Crops that keep yielding in drought

How close are drought-tolerant and higher-efficiency crops to protecting harvests as droughts worsen?

Drought-tolerant maize varieties have been released in 13 African countries. The authors of the release study report that they outperform commercial varieties under drought stress, and one farm survey in Zimbabwe links them to higher maize output in a model-based estimate. Adoption on farms is uneven: in a 2015 study of 3,700 households in six countries, 9% of maize plots in Zimbabwe and 61% in Malawi were planted with drought-tolerant varieties. In tobacco, faster photosynthetic adjustment raised leaf carbon uptake and dry matter productivity by about 15% under fluctuating light. A soybean field result of up to 33% is disputed. The sources reviewed do not show a crop protecting harvests across many farms and seasons.

AI illustration · Illustrative scene, not a photograph of the specific device or experiment.
WHERE WE AREScaling up

Nearly here. It works and is being scaled up.

Drought-tolerant maize varieties have been released in 13 African countries, so the technology is past pilot stage. Adoption is partial and varies widely between countries, and the yield benefit on farms rests on limited survey data. Higher-efficiency photosynthesis has been shown in tobacco and disputed in soybean field trials, and the sources reviewed show no food crop yet gaining yield in replicated trials. The page uses scaling because drought-tolerant crops are the main subject.

The tech tree

Everything recorded on Vrulum that this future needs, oldest foundations at the top and the goal at the bottom. Lines show what each step requires.

What it takes: Crops that keep yielding in drought Unlocked Being researched Locked
  1. 2016Crops with boosted photosynthesisResearch and prototypes Being researched.
  2. 2017Drought-tolerant cropsPilot and early commercial Unlocked.
  1. 2013Drought-tolerant maize varieties released in AfricaDone Unlocked.
  2. 2014Yield gain on farms in Zimbabwe measured in one surveyDone Unlocked.
  3. 2015Adoption across six African countriesIn progress Being researched.
  4. 2016Higher-efficiency photosynthesis in tobaccoDone Unlocked.
  5. 2022Soybean field trials with faster photosynthesis recoveryIn progress Being researched.
  6. Date not recordedIndependent replication of food-crop yield gains under droughtNot started Locked.
  7. Date not recordedDrought-tolerant crops protecting harvests across many seasonsNot started Locked.
  1. GoalCrops that keep yielding in droughtGoalRequires: Drought-tolerant crops, Crops with boosted photosynthesis, Drought-tolerant maize varieties released in Africa, Yield gain on farms in Zimbabwe measured in one survey, Adoption across six African countries, Higher-efficiency photosynthesis in tobacco, Soybean field trials with faster photosynthesis recovery, Independent replication of food-crop yield gains under drought, Drought-tolerant crops protecting harvests across many seasons. Locked.

The road so far

3 of 7 steps done, 2 in progress.

  1. Done · 2013Drought-tolerant maize varieties released in Africa

    According to Fisher and colleagues, 160 drought-tolerant maize varieties were released between 2007 and 2013 and disseminated in 13 African countries. The authors state that these varieties outperform commercial varieties under both drought stress and optimal conditions. This is the authors' own summary and was not independently checked. [1]

  2. Done · 2014Yield gain on farms in Zimbabwe measured in one survey

    Lunduka and colleagues surveyed 200 households in Chiredzi and Chipinge, southeastern Zimbabwe, in the 2013/14 season. Growing drought-tolerant maize was associated with about 617 kg/ha more maize, and about US$240/ha more income at 2014 maize prices. The yield figure is a model-based estimate, and the authors call their results conservative. The study is observational, and the authors say panel data would be needed to rule out unobserved household differences. [2]

  3. In progress · Nov 2015Adoption across six African countries

    Fisher and colleagues surveyed 3,700 farm households in Ethiopia, Tanzania, Uganda, Malawi, Zambia and Zimbabwe. Drought-tolerant varieties covered 9% of maize plots in Zimbabwe and 61% in Malawi. The abstract names the main barriers as unavailable improved seed, inadequate information, lack of resources, high seed prices and farmers' views of variety traits. [1]

  4. Done · 18 Nov 2016Higher-efficiency photosynthesis in tobacco

    Kromdijk and colleagues sped up the recovery of photosynthesis when light fluctuates, in tobacco, by speeding up the xanthophyll cycle and increasing a photosystem II subunit. The authors report about 15% more leaf carbon dioxide uptake and dry matter productivity under fluctuating light. Tobacco is not a food crop. The Crossref abstract says biomass rose about 15% in natural field conditions, but the sources reviewed name no field sites or seasons. The authors' calculation suggests this light dissipation could cost field crops up to 20% of potential yield, a model estimate. [3]

  5. In progress · 19 Aug 2022Soybean field trials with faster photosynthesis recovery

    De Souza and colleagues report that in replicated field trials, seed yield rose by up to 33% in some cases across five transformation events. The sources reviewed give no site or season numbers. A 2023 Science comment by Sinclair and colleagues argues that the field experiment was flawed and that there is little basis for expecting a yield increase from this transformation, so the result is contested. [4][5]

  6. Not startedIndependent replication of food-crop yield gains under drought

    The sources reviewed do not show a higher-efficiency photosynthesis food crop raising yield in replicated trials across several sites and seasons. The field experiment on soybean is disputed in the 2023 comment. [5]

  7. Not startedDrought-tolerant crops protecting harvests across many seasons

    Protection over several dry and wet years, measured across many farms, has not been shown for drought-tolerant maize in the sources reviewed. The farm survey covers one season, 2013/14, in two Zimbabwe districts. [2]

Why it matters

Fisher and colleagues report that occasional drought stress affects about 40% of Africa's maize-growing area, with yield losses of 10 to 25%. Varieties that keep yielding when rain fails could protect food supply and farm incomes. The open questions are whether gains seen in trials and on research plots reach farms, and whether they hold across seasons.

What stands in the way

  • Adoption of drought-tolerant maize on farms is uneven, at 9% of maize plots in Zimbabwe and 61% in Malawi in the 2015 study. Fisher and colleagues list unavailable improved seed, limited information, limited resources and high seed prices as main barriers.
  • The yield gain on farms from drought-tolerant maize rests on one observational survey of 200 households in two Zimbabwe districts, and the yield figure is model-based.
  • The soybean field result of up to 33% is contested, and the field experiment is disputed in a 2023 Science comment.
  • The photosynthesis gains reported so far come from tobacco, and the sources reviewed do not show a food crop gaining yield in replicated field trials.
  • Seed supply needs to reach smallholders in the regions most exposed to drought, and no source reviewed shows this is in place across those regions.

Signals to watch

  • Farm surveys across several seasons that compare drought-tolerant and conventional varieties in the same drought years.
  • National seed supply data showing how much drought-tolerant seed reaches smallholders in the highest-risk districts.
  • Independent, replicated field trials of higher-efficiency photosynthesis in a food crop, with site and season numbers reported.
  • Published responses to the soybean critique, and any replication of the soybean field result by other groups.
  • Drought-tolerant varieties reported to protect yields in a severe drought year across several countries.

Sources

  1. peer reviewed paper
    Drought tolerant maize for farmer adaptation to drought in sub-Saharan Africa: Determinants of adoption in eastern and southern Africa
    Monica Fisher, Tsedeke Abate, Rodney Lunduka et al.. Climatic Change (Springer), Nov 2015.
  2. peer reviewed paper
    Impact of adoption of drought-tolerant maize varieties on total maize production in south Eastern Zimbabwe
    Rodney Witman Lunduka, Kumbirai Ivyne Mateva, Cosmos Magorokosho et al.. Climate and Development (Taylor & Francis), 7 Sept 2017.
  3. peer reviewed paper
    Improving photosynthesis and crop productivity by accelerating recovery from photoprotection
    Johannes Kromdijk, Katarzyna Głowacka, Lauriebeth Leonelli et al.. Science, 18 Nov 2016.
  4. peer reviewed paper
    Soybean photosynthesis and crop yield are improved by accelerating recovery from photoprotection
    Amanda P. De Souza, Steven J. Burgess, Lynn Doran et al.. Science, 19 Aug 2022.
  5. peer reviewed paper
    Comment on "Soybean photosynthesis and crop yield are improved by accelerating recovery from photoprotection"
    Thomas Sinclair, James Specht, Kenneth Cassman et al.. Science, 24 Feb 2023.

Last reviewed 22 Oct 2026.