Why Conservation of Local and Traditional Varieties Is Important for Humanity
The Roots of Crop Diversity
Have you ever wondered where the huge variety of fruits, vegetables, and grains we enjoy today came from?
For thousands of years, farmers around the world have been cultivating wild plants. Over generations, they selected those that grew best, tasted better or were easier to harvest. This process of domestication began in the Neolithic Age, around 10,000 years ago and forever changed how humans and nature interact.
Domestication of crops and animals occurred roughly between 10,000 and 5,000 years ago in several world regions: the Middle East and Mediterranean Basin, East and West Africa, Mesoamerica, the Andean region of South America, China and India.
Through domestication, wild plants were gradually reshaped to suit human needs: edible parts became larger and more colourful and a remarkable diversity of crops emerged, each with unique traits.
As Charles Darwin noted in The Origin of Species, this variation in domesticated crops demonstrates humanity’s power to guide evolution. By choosing plants with desirable features, people created crops capable of thriving in many environments, from dry deserts to cold mountains, while also matching local tastes, colours and textures.
The Common Bean as an Example of Domestication
The common bean (Phaseolus vulgaris) illustrates how domestication drives diversity. Its wild ancestor arose in Central America (modern Mexico) and spread to South America about 200,000 years ago, forming two wild gene pools: Mesoamerican and Andean.
People domesticated both gene pools independently, earlier in Mesoamerica, about 9,000–8,000 years ago. Andean beans evolved larger seeds. Mesoamerican beans adapted to diverse soils and climates.
Early domesticated beans were sensitive to day length, which controls flowering. As farmers cultivated them in warmer, lower regions, they selected plants that flowered earlier and grew under different photoperiods.
Distinct “races” emerged: Jalisco, Durango and Mesoamerica in Mexico, Peru and Chile in South America. In Europe, the bean arrived through seeds brought by the Spanish after the conquest of Peru. Emperor Charles V presented them to Pope Clement VII, who promoted their spread, helped by Piero Valeriano Bolsanio of Belluno, the Pope’s secretary from the Medici family. Later, Mesoamerican material was also introduced, further broadening diversity.
Over millennia, farmers created numerous local varieties, or landraces, each adapted to its specific soil, climate, and symbiotic Rhizobium bacteria that fix nitrogen in the soil. People selected beans for taste, cooking quality, pest resistance and even for edible pods, fresh green beans, developed independently in several regions, showing humanity’s creativity in making food more versatile and enjoyable.
What Are Plant Genetic Resources?
All these varieties together form what scientists call Plant Genetic Resources (PGR), the living library of genetic information for all crops. They include:
- Wild relatives of cultivated species
- Domesticated forms, such as
- Landraces – traditional, locally adapted varieties
- Modern varieties – bred mainly over the last two centuries
Landraces evolved through centuries of farmer selection to perform optimally in local environments, integrating human needs, soil and climate. They thrive under low-input conditions (limited fertiliser or pesticides) and maintain high internal diversity, many genotypes coexisting and co-adapting, which gives them natural resilience to pests, drought and poor soils.
In contrast, modern varieties are uniform and optimised for yield potential, but depend heavily on chemical inputs and irrigation.
Why Conserve Local Varieties?
Although modern varieties are important, traditional and wild types are the foundation of global food security. They hold the raw genetic material that breeders and farmers use to create tomorrow’s crops with many traits of interest related to adaptation to different environments, to develop positive interaction between plants of the same or different species to favour the mutualistic interaction in heterogeneous variety often use in organic farming or intercropping between different species. Finally, traditional varieties have a large diversity for many traits related to nutritional value and adaptation to harsh environments.
Losing them means losing them forever as the genetic resources cannot be replaced:
- Indeed we will loose traits that enable plants to resist drought, floods, pests, or diseases
- Options for cultivation in harsh or changing environments
- Cultural heritage taste and traditional cuisines. Humanity’s biological “insurance policy” for the future
Once a local variety and wild relative disappears, they are irreplaceable.
That is why genebanks worldwide conserve seeds and living plants to safeguard this diversity for coming generations. And for the same reason, INCREASE proposes to develop decentralised conservation to make all this diversity available to citizens, favouring their conservation.
To all INCREASE Citizen Scientists:
Your participation is vital! By growing, observing and sharing data on bean varieties, even imperfect ones, you help maintain their unique traits and ensure that this invaluable genetic diversity endures.