Agricultural Biodiversity Weblog
Agrobiodiversity is crops, livestock, foodways, microbes, pollinators, wild relatives …
The IITA public awareness machine must be in overdrive, and it looks like it’s running on cassava. Today
Not that I’m complaining. It’s about time cassava got the attention it deserves in Africa.
The latest Plant Breeding News is out, though only if you’re registered for email alerts. However, in a couple of days you should be able to get October’s digest on the archive page, where you can also subscribe. Lots of stuff about breeding for climate change in this issue. It’s a great resource, brought to you by the Global Partnership Initiative for Plant Breeding Capacity Building (GIPB). And I’m not just saying that because they gave us a namecheck this month.
Back when I made my living applying an outmoded and discredited paradigm by going around collecting germplasm, I had the great good fortune of visiting the Hardamawt province of what at the time was the People’s Democratic Republic of Yemen. The region, and in particular the beautiful and historic city of Shibam has recently been hit by devastating floods. I could link to news accounts, but I think the series of photographs Jeremy just sent me does a better job of summing up the situation than any number of newspaper articles.
Agriculture in the Hadramawt relies on spate irrigation:
Flood water from mountain catchments is diverted from river beds (wadi’s) and spread over large areas. Spate systems are very risk-prone. The uncertainty comes both from the unpredictable nature of the floods and the frequent changes to the river beds from which the water is diverted.
So flood damage is to be expected every once in a while, and people by and large know how to cope, though on this occasion the flooding seems to have been particularly bad. One of the ways people cope is by building strong houses. Some houses in Shibam are hundreds of years old, despite being made of mud brick. I remember that while collecting (this was 20 years ago) I asked people why they were still growing their local wheats rather than the new Green Revolution varieties. They said that the new varieties, though giving a higher grain yield, were too short, ((In fact, you could say they give higher yields partly because they are shorter.)) and they needed a lot of straw to make the mud bricks they used to build their homes.
Now, I haven’t been back to Shibam since then, and I don’t know whether the use of shorter wheats has spread. And I don’t know whether even if they have this has affected the quality or quantity of the local bricks. But I wonder.
I was talking to Greg Edmeades tonight. Our conversation coalesced on the topics of the recent posts on maize water stress tolerance and on the usefulness of engineering purple tomatoes.
For many years, Greg led the maize crop physiology group at CIMMYT. He says that one of the main reasons for their success with drought tolerance is their long term institutional commitment to it: 35 years and counting. A particularly impressive feat is the widespread adoption of their maize varieties in southern Africa. For example, ZM623, selected from South African parents by Marianna Bänziger, is grown on about a million ha, says Edmeades.
His take on biotech for drought tolerance is, sure, “use whatever works, but if you are an African agricultural research institute, then, why bother?” Monsanto is reporting 10-15% yield increase under drought stress, and says it will make their technology freely available for use in Africa. Edmeades reckons that you can get a similar yield increase in about 7 years of conventional breeding and selection. And less when using molecular markers. If that is the case, it may not be worth it to deal with the complexities of genetic engineering.
Unless, perhaps, the approaches are entirely additive and you get a combined yield benefit of 30%. I think that’s unlikely. Drought tolerance is about making best use of the available water. It does not increase the amount of water.
Later:
Greg told me that I had been a little harsh in suggesting that he would not advise national programs in Africa to use a transgenic approach to drought tolerance. He would only advice against transgenes if “they had access to a steady stream of good germplasm improved for drought tolerance, and there was no regulatory framework for transgenes in place in that country. If regulatory frameworks exist, and there is no facility of improving their own varieties (or newly released commercial varieties) for drought tolerance in a systematic way, then certainly I’d take the transgenic option, especially since it is being offered on a royalty free basis.”