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More Mexican maize mayhem

It didn’t take long for my prediction to come true that the Mexican maize dataset I blogged about a couple of weeks back would get some more attention. The lead author of that previous paper, Hugo Perales, has teamed up with Quetzalcóatl Orozco-Ramírez and our old friend Robert Hijmans to do a deep dive into the database of 18,176 georeferenced observations of about 60 maize races. Some key findings:

  • Both at national and state level, there are a few very common races, and many races with very few observations.
  • 10% of the races account for 54% of the records.
  • Over half of the races account for 10% of the records.
  • The maximum distance between two records of the same race was just over 1000 km on average, the maximum about 2600 km, and lower than 200 km for 7 races.
  • There was a positive association between the number of observations and the number of races in both 50 km and 100 km square cell.

I particularly liked the new map of “maize communities,” that is, regions where more or less similar assemblages of races are found.

Although the previous paper had a similar map of “biogeographic regions,” this is more detailed and robust. Intriguingly, the hotspots of highest diversity tend to occur where distinct maize communities meet.

I’ll see if I can get Robert so say a few words about this work here.

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Brainfood: Dope diversity, Potato chips, Conservation costing, Island breeding systems, Indus civilization cereals, Drone phenotyping, Wild rice in Asia, Wild rice & Native Americans, Pearl millet temperature, Climate change & fruit/veg

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Everything about size

Whizz-bang websites in support of data-dense papers seem to be all the rage.

Remember “Farming and the geography of nutrient production for human use: a transdisciplinary analysis,” published in the inaugural The Lancet Planetary Health a couple of weeks back? We included it in Brainfood, and linked to an article by Jess Fanzo which summarizes the main findings. This is probably the money quote:

Both small and large farms play important roles in ensuring we have enough food that is diverse and nutrient-rich. While industrialised agriculture suggests domination of food systems, smallholder farms play a substantial role in maintaining the genetic diversity of our food supply, which results in both benefits and risk reductions against nutritional deficiencies, ecosystem degradation, and climate change. Herrero and colleagues argue that if we want to ensure that the global food supply remains diverse and generates a rich array of nutrients for human health, farm landscapes must also be diverse and serve multiple purposes.

Well, there’s also a graphics-rich website now, “Small Farms: Stewards of Global Nutrition?” The infographic at the left here puts it in the proverbial nutshell (click to embiggen).

But what you really want to know is on what kinds of farms are grown those Canadian and Indian peas we talked about yesterday in connection with other fancy websites. Well, unfortunately, the data are only available for “pulses” here, but, perhaps unsurprisingly, those are grown mainly on large(ish) farms (blue) in North America, and small(ish) farms (orange) in South Asia. Each square is 1% of global production.

You can get similar breakdowns for different food groups (cereals, oils, etc.), and for a bunch of different nutrients: Calcium, Calories, Folate, Iron, Protein, Vitamin A, Vitamin B12, and Zinc. For all of these last you can also see global maps of nutritional yields, or “the number of people who can meet their nutritional needs from all of the crops, livestock, and fish grown in an area.” Here’s the one for Vitamin A.

Which I’m sure will be of use in targeting the promotion of homegardening, say, or the roll-out of things like orange sweet potatoes. There is Biofortification Priority Index already, but only at a fairly coarse, country level. As far as I know, anyway.

Of course, those countries could always import sweet potatoes…

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Featured: Wheat disease

Tom Payne of CIMMYT was a bit worried about that Global Crop Loss Survey:

The wheat data suggests that a preponderance of responses came from Europe (where the trio of disease septoria tritici-yellow rust-fusarium head blight are prevalent). Interestingly, the emerging threats of “Ug99 types” of stem rust and wheat blast are not revealed though they may have far more dramatic impacts on a global basis.

But Andy Nelson has it covered:

Around 30% of wheat responses came from Europe, with the rest fairly well distributed in wheat growing areas around the rest of the world. Stem rust and wheat blast are in the complete list of response with numbers and locations that reasonably reflect their emerging threat status. They’re just not in the top five that we included in this preliminary report to the ISPP. More analysis and details will come though.