Luigi Guarino

February 10, 2009April 20, 2015

Maize aguafiestas

From Jacob van Etten.

Uncorking a big bottle of agrobiodiversity, that is what Mexico’s first farmers did when they domesticated maize. Not only is maize enormously malleable, genetic diversity also goes everywhere through cross-pollination. That is in traditional farming systems. Modern maize improvement has been about sorting out this abundance by “freezing” it into breeding lines, to get some control over the diversity feast. But what happens when the hybrids are released into the dance room again?

An Italian study just out quantifies the gene flow from hybrids to traditional varieties. It finds different degrees of purity in the traditional varieties, but no genetic erosion. This is an interesting finding in the light of writings about “creolisation” in Mesoamerican agriculture. Creolisation, the mixing of modern and traditional varieties, is thought to lead to plants that combine their benefits. I have always wondered if the creolised varieties of Mesoamerica are not modern varieties “creolised” by selection instead of mixing with traditional varieties. Something similar to the Italian study would be needed to find this out.

The question is only one step removed from the issue of gene flow from transgenic crops to traditional varieties. Perhaps you remember the Quist and Chapela paper published in Nature in 2001 on the presence of transgenes in Mexican traditional maize, and the controversy it generated. A new study confirms the presence of transgenes in Mexico with an improved study design. Through genetic population simulations it also explains why detection of transgenes is erratic and prone to giving false negatives. The distribution of the transgenes is likely to be very skewed. A few fields will have much of them, but most will have very few. This has to be taken into account and therefore authors call for more rigorous sampling methods to detect transgene presence.

There is little discussion or speculation about the effects of transgenes on maize diversity. Will the transgenes just add to the existing diversity, like the hybrids in Italy? Will they perhaps produce some benefits, like the creolized varieties? Or will, in some Monty Python-like scenario, the big seed companies pick up the message about rigorous sampling and start to trace transgenes in Mexico in order to charge farmers for unlicensed use of their technology?

February 9, 2009

Nibbles: Agroforestry

ICRAF gives Cameroon top marks for “planting the right tree in the right place.”

February 7, 2009February 7, 2009

A citrus species in need of research?

It seems that citrus canker, a nasty bacterial disease, has been officially eradicated in Australia. Good news, but there is a bit of a dark lining. Along with 495,000 commercial citrus trees and 4000 residential trees, the eradication programme has included destroying a lot of trees of native Citrus glauca in the affected area. Desert Lime is well-known bush tucker, as well as a potential resource for Citrus breeding. It’s not currently considered endangered, but there’s not really all that much research about it ¹, so that might be optimistic. There are only 8 germplasm accessions worldwide (page 29), apparently. That sounds inadequate to me. Especially given the historic proportions of the current drought, which is affecting the whole of SE Australia, including areas of C. glauca.

LATER: See also a map of the latest spate of bushfires in Australia. A threat to this and other crop wild relatives?

February 6, 2009February 6, 2009

Nibbles: Wolf, Conservation agriculture, ODI, Food policy, Stress, Sustainability

Evidence of extrogression from dogs. That would be the opposite of introgression, and there are apparently lots of examples from mammals.
â€œConservation agriculture is an essential element of … intensification.â€ Oh please.
Simon Maxwell, director of the Overseas Development Institute, on the Millennium Villages etc. Lukewarm, I’d say.
Louise Fresco makes bread at TED. Fiat Panis, eh?
India to manage abiotic stresses. I’ve got a few of those I’d like to manage a bit better.
Arab nations discuss differences of opinion on sustainability. Someone tell me the bottom line.

February 5, 2009February 5, 2009

New Scientist bottles it

I have a lot of respect for the New Scientist. I really do. I kind of grew up with it. But I don’t think it handled the Great Seed Bank Confusion very well. Let me remind you. Last week a blog post went up at Short Sharp Science confusing the Millennium Seed Bank at Kew with the Svalbard Global Seed Vault, which is demonstrably not at Kew. Here’s a screen grab of that original post (click to enlarge):

That was bad enough, as both places have been in the news a lot lately, and it elicited the predictable flood of comments ² — some unpardonably rude, it must be admitted ³ — setting the blogger right. But it was nearly a week before the post was corrected, thusly:

And, rather than being up-front, the apology for the mistake, and the notice that a correction has been made, is buried in the 18th comment.

Journalists often bitch and moan about bloggers not being sufficiently professional about checking sources etc etc. I think New Scientist was unprofessional in making the original mistake — but hey, that happens — but also, and unforgivably, in not owning up to it quickly and visibly enough. Anyway, at least now everyone knows the difference between Kew and Svalbard.