An Historical Perspective From the Green Revolution to the Gene Revolution

June 2003: (II)S124S134

An Historical Perspective from the Green Revolution to theGene RevolutionW Paul Davies, M.Sc, Ph.D.

Since the 1960s conventional crop breeding hasincreased food production commesurate with thegrowing population. For agricultural developmentto continue, the exploitation of greater geneticdiversity and modern biotechnology are becom-ing increasingly important. This article reviewsthe milestones achieved by the Green Revolutionand many of the recent breakthroughs of modernbiotechnoiogy.

Key words: crop improvement, genetios, foodsupply© 2003 International Life Sciences Institute

doi: 10.131 /nr.2003.jun.S124-S134

Advances in agriculture and food production have beensupported by many factors during the last 50 years or so,of which the application of modem science and technol-ogy to crop improvement has probably been the mostimportant.^ A great deal has been achieved. Between1960 and 1990, cereal yields, total cereal production, andtotal food production in developing countries doubledand, as a result, have kept pace overall with populationgrowth. Daily calorie supply improved by more than25%, much of which was provided by cereals.

The overlap, and increasing integration, of differentscientific approaches to crop improvement is recog-nized.^ Although conventional breeding will continue tomake a major contribution,^ the exploitation of greatergenetic diversity and modern biotechnology are becom-ing increasingly important to agricultural development.All of this requires continuing and substantial investmentin agricultural research to deliver future food needs.

This account reviews some key milestones in cropimprovement from the 1960s, from the outset of thehistoric "Green Revolution," to more recent break-throughs in agricultural biotechnology. Significantachievements are placed in the context of food supply,and future challenges and concerns are highlighted.

Professor Davies is with the Royal AgriculturalCollege, Cirencester, Gloucestershire, United King-dom, GL7 6JS.

The Green Revolution

William Gaud (of USAID) is said to have coined theterm "Green Revolution"^ to describe the breakthroughin food production in Asia resulting from the introduc-tion of new wheat and rice varieties developed by theInternational Maize and Wheat Improvement Centre(CIMMYT) in Mexico, and the International Rice Re-search Institute (IRRI) in the Philippines.

Although several traits are associated with the sig-nificant increases in yield potential of green revolutionvarieties of wheat and rice, the most important factor wasplant height reduction achieved through the incorpora-tion of specific genes (rht and dwg) for short stature."^Improved partitioning of the products of photosynthesisto grain yield gave a higher harvest index (of grain tostraw) in these new semi-dwarf varieties.^ The newvarieties had 50% grain by contrast to approximately30% of earher cultivars, and because of their smallerstature were more responsive to nitrogen fertilizer with-out lodging. Yield potential doubled as a result of thismost significant architectural change to the morphologyof these high-yielding varieties (HYVs).

Several other traits were also improved. In rice, theincorporation of genes for photoperiod insensitivity al-lowed planting at any time of the year, regardless of daylength. Together with the reductions in growth duration,this allowed cropping intensity to be increased to two orthree crops a year. Traditional rice varieties took 150 to180 days to mature and the new varieties initially took130 days (IR8) and some later-developed types (e.g., IR72) took 100 days.

New varieties of wheat were also selected for wideradaptability to growing conditions and insensitivity, inparticular, to changes in day length and date of planting.*^Photo-insensitive wheat genotypes were selected uncon-sciously initially in the "shuttle" breeding programadopted by CIMMYT, but this trait has since beenincorporated more specifically in new varieties.^

Yield stability was also subsequently improvedthrough the incorporation of genes for greater pest anddisease resistance, in particular, to races of stem, leaf,and stripe rust in wheat, and to blast, bacterial blight.

SI 24 Nutrition Reviews^, Voi. 61, No. 6

tiiDgro virus, grassy stunt vims, and green and brownplant hoppers in rice.

Greater adaptability and yield stability in poorergrowing conditions has also been provided by breedingsuccesses for some abiotic stresses, such as salinity,alkalinity, and iron and boron toxicities in rice soils.Particular success was achieved with the breeding oftolerant wheat varieties for acid soil conditions with highaluminum content in a joint breeding program betweenCMMYT and the Brazilian national research organiza-tion (EMBRAPA). These tolerant wheat varieties arenow grown extensively in the aluminum-toxic cerradosoils of Brazil. New varieties of rice with greater toler-ance of low temperature and salinity were released in1995 by IRRL''

The higher yield responses of the HYVs can prob-ably be best described as a "revolution," a sudden anddramatic change, in areas of Pakistan or Saudi Arabia,where irrigation provision strongly supported the intro-duction of the higher-yielding Mexican wheat varieties.*

Although extremely important, the issues of cropyield potential, yield stability, and crop adaptabilityalone are insuflicient from a consumer perspective. Par-ticular attention is also being given to grain qualityimproveiiieiit, SeiectioB for cooking qualities and taste inrice, and milling and baking properties in wheat, featurestrongly in more recent new variety selection.

Fischer and Cordova^ describe different phases ofgreen revoiution rice technology development as fol-lows:

Phase t Tn& Gmen Revolution—ImprovedSeed and ̂ Increased input UseMilestonese IRS aad the beginning of high-yielding varietiese Investment in irrigation® Policies to support inputs of nutrients and pesticides9 Seed multiplicatioo infrastructures and seed distribu-

tion by extension systemse Training of rice scientists• Rice genetic resources collected and conserved

Phase II: The Green Rewolution—IncreasingInput Use IntensityMilestonese Shorter duration, photoperiod-insensitive rice culti-

varsB Protecting yield gains from pestse Increased mechanization for land preparation and

threshing» Introduction of the farming systems methodologj'«> International sharing and testing of rice germplasm

The Green Revolution era took off in the late 1960swith the dissemination and wider adoption of new HYVsin Phase 17 Earlier maturing varieties encouraged double

and/or triple crop rice systems to be developed in PhaseII, leading to much greater intensification. This opportu-nity was particularly exploited in parts of Asia, with yearround water supply capable of supporting the muchhigher production, on an estimated 15 million hectares ofirrigated land.*

Evenson' refers specifically to the "Green Revolu-tion" era of 1962-1982. Fischer and Cordova' talk of apost-Green Revolution after 1992, witfci the further de-velopment of new types of rice plant. Others believe it iscontinuing, in many ways, and overlaps with the mostrecent phases of crop improvement."^

Impacts of the Green Revolution

Gradual replacement of traditional varieties of rice andwheat, by new "Green Revolution" types and supportinginputs, had a dramatic effect on cereal production.

World wheat production increased from 308 milliontons in 1966 to 541 tnillion tons in 1990, whereas totalrice production doubled over the same period from 257million tons to 520 million tons. Although the rice areaharvested has only increased marginally (by 17%) since1966, the average rice yield has increased substantially(by 71%). The impact of Green Revolution variety adop-tion has been particularly dramatic^ in some countries(Table 1).

The increase in per capita aviiilability of rice andwheat, and the decline in the costs of production per tonof output, contributed to a decline in the price, which wasof particular benefit to the urban poor and rural landlesspeople. Many argued that the small farmers, who are netconsumers of grain, also benefited considerably from thedecline in real grain price.'̂

The actual benefits, or otherwise, of Green Revolu-tion technologies to poverty alleviation and the wellbeing of the poor, have been much debated. Early adopt-ers of the new HYVs, and initial beneficiaries, weremainly the larger land-owning famaers. The same tech-nologies soon reached small farmers, however, and re-cent studies have revealed a more scale-neutral diffu-sion.' One of the biggest benefits has remained, however.

Table 1. Improvements in Rice Productivity inParts of Asia between 1966 and 1996

Area of Higher-Yielding Increase inVarieties Adoption (%) Production (%)

9316327618061209

Adapted from reference 4.

ChinaIndiaIndonesiaPakistanThailandVietnam

1007577411380

Nutrition Reviews'^, VoL 61, No. 6 S125

and that is the greater availability of more abundant grainas a result of the decline in real costs to the poor.Osmani^° concludes that "the Green Revolution has beena friend of the poor" as a result of enhanced entitlement.

The higher crop productivities generated additionalemployment, not only employment opportunities infarming and associated agricultural activities, but also intrade, transport, and construction. The higher farm in-comes stimulated economies more generally. Khush'* hasattributed the later economic development miracle inAsia to this period of substantial agricultural growth andto the higher, and more equitable, income distribution.

Higher cereal yields per unit area, from the wide-spread adoption of the HYVs on the most productiveland, have reduced potential pressures considerably forfarming in more fragile and marginal areas. At 1961yield levels, experts estimate that triple the land in Chinaand double the land in India would have been needed toequal grain production levels in 1992 in these countries.

A reduction in the number and diversity of moretraditional varieties and the intensification of productionsystems growing HYVs, significantly increased pest anddisease problems, requiring more frequent prophylactictreatments of insecticides and fungicides to protect cropsof the early cultivars. As a result, some accuse the GreenRevolution of ushering in an era of "chemical farming"to parts of the developing world. More recently, how-ever, the higher levels of multiple resistance bred intonewer varieties has reduced the need for frequent pesti-cide applications, which has since stimulated integratedpest management strategies.

One might argue, therefore, that the Green Revolu-tion has helped to conserve environmentally sensitiveregions by focusing intensive agriculture on the moreproductive land.'

Exploiting Hybrids

Hybrids, the first generation progeny of genetically dis-tinct and different parents, exhibit increased vigor andyield through heterosis. Hybrids are most commonlyexploited among outcrossing commercial crops.

In the United States, the relatively static yields ofmaize between about 1860 and 1930 were improveddramatically with the development of double-cross hy-brids. The yields of maize were further boosted (by 15%on average) in the 1960s with the adoption of newsingle-cross hybrids.''̂ Similar benefits have been derivedin sorghum hybrids.

Hybrid rice, grown in China since 1976, can have ayield advantage of 15 to 20% over conventionally bredHYVs. Tropical rice hybrids, based on indica linecrosses, have shown significant yield increases of over20% compared with conventional HYVs. The first re-lease of new rice hybrids from IRRI for the tropics was

in 1994. The degree of heterosis is currently beingenhanced in IRRI programs by using indica X tropicaljaponica rice hybrids.

Elite hybrids developed by cytoplasmic sterility andfertility restoration systems have been released for com-mercial use in India, Vietnam, and the Philippines. Thisinitiative has focused on high-potential irrigated ricesystems with a high labor-to-land ratio, and requires awell established supporting seed industry. The seed isrelatively expensive, and not commonly available (with-out appropriate support) to resource poor farmers.

Gene pools of rice and wheat are being widenedthrough the hybridization of crop cultivars with wildspecies and crosses between diverse germplasm groups.Many improved traits can be exploited from these widergene pools. Rajaram and Braun^ reported improved ge-netic resistance to a number of major diseases, togetherwith both yield and grain quality advances, from breadand durum wheat crosses with Triticum tauschii andTriticum dicoccoides.

Modern Biotechnology

Few issues have excited so many hopes and fears inrecent years as new developments in biotechnology. Inparticular, concerns about the applications of modernbiotechnology to agriculture and food production and itspotential environmental impact. The continuing debate,for or against these new technologies, is often heated andhighly polarized." Release of new genetically modifiedorganisms (GMOs), or so-called "genetically improved"products,'^ into the environment and their use in foodproduction has generated a range of public concerns andintense media interest." It has provoked, on occasion, anextreme reaction from advocacy groups. Curiously, per-haps, the longer established use of new biotechnologiesin industry, and pharmaceutical production in particular,has not attracted the same concerns as exploitation in theagri-food sector.'^ Several reasons have been put for-ward to explain such differences in perception of theU.K. public to GM food and environmental issues.'^

Most biotechnology-based businesses have devel-oped in North America, Japan, and Europe, and mostGM products on the market currently are for sale inindustrialized countries. Much of these modem biotech-nology developments have been pioneered by privatecompanies, and to recover large research investment thesales have understandably focused on developed mar-kets.'* Wealthier farmers with appropriate purchasingpower and commercial seed buying habits in temperatecountries particularly have mainly been targeted."

Arguably, the needs of the United States and Europeare very different from those of poorer developing coun-tries,^* and current biotechnology concems may belargely irrelevant to poor peoples' problems. ̂ ^ Some say

S126 Nutrition Reviews®, Vol. 61, No. 6

that much more emphasis should be given to life anddeath coacems of the world's hungry than to the well-fedregarding the GM question.^" The question then becomesmore an issue of social justice, of "to each according toneed."

As stated, the Green Revolution greatly reducedhunger in many developing countries in the 1960s and1970s and benefited the poor substantially through lowerfood prices and increased rural employment.' These cropvarieties were developed in public research institutions,however, and the new seeds are given away to farmers orsold at subsidized prices by government corporations.'^As a result, new varieties were rapidly and widelyadopted. Comparisons are sometimes made between theGreen Revolution and GM crop potential,^' but there aresignificant differences.

Do we,know what the so-called gene revolution cando for the developing world? Will transgenic crops helpto feed the ^Third World as promised by some develop-ers? Or is this argument perhaps, as some claim, "emo-tional blackmail" to justify GM development? It mighteven be argoed that many poor tropical countries, withhigh depensicBcy on agriculture and food production,have a much greater need for GM products than devel-oped countries who currently dominate adoption. Thepotential contributions of transgenic crops to povertyreduction and food security are not yet well under-stood.^'

Biotechnology is by nature complex, consisting ofmany differeot technologies. As a result it can be definedin a number of ways, which must be distinguished andclearly understood. Jones^^ describes it simply as "theapplication of biological knowledge for a useful end."

Regarded in this way, biotechnology has clearlydeveloped over time and continues to evolve as newprocesses are discovered. Early biotechnology, whichexploited whole organisms, could include agriculturaldevelopments based on plant and animal breeding andselection, and processes such as bread making and fer-meotatiori for making wine. Biotechnology later devel-oped at the, cellular level, allowing techniques such astissue culture and artificial insemination. More recently

biotechnology has focused on the miolecular level, allow-ing the characterization and isolation of individual genes,including possible gene movement on occasion, acrossspecies barriers.

Modem biotechnology embraces both cellular andmolecular dimensions. According to Persley and Pea-cock^^ it includes recombinant DMA (deoxyribonucleicacid) technology, monoclonal antibody production, andcell-tissue culture. These technologies support geneticengineering, which can facilitate tlie tramsfer of geneticmaterial and its subsequent expression in a recipient cellto produce genetically modified transgenic organisms.

Jones^ '̂ envisages a continuum of technologieswithin modem biotechnology, existitng as a gradient from"lower-tech" processes from biologic nitrogen fixation totissue culture, to the "higher-tech" recombinant DNAtechniques for diagnostics and genetic engineering. Hesees it as a scale that will embrace new techniques asthey are discovered. This type of concept is helpful inconsidering modern biotechnology adoption in develop-ing countries, which often differ in their acceptance oflow-tech and high-tech advances.

These terms must be specified as miuch as possible.Reference to biotechnology and GM products generi-cally in the literature and elsewhere is sometimes con-fusing, and often misleading. It is important to specifythe technologies being exploited and resultant products.Appropriate choice of words and the significance ofcorrect vocabulary in GM exchanges is also stressed byMalcolm."

Transgenic Crop Adoption

Of the 44.2 million hectares of transgenic crops beinggrown globally in 2000 (60 million hectares now re-ported in 2002), the International Service for the Acqui-sition of Agri-biotech Applications (ISAAA) estimatesthat 10.7 million hectares of GM crops are being pro-duced in the developing world.^ This represents approx-imately 25% of the current GM area, most of which is inArgentina. Smaller areas are grown in China, Mexico,South Africa, and Uruguay (Table 2). These figures are

Table 2. Transgenic Crop Production in Developing Countries

Country

ArgentinaChinaMexicoSouth AfricaUruguayTOTAL

Area(m/ha)

4.3<0.1<0.1<0.1—4.5

1998

Of Global (GM)Production (%)

15<1<1<1—16

Area(m/ha)

6.70.30.1

<0.1—7.1

1999

Of Global (GM)Production (%)

17<1<1<1—18

Area(m/ha)

10.00.5

<0.10.2

<0.110.7

2001

Of Global (GM)]t*roduction (%)

231

<1<1<124

Adapted from reference 24.

Nutrition Reviews*, Vol. 61, No. 6 S127

Table 3. Transgenic Crop Adoption (millions of hectares) Globally and Uptake in Developing GountriesGlobal Area Number of Countries Developing Developing Countries

Year (m/ha) Growing Transgenic Crops World (m/ha) Growing Transgenic Crops

1996*1997*1998199920002001

1.711.027.839.944.252.6

679

121213

01.54.57.1

10.713.25

24456

•Excludes the area in China. Adapted from 24.

rounded off to the nearest 100,000 hectares^"^ and do notinclude certain other countries where more limited acre-ages of transgenic crops have recently been grown, suchas Brazil and Paraguay.

There has been a very rapid uptake of transgeniccropping (Table 3). Between 1999 and 2000 the areacommitted to transgenic crops increased by approxi-mately 7% in developing countries (Table 3), which is asubstantially higher rate of increase than in industrialcountries in which the rate of adoption may be beginningto plateau.̂ "^

Traits being exploited commercially currently relatemainly to crop protection and product senescence (Table4). Many other new characters and combinations of traitsare, however, also being field tested.^^

Although the private sector accounts for approxi-mately 80% of the GM research and development invest-ment globally, much of these activities in developingcountries are being funded by national governments andbilateral and multilateral development agencies. ̂ ^ Thetotal amount of research and development in the ThirdWorld, however, is understandably much less than inindustrialized countries.

Potential Benefits

Although it is still early for commercial exploitation,several novel genes have been incorporated into plantsthat can specifically improve crop tolerance to stressessuch as drought, heavy metals, and various pest anddisease challenges. Plants of much greater nutritionalvalue, of medicinal potential, and longer post-harveststorage life have also been produced. These transforma-

Table 4. GM Traits Currently Being ExploitedCommercially in Developing Countries*

Crops Transgenic Trait

Soybean, oilseed rape, cotton,and maize

Cotton and maizeTomato

Herbicide resistance

Insect resistanceDelayed fruit ripening

*Argentina, China, Brazil, Mexico and Uruguay.Adapted from references 24 and 25.

tions (Table 5) and others could make an enormousdifference to the health, welfare, and hvelihood of mil-lions of people in developing countries.^"

One of the most exciting recent developments is anew transgenic rice to combat vitamin A deficiency."Golden rice" contains three novel transgenes that en-hance the presence of j8-carotene, which is convertedupon consumption into vitamin A. More than a millionchildren weakened by vitamin A deficiency die everyyear in poor countries, and at least 300,000 more goblind.^^ Very many more also probably suffer, althoughless severely, from inadequate vitamin A.''̂

A large number of patents cover techniques used todevelop "golden rice," which may delay further devel-opment and exploitation. Some of these patents havebeen licensed recently for no charge by Monsanto toencourage more rapid research development. Other pat-ents, however, still prevail. With rice being the staplefood crop of more than half the global population andmuch of the developing world, it is clearly of majorimportance. If this new rice could be distributed free toresource-poor farmers, it might have an enormous im-pact.

Similar benefits could derive from transgenic ricewith enhanced iron levels if the iron is found to bebioavailable. Cereal grain diets are mostly deficient iniron, which results in more than 400 milhon women whochronically suffer from anemia. In Asia and Africa, morethan 20% of maternal deaths after childbirth are attrib-uted to anemia.^'' Very many more are thought to sufferin various ways from iron deficiency.^^

Successful adoption will clearly be infiuenced by theavailable amounts of desired vitamins and minerals intransformed rice, in relation to required consumption.Other sources, such as improved sweet potato or fruit,might be preferred in some regions. Tripp^^ also cautionsagainst "golden rice" being regarded as a "low-statuspoor man's crop," which might discourage future con-sumption.

Leung^^ has highhghted several key targets for thetransformation of rice, which is being studied at theInternational Rice Research Institute, and recently em-phasized the value of functional genomics for future

S128 Nutrition Reviews*, Vol. 61, No. 6

Table 5. GM iechnoiogy Initiatives that Could Benefit Developing Countries

Improvement Objective Transformation Goals and Transgenic Examples

Higher yields

Better crop quality and food nutrition

Abiotic stress tolerance

Greater pest resistance

Better disease resistance and tolerance

Lower eovironmental impact of production systems(various approaches)

Phamiaceaticals and vaccines from transgenic crops

Delayed ripening and less post-harvest losses

From greater exploitation of dwarf genesIncreased production of j8-carotene and higher iron in

transgenic riceMore nutritious oils, starches and amino acidsBetter digestibility for animals"Salinity tolerance in transgenic maizeHigher tolerance of aluminum in acid soilsGreater tolerance of manganeseBetter di'ought toleranceUse of insect resistance genes, such as the Bacillus

thuringiensis (Bt) geneRice yellow mottle virusPapaya ringspot vimsCassava mosaic virusMaize streak vimsHigher genetic resistance reducing pesticide needImproved root growth from disease resistance to give better

water and fertilizer exploitationCheaper production and easier access to various beneficial

edible medicines (e.g., in bananas and cereal grains)Genes for delaying senescence in fruit and vegetables (e.g.,

in chili pepper and melon)

*Adapted from references 26, 27, 28, and 29.

improvenient programs. Objectives include much greatertolerance of salinity, drought, and submergence. Specifictargets for higher disease resistance include bacterialblight, lice blast, sheath bhght, and tungro virus. Betterphotosyiithetic efficiency and improved grain qualities,particularly starch deposition, were also stressed. ForCentral and South America, new GM rice lines withgreater resistance to the Hoja Blanca vims seem to haveconsiderable potential.

The practical benefits of "lower-tech" biotechnolo-gy.̂ * with significant potential impact on rural income,has been emphasized in Kenya by tissue culture pro-grams for b-anaoa improvement.̂ "*

To v'hat extent and how quickly new industrialcrops and potentially more nutritious GM crops can beexploited in aeveioping cooctries still remains to be seen.Ma^^ recenrly described new GM crops for the produc-tion of "accine proteirs such as immunoglobulins. Thecreation of soybeans with high sucrose content, im-proved amino acid composition, aod oleic acid has beenoutlined by Ma/ur,"''' together with efforts to produceimproved GM maize gi'ain with more available phos-phorus.

Current work in sub-Saharan Africa on genes gov-erning the ''anthesis to silking" phase of maize growth,which IS particularly sensitive to drought, could be ofcoiisiderable benefits for future crop production in drierconditions.

Growing GM Requirements

Modem biotechnology could continue to offer substan-tial potential benefits to the poor and developing world.Considerable progress with the sequencing of genes ofmajor food plants, and the creation of genomic databasesfor staple crops such as dee, wheat, and maize shouldrevolutionize agricultural development. Scientists hopethat GM technologies can become increasingly availableto developing countries where the need is arguably great-est. Constraints on intellectual property and differencesin convetitions relating to patent rights need to be clari-fied and resolved,^ '̂ to allow farmers in the developingworld to save GM seed for future use.

Publicly funded research for ithe Third World de-serves greater support and there is an increasing need foreffective cooperation between industriailized and devel-oping countries. Active public-private partnerships needto be encouraged. Tripp^' argues that private industrycould contribute more to poverty reduction.

Encouragement of local gene banks and the localprivate sector for crop biotechnology has also beenproposed, as has increasing investment in developingexpertise through education.

Greater consideration clearly must be given, on acase-by-case basis, to bio-safety and environmental im-pact issues for appropriate GM crop adoption. Thesetransgenic crops also require, in due course, to be suc-

Nutrition Reviews*, Vol. 61, No. 6 S129

cessfully grown in appropriately adapted farming sys-tems. All of which will demand supporting farmer train-ing and effective extension.

Food Supply

Poor people in developing countries face several criticalchallenges, the most demanding of which include alle-viation of poverty, better food security, improved nutri-tion, and opportunities for exploiting new technologiesfor more environmentally sustainable development.^'

Presently, more than 1 in 4 people worldwide live inextreme poverty.^''^^ Quoting World Bank figures for1999, Pinstrup-Andersen and Cohen*^ stated that about1.2 bilhon people live in a state of absolute povertyequivalent to $1 (USD) a day or less. Most of thispoverty is rural and, despite considerable urban drift, willprobably remain so for some time.^' Estimates predictthat more than 70% of food-insecure people reside inrural areas.'^ Many of these poor people are caught inwhat Dasgupta^^ calls the "poverty trap," and mostobtain their livelihoods directly or indirectly from agri-culture.

Many fanners in developing countries are small inscale, resource-poor, and often focused on subsistenceproduction. These farmers face a multitude of problems,some of which are familiar to fanners throughout theworld, and some of which are more severe. Growingconditions may be more extreme from stresses such asdrought, water logging, salinity, acidity, low fertility, orpoorly structured and degraded soils, not to mention pest,disease, and weed pressures in crops, and post-harvestdeterioration. Lack of access to credit, poorly function-ing markets, poor infrastructure, expensive inputs, lackof technical assistance, and limited government supportare amongst the many challenges experienced daily inthe Third World.^'

Approximately 820 million people are currently re-ported to be food insecure. About 15 to 20% of theworld's population lacks access to sufficient food to leada healthy and productive life, and 160 million preschoolchildren suffer from malnutrition and are underweight,which results in the death of more than 5 million childrenunder the age of five each year.^^ About 20% of theworld's poor population suffer from food insecurity.^^ Inthe mid-1990s roughly 60% of the undernourished werein Asia and approximately 25% lived in sub-SaharanAfrica.^'

Many people in the developing world also sufferfrom vitamin and micronutrient deficiencies. Up to 2billion people and more than half of pregnant women inpoor countries are said to suffer from anemia owing toiron deficiency, and up to 1.6 billion may have a vitaminA and iodine deficiency problem.^' Of the vitamin A-

deficient population, approximately 125 million are es-timated to be preschool children.^^

These problems of food security and malnutritioncontinue in the developing world in spite reportedlysufficient food supply to feed everyone.* A continuing"paradox of plenty" and a very mixed global food situ-ation creates a mismatch of supply and demand despitedecHning global food prices in recent years.^'''*°'*'

Based on the UN median estimate, the population ispredicted to grow from the current 6 billion to approxi-mately 8 billion people by 2020.^^ An increase of about80 million people, and mouths, to feed per year. Nearlyall of this population growth will take place in thedeveloping world, mainly in Asia and Africa. The pop-ulation of sub-Saharan Africa alone will probably morethan double.^' Until 2025, the bulk of the world's fooddemand will come from the engine of demographicgrowth.^^ It win be further increased by continuinggrowth in annual income and changing diets, in particu-lar, the increasing demand for meat products.'*"

Tim Dyson^^ is optimistic that a world of 8 billioninhabitants can be fed in 2025 if a global cereal harvestof 3 billion tons can be obtained. Such a situation willrequire both substantial yield increases and further ex-pansion of the cultivated area.

Without significant policy changes and substantialincreases in international trade, there could be a continu-ing "feast and famine" scenario. Sub-Saharan Africa,South Asia, the Far East, and possibly the Middle Eastcould be particularly challenged for future food supply.^^Estimates predict that although overall food supply mayimprove, approximately 135 million children may still beseriously malnourished globally in 2020."*° Althoughmost of us in the United States, Western Europe, andelsewhere will continue to enjoy an affluent life style,large numbers of people globally will remain hungry,and women, children, and the elderly in developingcountries will be particularly vulnerable in the years

The task of doubhng the world's food productionduring the next 30 or 40 years^' will put enormousadditional pressures on the global agricultural system.Economists and demographic modelers may be per-suaded, on the basis of past trends, that the overall globalfood needs can be met*''*""'*' but ecologists can be moreskeptical.^^ Ecologic constraints, such as increasing wa-ter scarcity and land degradation, are not taken suffi-ciently seriously in many forecasts, according to Das-

Inevitably as population pressures increase, particu-larly urban populations, good arable land will continue tobe lost to urban development, industrial activity, and newroads. Most of this lost land cannot be replaced. Somenew lands could be made available for cultivation in

S130 Nutrition Reviews'", Voi. 61, No. 6

South America and Africa, perhaps, but much of it maybe fragile, easily degraded, and of low fertility.^^ It raisesthe question "to what extent can biotechnology develop-ments help provide solutions for more marginal andstressed farming eavironments?" Another critical chal-lenge is the extent to which the remaining global arableresources can be more intensively farmed io the future,aud how GM technologies might best contribute. Thereis clearly also a need for more environmentally sensitiveagricultural development. ̂ '̂ ° Transgenic cropping will,therefore, need to play key roles in more sustainablefanning.

Sub-Saharan Africa and South Asia are likely toremain the most troubled poor regions for future foodsupply (Tables 6 and 7) owing, in particular, to thecoDtinuing high rates of population growth.®'̂ ^ Althoughsome concerns have been expressed about China'*^ andits future capacity to produce sufficient food, expertsbelieve China will mostly feed itself for the foreseeablefuture given continuing political stability.* Greater ef-forts to limit environmental stresses in China and degra-dation of the agricultural resource base, however, will beessential,"'"'

China and neighboring countries in East Asia, to-gether with South Asia and sub-Saharan Africa, willaccount for much of the global population growth up to2020 (Table 6) and increased food needs (Table 7). Theremaining demands will come from Latin America andthe Middle East (Table 8). Both of which (for differentreasons) seem more able through increased productionpotential and affordable imports to meet predicted fooddemands in 2020.®

The extent of these population increases in develop-ing regions (Table 6) is made more stark in comparisonwith some other countries, such as the United Kingdomwhere population increase by 2020 could be only 6%.̂

The significance of food availability figures in thedeveloping world (Table 8) is made more dramatic bycontrasting the intake of developed countries, whichwere on average 3350 kcals • person

Table 7. Projected Consumptjon of Cereals inDeveloping Regions, 1990-2020

day^' in 1990and a predicted 3530 kcals • person^' • day^' in

Table .8. Estimated Population Changes in

Developing fleg

Developing

ions, 1990-2(

Regions

)20Population

1990 2020

(millions)

Change

Sob-Saharan Africa 490 1097 124South Asia (including India) 1193 1996 67Far East Asia (including China) 1794 2397 33Latin America (and Caribbean) 440 676 54Middle East (West Asia and

North Africa) 276 511 85

Adapted from reference 8.

Developing Regions

Sub-Saharan AfricaSouth Asia (including

India)Far East Asia (including

China)Latin America (and

Caribbean)Middle East (West Asia

and North Africa)

CerealConsumption/Person (kg)

1990

150

237

338

265

386

2020

150

267

421

308

427

% Change

0

12.7

24.6

16.2

10.6

Adapted from reference 8.

Looking Ahead

Four decades have passed since the stajrt of the GreenRevolution and much has been achieved. Contrary tomany dire and frightening predictions, food productionhas more than kept pace overall with global populationgrowth. Towards the end of the twentieth century foodsupplies were approximately 25% higher per person thanin i961, and real food prices were 40% lower.''^ Theoriginal Green Revolution, however, is considered un-finished.'*^

These gains are diminishing in many countries in thedeveloping world as a result of substantial populationgrowth, inadequate poverty alleviation, and poor socio-economic circumstances. Although birth rates havefallen more than expected in some parts of the develop-ing world, the annual increment remains substantial. Inless than 20 years, with more than 80 million peoplebeing born each year, there could be 2 billion morepeople to feed and the number of poor and hungry willcontinue to grow.

In addition, there have been some parts of the worldwhere Green Revolution technologies could not beadopted. Sub-Saharan Africa and inaccessible upland

Table 8. Food Availability per Hesad F-orecast bythe^jMPACT Model for Developing Regions

FoodAvaUability/Head(kilocalories/day)

Developing Country or Region

Sub-Saharan AfricaIndiaChinaWest Asia and North AfricaLatin America (and Caribbean)

*Baseline scenario based on previous year's change.Adapted from reference 32.

1990

20502330267029902720

2020*

21352690341031103030

Nutrition Reviews'^, Vol. 61, No. 6 S131

areas in Asia and South America have considerableneeds that are still growing. The Green Revolution isunlikely to reach these needy regions unless significantinvestments are made in infrastructure, market support,and input supply.''^

Support and funding for agricultural research hasnever been more important. Overall, however, this sup-port is declining and publicly funded programs havesuffered in particular. International research cooperation,which was the hallmark of the Green Revolution, needsparticular attention and renewed commitment. A newemphasis must be given to access to, and the sharing of,international germplasm. This is more difficult to achievebecause intellectual property and patent rights are in-creasingly used to protect substantial investments ingenetic improvement programs in the private sector.Circumstances are different from the early 1950s andlater, when unrestricted international germplasm ex-change considerably benefited breeding advances.^^Agreements need to be reached with the private sector toallow more new genetic materials to be exploited forpublic good in the developing world. Greater benefitswill accrue through appropriate private-public partner-ships, which need to be developed. Access to interna-tional gene banks and the results of international testingprograms can provide considerable benefits to both theprivate sector and public research programs as in theGreen Revolution, and continuing efforts are going to berequired in the future to share new products and pro-cesses. This is particularly important with much of theexpensive biotechnology investment being made in theprivate sector."*^

A lot has been learned during the last 50 years thatwill benefit future development. Beyond the actual ge-netic improvement of Green Revolution varieties ofwheat and rice, it also becomes clear that a package of"input provision, technology-transfer, and policy" sup-port was required to maximize productivity. Breedingadvances alone were insufficient without better agron-omy, supporting crop management, and conducive agri-cultural policies to provide input subsidies and priceprotection. Whether conventional breeding or biotech-nology research produces new varieties, the developmentof appropriate crop management support will remaincritical.

Some experts argue that future growing systems willneed to become much more information and knowledgeintensive to improve input use efficiency. Better strate-gies for integrated nutrient management, integrated pestmanagement, and the utilization of water and soil re-sources have been advocated.^ Although the new genet-ics will continue to be provided simply in seed, totalfactor productivity in the growing system will becomeincreasingly important.^' The reduction of growing costs

per unit of output will be critical, not only to profitabilitybut also to future sustainability.

The environment of maximizing productivity on thefarm, within which green revolution technologiesthrived, is rapidly changing. The model of a "closed andself-sufficient food economy" is being replaced by one of"self-reliance" and exploiting more comparative advan-tage. Such a system emphasizes the current liberaHzationof world trade and lower food prices against a back-ground of rising input costs. Improved crop varieties,whether derived in the future by conventional breedingor genetic transformation, must be regarded as futureprospects only if they can deliver a lower unit costproduction system. Benign government policies of re-stricting trade and subsidizing inputs, which prevailedduring green revolution times, are much less likely toprevail in the future.

At the same time, new crop prospects must delivermore environmentally acceptable cropping systems withless prospect of deleterious impact on natural resourc-es."̂ * Assuming that appropriate seed costs and dissemi-nation issues can be satisfactorily addressed, the futureexploitation of, for example, Bt transformed crop variet-ies could meet such a need. In this case, by reducingpesticide use by the small farmer and therefore providingmuch more desirable farming systems. To achieve theseends, desirable transgenic crop prospects will probablyneed to reach the smaller farmer more quickly than by"diffusion dynamics from the rich man's table."^^

The Green Revolution was successful for a varietyof reasons, including the quality of science and technol-ogy leadership.^ It included the establishment of support-ive institutional frameworks and encouraging govern-ment policies. There was, as a result, a close relationshipbetween key scientists, policy makers, extension ser-vices, and farmers. This philosophy and approach thank-fully continues in CIMMYT and IRRI today.

Conway^ considers future goals to be more complex.He states that it is more than producing new HYVs(important though that is) or the design of packages ofinputs. The high-potential Green Revolution lands arenot, he stresses, now the only targets for innovativeresearch. He considers important the goals of sustainabil-ity, stability, and equity. Future goals have to includegreater employment and income generation opportunitiesso that more of the poor can have access to the food theyrequire.

At the time of writing this paper I am in An GiangProvince, in the Mekong Delta area of Vietnam, one ofthe most productive agricultural regions in SoutheastAsia. Double cropping of rice is practiced and some ofthe highest yields in Asia are obtained, but there is stillconsiderable poverty and deprivation in the farmingcommunity. There are many reasons why, including the

S132 Nutrition Reviews'^, Voi. 61, No. 6

smallholding size, but basically rice alone remains a poorman's crop in these farming systems. For this reason,greater emphasis is cuixently being given to diversifica-tion into fruits, vegetables, baby corn, soybean, andcotton in the Mekong Delta. Future sustainable cropimprovements must, therefore, maximize farmers' in-comes as well as minimize environmental costs.

Last but by no means least, mention must be made ofpublic fears of so-called genetic foods, which have beenfuelled in recent years by food safety concerns andvociferous pressure groups,'^ An anti-science cultureseems almost to be developing io some quarters, whichrequires, if it is to be more successfully countered, amore proacti^'e and illuminating public education pro-gram. An exccHsion initiative that will likely requirefunding from both public and private sources.

Many consumers have yet to be persuaded of thebenefits of modern agricultural biotechnology and ge-netic engineering. It is argued by some that most of therecent advances seera only to, have benefited multina-tional life science companies and large-scale farmers inindustrial countries. However, the more exciting pros-pects of nutritionally modified foods and/or vaccinedelivery in transformed foods should help to furthersway public opinion.^^ The substantial and positive con-tributions of bioteclinology to the pharmaceutical indus-try need much greater publicity in this respect.

Evenson''' believes that wide-reaching prograrns andtissue culture technologies will contribute increasingly tocrop improvement up to 2010, with the exhaustion ofconventional breeding gains. Modern, biotechnology(through bat Tiarlcet-aided selection and transgenicplant deve opi"!ieiit) must, he says, play an increasing roleand couio prcvide ^lajor contributions after 2010. Bor-laug and Dov swel'^^ argue that the world has the tech-nology ava la 'e o, in the advanced stages of develop-ment, to feed = futi'ie population of 10 billion people ona sustaiicDie bas'b They questioa remaics, however,whether tht- i,oiki's farmers will be permitted openaccess to '"le "••̂w echnologies needed to meet pressingfuture recure \ienU

It rru-., b' ecogniixd that issues of equitable distri-bution, net e acci,-s, and appropriate utilization willneed to be e'"<'ecti\ely addressed in addition to foodsupply. A'aapLs corrently there is no shortage of food,the coexistence 0"f least and famine remains in the wori.dtoday.

1. Conway G. The Doubiy Green Revolution: Food forAil in the 21st Century. London: Penguin Books;1997.

2. Rajaram S, Braun HJ. Ha!f a century of international"Wheat breeding. The Linnean. 2001 ;3:137-163.

3. Ruttan VvW. Research to meet crop productionneeds: into the 21st century. In: Buxton DR, ed.

Internationai Crop Science Congress I. Madison, Wl:CSSA; 1993:3-10.

4. Khush GS. Green revolution: preparing for the 21stcentury. Genome. 1999;42:646-655.

5. Reynolds MP, Rajaram S, Sayre KD. Physiologicaiand genetic cinanges for irrigated wiieat in the post-green revoiution period and approaches for meetingprojected global demand. Crop Science. 1999;39:1611-1621.

6. Boriaug NE. Wheat breeding and its impact onworid food supply. Proceedings of the InternationalWheat Genetics Symposium. 1968;3:1-36.

7. Fischer KS, Cordova VG. Impact of iRRI on ricescience and production. In: Pingali PL, Hossain M,eds. The impact of Rice Research. Manila, Philip-pines: international Rice Research institute andThailand Development Research Institute; 1998:27-51.

8. Dyson T. Popuiation and Food: Giobai Trends andFuture Prospects. London and New York: Rout-iedge; 1997.

9. Evenson RE. Rice varietal improvement and inter-national exchange of rice germplasm. In: Pingali PL,Hossain M, eds. The Impact of Rice Research. Ma-nila, Philippines: International Rice Ftesearch insti-tute and Thailand Development Research Institute;1998:51-83.

10. Osmani SR. Did the green revolution hurt the poor?A re-examination of the early critique. In: Pingali PL,Hossain M, eds. The impact of Rice Research. Ma-nila, Philippines: International Rice Research Insti-tute and Thailand Development Research Institute;1998:193-213.

11. Malcolm ADB. A mania for all .season—reflectionson the GM debate. J R Agric Soc Engl. 2000;161:167-175.

12. Persley GJ. Agricultural biotechnology and thepoor: Promethean science. In: Persley GJ, LantinMM, eds. Agricuitural Biotechnoiogy and the Poor.Conference Proceedings. Washington, DC: Consul-tative Group on International Agricultural Researchand the U.S. National Academy of Sciences; 2000:3-21.

13. Dixon B. GM frenzy: a lesson in communication.Bioiogist 2000;47:74-76.

14. Nottingham S. Eat Your Genes: i-iow GeneticaiiyModified Food is Entering Our Diet. London: ZedBooks Ltd.; 1998.

15. May R. Genetically modified foods: facts, worries,policies and public confidence. Note from the Officeof Science and Technology. London: Department ofTrade and industry; 1999:20.

16. Persley GJ, ed. Letter to a Minister. Brief 10, inFocus 2: Biotechnoiogy for Deveioping Country Ag-ricuiture: Problem and Opportunities. Washington,DC: international Food Policy Research Institute;1999.

17. Paariberg RL. Governing the GM crop revoiution.Food, Agriculture and Environment Discussion Pa-per 33. Washington, DC: Internationai Food PolicyResearch Institute; 2000.

18. Sacks J. Helping the world's poorest. The Econo-mist. 1999;August 14:16-22.

19. Pinstrup-Anderson P, Cohen MJ. Modern biotech-noiogy for food and agriculture: risks and opportu-

Nutrition Reviews'^, Voi. 61, No. 6 S133

nities for the poor. In: Persley GJ, Lantin MM, eds.Agricultural Biotechnology and the Poor. Confer-ence Proceedings. Washington, DC: ConsultativeGroup on International Agricultural Research andthe US National Academy of Sciences; 2000:159-169.

20. Nuffield Council. Genetically modified crops: theethical and social issues. London: Nuffield Councilon Bioethics; 1999:164.

21. Tripp R. Twixt cup and lip: biotechnology and re-source-poor farmers. Nat Biotechnol. 2001 ;19:93-94.

22. Jones KA. Classifying biotechnologies. In: PersleyGJ, ed. Agricultural Biotechnology: Opportunitiesfor International Development. Wailingford: CAB In-ternational; 1990:25-28.

23. Persley GJ, Peacock WJ. Biotechnology for bank-ers.Agricuitural Biotechnology: Opportunities for in-ternationai Deveiopment. Wailingford: CAB Interna-tional; 1990.

24. James C. Global status of commercialised trans-genic crops in 2000. ISAAA Briefs No 12. ithaca,New York: The International Service for the Acqui-sition of Agri-Biotech Applications; 2000.

25. James C, Krattiger A. The role of the private sector.In: Persley, ed. Brief 2, in Focus 2: Biotechnology forDeveloping Country Agricuiture. Washington, DC:International Food Policy Research Institute; 1999.

26. Royal Society. Transgenic plants and world agricui-ture. Report of the Royal Society and the Academyof Sciences of the USA, Brazil, Ohina, India andThird World. London: Royal Society; 2000.

27. Flavell R. Biotechnology, food and nutrition needs.In: Persley GJ, ed. Focus 2: Biotechnology for De-veloping Country Agriculture, Problems and Oppor-tunities. Washington, DC: International Food PolicyResearch Institute; 1999.

28. Williams R. Providing new technologies for the de-veloping world. Trop Agric Assoc Newsietter. 2000;20:19-25.

29. Wambugu F. Why Africa needs agricultural biotech.Nature. 1999;400:15-17.

30. Gonway G. GM foods can help the Third World. TheIndependent Newspaper. 1999;July 2:4.

31. McCalla AF. Food security and challenges to agri-culture in the 21st century. Presented at the RoyalAgricultural College, Cirencester, UK; 1998.

32. Dasgupta P. The economics of food. In: WateriowJC, Armstrong DG, Fowden L, Riley R. eds. Feedinga Worid Population of More than Eight Biiiion Peo-ple. Oxford: Oxford University Press in associationwith the Rank Prize Funds; 1998.

33. Leung H. Rice functional genomics: a public re-search platform for gene discovery and crop im-provement. Proceedings of the Global Agriculture2020: Which Way Forward Conference. Norwich,John Innes Centre. Available at: http://www.jic.bbsrc.ac.uk/events/agri 2020/index.htm.

34. Wakhusama S. Progress in transferring researchresults and technologies to end-users in Kenya.

Proceedings of the Giobai Agricuiture 2020: WhichWay Forward Conference. Norwich: John InnesCentre. Available at: http://www.jic.bbsrc.ac.uk/events/agri 2020/index.htm.

35. Ma J. New products—mammalian proteins andPharmaceuticals. Proceedings of the Global Agri-culture 2020: Which Way Forward Conference. Nor-wich, John Innes Centre. Available at: http://www.jic.bbsrc.ac.uk/events/agri 2020/index.htm.

36. Mazur B. Discovering and developing new cropseed and grain products. Proceedings of the GiobaiAgriculture 2020: Which Way Forward Conference.Norwich: John Innes Centre. Available at: http://www.jic.bbsrc.ac.uk/events/agri 2020/index.htm.

37. Carney D, ed. Sustainable Rural Liveiihoods: WhatContribution Can We Make? London: Departmentfor international Development; 1998.

38. World Bank. Attacking Poverty. Worid Bank Devei-opment Report for 2000-2001. Washington, DC:World Bank; 2000.

39. Dyson T. World food demand and supply prospectsto 2025. J R Agric Soc Engl. 1999;160:227-243.

40. Pandya-Lorch R, Rosegrant MW. World food in thetwenty-first century. American Agricultural Econom-ics Association, Ames, USA. Choices. Fourth Quar-ter, Special Millennium Issue. J Am Agric EconAssoc. 1999:31-34.

41. Pinstrup-Anderson P, Pandya-Lorch R, RosegrantMW. World food prospects: critical issues for theearly twenty-first century. 2020 Food Policy Report.Washington, DC: International Food Policy Re-search Institute; 1999.

42. Brown LR, Kane H. Full House—Reassessing theEarth's Popuiation Carrying Capacity. London:Earthscan Publications Ltd.; 1994.

43. Greenland DJ, Gregory PJ, Nye PH. Land resourcesand constraints to crop production. In: WateriowJC, Armstrong DG, Fowden L, Riiey R, eds. Feedinga Worid of More than Eight Biiiion People. Oxford:Oxford University Press in association with the RankPrize Funds; 1998.

44. World Bank. At China's Table. Food Security Op-tions. Washington, DC: World Bank; 1997.

45. Borlaug NE, Dowswell C. The unfinished GreenRevolution: the future role of science and technol-ogy in feeding the developing world. Proceedings ofthe Seeds of Opportunity. London, England; 2001:1-12.

46. Davies WP. Advancing crop biotechnology in devel-oping countries: New opportunities from the GeneRevolution? J R Agric Soc Engl. 2001 ;162:146-157.

47. Pingali PL, Rajaram S. Global wheat research in achanging world: options for sustaining growth inwheat productivity. World Wheat Facts and Trends:Challenges and Achievements. Mexico, DF:CIMMYT; 1991:18.

48. Gooding MJ, Davies WP. Wheat Production andUtilisation: Systems, Quality and the Environment.Wailingford and New York: CAB International; 1997.

S134 Nutrition Reviews^, Vol. 61, No. 6