Climate-resilient varieties
What makes a variety climate-resilient? escape, avoidance and tolerance, Sub1 and drought QTLs in rice, heat-tolerant wheat, breeding and seed systems.
On this page
A farmer in eastern India once faced a cruel choice. If floods came, a high-yielding rice variety would die after a few days under water. Traditional varieties survived floods, but yielded little in normal years. Swarna-Sub1 removed that choice. It is the popular Swarna variety with one added gene that lets it survive about two weeks of complete submergence and still yield well. Released in India in 2009, it was grown by millions of farmers within a decade.
Climate-resilient varieties are crop varieties bred to keep yielding under the stresses that climate change makes more common: drought, heat, floods, salinity, and new pest and disease pressures. They are among the cheapest and most widely adopted adaptation tools, because the resilience is carried in the seed. In August 2024, India released 109 new varieties of 61 crops, most described as climate-resilient or biofortified. ICAR reports that the large majority of varieties it released in the past decade carry tolerance to at least one major stress.
Three strategies: escape, avoidance and tolerance
- Escape: the crop completes its sensitive stages before the stress arrives. Early-maturing chickpea finishes before terminal heat, short-duration pearl millet and pigeonpea finish before late-season drought, and wheat can be sown earlier to avoid March heat.
- Avoidance: the crop keeps its tissues away from stress. Deep or vigorous roots reach stored water, and waxy leaves and leaf rolling reduce water loss.
- Tolerance: the plant functions despite the stress. Mechanisms include osmotic adjustment, heat-stable enzymes, ion exclusion under salinity, and quiescence under submergence.
Most resilient varieties combine more than one strategy. They also need good yield in normal years, otherwise farmers will not adopt them.
Success stories
Submergence: the SUB1 story
The SUB1A gene, from an Indian landrace called FR13A, was mapped and cloned by IRRI and partners in the 2000s. Under water, SUB1A makes the plant stop elongating and conserve its energy, so it survives until the flood recedes. Using marker-assisted backcrossing, breeders added SUB1 to popular varieties without changing their other qualities. The results include Swarna-Sub1, Samba Mahsuri-Sub1, IR64-Sub1, BR11-Sub1 in Bangladesh and CR 1009-Sub1. Studies in eastern India found yield advantages of around 1 t per ha or more after floods, with the largest benefits for poor and socially disadvantaged farmers on flood-prone low land.
Drought in rice
Breeders found large-effect yield-under-drought QTLs (qDTY), and developed varieties such as Sahbhagi Dhan (2010) and DRR Dhan 42 and 44. These yield about 0.8–1.0 t per ha more under drought than susceptible varieties, and similarly in good years. Varieties combining SUB1 and drought QTLs, such as CR Dhan 801 and 802, tolerate both floods and drought in the same season.
Salinity
Salt-tolerant rice varieties from CSSRI in Karnal (the CSR series) and the Saltol locus help farmers on sodic and coastal saline soils. Salt-tolerant wheat varieties such as KRL 210 serve similar areas.
Drought-tolerant maize in Africa
The Drought Tolerant Maize for Africa project (CIMMYT and IITA, 2006–2015) and its successors released more than 200 varieties and hybrids. They are grown on millions of hectares. On-farm studies showed yield gains and lower risk of crop failure in dry years.
Genome editing
In 2025, India released its first two genome-edited rice varieties. DRR Dhan 100 (Kamala), edited from Samba Mahsuri, is reported to give higher yield and mature about 20 days earlier. Pusa DST Rice 1, edited from MTU 1010, has improved tolerance to salinity and drought. Gene editing promises faster development of resilience traits.
Why resilience pays
Average yield over good and bad years
Variety A yields 5.0 t per ha in normal years and 2.0 t per ha in drought years. Variety B, a drought-tolerant type, yields 4.7 t per ha normally and 3.5 t per ha under drought. If drought strikes one year in three, A averages (2 × 5.0 + 2.0) ⁄ 3 = 4.0 t per ha, while B averages (2 × 4.7 + 3.5) ⁄ 3 = 4.3 t per ha. B is also far less risky: its worst year is 3.5 t rather than 2.0 t. As droughts become more frequent, B's advantage grows. This is why breeders now test lines under managed stress as well as in optimal conditions.
Breeding tools
- Germplasm from landraces and crop wild relatives is the source of most resilience genes, including FR13A for SUB1 and Nona Bokra and Pokkali for salinity.
- Managed stress screening: rain-out shelters, controlled flooding, late sowing for heat, and saline plots.
- High-throughput phenotyping with drones, thermal cameras and sensors.
- Marker-assisted selection and backcrossing for major genes and QTLs.
- Genomic selection for complex, multi-gene traits such as yield under drought.
- Speed breeding and off-season nurseries, which shorten breeding cycles.
- Participatory variety selection, in which farmers test and choose varieties in their own fields.
From variety to farm: seed systems
A variety helps only if farmers can get its seed. Barriers include:
- low seed replacement rates for some crops;
- slow certification, and limited production of breeder and foundation seed;
- poor awareness of new varieties;
- farmers' attachment to familiar varieties with known grain quality.
Approaches that help include seed villages, minikits distributed under national missions, community seed banks, private seed companies, and the "Stress-Tolerant Rice for Africa and South Asia" (STRASA) model, which combined breeding with seed delivery.
Limits
- Resilience is relative. Swarna-Sub1 survives about two weeks of submergence, not a month. Drought-tolerant varieties still lose yield in severe droughts.
- Trade-offs with yield potential or grain quality must be avoided, or farmers will not adopt.
- Varieties must be combined with agronomy: timely sowing, water harvesting, nutrient management and insurance.
Key points
- Climate-resilient varieties maintain yield under drought, heat, flooding, salinity and new pests. Strategies are escape (early maturity), avoidance (roots, leaf traits) and tolerance.
- SUB1A gives about two weeks of submergence tolerance; Swarna-Sub1 and others were made by marker-assisted backcrossing.
- Drought-tolerant rice (Sahbhagi Dhan, DRR Dhan 42 and 44) uses qDTY QTLs; CR Dhan 801 and 802 combine flood and drought tolerance.
- India released 109 varieties of 61 crops in 2024, and its first genome-edited rice varieties in 2025.
- Tools include germplasm, managed stress screening, phenotyping, MAS, genomic selection, speed breeding and participatory selection.
- Seed systems decide adoption: seed villages, minikits and community seed banks help.
What the exams ask
- Define climate-resilient varieties and distinguish escape, avoidance and tolerance.
- Explain how SUB1 works and how Swarna-Sub1 was developed.
- Name drought-, flood- and salt-tolerant rice varieties.
- Describe breeding tools for stress tolerance.
- Discuss seed system constraints to adoption.
Described in general terms: the kind of examination, not a past paper. Laisha never reproduces exam questions.
Questions people ask
Do climate-resilient varieties yield less in good years?
Well-designed ones should not. Swarna-Sub1 yields about the same as Swarna without floods, because the SUB1 gene acts only under submergence. Some early-maturing varieties trade a little yield potential for safety. Breeders now aim to combine resilience with high yield potential.
Are climate-resilient varieties genetically modified?
Most are not. They come from conventional breeding, often with marker assistance, using genes already present in the crop's gene pool. Genome-edited varieties without foreign DNA are a newer category, regulated more lightly than transgenic crops in India.
How can farmers find suitable varieties?
Krishi Vigyan Kendras, state agricultural universities and the ICAR seed portals list varieties recommended for each zone. Participatory trials in the village help farmers see how a variety performs under their own conditions before they switch.
Sources
- Xu, K. et al. "Sub1A is an ethylene-response-factor-like gene that confers submergence tolerance to rice." Nature 442, 705–708 (2006).
- Dar, M. H., de Janvry, A., Emerick, K., Raitzer, D. and Sadoulet, E. "Flood-tolerant rice reduces yield variability and raises expected yield, differentially benefitting socially disadvantaged groups." Scientific Reports 3, 3315 (2013).
- Kumar, A. et al. "Breeding high-yielding drought-tolerant rice: genetic variations and conventional and molecular approaches." Journal of Experimental Botany 65, 6265–6278 (2014).
- Cairns, J. E. and Prasanna, B. M. "Developing and deploying climate-resilient maize varieties in the developing world." Current Opinion in Plant Biology 45, 226–230 (2018).
More in latest in agriculture
Discussion
Questions, corrections and notes from readers on this article. Every comment is checked before it appears: keep it on the topic, and do not share phone numbers, links or contact details.
Last reviewed