Agricultural Biodiversity Weblog

The average agricultural research paper describes some kind of formal experiment, whether in the lab or the research station or even farmers’ fields, and that is as it should be. To know if something really works, you need to be able to keep everything else the same. But there are experiments going on all the time out there, in real life, if you but know how to look. There is surely room in the scientific literature for more of the kind of case study reported in a recent paper in Food Security entitled “The underlying cause of the 2009 sorghum failure in Kongwa district and its implications for Tanzania’s vulnerability to climate change.” ¹

Through a series of in-depth household and farm surveys the authors seem to have been able to identify the reason why the sorghum crop failed in Kongwa in 2009, and use that information to make general recommendations about what should be done to prevent this happening again in the future, not just in that area but elsewhere in Tanzania.

So let’s set the scene. People in Kongwa are poor, most living on less than $1 a day. They are on the edge of subsistence. They used to grow mainly maize, increasing the area of sorghum when the early rains were poor. Since about 2003, however, sorghum has been the main crop. They grow a suite of local sorghum landraces called Lugugu: long-duration, good-tasting and hard-grained, which means they can be stored for a long time if need be. They also have access to three improved open-pollinated varieties from ICRISAT ²: shorter-duration, which means they can cope with drought, but softer and thus more susceptible to storage pests, and also prey to the parasitic herb Striga. But then there are two Striga-resistant varieties on the market, bred by World Food Prize winner Gebisa Ejeta and released in Tanzania in 2002. Often, the early varieties are grown as a cash crop, sold to buy maize, which is the preferred food still.

In 2009 the rains started badly, and farmers were encouraged by local politicians, in their inimitable way, to “plant drought-resistant crops.” Of course they did, as they would have done anyway, but crop production was nevertheless below requirement. Why?

In fact, it seems that overall the rains, although relatively poor, should have been more than enough for the short-duration varieties. Problem was, there was no seed of these varieties at the optimum time for planting them. And when it finally arrived, too late to take advantage of what early rain there was, it was infected with Covered Kernel Smut. There was no seed at all of the Striga-resistant varieties in the area.

This is not a new problem. Shortage of improved sorghum seed was identified as a constraint as far back as 1987. But none of the village-based seed production projects that have been carried out has had much of an impact, clearly. At least not after the donor funding ceased. And, unfortunately

…the Government of Tanzania has actively discouraged farmers from conserving local sorghum landraces and this has resulted in increasing dependence on so-called improved varieties and is a long term threat to household food security.

Actively discouraged from keeping their long-duration but storable varieties; actively encouraged to plant new varieties that are more drought-tolerant, sure, but can’t be stored, cost money that they don’t have and whose seed is not available anyhow, or at least not in time. Who’d be a Tanzanian farmer?

Now, it seems that “the short rainy season that characterised the 2008–09
cropping season may become the norm,” so some answers need to be found. Better water management is one. And improvement of local seed storage practices. Also,

…attention should be paid to conserving indigenous landraces and breeding improved short season varieties that can be stored for longer periods using traditional, on-farm practices, as this would reduce the need for expensive and unsustainable external seed multiplication systems.

And, I would add, perhaps look into the feasibility of push-pull control measures for Striga.

But mostly the study seems to me a damning indictment of the existing seed system, and of it’s seeming lack of integration with the breeding sector. What good is breeding those “improved short season varieties that can be stored for longer periods using traditional, on-farm practices” if they don’t get to the farmers in time? Indeed, why has storability not been a breeding objective? Well, perhaps it has, and weevil-resistant stuff is on the way. But will it ever get to the farmers?

Now, talk of an integrated germplasm pipeline — from genebank to breeder to farmer — is all the rage these days, and about time too. The case is only strengthened by studies such as this. You don’t always need a replicated trial to do useful science.