Choose drought-tolerant crops by how they get through a dry spell: some finish before the dry season, some reach deep water or limit water loss, and some go dormant and resume when rain returns. Local landraces and varieties already grown in your area are the best starting seed, and the only reliable test is to grow candidates side by side in a dry year and keep seed from the survivors. A crop that tolerates drought at one growth stage can fail at another, such as flowering, so judge the whole season.
Drought-tolerant varieties are crop types that produce a harvest with less water than ordinary types, by finishing early, rooting deeply, conserving water or surviving dormancy.
Three Ways A Plant Gets Through A Dry Spell
- Escape: a short season, so the crop completes its cycle before the dry period. Lentils, which the carrier guide says mature before peak summer drought in most climates, and fall-sown winter wheat, harvested in early summer before peak drought, work this way.
- Avoidance: deep roots, or leaves that limit water loss.
- Tolerance: the ability to go dormant and resume, as the carrier says of grain sorghum.
The carrier (Drought Resilience & Water-Efficient Agriculture) lists drought-tolerant grains, legumes, vegetables and roots; the following pages cover them: Grain: Sorghum, Millet, Dry-Land Wheat, Legumes: Tepary Beans, Cowpeas and Root Crops and Vegetables for Dry Conditions.
Local Seed Has Already Been Tested By Your Weather
A variety that has been grown in your district for generations has been selected by your droughts. Seed from outside may carry a name that says drought tolerant but have been bred somewhere wetter. See Seed Selection for building a locally adapted landrace by saving seed from the best plants and Community Seed Bank Management for keeping it.
What You Need
- Seed of several candidate varieties, with their origin recorded.
- A trial plot with the same soil, spacing and care for each.
- A record sheet.
Method
Step 1: Grow candidates side by side, at the dry-farming spacing, in a block with replicates if space allows, so one patch of poor soil does not decide the result.
Step 2: Record survival, vigour, flowering date and yield per plant and per square metre.
Step 3: Judge in a dry year. A trial in a wet year shows nothing about drought. If the year is wet, repeat the trial.
Step 4: Save seed from the best survivors and repeat the process each year.
Step 5: Keep several varieties, not one, so one failure does not take the crop.
Common Mistakes
- Trusting a label — “drought tolerant” depends on the place and the stage.
- Judging in a wet year.
- Planting a single variety — all of it fails together.
What’s Next
- Learn next: Grain: Sorghum, Millet, Dry-Land Wheat — the staple grains
- Combine with: Legumes: Tepary Beans, Cowpeas — protein and nitrogen