Pre-Breeding: Shaping the Future of Crop Improvement and Sustainable Agriculture
Pre-breeding is a crucial yet often overlooked aspect of modern agricultural development, especially when it comes to enhancing genetic diversity and important traits in crops. These traits are vital for adapting to fluctuating environmental conditions such as those brought about by climate change—as well as pest and disease pressures and other market and grower needs.
In essence, pre-breeding refers to the preparation of genetic materials for breeding purposes, such as the creation of new, improved crop varieties. This process involves identifying and incorporating genetic diversity from various sources, including wild plant relatives and traditional landraces, into desired (elite) breeding lines. The goal is to expand their genetic base and improve characteristics such as yield, nutritional value, and stress tolerance (Vikram et al., 2024).
More specifically, pre-breeding enhances genetic diversity by introducing one or more genes from outside sources into modern cultivars. This approach provides a more sustainable and environmentally friendly solution to the challenges posed by food production. Unlike traditional breeding techniques, which focus on refining existing traits within current cultivars, pre-breeding broadens the genetic foundation of crops by tapping into an often unused genetic pool.
Why Pre-Breeding is Important
The significance of pre-breeding has grown on a global scale due to increasing challenges like climate change, intensifying pest and disease pressures, and the need for sustainable agricultural practices. Cultivars that were developed for specific environmental conditions can become unsuitable when those conditions change, often leading to yield losses.
A 2022 report by the Food and Agriculture Organization (FAO) highlights a drastic decline in the genetic diversity of cultivars, primarily due to the continuous cultivation of uniform crop varieties. Pre-breeding addresses these challenges by introducing traits such as heat, drought, and salinity tolerance from wild relatives into modern cultivars (Mba et al., 2012). For instance, drought-resistant genes from Hordeum spontaneum, a wild barley species, were successfully integrated into modern barley varieties (Lakew et al., 2011). Similarly, the Sub1 gene, which confers flood tolerance, was transferred from the wild rice species Oryza rufipogon into cultivated rice varieties, allowing them to survive prolonged submergence (Fukao et al., 2009). Beyond improving climate resilience, pre-breeding is also crucial for enhancing disease resistance in crops.
Due to changing environmental conditions and the widespread practice of monoculture, pests and pathogens often find favorable conditions to evolve rapidly, thereby breaking down the resistance of cultivars in a short period. This phenomenon poses a global food security threat, underscoring the need for a more robust and long-term breeding strategy.
The Challenges in Pre-Breeding and new Technologies to Overcome them
Despite its clear importance, pre-breeding comes with several challenges. Identifying and incorporating new genes is often a lengthy and labor-intensive process, requiring years of research and development. This extended timeline can discourage breeders and funding agencies. Furthermore, the genetics associated with specific traits can be complex and poorly understood, making it challenging to transfer desired traits without inadvertently introducing undesirable ones. Crossbreeding with wild varieties often results in progeny with both desirable and undesirable traits, necessitating further back-crossing to refine the final product—a process that is both time-consuming and costly.
Another significant challenge in pre-breeding is the need for intensive resources. Cutting-edge technologies, such as gene sequencing, marker-assisted selection, and bioinformatics tools, are often required to ensure success. While these tools enable researchers to identify and screen gene sets more accurately, they are also expensive and require specialized expertise, which is not always readily available. Despite these challenges, the need for pre-breeding practices is becoming increasingly apparent as global environmental conditions continue to change. The push to unlock genetic diversity is crucial to supporting global agriculture, which is currently at high risk.
Advances in Biotechnology and the Future of Pre-Breeding
Recent advancements in biotechnology have led to significant improvements in pre-breeding techniques. Innovations such as CRISPR gene editing have made pre-breeding more effective and efficient by allowing precise gene editing within plants without the need for multiple backcrossings. This advancement reduces the time and resources required for pre-breeding, making it a more economically viable option for a wide range of breeding programs. Additionally, advanced bioinformatics tools can now predict the locations of desired genes, enabling breeders to target them more quickly.
Conclusion
Pre-breeding is a critical component of modern agriculture, playing a key role in developing high-potential and resilient crops. It opens the door to previously untapped genetic diversity, allowing for the improvement of crop performance by incorporating advanced traits. This process lays the foundation for sustainable agriculture by enhancing the ability of crops to adapt to environmental changes. Despite the challenges associated with pre-breeding, its benefits are manifold. To meet the future demand for global food security, there is a pressing need to invest in pre-breeding and support advancements in biotechnology. These advancements will improve existing techniques, enabling them to better cope with climatic variations and environmental degradation, thereby making pre-breeding a central focus for agricultural researchers and policymakers.
References:
- Fukao T, Harris T, Bailey-Serres J. Evolutionary analysis of the Sub1 gene cluster that confers submergence tolerance to domesticated rice. Ann Bot. 2009 Jan;103(2):143-50. doi: 10.1093/aob/mcn172. Epub 2008 Sep 29. PMID: 18824474; PMCID: PMC2707309.
- Lakew, B., Eglinton, J., Henry, R. J., Baum, M., Grando, S., & Ceccarelli, S. (2011). The potential contribution of wild barley (Hordeum vulgare ssp. spontaneum) germplasm to drought tolerance of cultivated barley (Hordeum vulgare ssp. vulgare). Field Crops Research, 120(1), 161-168. https://doi.org/10.1016/j.fcr.2010.09.011
- Mba, C., Guimaraes, E.P. & Ghosh, K. Re-orienting crop improvement for the changing climatic conditions of the 21st century. Agric & Food Secur 1, 7 (2012). https://doi.org/10.1186/2048-7010-1-7
- Vikram P, Sehgal D, Prasad M, Singh S, Raman H. Editorial: Harnessing crop biodiversity and genomics assisted pre-breeding approaches for next generation climate-smart varieties, volume II. Front Plant Sci. 2024 Mar 6;15:1387016. doi: 10.3389/fpls.2024.1387016. PMID: 38510441; PMCID: PMC10951096.
- Visioni A, Basile B, Amri A, Sanchez-Garcia M, Corrado G. Advancing the Conservation and Utilization of Barley Genetic Resources: Insights into Germplasm Management and Breeding for Sustainable Agriculture. Plants (Basel). 2023 Sep 6;12(18):3186. doi: 10.3390/plants12183186. PMID: 37765350; PMCID: PMC10535687.
Further reading
Plant Breeding Technologies: Exploring Mutagenesis and Gene Editing for Crop Improvement
How Epigenetics Can Help Farmers Grow Healthier and More Resilient Crops
The Importance of Crop Wild Relatives for Enhanced Plant Stress Resilience
Hybrid Potatoes – A Climate-Smart Solution for Potato Farmers
Nanomaterial-Based Seed Priming: Boosting Crop Resilience and Stress Tolerance
Seeds of Success: Choosing and Caring for Quality Seeds
What is Plant Propagation – Types and characteristics of Sexual and Asexual propagation material