Drought Tolerance in Potatoes: Building Resilience for a Changing Climate

Introduction

Environmental stresses, particularly drought, can reduce crop yields by over 50%, posing a severe threat to food security in arid and semi-arid regions that cover about 40% of Earth’s land surface. Potatoes (Solanum tuberosum L.), domesticated 8,000 years ago in the Andes and introduced to Europe in the 16th century, are now the fourth most important food crop globally. In 2019, production reached around 370 million tonnes despite a decline in harvested area. However, their shallow root system and high water requirements make them highly vulnerable to drought, with even short water deficits during the tuberization stage causing substantial yield and quality losses.

Climate change is intensifying this risk by increasing water scarcity, which is projected to affect more than 50% of arable land by 2050. Integrated strategies such as enhancing ABA-mediated signaling for stress tolerance, improving soil management practices, selecting drought-resilient genotypes, and applying recent breeding innovations offer promising pathways to sustain productivity under worsening climatic conditions.

Did You Know?

Potatoes require only 105 liters of water per kilogram, yet drought can cause up to 90% yield loss due to their shallow roots.

Drought and Its Global Impact on Crops

Drought is one of the most critical abiotic stresses affecting global agricultural productivity, leading to significant economic losses and food insecurity across both developed and developing countries. It restricts plant growth by inducing moisture stress, which limits water and nutrient absorption and disrupts key physiological processes. As a result, crops fail to reach their full genetic yield potential, making drought a major constraint to sustainable agricultural production.

Abiotic stresses such as drought, salinity, temperature fluctuations, and adverse soil conditions often act synergistically, amplifying their harmful effects. Together, these stresses can reduce crop productivity by 30–90%, depending on crop species, growth stage and environmental severity. The availability of water during critical developmental phases particularly germination, flowering and maturation is essential for normal physiological functions. When water deficits occur, plants show visible stress symptoms such as reduced leaf expansion, smaller canopy cover, stunted root growth and a marked decline in photosynthetic efficiency. These responses lead to reduced biomass accumulation and yield loss.

Beyond physiological effects, prolonged drought also impacts soil health by reducing organic matter, microbial activity and nutrient cycling, which further undermines future crop productivity. The global expansion of arid and semi-arid zones under climate change is expected to intensify these challenges. Addressing drought’s widespread impact requires a combination of resilient crop varieties, improved soil and water management, and climate-smart agricultural practices to ensure long-term food security.

Did You Know?

Drought combined with high temperatures can reduce potato yields by up to 20% in Europe, as observed in 2025.

Effect of Drought Stress on Potato

Among the many crops vulnerable to drought, potatoes are highly susceptible, with stress leading to significant yield reductions due to their shallow roots limiting water uptake. Water scarcity during tuberization delays formation and reduces tuber count and growth, impairing photosynthetic activity and accelerating leaf senescence. The growth phases establishment, stolon initiation, tuber initiation, bulking and maturity are affected, with early tuber development most sensitive. Physiological effects include decreased photosynthesis and assimilate translocation, compromising energy storage and tuber quality.

Did You Know?

A water deficit during tuber initiation can reduce potato tuber numbers by up to 50%, critical for yield.

Effects of Drought on Canopy Development, Root Growth and Tubers in Potatoes

Drought stress significantly affects potato canopy, roots, and tubers, influencing yield and quality. Understanding these effects aids in breeding tolerant varieties and improving practices in water-scarce regions.

Leaf and Canopy Responses

Potato canopy architecture is highly susceptible to drought, with reduced leaf size hindering photosynthesis and carbohydrate synthesis. Drought limits leaf expansion, restricts new leaf formation and accelerates senescence, with vein density increasing to enhance hydraulic conductivity and tolerance. Leaf water potential below -1.0 MPa halts growth, with relative water content (RWC) distinguishing tolerant cultivars like 'Raritan' from sensitive ones like 'Shepody'.

Effects of Drought on Roots, Stolons and Tubers

Potatoes shallow roots make them vulnerable with drought affecting root, stolon and tuber growth, reducing yield and quality. Water scarcity during tuberization delays initiation and limits tuber number and size. Root responses vary some studies show increased length and dry mass, others decrease while stolon growth may increase or decrease based on stress timing.

Effects of Drought on Fresh and Dry Tuber Mass

Drought profoundly impacts tuber mass and water content, influencing quality and yield. Tuber weight relies on water availability, with content up to 80% in some cultivars prolonged stress reduces it by 69%. Tuber number decreases under early or season long stress, with late stress affecting dry matter less. Reduced photosynthesis limits assimilate translocation, decreasing dry mass and suitability for processing.

Breeding and Research for Drought Tolerance

Global efforts are advancing drought tolerant potato varieties through diverse approaches.

Global research efforts are actively advancing drought-tolerant potato varieties through multiple strategies. Conventional breeding programs, led by institutions such as CIP, screen germplasm for key traits like deep root systems and early maturity. This approach has produced varieties such as Asante and Unica, which maintain 20–30% higher yields under drought stress in Africa, with trials in Uganda demonstrating promising results.

Biotechnological advances complement traditional methods, with marker-assisted selection targeting critical genes such as DREB1A, while CRISPR-Cas9 gene editing enhances ABA-related pathways. In Kenya, the release of biotech drought-tolerant lines has improved yields by 15–25% under water-limited conditions.

International collaborations further accelerate progress. Partnerships between institutions like the Central Potato Research Institute and the Royal HZPC Group integrate traits from wild relatives with hydroponic studies identifying drought-resilience biomarkers. These combined efforts are fast-tracking the development of hybrid varieties suitable for climate-vulnerable regions, strengthening global food security.

Drought Stress Avoidance Strategies in Potato Crops: Mechanisms and Mitigation Techniques

Drought stress avoidance in potato crops involves a combination of genetic, physiological and management-based strategies that help plants reduce exposure  or minimize the effects of water scarcity. Potatoes can escape drought by completing their life cycle before severe stress occurs. Early-flowering and early-maturing cultivars are especially effective in regions like the Mediterranean, where terminal droughts are common. These varieties initiate flowering and tuberization while soil moisture is still sufficient, avoiding yield losses from late-season dryness. Breeding programs often target this trait to match local climate patterns and ensure stable production.

On a physiological level, drought stress triggers a series of responses controlled largely by the hormone abscisic acid (ABA). Increased ABA levels cause stomatal closure, reducing water loss through transpiration. This hormone also activates stress-response genes through signalling molecules such as SnRK2 kinases. Transcription factors like ABF, ABI5, WRKY and heat shock proteins (HSPs) play essential roles in protecting cells from dehydration. Likewise, the DREB1A gene is upregulated under stress, enhancing tolerance by promoting osmoprotectant synthesis and improving membrane stability. These molecular and physiological changes help the plant maintain turgor pressure and photosynthetic function during drought periods.

Agronomic mitigation techniques complement these natural defenses. Using mulch made from straw, crop residues, or plastics reduces evaporation and maintains soil moisture. Conservation tillage and residue management preserve soil organic matter, improving water infiltration and retention. Organic amendments such as compost, manure and biochar further enhance soil structure and moisture-holding capacity, creating a more favorable root environment.

Proper nutrient management also plays a vital role in building drought resilience. Key macronutrients like nitrogen (N), phosphorus (P), and potassium (K) strengthen photosynthesis, root growth, and osmotic regulation. Micronutrients including zinc (Zn), silicon (Si), boron (B) and manganese (Mn) support physiological stability and stress enzyme activity. When managed together, these techniques enable the potato crop to maintain productivity even under fluctuating water availability.

Did You Know?

Mulching can increase soil water retention by 20–40%, significantly aiding drought stressed potatoes.

Challenges in Drought Tolerance

Genetic Complexity: The tetraploid genome structure in potatoes makes breeding for drought tolerance technically challenging due to complex inheritance patterns and the low genetic diversity in most commercial cultivars. This limits the potential for rapid gains through conventional breeding. Integrating traits from wild relatives could address this gap, but regulatory barriers to importing and using these species slow progress. Marker-assisted selection and genomic tools help somewhat, yet trait introgression remains time-consuming and resource-intensive.

Climate Pressures: Climate change is intensifying the difficulties of developing drought-tolerant varieties. Rising temperatures, especially prolonged periods above 29 °C, disrupt tuber initiation and development, directly impacting productivity. In 2025, much of Europe experienced erratic rainfall patterns combined with heat waves, leading to yield reductions of 15–20% in affected regions. These conditions also interact with other stresses, such as early blight outbreaks, compounding farmer losses and restricting the testing windows for new drought-tolerant lines.

Access Barriers: For smallholder farmers in Africa and Asia, the high upfront cost of drought-tolerant seeds and complementary technologies (like advanced irrigation systems) remains a major obstacle. Even with targeted 2025 training initiatives promoting water-efficient practices, adoption rates in some regions are still below 20%. Limited credit availability, weak distribution networks, and cultural preferences for familiar varieties further slow uptake. Without stronger policy support and subsidies, the benefits of drought-tolerant breeding risk being concentrated among larger, well-capitalized farms.

Global Impact and Role in Food Security

Drought-tolerant potatoes significantly improve agricultural productivity in water-limited regions, boosting yields by 20–30% for smallholder farmers in Sub-Saharan Africa and Asia. These varieties also help combat malnutrition, particularly with iron-rich lines that enhance dietary nutrition. In Kenya, the deployment of 2025 biotech drought-tolerant potato lines has reached approximately 480,000 farmers, providing resilient crops capable of withstanding erratic rainfall and prolonged dry spells, there by enhancing food security and farmer livelihoods.

On a global scale, drought-tolerant potatoes contribute to more sustainable agriculture by reducing the need for chemical inputs and promoting biodiversity through the use of resilient genetic traits. The sector is projected to support a USD 16 billion market by 2031, reflecting their growing importance in ensuring stable food supplies amid the challenges of climate change. By combining increased yields, improved nutrition, and environmental benefits, drought-tolerant potatoes are becoming a vital tool for securing food systems worldwide.

"Drought tolerance in potatoes is a cornerstone of sustainable agriculture, blending cutting-edge science with practical farming wisdom to secure food for future generations. As water scarcity intensifies, this resilience is vital to empower farmers and nourish a growing world."