Indispensable resources

There can be no doubt that the Green Revolution has saved millions – possibly billions – of lives, most particularly in Asia. Increases in yields enabled countries such as India to transform its agricultural economy from one in which famines, albeit localised, were relatively common to one in which the country became a net exporter of food.

The primary enabling technology of the Green Revo­lution was genetic resources. Transfer of dwarfing genes into rice and wheat resulted in a shorter straw that allowed the plant to divert more nutrients into grain. At the same time, the shorter, stiffer straw was better able to support a heavier ear of grain. With dwarf and semi-dwarf varieties, breeders were then able to pursue higher yields and better agronomic performance in other realms too.

Many other improvements then came about through further use of genetic resources. Canonical examples, such as the discovery of resistance to brown planthopper in a single accession of a weedy rice, serve to mask the huge contribution of other genes from other sources, all of which contributed to steady increases in yield.

Genetic diversity, however, while necessary, was not sufficient for the flourishing of the Green Revolution. There were crucial external factors. One was the availability of water and land suitable for irrigation. Asia has large areas of flat, fertile land with good access to water. Other crucial inputs were fertilisers and plant protection chemicals. While the Green Revolution did depend on biodiversity, it would not have succeeded without those other inputs.

Talk now is of a Green Revolution for Africa, but it is worth remembering why the first Green Revolution was not as great a success in Africa. Perhaps the fundamental reason is that the agricultural systems of Africa are not as uniform as those of Asia. In much of sub-Saharan Africa, water is a limiting resource. The topography is also very diverse. Slope and soil types, for instance, change over reasonably short distances. Moreover, many African soils are relatively depleted.

Thus, no Green Revolution for Africa will follow the exact example of the Asian one. Breeding improved varieties and, indeed, livestock, to achieve higher productivity will be important – and that task will depend on access to and use of the genetic resources inherent in agricultural biodiversity. However, biodiversity matters in other respects as well. Not least, it will be essential for humankind to cope with climate change (see page 192).

The curse of malnutrition

Perhaps the biggest problem associated with the success of the Green Revolution is, paradoxically, malnutrition. Thanks to additional calories from high yielding varieties, humankind has come to the point where “only” about 850 million people are chronically hungry. Some 2 billion, however, suffer malnutrition. Diseases such as iron-deficiency anaemia and vitamin-A deficiency exert a terrible toll of mortality and morbidity, particularly among women and young children. It has been estimated that almost 60 % of the roughly 10 million deaths annually among children under five years old in developing countries are the result of hidden hunger of this kind, rather than classic protein-calorie deficiencies.

At the same time, so-called diseases of affluence, such as type-2 diabetes, heart disease, cancers and obesity, are increasing rapidly among poor people. Indeed, the WHO has recently identified a particularly worrying trend that it labels the double-burden household. These are households in which some family members are overweight, with the attendant health problems of obesity, while other members of the household are underweight and malnourished. According to the International Journal of Obesity in countries as diverse as Brazil, China, Indonesia and Vietnam between 22 % and 66 % of households can be considered double-burden households. The double burden of obesity and hidden hunger is to a large extent the result of a simplification of the diet. Since the Green Revolution refined carbohydrates and fats have replaced pulses and other more nutritious sources of energy and protein, especially in urban areas. For several reasons, science and the general public have neglected a wide range of crops and varieties.

Research by Bioversity International and others has shown that such “traditional” crops can play a vital role in improving nutrition as well as livelihood options for poor farmers. In India, for example, a project with the M.S. Swaminathan Research Foundation has demonstrated the nutritional value of small grains such as local species of millet. These have been transformed into nutritious snacks for urban dwellers, creating demand for millet that has enriched the lives and the agricultural biodiversity of poor farmers in nearby marginal areas. At the same time, the nutritional status of the farming families improved thanks to the millet they were eating.

A similar project on traditional leafy vegetables in East Africa had similar benefits. In Kenya alone, some 200 different species of plants are consumed as leafy vegetables accompanying starchy staples. They deliver considerably more nutrients than “exotic” imports to the region such as cabbage. Amaranth leaves, for example, contain more than 10 times the iron of cabbage. Cleome gynandra (cat’s whiskers) contains 1000 times more beta carotene than cabbage, and similar differences have been found for other nutrients and other species.

Traditional leafy vegetables, however, are often considered “backward” and associated with poverty. They tend to be sold in poor and unhygienic circumstances. Many urban dwellers have lost the knowledge needed to make full use of such food.

A concerted effort, in concert with NGOs such as Family Concern and a local supermarket chain, trained farmers to grow high-quality greens and to package them to meet the high standards of the supermarket. At the same time, promotional campaigns extolled the nutritional benefits of traditional leafy vegetables, including colourful and attractive recipe cards in the supermarket. The impact has been considerable, with a 1100 % increase in sales of traditional vegetables over two years (admittedly from a very low base). Supply currently does not fully meet demand. The farmers involved in the project report an increase in their incomes, and in Nairobi families say that they are eating traditional leafy vegetables more often and that they have experienced less illness.

While there is definitely a role for both supplementation and biofortification in the treatment of hidden hunger and malnutrition, food-based solutions that increase dietary diversity through the use of agricultural biodiversity offer considerable additional benefits. They make fewer demands on infrastructure and are inherently more sustainable. In addition, they offer opportunities for income generation and for the maintenance of cultural practices associated with particular foods.

Food security

Another important use for agricultural biodiversity is to deliver greater food security through resilience and stability. Intensive production basically depends on genetically homogeneous varieties that need external inputs if harvests are to be guaranteed. Irrigation substitutes for erratic rainfall. Pesticides protect vulnerable plants. Without those inputs, yields are low and can fluctuate wildly. Different genotypes within the population respond best to different conditions, thus ensuring a relatively stable yield from year to year despite changing conditions. The ability to withstand pests and diseases likewise favours the production of yields that are possibly lower than might be obtained with advanced varieties and appropriate inputs, but that are considerably more dependable and stable than those same varieties without their required inputs. Long-term adaptability of landraces, based on genetic diversity and natural and artificial selection, also favours their use by poor farmers in marginal areas.

Judicious use of agricultural biodiversity offers opportunities to limit risks and to intensify production at the same time. Such diversity can be deployed at all levels, from landscape to gene. Farmers whose lands encompass different growing conditions will use a range of species that take advantage of the different conditions available. Sorghum farmers in Africa, for example, will use different varieties for bottom lands, where water is more reliable, and for the upper slopes, where thriftiness under drought conditions is essential. They also maintain fast-maturing varieties that are brought into play when rains are late.

Resource-poor farmers base their strategies on minimising risk rather than maximising production. Agricultural biodiversity is an essential element of such strategies. Moreover, this is one of the few assets that such people have access to and can control. In its ability to buffer yields from season to season and to deliver improved nutrition, and to do so when few other options are available, agricultural biodiversity is perhaps at its most useful in precisely the kinds of marginal and fragile environments that are occupied by the poorest farmers.

Intensification without simplification

This is not an argument for no change. It is a recognition of the need for the strategic use of agricultural biodiversity to improve productivity without oversimplifying systems, and to make use of the special additional benefits that agricultural biodiversity, used in this way, can bring, especially in fragile environments.

There is no doubt that before world population stabilises there will need to be considerable increases in food production, and that this need is greatest in Africa. A Green Revolution is needed, but in many respects this will need to be a different kind of Revolution from the one that was successful outside Africa. It will depend on genetic diversity as a source of useful traits, to be sure, but it will have to make far greater use of agricultural biodiversity than that. Agricultural biodiversity will be essential to deliver improved nutrition, productive and environmental sustainability, resilience and stability – all vital components of food security – and for enhanced livelihoods.

One obstacle to date is that other inherently simpler approaches to the use of genetic resources, and to the treatment of malnutrition, have tended to receive the lion's share of investment. This is not unexpected; the appeal of straightforward approaches is understandable, and in some areas the impact has been considerable. Africa, however, will be different. It is also the case that agricultural improvement and malnutrition are among the most effective areas in which to invest for economic and general development.

Agricultural biodiversity is crucial for sustainably improving the productivity of agriculture in Africa and in delivering better health through better nutrition, particularly in the fragile environments where the greatest poverty prevails. Any attempt to foment a new Green Revolution for Africa will fail unless it recognises the value of agricultural biodiversity as more than a source of traits. However, a sustained and well-resourced effort to make use of agricultural biodiversity could help to reduce poverty and malnutrition in Africa and elsewhere.