As the UN Conference on Climate Change (COP23) draws to a close in Bonn, Ann Tutwiler explains how adapting farming systems to climate change may require looking beyond national borders for diverse crop varieties adapted to future climatic conditions.
She highlights an example from Zambia, where maize and sorghum varieties in the national genebank collections may not hold all the answers.
Government negotiators are meeting in Bonn at the Climate Change Conference to thrash out the details for implementing the Paris Agreement. Activists are there too, each pushing their own particular agenda. Naturally I want to do the same, for agricultural biodiversity.
Agriculture is in a very peculiar position with regard to climate change. It is a major contributor to greenhouse gasses. It is also one of the sectors most affected by climate change. This means that agriculture will need to adapt, not least by adopting new crop varieties that are more suited to predicted weather patterns. In the past, plant breeders were generally able to keep up with the needs of local farming systems, but the pace of climate change means that we need to speed things up.
Of course, plant breeders can look in their national genebank collections for the raw materials to produce new varieties. The problem is that in many cases they are facing quite dramatically new climates, unlike anything to which their existing local genetic resources might be adapted.
Those climates might, however, exist elsewhere, so one way to overcome this problem is to use climate crops suitability modelling. This approach combines climate information with geographic information about suitable crop varieties housed in existing collections.
The idea is that plant breeders in a country can scour the globe for faraway places that have the sort of climate today that is predicted to occur in their country in the future. The crops that grow in these climate analogues are likely to be pre-adapted to the predicted climate, offering a shortcut to suitable new varieties. Recent research results from nine African countries show that this approach would work, given a chance.
Zambia is a good example. The country faces shifting and shorter growing seasons, hotter dry spells, more unpredictable rains and longer droughts, all of which point to a drop in yield of about 30% by 2050 in maize, the main staple crop. Bioversity International scientist Gloria Otieno worked with local communities to explore ways in which they might adapt their farming systems.
In Chikankata and Rufunsa farmers helped us to see which traits are most important to them and which varieties they prefer, of maize in Chikankata and sorghum in nearby Rufunsa.
In Chikankata, farmers have already felt the effects of higher temperatures and shorter growing seasons, prompting them to look for faster-maturing local varieties. Many households grow a small area of these varieties, which they often eat fresh during the hungry period in February and March, before the main crop has matured.
In search of new varieties, Bioversity International, working with the Zambia Agricultural Research Institute, the Zambian Agricultural Research Organization and Community Technology Development Trust, looked at the National Genebank’s maize collection.
Of the 300 accessions there, 48 are suitable for Chikankata today, but only 11 of them might be suitable for the predicted climate in 2050. A similar picture emerges for sorghum. The national genebank has 176 accessions, 25 of which are adapted to current conditions and 21 to conditions in 2050. As climate changes, Zambia will need to look further afield for suitable maize and sorghum varieties.
So further afield we went, looking at more than 22,000 accessions of maize and almost 24,000 of sorghum made available through the International Treaty for Plant Genetic Resources for Food and Agriculture’s Multilateral System.* Taking 19 climatic variables into account, we found, for maize, 280 varieties that would suit Chikankata’s current climate, and 109 that would suit its 2050 climate. For sorghum, the numbers are 300 and 195 respectively. In both cases, some of the suitable accessions are from Zambia’s neighbours in Africa.
So we know that varieties suitable for adaptation to climate change are out there. And we know, thanks to our work with farmers in Ethiopia, that farmers are more than capable of working with plant breeders to select the varieties that offer them the qualities they need and value. The question now for farmers in Chikankata and Rufunsa and the rest of Zambia is how they can get hold of those potentially promising varieties.
That comes down to Zambia’s own seed laws.
The national seed policy is admirably inclusive in theory, addressing both the formal seed sector, on which highly commercial farms depend, and the informal sector that supplies almost all the needs of smallholder farmers like those in Chikankata. However, the actual implementation of the policy currently favours the formal sector, for example allowing only registered varieties to be sold commercially. This effectively excludes farmers from taking advantage of locally developed varieties, whether from Zambia or other countries around the world.
If Zambia can adapt its domestic policies to suit smallholder farmers and the informal sector, at the same time as taking full advantage of global agreements that offer access to plant genetic resources, such as the International Treaty on Plant Genetic Resources for Food and Agriculture, it will have gone a long way to ensuring its food security regardless of what happens in Bonn.
Notes: This work is carried out by Bioversity International working in partnership with the Zambia Agricultural Research Institute, the Community Development Trust and the Zambian Agricultural Research Organization and Community Technology Development Trust. It is part of the CGIAR Research Program on Climate Change, Agriculture and Food Security and is supported by CGIAR Fund Donors
*Information was taken from Genesys, a global portal to information about Plant Genetic Resources for Food and Agriculture.
Ann Tutwiler took part in three events with partners at the Climate Change COP23 meeting in Bonn.
Ann Tutwiler, Director General. Credit: Bioversity International
Maize varieties. Credit: Bioversity International/C. Zanzanaini
Evaluating Sorghum Varieties. Credit: Bioversity International/J. van de Gevel
Farmer with sorghum. Credit: Bioversity International/ Y. Wachira