• Ramzi Belkhodja, administrator of the training area ‘Plant Production, Health and Breeding’ at CIHEAM Zaragoza, addresses in this article the challenges faced by Mediterranean agriculture, with a focus on the impacts of climate change on plant health and crop production.
• The article explores emerging threats, pest control strategies, plant breeding to produce new, resistant varieties, and sustainable agricultural practices. The article also underlines the role of international cooperation and technological innovation in the Mediterranean agricultural sector in order to adapt to evolving climatic conditions.

Current context of Mediterranean agriculture

Throughout history, agriculture in the Mediterranean region has been a fundamental pillar of local livelihoods and international trade. Characterised by emblematic crops such as olives, vines, cereals, citrus, and horticultural products, the region hosts a diverse agricultural system of enormous cultural, social and economic value. Mediterranean countries are located in Europe, northern Africa and western Asia, united by a common climate featuring mild, rainy winters and hot, dry summers. These climatic conditions favour certain crops but they also make them highly vulnerable to climatic fluctuations and emerging phytosanitary threats.

In this context, plant health plays a vital role in protecting crops against pests, diseases, and other biotic factors that threaten agricultural production. The expansion of invasive pests, increasing prevalence of diseases, and extreme climatic variations seriously jeopardise the stability and productivity of Mediterranean agricultural systems. Advances in plant health - from integrated pest management to advanced monitoring technologies - are essential to ensuring sustainable production in the region.

Plant breeding is a key instrument for developing crop varieties that are not only more productive, but also resilient to adverse conditions such as water stress, high temperatures, and emerging diseases. Modern breeding techniques, including gene editing and biotechnology, are transforming scientists’ capacity to develop crops adapted to current climatic and phytosanitary challenges.

At a moment when global food security is a critical issue, Mediterranean agriculture faces a dual challenge: meeting the growing demand for high-quality food products while mitigating and adapting to the effects of climate change and biotic threats. Consequently, plant health and breeding are not only fundamental for maintaining crop production, but also to ensure sustainable production that can feed future generations, conserve natural resources, and preserve the ecological balance of the region.

Climate change as a key challenge

Climate change is widely regarded as one of the greatest challenges facing agriculture across the world, particularly in the Mediterranean. This region is among the most vulnerable to global warming due to its geographical location and unique climatic characteristics. Rising temperatures, unpredictable rainfall patterns, and an increased frequency of extreme meteorological phenomena, including heat waves, prolonged droughts, and torrential rains, are having devastating impacts on traditional agricultural systems.

One of the most pronounced effects of climate change in the Mediterranean is the rise in temperatures. The summers have always been hot, but they are now longer and more intense, disrupting the growth cycles of many key crops. High temperatures exacerbate drought stress, reducing both the productivity and the quality of agricultural products. For instance, in typical Mediterranean crops such as olives and vines, heat stress can significantly diminish the quality of olive oil and wine, with adverse effects on local economies. Extreme heat also impairs pollination and fruit set, lowering yields in many fruit and horticulture crops.

Unpredictable rainfall patterns pose another critical challenge. In the Mediterranean, rains typically occur in in autumn and winter, but recent years have seen increasingly erratic precipitation. Some areas experience insufficient rainfall, leading to prolonged droughts, while others suffer from torrential rains that cause floods, soil erosion, and damage to agricultural infrastructures. This phenomenon complicates water resource planning and management, an essential factor for irrigation and crop survival in a region where water is already scarce.

Climate change makes matters worse with the proliferation of emerging pests and diseases. Disruptions in the life cycles of pests and their natural predators, together with the increased survival of invasive species from warmer climates, have heightened the risk of crop infestations. For example, Xylella fastidiosa, a bacterium causing devastation in olive groves, vineyards, and almond orchards, has spread across the Mediterranean partly due to rising temperatures. Similarly, the olive fruit fly and other diseases affecting key crops are proliferating in previously unaffected areas, increasing production costs through greater phytosanitary controls.

Adapting to these changes requires progress in agricultural technology, together with integrated approaches including water management and genetic improvement to develop more heat and drought-resistant varieties, and new integrated pest management strategies. The resilience of Mediterranean agriculture to climate change will depend significantly on the capacity of farmers and governments to implement sustainable and innovative solutions that protect natural resources and ensure long-term productivity.

Plant breeding as a solution

Plant breeding has long been one of the most powerful tools in agriculture to address the challenges related to pests, diseases, and adverse climatic conditions. In a context of climate change, this discipline has become even more critical as it enables the development of more resilient crops capable of adapting to emerging phytosanitary threats and changing environmental conditions. For Mediterranean countries, where olive groves, citrus orchards, vineyards and other essential crops are under severe pressure, plant breeding offers long-term solutions to reduce the vulnerability of the agricultural sector.

One of the main advantages of plant breeding is its ability to introduce genetic resistance to pests and diseases, thereby reducing reliance on plant protection products and enabling more sustainable production systems. This is particularly relevant in the Mediterranean, where new pests and diseases, such as Xylella fastidiosa in olive groves and Tuta absoluta in tomatoes, have caused substantial economic losses.

Xylella fastidiosa has devastated olive groves in Italy and poses a serious threat to other Mediterranean countries, highlighting the need for resistant varieties. Breeding programmes are actively identifying and selecting olive varieties that are less susceptible to infection. Conventional and more advanced techniques, such as gene editing, have facilitated the development of crops that are more tolerant to this bacterium, which is a significant breakthrough in the fight against this devastating pest.

In addition to pest and disease resistance, plant breeding also plays a key role in developing crops tolerant to adverse climatic conditions, such as drought, extreme heat, and salinity. As climate change intensifies these challenges, new varieties capable of withstanding such conditions are essential for ensuring stable crop production in the region.

In Mediterranean countries, water is a limited resource and increasingly threatened by climate change. The genetic breeding programmes have successfully developed olive, vine and cereal varieties with greater water use efficiency and drought tolerance. These crops enable farmers to maintain acceptable production levels even in conditions of scarce water availability, thus contributing to the sustainability of the sector.

With the rise in mean temperatures and more frequent heatwaves in the region, crops must be able to maintain yield at extreme low temperatures. Plant breeding has been fundamental in developing horticultural and fruit crop cultivars as well as cereals that can adapt better to these conditions and mitigate yield losses.

Another challenge related to climate change is soil salinisation, which is exacerbated by less available freshwater and excessive irrigation in some areas. Plant breeding has produced of wheat, barley, and fruit-tree varieties with increased salinity tolerance, ensuring production in affected areas.

Through advances in biotechnology and incorporation of tools such as CRISPR-Cas9, plant breeding has taken a large leap forward through precision gene editing. This can accelerate the development of resistant varieties pests, diseases, and adverse climatic conditions. Unlike conventional breeding methods, which can take years or even decades, by using gene editing, breeders can modify a plant’s DNA to improve specific characters quickly and efficiently.

One of the main advantages of gene editing is the ability to introduce resistance to multiple threats into a single variety. For example, plants resistant to both pests and drought are essential in the Mediterranean, where farmers have to deal with multiple challenges simultaneously.

Although biotechnological tools are very promising, there are also other challenges including regulatory constraints and public acceptance. Some Mediterranean countries remain cautious about genetically modified or edited varieties due to regulatory issues or consumer concerns. However, research is ongoing and clear regulatory frameworks can be established to facilitate the adoption of these technologies in the future.

Conclusions

The article highlights the profound impacts of climate change on plant health in the Mediterranean, making the situation of pests and diseases worse and compromising agricultural production. Changes in temperature and rainfall patterns have increased risks to plant health, underlying the need for adaptive approaches such as plant breeding and integrated pest management.

CIHEAM Zaragoza plays a critical role in finding solutions for these challenges, through cooperation projects to promote sustainable agricultural practices. By focusing on training and knowledge transfer, CIHEAM Zaragoza delivers capacity-building programmes for scientists and technical specialists, equipping them with innovative technologies and methodologies to safeguard plant health under adverse climatic conditions.