Biodiversity can be a difficult concept to pin down and for good reason: this one term aims to encapsulate the variety of all life on earth. By taking a look around a garden or a park, you’ll see biodiversity in action through the different plants growing or insects buzzing around. On a large scale, biodiversity plays a critical role in maintaining ecosystem health, supporting people’s livelihoods and ensuring sustainable food production. Around the globe, biodiversity loss is being reported at a dangerously large scale and species extinctions are occurring at increasingly rapid rates. Agriculture is one of the major drivers of biodiversity loss, but it also benefits immensely from robust biodiversity. Many positive benefits of biodiversity in agriculture come from crops’ lesser-known counterparts, their wild relatives. Crop wild relatives are plant species from which major crops have arisen or to which they are closely related. These plants aren’t ones you’d usually eat, but they still deserve our attention because they are the foundation of sustainable food production.
For a long time, plant breeders have recognized the potential of crop wild relatives to impart disease resistance, drought tolerance, or improved flavour to cultivated crops. In apple, the main cultivated and consumed species is Malus domestica, however, there are over 50 wild apple species distributed around the world. Multiple wild apple species have been used to breed resistance to diseases like apple scab and fire blight. Similarly, plant breeders have exploited crop wild relatives of tomato to improve disease resistance and fruit quality of cultivated tomatoes. Recently, a wild coffee species was shown to not only taste delicious but come with the added benefit of heat tolerance; a crucial trait sought after in the warm coffee growing regions. In chickpea, breeders are looking to use wild species with elevated levels of protein and minerals to boost nutrition of new chickpea cultivars. These are just a few examples of how harnessing the diversity of crop wild relatives can improve the quality of our food and allow agriculture to adapt to climate change.
Unfortunately, many crop wild relatives are at risk of disappearing due to factors such as climate change, pollution and habitat loss. For example, the center of diversity of the apple in Central Asia is reported to be threatened due to urbanization and agricultural activities that are closing in on wild apple forests. A recent study of crop wild relatives across the United States found that over half of the 600 species studied were endangered. Although maintaining the ability of crop wild relatives to thrive in their natural habitats is ideal, it isn’t always practical or possible. To ensure that crop diversity is protected, major crops along with their wild relatives can be collected and placed into gene banks or botanical gardens. Gene banks and botanical gardens play important roles in housing seeds or living specimens of plants for educational purposes, research and to serve as backups in case plants are lost within the wild. Scientists and plant breeders can make use of these valuable resources to screen diverse plants for beneficial traits that can help develop improved crop varieties. Although there are hundreds of gene banks and botanical gardens around the world, there are still many crop wild relatives that are not adequately protected.
International Biodiversity Day is held on May 22nd and this year’s theme is “We are part of the solution”. Although our collective actions are a driving force behind biodiversity loss, we are also key players in slowing it down. We can’t fully predict the challenges crop production will face in the coming years. Therefore, we need to protect biodiversity and crop wild relatives now so that when the time comes to reach to them for help, they still exist.