Agrobiodiversity for Sustainable Agriculture: Reversing Genetic Erosion for Future Food Security

For over 10,000 years, farmers have been the world’s original plant breeders. Through careful observation and selection, they cultivated crops that could withstand local droughts, resist pests, and yield enough to feed their communities. This patient, generation-by-generation work created an extraordinary tapestry of agricultural diversity. But today, that diversity is unravelling at an alarming rate. More than half of the world’s caloric demand is now satisfied by just three grains – rice, maize, and wheat – and within each of those crops, genetic variation is shrinking fast. Understanding how we got here, and what we can do about it, is essential for securing the future of food.

What is agrobiodiversity, and why does it matter? 🔗

Agrobiodiversity refers to the variety of plants, animals, and microorganisms that are directly or indirectly involved in agriculture. It is the product of millennia of natural evolution combined with deliberate human selection. Farmers across continents chose seeds that suited their soils, climates, and cultural needs – resulting in thousands of locally adapted crop varieties known as landraces. These landraces carry unique genetic traits for drought tolerance, disease resistance, and nutritional value that modern high-yield varieties often lack.

Agrobiodiversity doesn’t just support food production. It underpins critical ecosystem services such as pollination, natural pest regulation, nutrient cycling, and soil health. When this diversity shrinks, farmers become increasingly dependent on synthetic fertilizers and pesticides, creating a cycle that further simplifies ecosystems and erodes the very genetic foundation agriculture depends on.

10,000 years of farmer-led selection 🔗

The story of agriculture is fundamentally a story of selection. Since the earliest days of crop domestication in regions like the Fertile Crescent, Mesoamerica, and Southeast Asia, farmers have selected plants that exhibited desirable traits – higher grain yields, uniform ripening, resistance to local diseases, and better taste. Over thousands of growing seasons, this process generated enormous diversity.

A single crop species like rice, for example, came to exist in tens of thousands of distinct varieties, each adapted to specific altitudes, rainfall patterns, and soil types. Wheat varieties thrived from the semi-arid plains of Central Asia to the wet lowlands of Europe. This diversity was not accidental – it was the cumulative result of farmers continuously experimenting, saving seeds, and sharing knowledge across communities.

This farmer-driven innovation created a vast genetic reservoir – one that has served as the raw material for virtually all modern crop improvement. Every disease-resistant wheat variety or drought-tolerant maize hybrid traces its genetic roots back to these traditional selections.

The Green Revolution: a double-edged sword 🔗

Beginning in the 1960s, the Green Revolution transformed global agriculture. Through the introduction of high-yielding crop varieties, synthetic fertilizers, chemical pesticides, and expanded irrigation, food production surged. Cereal crop production tripled globally with only about a 30% increase in cultivated land area. Countries like India went from dependence on food imports to self-sufficiency within a couple of decades. The revolution also contributed to significant poverty reduction and lower food prices worldwide.

However, these gains came with serious trade-offs. The Green Revolution’s high-input model was designed for fertile, well-irrigated land under optimal conditions. Smallholder farmers working marginal, rain-fed lands in sub-Saharan Africa, South Asia, and Latin America saw far fewer benefits. These farmers needed crops adapted to their specific local conditions – not standardised varieties that required expensive inputs to perform.

Environmental and nutritional costs 🔗

The environmental consequences have been significant. Overreliance on a narrow set of high-yield varieties led to dramatic reductions in cultivated crop diversity. As modern varieties replaced local landraces, traditional crop knowledge was lost alongside the seeds themselves. Soil degradation, waterlogging, salinisation, and groundwater depletion became widespread in Green Revolution heartlands. In India’s Punjab region, for instance, rice yields eventually stagnated and even declined after decades of intensive monoculture.

Nutritional diversity also suffered. The emphasis on calorie-rich staples like rice and wheat displaced nutrient-dense crops such as millets, pulses, and indigenous vegetables. The Green Revolution delivered more calories but often at the expense of balanced diets, contributing to what nutritionists now call “hidden hunger” – adequate caloric intake combined with micronutrient deficiency.

Genetic erosion: the silent crisis 🔗

The most profound consequence of agricultural modernisation has been genetic erosion – the irreversible loss of genetic diversity within crop species. Approximately 75% of plant genetic diversity was lost during the 20th century as farmers globally shifted to genetically uniform, high-yielding varieties. Today, just nine plant species account for about two-thirds of global crop production.

This narrowing of the genetic base is deeply concerning. When a traditional crop variety disappears from farmers’ fields, we lose not just the seeds but thousands of years of evolutionary adaptation. These genetic resources contain traits for stress tolerance, disease resistance, and nutritional qualities that may prove invaluable for adapting to future challenges – but once lost, they cannot be recreated.

The vulnerability this creates is well illustrated by historical events. The devastating Irish potato famine of the 1840s was directly caused by dependence on a single, genetically uniform potato variety. Today, our global reliance on an even narrower crop base presents risks of similar – but far larger – scale disruptions from pests, diseases, or climate extremes.

Traditional agriculture: still feeding the world 🔗

Despite the narrative of modernisation, traditional farming systems continue to play a vital role in global food security. Smallholder farmers manage a significant portion of the world’s agricultural land, and their practices remain fundamental in challenging environments where high-input agriculture simply doesn’t work – steep hillsides, arid zones, flood-prone lowlands, and areas with poor infrastructure.

These traditional systems are not “backward.” They represent sophisticated, place-specific strategies for food production that have been refined over centuries. Mixed cropping, agroforestry, rotational farming, and the cultivation of diverse crop varieties are all features of traditional agriculture that enhance resilience. Traditional farmers often maintain dozens of crop varieties in a single season, providing a natural buffer against weather variability, pest outbreaks, and market fluctuations.

These farming communities are also living repositories of agrobiodiversity. The landraces and indigenous varieties they grow contain genetic material that formal gene banks often fail to capture. Protecting traditional agriculture, therefore, is not just about preserving culture – it is a practical strategy for conserving the genetic resources that all of agriculture depends on.

The intensification challenge: feeding 9 billion sustainably 🔗

The world’s population is projected to reach approximately 9 billion by 2050. Feeding this many people will require substantial increases in food production, but the potential to expand agricultural land is limited – most suitable land is already being farmed. The answer, clearly, lies in sustainable intensification: producing more food from the same or less land, while minimising environmental damage.

This is no small task. Agriculture must simultaneously use nutrients and water more efficiently, sustain the ecosystems it depends on, conserve biodiversity, reduce greenhouse gas emissions, and adapt to climate change. The FAO has emphasised that achieving these gains will require combining modern technology with traditional knowledge and a strong emphasis on agroecological systems – not just yields.

Why agrobiodiversity is central to sustainable intensification 🔗

Agrobiodiversity is not a luxury to be preserved after food security is achieved – it is a prerequisite for achieving it. Genetic diversity within and across crop species provides the raw material for breeding varieties that can withstand new diseases, tolerate drought and heat, grow in poor soils, and deliver better nutrition. Without this diversity, plant breeders have fewer tools to work with, and agriculture becomes more brittle in the face of mounting pressures.

Diverse farming systems also reduce the need for external inputs. Crop rotations and intercropping can naturally suppress pests and diseases, fix nitrogen in soils, and break weed cycles. These practices reduce costs for farmers and decrease agriculture’s environmental footprint – a critical requirement as the world confronts climate change and resource depletion simultaneously.

Evolutionary plant breeding: a promising path forward 🔗

One of the most exciting approaches for integrating agrobiodiversity into modern food production is evolutionary plant breeding. This method involves cultivating genetically diverse crop populations and deliberately exposing them to natural selection pressures – including variable weather, pests, and diseases. Over time, these populations adapt to local conditions, with the most resilient and productive plants naturally becoming more prevalent.

The concept draws on nearly a century of research into evolutionary populations and mixtures. Rather than seeking a single “best” variety for widespread use, evolutionary breeding embraces the reality that agriculture operates across enormously varied environments. What works in irrigated lowland fields will not necessarily perform on rain-fed hillside plots. Evolutionary populations can adapt to this diversity in ways that uniform modern varieties cannot.

The participatory dimension 🔗

What makes evolutionary breeding particularly powerful is its participatory component. Participatory plant breeding (PPB) involves farmers directly in the selection process, working in their own fields under their actual growing conditions. Farmers and breeders collaborate at every stage – from setting breeding goals to evaluating and selecting the most promising plants.

This decentralised approach has several advantages. First, it produces varieties that are specifically adapted to local environments, rather than broadly adapted but optimised for no particular condition. Second, it increases variety adoption rates because farmers have been involved in developing them. Third, it empowers farmers by restoring their traditional role as plant breeders and seed stewards, building local capacity and reducing dependence on commercial seed systems.

Research across multiple countries – including Iran, Italy, and several nations in Africa and Asia – has demonstrated that evolutionary-participatory breeding can produce yields comparable to modern cultivars, particularly in organic and low-input systems. In Iran, farmers selected barley, rice, and wheat varieties from evolutionary populations that delivered broad benefits for the environment, human health, and farming income.

Addressing climate change through diversity 🔗

Climate change makes the case for evolutionary breeding even stronger. Adaptation to climate change is a difficult breeding target because climate impacts are complex, unpredictable, and location-specific. A heat wave that devastates crops in one region may not affect another just 100 kilometres away. Evolutionary populations, with their built-in genetic diversity, can respond to this variability because different genotypes within the population are suited to different conditions.

This stands in stark contrast to conventional breeding strategies that attempt to identify single varieties resistant to specific stresses. While useful, such approaches are inherently limited because pests and diseases evolve too, often outpacing the introduction of new resistant varieties. Spatial and temporal crop diversity, by contrast, offers a more durable form of resilience.

What needs to happen next 🔗

Reversing genetic erosion and harnessing agrobiodiversity for sustainable agriculture requires action on multiple fronts. Seed banks and gene banks – including the Svalbard Global Seed Vault – are essential for preserving genetic material. But ex situ conservation alone is not sufficient. On-farm conservation, where farmers continue to grow and adapt traditional varieties, is equally critical because it allows ongoing evolution and adaptation to changing conditions.

Policy reforms are also needed. Current seed certification systems in most countries are designed around uniformity criteria that exclude the genetically diverse materials produced through evolutionary breeding. The European Union has taken promising steps by allowing the marketing of heterogeneous plant material under its organic agriculture regulation, but similar reforms are needed globally.

Investment in participatory breeding programmes needs to increase significantly. These programmes have demonstrated their effectiveness, but they remain underfunded relative to conventional breeding. Public research institutions, international agricultural research centres like those in the CGIAR network, and national governments all have roles to play in scaling up these approaches.

Finally, consumer awareness matters. Dietary choices that favour diversity – eating a wider range of grains, pulses, vegetables, and fruits – create market demand that supports farmers in maintaining diverse cropping systems. The food on our plates is directly connected to the genetic diversity in our fields.

What do you think? Can evolutionary and participatory plant breeding approaches scale fast enough to reverse genetic erosion before we lose irreplaceable crop diversity? And in your own experience, how has the shift toward fewer crop varieties affected the food choices available in your community?

References

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