More sorghum for Zimbabwe

A press release from the Netherlands Organisation for Scientific Research is creating tiny ripples in the blogosphere because it suggests that fertilizer, rather than water, is what poor farmers in semi-arid regions of Zimbabwe need to improve their crops. That’s certainly one conclusion from the research of Dr Bongani Ncube, who successfully defended her doctoral dissertation 10 days ago. (Congratulations, Bongani.) More important, I think, is the demonstration that almost regardless of water, sorghum crops benefit enormously from a preceding grain legume. There’s an interaction with rainfall to be sure. In a dry year, cowpea yields more than groundnut or bambara groundnut, but sorghum is always better after a nitrogen-fixing legume. That’s not to say that farmers shouldn’t make use of a little artificial fertilizer if they can afford it. But a better strategy might be to grow a variety of grain legumes, to buffer any possible effects of rainfall, and then plant sorghum, using agricultural biodiversity instead of cash to increase the harvest.

Cereals databases

Before I disappear for a few days of immersion in the First International Breadfruit Symposium back in Fiji, let me point to two somewhat complementary online resources on cereals genetic resources that I have come across – no doubt Jeremy will say and about time too – in the past couple of days.

The FIGS database brings together passport and evaluation data on bread wheat landraces from a number of the major genebanks and “allows the user to efficiently interrogate the data associated with this collection and provides the capacity to identify custom subsets of accessions with single and multiple trait(s) that may be of importance to breeding programs.” FIGS stands for “Focused Identification of Germplasm Strategy,” and the focus is on identifying material with resistance to abiotic and biotic stresses.

The other database is that of Israel’s Institute of Cereal Crop Improvement, which includes information on accessions of wild cereal relatives collected over the past 30 years. Again, there’s a particular focus on data on disease resistance.

Local and exotic crops in Africa

The long dry spell throughout much of February and March, caused by an unexpected El Nino that kept the main rain belt to the north of Zimbabwe, will cause serious hardship in significant areas of the country.

That’s not the only thing, of course, but an article from the Harare Herald1 makes a plea for farmers to grow local indigenous grains such as “sorghum, mhunga and rapoko” rather than watch maize “wilt and die four years out of five”.

It is a wonderful article, making lots of good points. That food-for-work programmes should be accompanied by intensive training on growing small grains, so that those who need it most can become self-reliant in food and maybe even sell a bit for income. That modern machinery makes preparation much easier, and it isn’t expensive. That an advertising campaign could make a virtue of sadza2 the way grandmothers made it. That there are benefits for urban consumers too. And finally, “Variety is wonderful. But we should not be rejecting indigenous grains simply because they are not “modern” or “Western”. We should be using them as well”.

I wonder whether anyone is listening?

The Ethiopian Herald, meanwhile, says green gram is becoming the crop of choice in Southern Wollo zone. A legume, green gram (Vigna radiata, maybe most familiar in the West as mung bean) improves soil fertility, ripens more rapidly and doubles or even triples incomes. One farmer is quoted as having replaced his teff crop with green gram, but if everybody does that, who is going to supply the teff flour for njera?

  1. Posted at allAfrica.com []
  2. Zimbabwean porridge? []

Multiple founder effect

The common wisdom is that crops are most diverse in their centres (or secondary centres) of domestication, because that’s where people have been playing with them longest. Wild species, too, are often less diverse when they have moved to a new area. That’s down to the founder effect; a small bunch of founding individuals will have a less diversity than the population as a whole and is also more subject to random fluctuations that can change things from the original population. But on the Invasive Species Blog (via this month’s Mendel’s Garden) I recently read that reed canary grass (Phalaris arundinacea) is much more diverse in North America, where it is a recent arrival, than in Europe, its home. Genes from all over the old world are mixed up within single individuals in North America, whereas they are never found together in Europe. The reason, apparently, is that the species has been introduced many times, presumably from many places, and this has brought widely separated populations together and given the opportunity to mingle their genomes.

I wonder whether the same is true for some of the crops that have really travelled around, like tomatoes or peppers.

Reindeer, caribou, genetics and global warming

Reindeer (Rangifer tarandus tarandus) were domesticated probably around 20,000 years ago in northern Europe and Asia. They are still kept by many herders in the Eurasian Arctic, who derive their livelihood from their animals. Reindeer from Siberia were imported into Alaska in the late 19th century in an attempt to provide income for indigenous people. In the 1930s an estimated 600,000 reindeer existed in Alaska, but that number is now down to about 20,000. It seems that most people didn’t quite see the point of managing reindeer when all they had to do was go out and hunt its wild cousin, the caribou (Rangifer tarandus granti). One of the unforeseen consequences of this endeavor has been the migration of reindeer into caribou herds and until recently it was unknown to what extent this influx has had an impact on the genetic diversity of caribou. A recent analysis of microsatellite DNA in caribou and reindeer in Alaska, however, shows that very little genetic introgression seems to have taken place into either species and the authors think the reason could be that hybrid offspring may have a lower chance of survival. It is interesting to note that their study also indicates that the Alaskan/Russian reindeer and the Alaskan and Canadian caribou are much more closely related to each other than either is to the Scandinavian reindeer.

Caribou, which can be found throughout Alaska and the Canadian territories, migrate often in large herds between their summer and winter pastures. The porcupine herd, for example, numbers in excess of 100,000 animals and covers a distance of over 2000 km on its yearly route from the Yukon to the calving grounds on the Alaskan Arctic coast (the very same area the US government is trying to open up for oil exploration).  Many native people in Canada and Alaska still depend on these animals for their survival and they are becoming concerned that increasing human development and global warming may either affect the size of caribou herds or change their migration patterns.

From Michael Kubisch