With climate change threatening world food supplies, Dr Nigel Maxted is on a quest to save our crops. Ben Goodwin learns more.
One of the biggest challenges facing humans over the next century will be the issue of food supply. With the world’s population expected to reach 9.6 billion by 2050 and weather patterns changing drastically, the food we eat is under threat.
‘The varieties of crops that we have traditionally used have a very narrow genetic base,’ says Dr Nigel Maxted, Senior Lecturer in Genetic Conservation in the School of Biosciences. ‘Crops today have to cope with more challenging weather patterns than ever before and the conventional material used for breeding does not contain enough genetic variation to meet changing demands.
‘If climate change becomes more evident, crops will start failing more often and there won’t be enough food to feed us all. Coupled with an increasing human population, this is a serious problem.’ Despite this gloomy prediction, Dr Maxted is leading research that aims to combat this, by publishing the first database of crop wild relatives (CWR) and their locations around the world.
Crop wild relatives are species that are closely related to crops, grow under a much broader range of conditions and are much more genetically variable. ‘The database we have collated contains the 1,392 species that are closely related to 173 crops eaten by humans. By transferring the genetic diversity from the wild species to the crop, we can utilise their adaptive traits to withstand extreme weather conditions and exposure to different pests and diseases, which helps sustain food production.’
For example, Aegilops tauschii, a crop wild relative of wheat, is resistant to the Hessian Fly, a major pest of cereal crops; Saccharum arundinaecuem, a relative of sugarcane, can survive in very low temperatures; and Prunus ferganensis, a CWR of peach, is tolerant to drought conditions.
CWR are literally found all over the world, but there are eight hotspots where the majority are located. ‘These hotspots account for around 1.5 per cent of the world’s terrestrial surface but boast a 95 per cent concentration of species closely related to crops, with the richest localities being in the Fertile Crescent of the Middle East.
‘My initial PhD was working in the Fertile Crescent, so I’ve maintained a specialisation in that region, but I’ve visited all of the eight hotspots throughout my career.’ There are also CWR hotspots in Central America, the Andes, Ethiopia, Central Asia, India and Southeast Asia. As well documenting known species in these regions, Dr Maxted has made some remarkable discoveries.
Dr Maxted recalls a trip to Turkey in 1987. ‘I was travelling along a new road cut through a mountainous area of Turkey and stopped for a cup of tea in the village of Belin. Whilst there, I noticed a plant that I had never seen before and, on closer inspection, I realised that it was a wild relative of the sweet pea not previously known to science. Because this was a new road, no botanist had driven along the road before and so it was a lucky discovery. It’s fairly uncommon to find new plant species, but it does happen. After finishing my cup of tea, I collected some seeds from the wild relative and made sure they were delivered to the national gene bank.’
Hearing Dr Maxted speak with such enthusiasm for his work clearly indicates it was a natural career choice for him. ‘I always had a love of nature and the countryside since my early childhood, so I wanted a job associated with the countryside, first working in agriculture and then gravitating to the preservation of wild species for use in agriculture.’ Since that first job, Dr Maxted has gone on to be at the helm of many national, European and international CWR and landrace agrobiodiversity conservation projects; one such project is the establishment of the so-called Harlan and de Wet CWR Inventory, in honour of the scientists who originally proposed the crop gene pool concept.
‘It took PhD student Holly Vincent about a year’s research to create the database and she is still refining its content. Five million individual data points from the last 50 years for the known locations of the 1,392 species in the wild have been included in the database so far.’
Now a comprehensive database of CWR exists, the aim is to systematically conserve their diversity and make the wealth of resilient characteristic available to plant breeders. ‘Along with gene banks, we will need to increase the amount of in situ conservation taking place in the global and national hotspots,’ says Dr Maxted.
At the University of Birmingham scientist Shelagh Kell has recently published a checklist and conservation strategy for the CWR of China and, closer to home, PhD student Hannah Fielder is working with Natural England to set up the first specific genetic reserve for CWR on the Lizard Peninsula in Cornwall. Although the UK is not a global centre for CWR diversity, the Lizard reserve has wild relatives of sugar beet, carrot, parsnip, asparagus, clover and oil seed rape.
‘Before I retire, I hope we have a secure, global network of in situ conservation for these important sites, as well as a link between the adaptive genetic diversity found within the species they contain and their sustainable use in crop breeding.
‘Some may think our work is esoteric, collecting or managing populations of plants in the remoter corners of the world, but research around crop wild relatives is essential if widespread hunger and malnutrition is to be avoided in the future.’
The database will now be handed to the US Department of Agriculture, which will continue to maintain and extended the inventory. ‘No database of these species existed before, but all future conservation planning of these species will be based on the research conducted here at Birmingham.
‘The CWR research undertaken at Birmingham is providing a significant step in safeguarding global and UK food production and will help underpin human survival for the next 100 years.’