James and the Giant Corn Genetics: Studying the Source Code of Nature

November 12, 2009

Hawaiian Pineapples and the Seed Industry

Filed under: agriculture,Fun With Numbers — Tags: , , , — James @ 2:37 pm
Pineapple. Wish I'd thought to check for a country of origin...

Pineapple. Wish I'd thought to check for a country of origin...

Since today seems to have a tropical theme, here’s another post about Hawaii:

The corn breeding industry is expanding in Hawaii*. The pineapple industry is contracting. People seem to be blaming the second on the first, and are passing this article around. My reading of the article, and some other statistics I looked, don’t seem to agree with the story line (evil GMO seed companies driving out the pineapple industry) that people seem to be suggesting.

Yes, Monsanto did buy out one of Hawaii’s three remaining large pineapple growers several years ago (as of 2007 there were also 49 small pineapple producers growing pineapples on 1-15 acres and a single medium sized grower with between 100-250 acres), but Maui Land & Pineapple Co., the company this article talks about, isn’t selling out to a seed company, they’re switching to the production of other crops instead of pineapples. One company sells its land and shuts down, another stays in the farming business but gives up on pineapples and announced plans to grow a more diverse range of crops. To me, that suggests it is becoming harder and harder to make a profit growing pineapples in Hawaii. (more…)

Genetically Engineered Crops: Papaya

Photo Reeding, Flickr (Click for photo stream)

Photo Reeding, Flickr (Click for photo stream)

Scientific Name: Carica papaya

Genetically Engineered Trait: Resistance to the papaya ringspot virus

Details of Genetic Engineering:

In the 1990s papaya ringspot virus was in the process of wiping out the Hawaiian papaya industry, then the second largest fruit industry in Hawaii. Conventional approaches such as selective breeding for resistant papayas or attempting to grow trees in isolation had failed. The virus is transmitted by small sap-sucking insects such as aphids. Infected papaya trees can be recognized by the discolored rings on their fruit (that the virus gets its name from) yellow leaves, and most importantly from a papaya farmer’s perpsective a 60-100%* loss of fruit production. (more…)

November 11, 2009

bt: The Bacteria and the Protein

Filed under: agriculture — Tags: , , , , , — James @ 9:02 pm

I figured if I am going to do a review of genetically engineered crops, I needed to address the other major traits besides resistance to herbicides presently on the market. This one addresses a family of proteins found in the bacteria Bacillus thuringiensis that can kill insects.

Anyone who reads about the public policy debates swirreling around genetically engineered crops will be familar with the two letter abbreviation ‘bt’ as in bt corn, bt cotton, bt ginseng (the last is fictional). What always surprises me is that some people STOP reading before they come across an explanation of what bt stands for. Just typing bt into google won’t bring up a relevant result until the 30th hit (two letters just isn’t very unique). I have talked with people who are convinced bt stands for everything from biologically treated to BioToxin. It doesn’t.

Golden Eyed Lacewing Adult. It's not much use, but the larva vicious predators of certain plant pests. (Photo public domain courtesy of USDA. You guys are awesome!)

Golden Eyed Lacewing Adult. It's not much use, but the larva vicious predators of certain plant pests. (Photo public domain courtesy of USDA. You guys are awesome!)

The name actually comes from a species of bacteria called Bacillus thuringiensis. Different substrains of the species carry different members of a family of genes that code for Cry proteins (and separately can also carry genes that code for Cyt proteins*), which can kill insects. Finding chemical or biological means to kill insects isn’t that hard. What makes the Cry proteins noteworthy is how selective they are in their killing. A given Cry protein is dangerous to only a small subset of insect species. And that’s important, because, for every** western corn rootworm, european corn borer, or earworm there are also benign or even beneficial insects in and around fields like lacewings, trichogramma wasps, or those rootworm eating nematodes I talked about a couple of days ago, which aren’t insects, but also harmed by insecticides. (Agro-ecology is beyond my field of expertise, had to call up my tipster from the previous post to get this list) When a crop is genetically engineered to produce one of the dozens of Cry proteins discovered in Bacillus thuringiensis, it replaces or reduces the spraying of insecticides to control insect pests, with positive effects on insect biodiversity. (more…)

November 10, 2009

Genetically Engineered Crops: Soybean

Soybean field. Photo: Big Grey Mare, Flickr (click photo to view photostream)

Soybean field. Photo: Big Grey Mare, Flickr (click photo to view photostream)

Scientific Name: Glycine max

Genetically Engineered Traits: Herbicide Resistance

Details of Genetic Engineering:

The genetic engineering of soybeans is pretty similar to that of Canola. Roundup Ready soybeans (produced by Monsanto) have been on the market for some time. The soybeans, which allowed farmers to spray an herbicide that kills all the plants in the field besides the soybeans themselves, have been a huge hit with market shares >90%. The benefit here is that being able to use herbicide resistant soybeans has been linked to increased use of no-till farming.* Bayer CropScience recently received regulatory approval for LibertyLink soybeans, their own herbicide + resistance system. Having another system is good for two reasons:

  1. Competition brings down prices for farmers
  2. Being able to rotate between two different herbicides prolongs the usefulness of both. Even if weeds develop some resistance to glyphosate (the active ingredient Roundup Ready crops are resistant to) the weeds are killed next year when the farmer sprays Glufosinate (the active ingredient that Liberty Link crops are resistant to).

About Soybeans: (more…)

November 9, 2009

Genetically Engineered Crops: Canola

Field of Canola in Bloom. Photo: Joe Shlabotnik, flickr (click photo to view Joe's photostream)

Field of Canola in Bloom. Photo: Joe Shlabotnik, flickr (click photo to view Joe's photostream)

Scientific name: Brassica napus

Genetically Engineered Traits: Herbicide Resistance.

Details of Genetic Engineering:

Two companies have produced canola that is resistant to different herbicides.
Monsanto sells canola (Roundup Ready canola) that is resistant to glyphosate, an herbicide monsanto sells under the brand name Roundup and lots of other companies sell under lots of other brand names since the herbicide itself recently came off patent (the resistance trait is still under patent.)
Bayer sells canola (Liberty Link canola) that resists the completely different, if similar sounding herbicide, glufosinate. Glufosinate is sold under a number of brand names (including, you guessed it, Liberty), but I wasn’t able to figure out whether or not it is still under patent.
About Canola:
Derived from the name “Canadian Oil” canola is an oilseed plant also known as rapeseed. The name change came in the 1970s when conventional breeding (this was approx. two decades before the first genetically engineered plants hit the market) created plants with healthier oil and without the bitter taste , and presumably someone to majored in advertising suggested that selling “Rape Oil” would be a good way to go bankrupt.

Two companies have produced canola that is resistant to different herbicides.

Monsanto sells canola (Roundup Ready canola) that is resistant to glyphosate, an herbicide Monsanto sells under the brand name Roundup and lots of other companies sell under lots of other brand names since the herbicide itself recently came off patent (the resistance trait is still under patent.)

Bayer sells canola (Liberty Link canola) that resists the completely different, if similar sounding herbicide, glufosinate. Glufosinate is sold under a number of brand names (including, you guessed it, Liberty), but I wasn’t able to figure out whether or not it is still under patent.

About Canola:

Derived from the name “Canadian Oil” canola is breed of the oilseed crop rapeseed. The name change came in the 1970s when conventional breeding (this was approx. two decades before the first genetically engineered plants hit the market) created plants with healthier oil and without the bitter taste people associated with rapeseed oil, and presumably someone to majored in advertising suggested that selling “Rape Oil” would be a good way to go bankrupt.

Close up of Canola Flowers. Photo: Pollobarca2, flickr (click photo to see pollobarca2's photostream)

Close up of Canola Flowers. Photo: Pollobarca2, flickr (click photo to see pollobarca2's photostream)

Rapeseed (the USDA doesn’t break out separate statistics for Canola) was the third biggest source of vegetable oils around the world in 2008-2009 at 20.5 million metric tons, coming in behind only soybeans and oil palms.

Canola is the main oil I use in my own cooking. Canola is apparently one of the healthier sources of vegetable oils, but the two things I most appreciate about it are the high smoke point (it’s harder to burn the oil itself*), and low cost. Last time I checked I was able to find a 48 oz bottle of canola oil for 2.99 which was better than local prices for peanut or corn oil. (Olive oil of course comes in much smaller containers that cost $10 or more, not at all suitable for graduate students.)

*Good for someone who is both as indifferent a cook, and as easily distracted as I am.

November 8, 2009

Biological Control of Western Corn Rootworms

Filed under: agriculture,biology,Genetics,Plants — Tags: , , , , — James @ 8:52 pm
Face of the Enemy: Adult Western Corn Rootworm chewing on the silks of a corn ear. Picture from wikimedia, apparently in the public domain

Face of the Enemy: Adult Western Corn Rootworm chewing on the silks of a corn ear. Picture from wikimedia, apparently in the public domain

This post discusses the paper Degenhardt, J et al. (2009) “Restoring a maize root signal that attracts insect-killing nematodes to control a major pest”

The Western Corn Rootworm (which as you can see from the picture to the right are not actually worms) is estimated to cost farmers in the US alone one billion dollars a year in lost yield and pest control measures. The newly hatched larva begin feeding on root hairs and as they get bigger start attacking the main roots of a corn plant. The damage to the roots from the feeding itself is exacerbated by the open wounds becoming infected. The loss of roots both stresses the plant and reduces yield by decreasing the plant’s supply of nutrients and water, but also makes it much more vulnerable to lodging (getting blown down by a gust of wind). Oh, and did I mention the adults like to feed on the corn plant’s reproductive tissues, decreasing yield even further?

Rootworms are one of the pests controlled by plants genetically engineered to express BT a protein taken from organic agriculture. Without it, the 1 billion dollar price tag for rootworm damage and control would be even higher. But this isn’t an article about bt, it’s an article about how some corn already knows how to call for help when rootworms attack.

Rootworm larva may feast on the roots of maize, but they are in turn eaten by some species of nematodes.* And it turns out some kinds of corn know how to attract nematodes, and when they’re under attack by rootworms they do just that. The nematodes get a delicious meal of rootworms and the corn plant gets to keep more of its roots intact.

How do corn plants attract their, unintentional, nematode defenders? (more…)

November 5, 2009

Why Don’t People Like Corn?

Filed under: agriculture,Feeding the world — Tags: , , — James @ 4:13 am
My favorite crop, but many people don't seem to care for it these days.

My favorite crop, but many people don't seem to care for it these days.

I read an interesting question on the still growing thread on the problems with CSI: Miami’s “Bad Seed” episode.

Between this episode and some other stuff I’ve heard about corn, I started wondering what all the concern is about corn lately. … Can you now help shine some light on why the corn industry has been getting such a bad reputation lately? (more…)

November 3, 2009

Sugar Belle Citrus and Patents

Filed under: agriculture,biology,Plants — Tags: , , — James @ 2:02 am
Mandarin Orange (Not a Sugar Belle)

Mandarin Orange (Not a Sugar Belle) from dungodung on flickr

We’ve been talking about grains and genetic engineering strait for a few days, so I thought it’d be the perfect time to put up a story about conventionally bred citrus. The University of Florida put out a press release about a new mandarin orange breed developed by Fred Gmitter, called Sugar Belle. The fruit is of course described as delicious and it may well be, I can’t say one way or the other. Importantly to a different group of people (producers rather than consumers of citrus fruit), the fruit matures 4-6 weeks earlier than other varieties of mandarin, making the harvest better timed to cater to the demand for citrus around Christmas.

Fred has been developing the breed since 1985, when he found the tree Sugar Belle was bred from in the experimental plot of another plant breeder who’d just retired. That’s twenty-four years of research and development. 1985 is the year “new coke” was released. Soviet and Western forces still faced off against each other across the Berlin Wall. If Sugar Belle was a person, it’d already be old enough to be in grad school right now.

The lesson here (one of them) is that it takes a long time to breed fruit trees.

But that’s not the only interesting thing about this story. (more…)

November 1, 2009

Domestication Bottlenecks

Driveway tomato garden. How much diversity do these plants contain?

Driveway tomato garden. How much diversity do these plants contain?

Crops like tomatoes, even heirloom tomatoes, aren’t found in the wild. Domestication of crops usually involves only a relative handful of individual plants. Narrowing the species down to a few hundred (or possibly even a few dozen plants) means only a limited number of copies of each gene will be carried through and many of the variant copies of the genes present in the wild population won’t be included in that number. Keeping the population small for multiple generation reduces variability even more as by chance some rare version of genes in one generation won’t be passed to any of the offspring in the next.

Genetic bottlenecks happen in the animal world as well. Skin grafts between unrelated Cheetahs aren’t rejected because the animals are so genetically similar their immune system can’t distinguish the grafted skin as being different from its own skin. Even less fortunate are the tasmanian devils who have so little genetic diversity that they are being decimated by a transmissible cancer. After fighting with an infected devil, which has tumors on its face and neck, tiny bits of the cancer will get into an uninfected devil’s wounds, and since the immune system can’t distinguish the foreign cancer cells from the devil’s own cells, the cancer cells reproduce unchecked, the trait that makes normal cancers, produced by mutated versions of our own cells, so deadly. And the solution mentioned in the article, to save the species by protecting 200 individuals, while better than letting them all die, will sacrifice even more genetic variability by subjecting the already inbred devils to a new population (and genetic) bottleneck. (more…)

Disease Resistance and Diversity

Filed under: agriculture,Link Posts — Tags: , , , — James @ 12:51 am

Matt has a great new post up on The Scientist Gardener called The Myth of Monocultures. He gives talks about the PBS special on Michael Pollen’s Botany of Desire (which I still need to watch myself), addresses some misconceptions about diversity and monoculture and talks about the best way to ensure crops aren’t wiped out by pathogens that can evolved to overcome a single resistance gene:

Theoretically, it would be useful to maintain crop populations with diverse resistance genes. The industrial application of this (multilines) invovles breeding many different versions of a favorite crop variety that are identical except for their resistance genes. As appealing as this idea is, it hasn’t really worked out in the real world. The alternate approach (pyramiding) seems to be more effective. Here, many different resistance genes are combined into a single crop variety. Pests and pathogens may be able to overcome a single gene at a time, but it’s usually almost impossible to simultaneously overcome several.

Think of it like the story of the three little pigs. [spoilers ahead ;)] (more…)

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