, WE DO HAVE BANANAS, FOR NOW

America?s most widely eaten banana type, the Cavendish, is threatened by a fungus that could wipe out U.S. banana supplies if it spreads to Latin America. Banana expert Dan Koeppel discusses the problem of banana monoculture, and why he says we should demand banana variety.

IRA FLATOW, host: You?re listening to SCIENCE FRIDAY. I?m Ira Flatow. Why is it when you go to the grocery store you can find a dozen kinds of apples? You got your McIntosh, your red delicious, your Granny Smiths. You got other varieties of fruit like the tangerines, your tangelos, your mandarin oranges, your red and green seedless grapes, big variety there. But there?s only one kind of banana. There are thousands of varieties of bananas, but the big U.S. banana suppliers grow only one that we can get, the Cavendish.

So that?s the one we eat, and we eat a lot of them, billions and billions of pounds each year. We slice them on our oatmeal, in our cornflakes. We whip them up in smoothies. We rely on them as a backbone of the banana split. But could our favorite fruit soon become history? Well, a lethal fungus is spreading through Cavendish banana plantations in Asia and Australia. What happens if it makes its way to Latin America, where the U.S. banana supply is grown?

Joining me now to talk more about them is Dan Koeppel, science writer and author of ?Banana: The Fate of the Fruit that Changed the World.? He joins us from KPCC. Welcome to SCIENCE FRIDAY.

DAN KOEPPEL: Thank you so much.

FLATOW: Is it true that the song ?Yes! We Have No Bananas? was written because of a shortage of bananas once?

KOEPPEL: Well, the original banana that Americans came to know was called the Gros Michel banana, and that one was wiped out by a blight between 1906 and 1960. That song appeared in the 1920s. And it?s likely that there were banana shortages during that time. I can?t say that the writers of the song were aware of this...

(SOUNDBITE OF LAUGHTER)

KOEPPEL: ...just like most people aren?t aware of it now. But I would like to believe that it had something to do with it, and it?s not a complete myth.

FLATOW: And you say that just like the Gros Michel bananas were wiped out by disease that we may be headed toward another wipeout.

KOEPPEL: Correct. That disease that killed Gros Michel, which was actually a better tasting better banana than what we eat now - the Cavendish - was called Panama disease. It?s a fungal wilt. And in fact, what?s killing Cavendish is another version of that very same disease. Cavendish was adopted because it was resistant to the original version of Panama disease, but it is not resistant to this newly discovered strain, and that?s a big problem.

FLATOW: So why, as I mentioned in my introduction, we have all these varieties of other fruits and vegetables, why do we only have one banana to choose from?

KOEPPEL: Well, I like to answer that by asking why don?t we have filet mignon, pad Thai and tofu scrambles at McDonald?s?

FLATOW: OK.

KOEPPEL: The banana...

(SOUNDBITE OF LAUGHTER)

KOEPPEL: The banana is the cheapest fruit in the supermarket, and that?s pretty weird because it?s shipped from great distances, and it requires a lot of handling and refrigeration, much more than apples, for example. To do that, the banana industry has for 100 years had a business model that focuses on a single product. That?s the McDonald?s comparison. And I like to tell people, imagine a pipe from Ecuador to your supermarket that can only fit one variety of the world?s 1,000 banana varieties, and that?s basically the way it works.

That?s why bananas are so cheap. In order to bring new bananas, you have to build entirely new infrastructure, ranging from plantation to shipping to packing methods and to ways to tell consumers about it.

FLATOW: But you would think that the banana people who control the banana flow would know that there is a fungus among us out there someplace and headed in our direction.

KOEPPEL: Well, they know. They didn?t admit it for a long time. Just a couple of years ago, Chiquita started talking about it, and Chiquita also has been doing some work on developing alternate varieties. But for the most part, the history of the industry has been to look at chemical means of control for blight and to stick to this monocultural business model because that?s all they know. And in some ways, you can think of them as maybe the old department stores in the 1970s or digital equipment corporations, some of these hidebound tech companies that couldn?t change and disappeared. I?m not predicting Chiquita will disappear, but they?re stuck in this century-old business model, and they have a really difficult time thinking about things any differently.

FLATOW: Is there any niche here for someone to get in with a different variety of banana then?

KOEPPEL: You know, I tell people every single day that if you want to get into a possibly lucrative business, because the banana is the most popular fruit in the supermarket and the world, look into importing new bananas. That said, it is a daunting task. Because each banana ripens differently, each banana ships differently, each banana has to be grown differently, you need sort of industrial-strength capital and knowhow to get the product. But that said, the kiwi fruit was unknown about 20 years ago and was introduced and is now pretty popular. So there?s knowhow and there - if someone was willing to invest, I think it can happen.

FLATOW: You know, when you go to the store, you can. And if you go to other countries in the Caribbean, Latin America, well, in the stores, we see plantains or plantains - depending on how you want to produce it - say it - and then there?s these little finger-shape bananas. Are they - you?re saying that they?re not different from the Cavendish bananas?

KOEPPEL: They are different and some of them are susceptible to these banana diseases. There?s about a dozen pretty virulent diseases. There are a few alternate varieties. We have a pretty good selection in Los Angeles because of our large Filipino population. But those varieties account for a statistical zero in terms of the Cavendish market share.

And the banana companies have not had a lot of success with what they call the baby finger bananas. One of the reasons is that educational component in bringing the new variety. Baby bananas need to be served much more brown than a traditional Cavendish to taste right. But most people are used to that visual cue the Cavendish gives and so don?t allow them to go brown, and that?s been a real problem in getting people to actually like this variety.

FLATOW: How many of these varieties have you actually tasted and how different are they?

KOEPPEL: I?ve tasted about, I?d say, 100 different banana varieties all over the world.

FLATOW: Wow. You got a favorite?

KOEPPEL: Absolutely.

(SOUNDBITE OF LAUGHTER)

KOEPPEL: My favorite is called Ibota Ibota. It?s a variety found - I discovered it or tasted it first in the Democratic Republic of Congo. Ibota Ibota - the word Ibota means fertile in Swahili. And this banana yields huge bunches, and so it?s called fertile fertile. It?s so fertile. And it is absolutely delicious. It has - you know, you can only describe it the way you describe a really interesting wine. It?s got complex taste. It?s got notes and colors to it. But, unfortunately, it doesn?t have the properly characteristics for import and it?s too bad because it?s a revelation. Our Cavendish banana is a lousy banana. In India, the world?s largest growing - banana-growing country, they call the Cavendish the hotel banana.

FLATOW: Wow. And there?s no way to get us closer to that banana that - did you say was in the Congo? It was growing over there?

KOEPPEL: In the Congo. There are similar varieties in Thailand. I wouldn?t say there?s no way. I would say that it will take creativity and guts and...

FLATOW: Well, why not grow it locally? Tell - what prevents it from, you know, importing it? Does the banana have a range of temperature and humidity and things like that it needs to grow in?

KOEPPEL: There are about 30 categories of the banana - or 30 checkmarks that the banana industry has come up with to make a suitable import banana. One of which is that it can be grown in the regions where they operate. It definitely can?t be grown up here in the U.S. But other ones include height of the tree, because banana-growing countries are susceptible to hurricanes so you want a lower tree. One includes how it indicates ripeness. Some bananas don?t actually turn yellow when they ripen.

And for Ibota Ibota, the problem is something called finger drop. Each banana fruit that we eat is actually known a finger. And the problem is when you touch these wonderfully huge bunches of 20 or 30 of these bananas all of the bananas fall off and their skin is torn and exposed. And you can?t ship a banana that?s already been opened, and that?s the problem with Ibota Ibota.

FLATOW: But if you live there, it?s easy to get it off of the plant then.

KOEPPEL: Oh, yeah. Yeah. And, in fact, that could be a good thing if this is a village banana in the Congo and you?ve got a bunch of people relying on this one tree, then, yeah, it?s like a flip top can.

(SOUNDBITE OF LAUGHTER)

KOEPPEL: So, yeah, it works pretty well.

FLATOW: How certain is it that the fungus that?s not in Caribbean yet is going to get to Latin America?

KOEPPEL: Well, I?ll say first of all that this my opinion, and I will also say this that this backed up by most people in science who know, but it is not backed up by Chiquita and Dole who say, we don?t know when. The truth is we don?t know when. The problem is that this disease is so virulent that it could come to tomorrow. It?s transmitted via no more than a speck of dirt on a shoe or a tool.

Now, if I was in a place like the Philippines where the diseases exist and I had some dirt on my shoe and I landed in Costa Rica and stepped on a banana plantation, that?s the beginning. So it could come in 20 years, but it could come tomorrow. It?s like one person who?s sick wandering around the Earth and you don?t know when he?s going to open your door. But as soon as he does, you?re finished. That?s the way it?ll work.

FLATOW: Yeah. So it?s that simple. And so...

KOEPPEL: Right. And...

FLATOW: ...it lives in the soil. It lives in the soil?

KOEPPEL: Correct, it lives in the soil. And that randomness, you know, the banana industry likes to say, well, we - you know, it?s a long way away because it?s not here yet and it takes awhile. In fact, they need to prepare right now because it could come tomorrow. It?s not a long way away or a short way away. But if you know a disaster is coming - you know, like out here in L.A., we prepare for earthquakes because we don?t know if the big one is going to happen today or tomorrow or in 10 years, but we want to be ready.

FLATOW: Could you genetically engineer a better banana so it?s not susceptible to this fungus.

KOEPPEL: Yes. And there?s been quite a bit of good work involved in that, mostly done in Australia through a Gates Foundation grant. And there has been some success but we don?t know for sure how well these bananas will perform in the field in large scale.

In addition, Chiquita and Dole and the other banana companies have promised never to sell a GMO banana. And in Europe, for example, you can?t even sell a product like that. So whether you?re going to solve that problem through genetic modification, which I?m in favor of, you may never have a commercial variety that can actually hit store shelves.

FLATOW: One quick question from Judith in Chico, California. Hi, Judith. Quickly.

JUDITH: Yes. I buy short, fat, red bananas in my local food coop. Are these something that are also going to be threatened by this fungus?

KOEPPEL: Not this fungus. Those bananas - those red bananas which is what we call them, are a relative of a really great banana called a Philippine Lacatan, and those are wonderful, wonderful bananas. They?re available at places like food coops or Whole Foods, not generally in regular supermarkets. One of the problems with those bananas is that they?re quite fragile. It?s hard to ship to them in the quantities needed to satisfy the American banana appetite, which is about 25 pounds of bananas a year without damage in an extraordinary handling measures. So they tend to be a gourmet item, and they are really good.

FLATOW: Well, thank you, Dan. You?ve set out the alarm bells here for everybody to watch out for this.

KOEPPEL: Right. You?re most welcome.

FLATOW: Dan Koeppel is a science writer and the author of ?Banana: The Fate of the Fruit that Changed the World.? A great read. He joined us from KPCC in California. Thanks again.

KOEPPEL: Thank you so much for having me.

FLATOW: And if you want to follow Dan, you can read his latest story about bananas in today?s issue of The Scientist. I?m Ira Flatow. This is SCIENCE FRIDAY from NPR.



                                  PART 3

------------------------------- GENET-news -------------------------------

TITLE:   STUDY REVEALS BANANAS HEAVILY INBRED

SOURCE:  Australian Broadcasting Corporation, Australia (ABC)

AUTHOR:  Branwen Morgan

URL:     http://www.abc.net.au/science/articles/2011/07/05/3257726.htm

DATE:    05.07.2011

SUMMARY: "The standard yellow banana currently found on most supermarket shelves are mass cultivated as infertile clones and are therefore genetically identical. But this makes them particularly susceptible to disease, pests and ecological challenges, writes a team of European and Australian scientists in the journal Proceedings of the National Academy of Sciences. [...] Jonathan Eccles, CEO of the Australian Banana Growers? Council, says that while there are no banana breeding programs in Australia, they do evaluate different varieties through their research program."

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STUDY REVEALS BANANAS HEAVILY INBRED

A study retracing the bananas? family tree has found their wild ancestors have rarely crossbred in the last seven thousand years, strengthening calls to diversify the popular crop.

The standard yellow banana currently found on most supermarket shelves are mass cultivated as infertile clones and are therefore genetically identical.

But this makes them particularly susceptible to disease, pests and ecological challenges, writes a team of European and Australian scientists in the journal Proceedings of the National Academy of Sciences.

Co-author Dr Mark Donohue, from the Australian National University in Canberra, says 85 per cent of cultivated bananas are for local consumption.

?This means that any disruption to the supply of bananas will have immediate consequences ... possibly leading to famines,? he says.

Reduce vulnerability

In order to be able to generate diversity and improve future banana crops, the authors of the study believe it is necessary to understand which species were historically crossed and selected for breeding.

To reconstruct the banana?s geographical spread and its road to domestication they analysed genetic, linguistic and archaeological data.

?The genetic descent is one thing, but knowing whether they [bananas] are being used by humans is another.?

?The archaeologists could tell us when they were actually being used, the geneticists could tell us which direction and which kind of cross-breeding happened and, through the linguistics, we managed to get an idea of how culturally important bananas were for the regions they were in,? explains Donohue.

Analysis of microscopic remains of banana leaves at the world heritage-listed Kuk swamp in New Guinea confirmed banana cultivation was taking place approximately 7000 years ago.

Genetic analysis showed that bananas in the islands around Southeast Asia and Western Melanesia hybridised into subspecies that could not have formed without human intervention.

Linguistic research identified more than 1100 terms from different languages that relate to banana varieties. They also found four key derivations of the term for banana, each suggestive of a different dispersal trajectory.

Survey of banana crops needed

While the new research may provide a basis on which to formulate a banana breeding strategy, Donohue believes we also need to encourage local diversity.

There are hundreds of varieties of bananas, from plantains to ladyfingers, and there are many more yet to be documented.

?Many parts of the world, like Indonesia, don?t really know the sort of genetic diversity that?s out there - there?s never been a survey,? says Donohue.

?Given the different kinds of climate we see, from New Guinea to South East Asia, there?s probably a specialised variety, already being grown or present in the wild, that can hit that [disease resilient] niche quite well if we could only find it.?

History never repeats?

In the 1950s, a fungal disease, known as Panama disease, led to huge losses of ?Gros Michel,? then the biggest export and most widely consumed banana species.

Similarly, the Irish Potato famine in the 19th century was the result of over-reliance on a few species of potato.

Jonathan Eccles, CEO of the Australian Banana Growers? Council, says that while there are no banana breeding programs in Australia, they do evaluate different varieties through their research program.

?The whole supply chain has to be taken into account when evaluating different varieties,? he says.

This includes whether there is consistent productivity and the length of transport time, as well as market attributes such as flavour characteristics.

?Offering a range of products, such as plantain, is a good way to encourage expansion of banana varieties,? says Eccles.