Exploiting wild relatives and landraces to breed future-ready, resilient crops

Co-authors: Jason Lourantos, Giorgos Mitronikas, and Ephthymis Spanopoulos

Wild Relatives and Landraces for Breeding Climate-Resilient Crops 

The importance of wild relatives and landraces, and how can we use them to create new varieties

The practice of agriculture began by humans approximately 105,000 years ago in different regions of the planet. As early as 9,500 BC, systematic cultivation was recorded for wheat, barley, peas, lentils, chickpeas, and flax in Mesopotamia. From its inception, agriculture relied on the selection and cultivation of plants that provided food, fibers, and other resources. Over time and with the evolution of science and technology, the techniques used to improve crop plants also evolved, ultimately achieving the shortening of generation cycles of breeding programs and speeding up the creation of new varieties. Today, the need for sustainable agriculture systems and climate-resilient crops is more persistent than ever. However, the continuous selection and improvement that modern popular varieties have undergone has led to the loss of traits/genes related to tolerance to biotic and abiotic stresses.

What Are Wild Relatives and Landraces?

In this context, wild relatives and landraces of plants emerge as valuable allies in addressing this specific issue. But what exactly are wild relatives and landraces? In agronomy, the term "wild relatives" refers to wild plant species that are genetically related to cultivated varieties. Crop wild relatives (CWRs) are the wild ancestors of modern domesticated and improved crops. They can sometimes naturally breed with cultivated crops, and in some cases, scientists use special methods to help them cross successfully. They grow in natural ecosystems and represent a vast reservoir of genetic diversity, while also having evolved through natural selection, acquiring adaptations to various environmental pressures and stresses.

The term "landraces" refers to traditional varieties of cultivated plants that have evolved through long-term cultivation and selection by farmers. These varieties exhibit genetic variability and are adapted to the local agricultural practices and environmental conditions of the region where they are cultivated. Additionally, they represent a valuable cultural and agricultural heritage of each region, which we must preserve and protect.

The Role of Genetic Diversity in Modern Crop Breeding

As previously mentioned, today's cultivated varieties lack certain genetic traits due to the selection processes aiming for higher yield and improved product quality. In contrast, wild relatives and landraces possess all the necessary genetic diversity and information and can serve as sources of new genes, alleles, and genetic combinations. Bringing in new genetic diversity can increase crop plants’ adaptability and resilience to diseases and pests as well as drought, as well as other environmental issues. The primary goal of breeding using wild relatives and landraces is to create varieties capable of addressing contemporary agricultural challenges.

How Pre-Breeding can contribute to crop improvement?

Pre-breeding is a fundamental process in crop improvement, enabling the transfer of valuable genetic traits from wild or agronomically “inferior” sources to domesticated genotypes. Its primary goal is to harness genetic diversity to develop new, resilient, and high-yielding crop varieties. Through this process, beneficial traits from diverse genetic resources can be systematically incorporated into modern crop varieties, ultimately enhancing their agronomic performance and adaptability.

Pre-Breeding as an Intermediate Step Towards New Varieties

Pre-breeding represents a crucial intermediate phase between the conservation of genetic resources and the development of commercially viable crop varieties. It involves the evaluation and incorporation of desirable traits into breeding lines, ensuring that the genetic material is both agronomically relevant and adaptable to target environments. However, one of the challenges in this process is genetic linkage, a phenomenon where genes that are located close to each other on the same chromosome are inherited together. Although genetic linkage can be advantageous in certain contexts, it often presents challenges when incorporating beneficial traits from diverse sources. Closely linked genes can hinder the separation of desirable and undesirable traits, resulting in the unintended co-transfer of unfavorable genetic material. In pre-breeding, overcoming this genetic linkage is crucial to ensure the new varieties only contain the desirable traits and are free from any genetic flaws.

Figure 1: Pre-breeding as a bridge between genetic resources and crop improvement. (Sharma et al., 2013)

How Does Pre-Breeding Work? - Techniques Used in Pre-Breeding Programs

Pre-breeding focuses on transferring beneficial genes into adapted genetic backgrounds, creating intermediate genetic material before the development of new varieties. This is achieved through modern techniques such as:

1. Traditional crossbreeding with wild relatives to introduce resistance traits.
2. Techniques like embryo rescue and tissue culture to overcome genetic barriers.
3. Molecular tools for precise selection of desired genes.

What Pre-Breeding can offer

• Resistance to climate change and diseases: New varieties gain increased adaptability to environmental fluctuations and resistance to pathogen threats.
• Improved nutritional value: The introduction of genes that are responsible for enhanced vitamin, mineral or protein content leads to more nutritious crops, ensuring global food security.
• Preservation of genetic diversity: Maintaining genetic resources ensures the long-term sustainability of agriculture.

Pre-breeding serves as the crucial link between conserving genetic diversity and developing modern, high-performance crops.  Utilizing advanced biotechnological tools can be the key to sustainable agricultural development and future food security,

as they enable precise and efficient crop improvement.

Breeding for Climate Resilience

Impact of Climate Change on Crop Production

Climate change is reshaping the way we grow plants, bringing new challenges for farmers across the globe. Once-predictable weather patterns have become unreliable, giving way to more extreme and unpredictable conditions. Farmers are now dealing with higher temperatures that lead to longer and more intense heat waves. These heat extremes stress plants, deplete soil moisture and reduce overall crop yields. Additionally, rainfall has become increasingly irregular, causing long water-deficit periods in some regions and flooding in others, both of which put pressure on crop production. More frequent and severe weather events, such as storms, hurricanes, and frost, further damage crops and farm infrastructure, leaving farmers vulnerable. Rising temperatures also create favorable conditions for pests and diseases that were once confined to certain areas but are now spreading to new regions, jeopardizing previously unaffected crops.

To address these challenges, resilient crop varieties are essential. These crops are either selectively bred or genetically improved, mostly derived from wild relatives that have naturally developed traits to survive under harsh environmental conditions. These varieties are designed to withstand specific stress factors such as drought, extreme heat, floods, and pest infestations.

• For example, maize varieties that are drought-resistant can grow effectively in areas with low rainfall, using water more efficiently than traditional varieties.
• Salt-tolerant rice is another example, allowing crops to thrive in saline soils, a problem that is increasingly common as coastal areas experience rising sea levels.
• Heat-resistant wheat varieties, designed to endure higher temperatures, help ensure that yields remain high even during hot spells.
• While disease-resistant tomatoes, such as those that combat blight or viral infections, reduce crop losses.

By adopting resilient varieties, farmers are better equipped to handle unpredictable conditions and ensure food security. These crops not only help preserve yield stability in tough climates, but they also reduce the reliance on chemical inputs, such as pesticides and fertilizers, which are costly and environmentally damaging. Resilient crops are inherently more robust, meaning they can resist pests and diseases naturally, reducing the need for chemical intervention. This shift to less chemical-intensive farming practices contributes to healthier ecosystems, pollution reduction, and the sustainability of agriculture in the long run.

Wild relatives and Landraces: Sources of desirable traits

As the challenges of climate crisis intensify, wild relatives and landraces appear to be promising solutions for developing new crop varieties with resilience to abiotic stresses, as they possess a wealth of genes. Below are the traits of some economically important cultivated species that have been improved with the contribution of wild relatives.

Conclusion

The utilization of wild relatives and landraces for developing new crop varieties that are capable of addressing the urgent challenges agriculture faces from climate change and environmental degradation is of paramount importance. These genetic resources harbor a wealth of traits-such as tolerance to abiotic and biotic stress-that has diminished due to selective breeding. Pre-breeding is a bridge between genetic resources and crop improvement programs, allowing the performance of beneficial traits into cultivated varieties. With pre-breeding activities, it is guaranteed that the generation of new genetic variability will create new resilient and high-yielding varieties that are adaptable to current agricultural needs.

References:

Hajjar, R., Jarvis, D. I., & Gemmill-Herren, B. (2008). The value of crop wild relatives in agriculture. Crop Science, 48(5), 1636-1645.

Dempewolf,  H.,  Baute,  G.  J.,  Anderson,  J.,  Kilian,  B.,  Smith,  C.,  &  Guarino,  L. (2014). Past and future use of wild relatives in crop breeding. Crop Science, 54(4), 1370-1382.

Kapazoglou, A.; Gerakari, M.; Lazaridi, E.; Kleftogianni, K.; Sarri, E.; Tani, E.; Bebeli, P.J. Crop Wild Relatives: A Valuable Source of Tolerance to Various Abiotic Stresses. Plants 2023, 12, 328. https://doi.org/ 10.3390/plants12020328.

Tefera, A., & Tafa, Z. (2021). Pre-Breeding Concept and Role in Crop Improvement. International Journal for Research in Applied Sciences and Biotechnology, 8(2), (pp 275-279.)

Prakash, K. & Kumar, R.  et. al. (2017). Pre-Breeding in the Omics Era: A review in vegetable crops.  Chemical Science Review and Letters 6(22) (pp 752-762)

Sohi A, Dogra BS, Dhiman S, Pathania R, Chaudhary A, Singathiya P, Ranga A D, Kumari A. Pre-breeding approaches towards vegetable improvement: A review. Plant Science Today. 2025; 12(1): 1-11. 

Lazaridi E, Kapazoglou A, Gerakari M, Kleftogianni K, Passa K, Sarri E, Papasotiropoulos V, Tani E, Bebeli PJ. Crop Landraces and Indigenous Varieties: A Valuable Source of Genes for Plant Breeding. Plants (Basel). 2024 Mar 7;13(6):758. doi: 10.3390/plants13060758. PMID: 38592762; PMCID: PMC10975389.

Further reading

The Importance of Crop Wild Relatives for Enhanced Plant Stress Resilience

Key Traits Breeders Prioritize for Enhancing Greenhouse Crop Performance

CRISPR and Phytoremediation: Engineering Plants to Clean and Restore Polluted Soils

Key Breeding Traits and Future Prospects of Processing Tomatoes

CRISPR-Cas: The Key to Global Food Security and Farmers’ Profitability

Pre-Breeding: The Future of Crop Improvement