Genetic Maize

There was an Op-Ed in the New York Times on August 23 by Dickson D. Despommier: A Farm on Every Floor. Dr. Despommier is Professor of Public Health in Environmental Health Sciences (and Microbiology) at Columbia University. One of his interests is vertical farming, as can be found on his website The Vertical Farm Project. The op-ed is brimming with enthusiasm that I heartily share.

The idea is not just cool from a what-if sci-fi standpoint. It’s the only way that humans can produce enough food in urban areas (where 60% of humans live, according to the VF website) without resorting to shipping food in from rural areas as we currently do. Vertical farming will make a varied diet available year round in cities with low input and little to no environmental degradation. It’s certainly far from the idyllic vision of farming that some people have, but it is not possible to feed the world that way (especially impossible without chemical heavy intensive farming) – unless everyone moves out of the cities and there is a massive population decrease.

“The Living Skyscraper: Farming the Urban Skyline” by Blake Kurasek, Graduate School of Architecture, University of Illinois at Urbana-Champaign, image from the Vertical Farm Project.The VF website includes many concept drawings of exactly how vertical farms could be implemented. My favorite simply wraps tiers around skyscrapers. People can live and work inside this living insulation.

Vertical farming also has the potential to bring many people into agriculture. On the VF site, Dr. Despommier describes a visit to a 4th grade class in 2006. They sent him letters thanking him for his visit, and are just full of enthusiasm. How many of those children were inspired to pursue careers that don’t even yet exist? Hopefully many.

The idea of vertical farms is dear to my heart. Growing up in the heart of Tampa, Florida didn’t give me many opportunities to interact with agriculture. However, I did get to go to Epcot in Orlando pretty frequently. My favorite part of the park was and still is The Land, particularly the Living with the Land ride. The ride takes you through different ecosystems around the world before showing you what I think is the masterpiece of Epcot: a massive hydroponic greenhouse. One of the best parts of my honeymoon was a behind the scenes tour of the greenhouses, research labs, and aquaculture tanks. All this talk of Epcot reminds me that I really should try to apply for an internship as a research scientist there (believe it or not, they have a few), and attempt to fulfil a childhood dream.

h/t Drake Larsen via the ISU Sus Ag mailing list

“Terminator seed” has been back in the news and blogs, due to some rumors that the Convention on Biological Diversity would consider rescinding the ban on the technology. Before I get knee deep into the politics, I’d like to make some quick comments on gene flow. First, pollen of many types of plants are capable of traveling quite far. The exact distances are dependent on wind, weather, plant density, species, etc. For the most part, though, pollen stays near its origin, so that gene flow between separated populations is slow (not many fertilizations between populations). It is fairly easy to test gene flow and pollen spread rates.

An elegant example was prepared by Jason Haegle, an undergraduate at Iowa State under distinguished professor Peter Peterson. As described in The Flow of Maize Pollen in a Designed Field Plot, Jason planted purple corn surrounded by yellow corn. He planted the rows 0.76 meters apart (much wider than normal) to eliminate any effect of plant density. He simply counted the purple kernels on the ears in the yellow corn fields to determine how much and how far the pollen spread. Yellow corn plants that were closest to the purple corn of course had the most purple kernels. Three rows into the yellow corn, numbers of purple kernels (thus amounts of pollen from those plants) dropped dramatically. Other studies on maize pollen flow agree that the majority of pollen stays near the plot. As Jason says in his paper, this is likely because maize pollen is large and heavy compared to pollen from other grasses.

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Dr. Barney Gordon, soil scientist at Kansas State, isn’t willing to let his work be misrepresented by the media. In a letter to Seed Today, he explained exactly what his work is and isn’t.
As I described in my post Exposed, Indeed about the original article Exposed: The Great GM Crops Myth, I’m so fed up with the media twisting science. I’m very glad that Dr. Gordon took the time to set the record straight, although I wish more blogs and news sites had picked it up.
Thanks to GMO Pundit for posting this in Man Bites Dog.

In order to make sound conclusions about different types of genetically engineered crops and to plan for the future, we’ll need to have sound data about any possible environmental effects of said crops. Researchers from a variety of institutions and disciplines* plan to collect that data. Harvesting Data from Genetically Engineered Crops**, published in the 25 April issue of Science, explains that we can use existing data about pesticide and fertilizer usage, water quality, and information about birds, amphibians, and other animals – if we can connect that data to what types of crops the farmers are planting. A news story, UA Scientists and Colleagues Call for More Access to Biotech Crop Data, has been posted by the U of Arizona. The authors conclude their proposition:

The United States has the world’s most extensive history of using GE crops and one of the world’s best continentalscale programs in environmental monitoring. Combining these two sources of information
provides an opportunity to lead the world in identifying agricultural pathways for the future that best serve people and the environment. Providing scientists access to data on GE crop use at the county scale is a small and relatively inexpensive step with enormous scientific and public benefits.

** I don’t know if it’s legal for me to post a link to the pdf here. If you know the rules, please fill me in!

In India and other Southeast Asian countries, large areas of the bedrock naturally contain arsenic (As), which leaches into the groundwater. The FAO estimates that up to 500 million people are at risk of being exposed to dangerous levels of arsenic in both drinking water and in the crops that were irrigated with the groundwater. The problem was investigated by the FAO in Bangladesh in 2006. They found that:

[A]rsenic levels in the grain of different varieties of rice in Bangladesh were as high as 1.8 parts per million, compared to levels of just 0.05 parts per million in Europe and the US. Contamination was even greater in leafy vegetables – in amaranthus and spinach, arsenic content can be double or triple the levels found in rice. For drinking water, WHO recommends a maximum arsenic level of 0.01 parts per million, which indicates that for some people, staple food crops such as rice may be an important source of exposure to arsenic.

Until now, the farmers essentially have three options: leave the fields fallow, plant rice and hope it doesn’t have too much arsenic, or attempt to plant a crop that doesn’t need as much water.
Om Parkash (photo and story from Newswise) of the University of Massachusetts Amherst primarily works on bioremediation, which aims to remove pollutants from the soil by binding it up in plants. His recent work branches into the opposite direction, using genetic engineering to produce rice plants that take up less As. The work is in the process of patenting, so technical details are scarce. For now, I’ll have to be content with the following:

“By increasing the activity of certain genes, we can create strains of rice that are highly resistant to arsenic and other toxic metals,” says Parkash, a professor of plant, soil and insect sciences. “Rice plants modified in this way accumulate several-fold less arsenic in their above-ground tissues, and produce six to seven times more biomass, making the rice safer to eat and more productive.” This could help alleviate the current world-wide rice shortage.

I’m really looking forward to learning more about the genetics, and hope that Dr. Parkash is able to move forward with this exciting crop improvement.
While As is actually a necessary mineral in small amounts and only becomes dangerous to health when consumed in high levels (as in Bangladesh), decreasing As in the food supply is definitely a worthy cause. Dr. Parkash says that As can accumulate in all parts of the rice plant, including grain and straw. High As levels in rice not only affect people, but can sicken animals who eat the straw and contaminate their meat (think bioaccumulation). See GreenFacts for a good summary of arsenic as it relates to human health and the environment (incidentally, they also have some of the most levelheaded information on GM crops that I’ve ever seen).
Other recently published work on arsenic levels in rice by Yamily Zavala and John Duxbury of Cornell was reported in the 2 May 2008 ISAAA Crop Biotech Update. For a summary of the articles, see the press release from the American Chemical Society. Disclosure: I wasn’t able to access these two articles themselves as ISU’s library site is down while I write this.
In Arsenic in Rice: I. Estimating Normal Levels of Total Arsenic in Rice Grain, they showed that mean As concentrations in samples of commercial rice in Europe and the US (0.198 mg/kg) were higher than in samples from Asia (0.07 mg/kg). The concentrations varied greatly by region, but not by farming method. Their data confirmed that irrigation with As contaminated groundwater in Bangladesh is correlated with higher As concentrations in grain. In the US, where groundwater is not contaminated with As, the authors suggest that historical contamination of soil is a likely cause. Note: mg/kg and ppm are equivalent units.
In Arsenic in Rice: II. Arsenic Speciation in USA Grain and Implications for Human Health, they showed that the As in some rice varieties accumulates in a less toxic form than inorganic As (inorganic = molecules do not contain carbon). Arsenic in rice grown in the US is bound into mostly into dimethyl arsinic acid (DMA), which . This data is in agreement with previous studies done by Andrew Meharg of the University of Aberdeen in the UK. There is evidence that DMA is safer than inorganic As, which means that US rice may be safer than European or Asian rice. The authors hypothesize that 30 years of breeding in the US for straighthead disorder resistant rice could have caused US varieties to acquire this As metabolic pathway.
Huge phenotypic variance is present in rice grains across varieties. It’s easy to imagine that metabolic pathways vary widely from variety to variety as well.