The third of our periodic blogs which discuss food security, with a specific focus on how plant genetic research might contribute to addressing the challenge of feeding a fast-growing global population in increasingly uncertain climatic conditions.
Achieving food security is a complex problem that goes far beyond just producing more food. Its realisation will require deep transformations of food systems, and for many, it will also mean fundamentally changing our relationship with food.
(Lower, left to right) Sorghum, pigeon peas, pearl millet (Claudia Canales)
More sugar cane is produced than any other crop, yet it provides little nutrition and its over-consumption is causing serious health problems. In terms of the global food supply, around 75% of the diversity on farms has been lost, and the world is increasingly more dependent on the “big 3” cereals –maize, rice and wheat, which make up around two-thirds of the food eaten – plus a handful of high-energy crops.
Widening food sources is important if farmers are to produce enough nutritious food to satisfy the demands of the expanding global population, especially in the face of climate change. This means returning to those grains, pulses and vegetables that were once common in fields, kitchens and on plates, but lost favour as diets became globalised and more meat-dependent. This would be good for people, and also good for the environment.
But as so often it is not that simple.
Plant breeding efforts need to be continuous and sustained. This is because some of the problems that affect crop production are ever changing, especially the nature of attacks by pests and diseases – the evolutionary pressure to break-down the plant defences is very strong, and a cultivated field potentially contains a lot of food, and not just for people.. The continuous development of crops is needed just to keep them healthy and productive, and the price of neglect can be high. But unfortunately, the strong focus on a small number of crops has meant that others have been left behind.
Some have not fared too badly. Although the overall investment in their improvement is much smaller than that devoted to the “big 3”, chickpea, finger millet, groundnut, pearl millet, pigeon pea, small millets and sorghum have an international research organisation dedicated to them, the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT). The semi-arid tropics in Africa and Asia are home to more than 2 billion people, a third of whom live below the poverty line. Millets and sorghum have high levels of iron, zinc and calcium, and legumes (chickpea, groundnut and pigeon pea) provide affordable sources of protein.
In addition, legumes fix nitrogen from the air in the soil, so their cultivation improves soil fertility. These crops are also better suited to hot temperatures and little water, and cope better in poor soils. ICRISAT has released a large number of improved varieties. And, excitingly, they have also succeeded in developing hybrid varieties of pigeonpea, the first time for a legume, which are achieving record yields.
Others, sometimes described as “orphan”, “underutilised” or “minor” crops, have been neglected. Now, however, some are attracting more attention. In an effort to improve nutrition across the continent, for example, the African Orphan Crop Consortium is working to sequence 101 African crops and train African scientists in advanced crop breeding strategies.
The availability of whole genome sequences for locally important crops will be an important resource to support plant-breeding efforts. It is, however, not a replacement for the careful study of the biology, including improving the understanding of how they reproduce, and their physiology, especially of those that are not yet fully domesticated. Just as important is to determine, catalogue and safeguard these crops’ genetic diversity, the essential ingredient for plant improvement. These steps do not require the sequencing of entire genomes, but do need considerable time and resources.
Dr Claudia Canales Holzeis is a plant molecular biologist with a near-decade of experience in plant genetics research. She previously worked as Senior Project Officer for the International Service for the Acquisition of Agri-Biotech Applications (ISAAA), based in the Philippines. A graduate of the University of Reading in Environmental Biology, Dr.Canales gained a DPhil. in Plant Genetics at Oxford.