Impacts of Food Crop Improvement Research in Africa

By

Mywish Maredia, Derek Byerlee and Peter Pee

SPAAR Occasional Papers Series, No.1

December 1998

Special Program for African Agricultural Research, Washington D.C.

i

CONTENTS

FOREWORD ..................................................................................................................... iii

ACRONYMS AND ABBREVIATIONS .................................................................................. iv

ABSTRACT ........................................................................................................................v

1. INTRODUCTION ............................................................................................................1

2. RESEARCH INPUTS AND IMPACTS IN AFRICA: AN AGGREGATE OVERVIEW..................2

2.1. Research Inputs.....................................................................................................2

2.2. Impacts on Agricultural Production and Yield....................................................4

3. RESEARCH IMPACT ASSESSMENT BY MAJOR FOOD CROPS...........................................5

3.1. Maize.....................................................................................................................6

3.2. Sorghum and Millet ............................................................................................11

3.3. Rice .....................................................................................................................14

3.4. Wheat ..................................................................................................................17

3.5. Other Food Crops in Africa................................................................................21

4. SUMMARY AND CONCLUSIONS....................................................................................24

REFERENCES ...................................................................................................................27

ANNEXES

Annex A. Summary of Rates of Return Studies for Africa by Major Food Crops

TABLES

Table 1: Measures of aggregate research inputs by African NARSs, 1961-1991............3

Table 2: Area, production and yield of major food crops in Africa, 1996-97..................5

Table 3: Comparison of maize research resources in Africa, Asia and Latin America,early 1990s .........................................................................................................6

Table 4: Maize area planted to improved germplasm in several African countries,1990 ...................................................................................................................8

Table 5: Adoption of improved sorghum and millet varieties in Southern Africa,1996 .................................................................................................................12

Table 6: Adoption of improved sorghum and millet varieties in Eastern Africa, 1996.12

Table 7: Release and diffusion of improved NARS-ICRISAT sorghum and milletvarieties in West Africa ...................................................................................13

Table 8: Rice varietal adoption in West Africa, by ecology ..........................................16

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Table 9: Adoption of improved varieties in mangrove rice eco-system ........................16

Table 10: Wheat research inputs in Africa and other developing regions, early 1990s...18

Table 11: Number of wheat varieties released and releases per million hectares inAfrica and other developing regions. ...............................................................18

Table 12: Sources of new wheat varieties in Africa and other developing regions .........19

FIGURES

Figure 1: Expenditure as a percentage of agricultural GDP, 1991....................................4

Figure 2: Growth rate of area and yield by crop in Africa, 1971 to 1996-97 ....................5

Figure 3: Maize varietal releases in Africa by type of release per five-year period ..........7

Figure 4. Percent area sown to maize hybrids and improved OPVs by sub-regions inAfrica. 1992. ......................................................................................................9

Figure 5. Adoption of improved maize varieties by developing regions, 1992 ..............10

Figure 6. Adoption of semi-dwarf wheat varieties in Africa from 1970 to 1990............20

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FOREWORD

One of the recommendations of the 1997 External Program and ManagementReview of SPAAR was for the Secretariat to pool together “SPAAR’s collectiveexperiences, products and services of a public goods nature in major publications ofenduring value that will be a source of reference and use by donors, SROs, NARSs,farmers’ organizations, IARCs, the science community, policymakers, and the generalpublic.” It was agreed, during the discussion of the EPMR recommendations at theEighteenth SPAAR Plenary Session in Arusha, that the Secretariat would initiate aSPAAR Occasional Papers Series on issues of a public goods nature that would be ofenduring interest to a wide spectrum of SPAAR stakeholders.

The “Impacts of Food Crop Improvement Research in Africa” is the first paperto be published under the SPAAR Occasional Papers Series. This paper attempts toreview and summarize the available evidence on the impacts and rates of returns toinvestments in food crops research in Sub-Saharan Africa (SSA).

The evidence available is clear and unambiguous: investments in food cropsresearch in SSA have paid handsome dividends. However, it was noted that ifagricultural research is to continue to be a catalyst for modernizing African agriculture,many important issues will need to be addressed. These include: the size of NARSs,commodity research programs, relative emphasis on testing versus breeding, allocationof resources to different research activities and geographic regions, as well as lowsalaries and the resulting high turnover among scientists.

It may be of interest to indicate that these are some of the issues that SPAAR,through its Frameworks for Action in Agricultural Research in the main eco-politicalregions of Sub-Saharan Africa, have identified and is assisting selected NARSs toaddress.

Jean-Louis Sarbib

Chairman, SPAAR

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ACRONYMS AND ABBREVIATIONS

CGIAR Consultative Group for International Agricultural ResearchCIAT International Tropical Agricultural CenterCIMMYT International Maize and Wheat Improvement CenterFTE Full-time equivalentGDP Gross domestic productIARCs International agricultural research centersICRISAT International Crops Research Institute for the Semi-AridTropicsIITA International Institute for Tropical AgricultureINTSORMILCRSP International Sorghum and Millet Collaborative ResearchSupport ProgramIRRI International Rice Research InstituteNARSs National agricultural research systemsNGOs Non-Governmental OrganizationsRORs Rates of ReturnSSA Sub-Saharan AfricaTAC Technical Advisory CommitteeWARDA West Africa Rice Development Association

v

ABSTRACT

In recent years, an increasing number of studies have been undertaken todocument agricultural research impacts and estimate rates of returns (RORs) toagricultural research investment in Sub-Saharan Africa (SSA). These studies providetangible evidence of the increasing availability of improved varieties of major foodcrops to farmers in Africa, increased food production in regions where adoption hasoccurred, and positive returns to research investment. The widespread adoption ofimproved maize, wheat and rice varieties is especially noteworthy, with more than50% of the area planted under these improved cereal crops by the early 1990s.

The growing body of evidence on the impacts of agricultural research in Africaindicate that agricultural research in Africa has had productivity-increasing impacts.The generation and diffusion of: improved, higher-yielding maize OPVs in WesternAfrica and hybrids in Eastern and Southern Africa; higher-yielding wheat in Easternand Southern Africa; hybrid sorghum in Sudan; semi-dwarf rice for irrigated regions inWestern Africa; early-maturing cowpeas in Western Africa; and disease-resistantpotatoes in the Eastern and Central African highlands are now cited as outstandingsuccess stories of technological change in food crop production in SSA.

However, it should be noted that the results are patchy or uneven, by countryand over time. The results also reflect wide variability as a result of differences inagroclimatic factors and the policy environment. Furthermore, the increasingavailability of improved varieties is a necessary but not sufficient condition forincreasing agricultural productivity.

While crop improvement research in Africa can be regarded as a qualifiedsuccess story, there are many important issues that will need to be addressed ifagricultural research is to continue to be a catalyst for modernizing African agriculture.These include: the size of NARSs, commodity research programs, relative emphasison testing versus breeding, allocation of resources to different research activities andgeographic regions, and low salaries and consequent high turnover among scientists.

There is considerable potential for improving research efficiency. A key toimproving research efficiency is to improve coordination among national agriculturalresearch systems (NARSs) and for them to increase their collaboration with regionaland international organizations. NARSs should also strengthen their capacity forimpact assessment work, since their results can influence agricultural policyformulation and guide the development of a national agricultural research agenda toenhance the impact of research on agricultural productivity.

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1. INTRODUCTION

After two decades of steady increases in public-sector agricultural research investmentin the 1960s and 1970s, many African national agricultural research systems (NARSs)began to experience stagnant or declining real support in the 1980s and 1990s (Pardey,et al., 1995). The decline in support was attributable, in part, to the perception of bothnational governments and donors that agricultural research and development in Africahave had little impact. This perception was largely a result of aggregating foodproduction statistics, which translated into stagnant per capita food production inAfrica, and of the problems that African NARSs were experiencing in organizing theirresearch.

As a consequence, policymakers and researchers have paid increasing attention toresearch efficiency issues, in order to convince their governments and donors of theimportance of investing in agricultural research. One outcome of the increase inattention to agricultural research efficiency issues has been the growing number ofstudies to document the impacts of, and rates of returns to, research in the major foodcrops in Africa (Oehmke and Crawford, 1990; Sanders, 1996).

The purpose of this paper is to review and summarize the available evidence on theimpacts of major food crops’ research in Sub-Saharan Africa (SSA), with the aim ofidentifying further opportunities to increase research efficiency in Africa.1 The primaryfocus of this paper is on varietal improvement technology because of the greaterconcentration of research resources on developing improved varieties and,consequently, the availability of a relatively larger body of evidence on this subject.The information available, however, is not uniformly comprehensive across all themajor food crops of Africa. Hence, the review covers major cereal food crops namely,maize, wheat, rice, sorghum and millet in greater depth than other legume and roots &tuber food crops for which relatively few studies have been conducted. Furthermore,the information presented in this paper is mainly drawn from the diffusion and impactsof varieties generated by CGIAR centers in Africa. The constraints of time andinformation meant that we were not able to include many important studiesdocumenting the impacts of indigenous research conducted by African nationalprograms.

The purpose of investing in agricultural research and extension is to develop andtransfer new technologies, with the ultimate goal of increasing agriculturalproductivity and incomes. Achieving this goal would require a four-stage process:creation of the institutional capacity to develop improved techniques of production;

1 Although, the impacts of agricultural research are likely to be significant in South Africa,

the focus of its research has been on large-scale commercial agriculture. There is littleinformation available on the impacts of research on smallholder agriculture, especially inrelation to the kinds of impacts of food crops’ research discussed in this paper. Hence,unless indicated otherwise, Africa, as the term is used here, refers to Sub-Saharan Africa(SSA) excluding the Republic of South Africa.

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expansion of the technology frontier; transfer of improved techniques; and theadoption and use of these techniques (Oehmke and Crawford, 1996). Investments inagricultural research will have immediate effect on the first two stages of this process,i.e., the productivity of the research system and expansion of the technology frontier.Traditional indicators of research output such as number of varietal trials, number ofcrosses, improvements in research techniques, number of varieties released, andpotential yield improvements on experiment stations, are important indicators ofresearch success, but they are measures of success at intermediate stages. They do notquantify impacts of research on farm income, consumer welfare or agricultural growth,which depend on the actual adoption of new technology by end-users.

In this paper we attempt to supplement the intermediate indicators of research output(such as varieties released and their potential yield improvement effects) with theestimates of technology adoption and rates of return, that capture the impact ofresearch investment on farm productivity and consumer welfare. The estimated ratesof return also provide a measure of the profitability of research investments in a givenproject.

We begin this paper with an aggregate overview of the research effort and its impacton food production in Africa. Research efforts are measured in terms of both researchscientists and expenditures. In section three, we present crop specific evidence ofresearch impacts in Africa, including a summary of evidence on economic rates ofreturn to research investment. In the final section, we generalize the results andevidence of research impacts to address the questions of whether and why researchinvestments have or have not paid-off in Africa, and how returns to future investmentcan be increased.

2. RESEARCH INPUTS AND IMPACTS IN AFRICA: AN AGGREGATE

OVERVIEW

2.1. Research Inputs

Over the past three decades or so, the development of agricultural research systems inSSA has been quite impressive. According to a comprehensive study by Pardey et al.(1995), many African countries have made significant strides in increasing the numberand quality of scientists working in their agricultural research institutions. The numberof full-time equivalent (FTE) scientists increased at an annual rate of about 5% during1961-91, increasing from about 2,000 FTE researchers in 1961 to more than 9,000 in1991. Over this period, the size of African national agricultural research systems(NARSs) grew rapidly. In 1961, 33 African NARSs had less than 25 FTE scientistseach, by 1991 this number had declined to 8. Similarly, the number of medium-sizedNARSs (those employing 100-400 researchers) increased from 3 in 1961 to 18 in 1991(Pardey et al., 1995). Over the same period, there was a significant Africanization ofresearch systems (from about 90% expatriates in 1961 to 11% in 1991), and anincrease in the qualifications of research staff (with nearly 65% of national researchersholding a postgraduate degree in 1991).

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In twenty one countries, accounting for about 75% of the region’s researchers, wheremore complete time series data are available (Table 1), there was a declining overalltrend in the annual growth rate of researchers over the last three decades -- falling from6.4% in the 1960s to 5.1% in the 1970s and further slowing down to 3% per annum inthe 1980s. Over the same period, real agricultural research expenditures grew rapidlyduring the 1960s, moderately during the 1970s and ceased to grow throughout the1980s and early 1990s (Table 1). As a result of this starkly contrasting pattern ofgrowth of real research expenditures and research personnel, the research expenditureper researcher declined dramatically over time (Table 1). In 1991, the expenditure perresearcher averaged about 66% of the 1961 figure.

Table 1: Measures of aggregate research inputs by African NARSs, 1961-1991

Total number Growth rate (%/year)

1961 1971 1981 1991 1961-71 1971-81 1981-91

Total number of researchers inAfrican NARSs(full time equivalents)

1576 2926 4864 6792 6.4 5.1 3.0

Total research expenditures byAfrican NARSs(million 1985 PPP dollars)

256 518 701 685 6.8 2.6 -0.1

Research expenditures perresearcher(thousand 1985 PPP dollars)

162 177 144 101 0.9 -2.0 -3.5

Source: Pardey, Roseboom and Beintema (1995)

Note: The FTE data cover the following 21 countries: Botswana, Burkina Faso, Cote d’Ivoire, Ethiopia, Ghana,Kenya, Lesotho, Madagascar, Malawi, Mauritius, Niger, Rwanda, Senegal, South Africa, Sudan,Swaziland, Tanzania, Togo, Zambia, Zimbabwe. Research expenditure data cover 19 countries (theabove 21 excluding Tanzania and Togo).

In terms of comparison between francophone and anglophone Africa, both the numberof researchers and the amount of research expenditures grew more slowly in thefrancophone region (5.0% and 2.2%, respectively) than in the anglophone region(6.4% and 3.3%, respectively). However, expenditure per scientist is about 15-20%higher in francophone than in anglophone countries, reflecting, in part, the higherdependency of francophone Africa on expatriate researchers and donor support(Pardey et al., 1995).

The research intensity measures given in Figure 1, place agricultural researchexpenditure data in a more meaningful context. Agricultural research spending, as apercentage of agricultural GDP for all of Africa, averaged 0.73% in 1991 (Pardey etal., 1995). Six countries spent more than 2% of their agricultural GDP on agriculturalresearch: Cape Verde, Botswana, Namibia, South Africa, Zambia, and Swaziland. Forsome of these countries, the high research intensity ratio reflects the significant shareof donor funds in their total agricultural research budgets. On average, donor fundingin the form of loans and grants accounted for about 43% of total expenditures onagricultural research in Africa in 1991 (49%, if Nigeria is excluded), up from about34% in 1981 (Pardey et al., 1991). The dependence on donor funding varied markedly

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among countries. Nigeria received only 6% of its funds from donors, while countriessuch as, Cape Verde, Burkina Faso, Mali, Rwanda, Senegal, Tanzania and Zambiareceived more than 60% of their funds from donor sources.

0 1 2 3 4 5 6 7

Rwanda

Nigeria

Burkina Faso

Sudan

Madagascar

Niger

Ghana

Ethiopia

Tanzania

Mali

Côte d'Ivoire

Senegal

Zambia

Malawi

Kenya

Zimbabwe

Lesotho

Cape Verde

Swaziland

Mauritius

Namibia

South Africa

Botswana

Percentage

National expenditures Donor expenditures

Source: Pardey, Roseboom and Beintema (1997)

Figure 1: Expenditure as a percentage of agricultural GDP, 1991

Beginning in the 1970s, the growing agricultural research effort in Africa has beencomplemented by that of the international agricultural research centers (IARCs). Anestimated 40% of the budgets of IARCs is spent in Africa (Gryseels and Anderson,1991).

Agricultural research in Africa, as in other developing regions, is mainly focused (overtwo-thirds) on crops (Pardey et al. 1991). Data on research inputs by crop are scantyboth in terms of geographic coverage and over time. The information available onmaize and wheat is perhaps the most comprehensive of all the major food crops inAfrica.

2.2. Impacts on Agricultural Production and Yield

The size and relative importance of different food crops in African agriculture areindicated by the aggregate statistics in Table 2. In terms of area harvested, about 20million hectares are cultivated with maize and sorghum/millet, making them the twomost important food crops, followed by roots and tuber crops.

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Figure 2 provides an aggregate picture of the underlying trends in the growth rates ofarea, yield and production of major food crops over the past two decades. From 1971to 1996-97, production increased at more than 2.0% per year for all the major foodcrops in Africa. Of these, wheat and rice, with annual growth rates of more than 3%each, experienced one of the highest growth rates. Almost three-fourths of theincrement in rice production was the result of an increase in the area under ricecultivation. At the other extreme, almost 70% of the increment in wheat productioncame from yield improvements. For maize, which is one of the important cereal cropsin Africa, an annual yield increase of about 1.0% per year, was responsible for aboutone-third of the increase in production. For sorghum and millet, the yield increasecontributed less than 30% of the production increase.

Table 2: Area, production and yield of major food crops in Africa, 1996-97

Total area harvested(Million ha)h

Total production(Million tons)

Yield(t/ha)

Cereals Maize 19.5 25.9 1.32

Sorghum 23.7 19.1 0.80

Millet 19.7 12.8 0.65

Rice 6.7 11.0 1.64

Wheat 2.3 3.4 1.47

Roots and Tubers Cassava

16.910.1

--84.1

--8.32

Source: FAO production statistical data files

1.0

2.31.9

1.4

2.0

1.5

2.4

0.8

1.0

1.30.4

0.6

0.0

1.0

2.0

3.0

4.0

Wheat Rice Maize Roots &Tubers

Sorghum Millet

Per

cen

tag

e A

nn

ual

Gro

wth

(%

)

Yield

Area

Figure 2: Growth rate of area and yield by crop in Africa, 1971 to 1996-97

3. RESEARCH IMPACT ASSESSMENT BY MAJOR FOOD CROPS

In the following sections, we examine, for each major food crop, the contribution ofcrop improvement research towards the productivity increments underlying theseaggregate statistics.

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3.1. Maize

The impacts of maize research are probably the most widely documented of all thefood crops in Africa. This is because maize is the most important single food crop inAfrica, contributing to more than 40% of total cereal production. In eight countries ofEastern and Southern Africa, maize accounts for 50% or more of the calories providedby starchy staples (over 80% of staple calories in Malawi and Zambia). In WesternAfrica, maize is a less important food staple (accounting for about 10% of calories),but the maize area has rapidly expanded in the savanna zone in the past two decades(Byerlee and Heisey, 1997).

Overall, maize is a major food crop in more countries in Africa than in Asia or LatinAmerica. However, the size of the maize production environment in African countriesis much smaller than that in countries of other regions. In these small environments, itbecomes a real challenge for African countries to organize and allocate their resourcesfor research. There is, therefore, a stronger presence of IARCs, through theinvolvement of CIMMYT and IITA, in maize research in Africa than in other regions.

Since the 1960s when most African countries gained their independence, investment inmaize research by NARSs has increased rapidly. According to a survey undertaken byCIMMYT in 1990, the total number of maize researchers (breeders and others) in thepublic sector were estimated to be about 272 in the early 1990s, which is of the sameorder of magnitude as in Latin America (Table 3). Interestingly, breeders outnumbernon-breeders in Asia and Latin America but not in Africa, suggesting the relativelygreater emphasis given in Africa to crop management research to meet the specialneeds imposed by the heterogeneous agroecological conditions under which maize isgrown. The involvement of the private sector in maize breeding (employing about27% of maize breeders), although the highest among all crops, is lower in Africa thanin other developing regions (Table 3). Overall research intensity, measured by thenumber of total researchers per million tons of maize production, in Africa is alsolower than in Asia and Latin America.

Table 3: Comparison of maize research resources in Africa, Asia and Latin America,early 1990s

No. of public sector maizeresearchers

RegionNo. of

countriessurveyed

Maizearea percountry(M ha)

No. of maizeenvironments Breeders Non-

breedersTotal

Percentmaize

breeders inprivate sector

Total no. ofpublic and

private maizebreeders/M t of

maize

Africa 20 0.67 5.4 86 186 272 27 6.7

Asia 9 1.86 5.7 175 240 415 42 10.7

LatinAmerica 12 0.96 4.4 182 87 269 37 13.0

Source: CIMMYT 1990 Maize impact survey (Morris et al. 1992)

Indicators of Research Success

Maize improvement research over the past two decades has resulted in the release of asteady stream of new improved maize varieties (open pollinated -- OPVs, and hybrids)

7

by national maize research programs in Africa (Figure 3). The rate of varietal releasesin Africa increased steadily from 1966, before leveling off in the 1980s. From 1966 to1990, African public maize research programs released just under 300 new varieties,consisting of more than 165 OPVs and about 100 hybrids. In terms of the compositionof OPVs and hybrids over the last three decades, national programs in Africa haveconsistently released more OPVs than hybrids, reflecting the fact that relatively fewnational programs in Africa are actively involved in hybrid development. Theproportion of hybrids released has remained relatively stable at about 40% over thepast three decades, indicating little or no change in public sector breeding strategiesand capacities (Figure 3).

Maize research success in Africa, as measured by the intermediate indicator of varietalreleases, is quite comparable to other regions. The number of maize OPVs and hybridsreleased per million hectares of maize during 1966-90 is estimated to be about 25 forAfrica, 11 for Asia and 30 for Latin America (Byerlee and Heisey, 1996). Thus,African farmers have had as many varieties and hybrids to choose from as in otherdeveloping regions.

0

10

20

30

40

50

60

70

80

1966-70 1971-75 and 1976-80 1981-85 and 1986-90

Nu

mb

er o

f va

riet

al r

elea

ses

per

fiv

e-ye

ar p

erio

OPVs

Hybrids

60%

40%40%

60%

38%

62%

Source: CIMMYT (1992)

Figure 3: Maize varietal releases in Africa by type of release per five-year period

Impacts of Maize Research

The number of varietal releases provided a good measure of the intermediate output ofthe research effort. However, a better measure of the impact of crop improvementresearch is the area planted to improved materials, since this provides an indicator thatcan be used to estimate the maize production gains and its effect on consumer welfare.The estimated rates of adoption of improved varieties in Table 4 indicate that ratesvaried from as low as 15 -20% of the maize area in countries like Malawi, Tanzaniaand Mozambique to nearly 100% in Zimbabwe.

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Table 4: Maize area planted to improved germplasm in several African countries, 1990

Percent areaimproved

OVPs

Percent areaimproved

germplasm (MVs)Country

Totalmaize area(000 ha)

Mina Maxa

Percentarea

hybridsMina Maxa

Percent of MV area withCIMMYT germplasm

(sometimes incollaboration IITA)

Tanzania 1,631 6 18 6 12 24 60

Nigeria 1,500 22 87 2 24 89 59b

Kenya 1,500 8 8 62 70 70 1

Malawi 1,344 3 3 11 14 14 1

Zimbabwe 1,150 0 0 96 96 96 0

Ethiopia 1,050 8 24 5 13 29 33

Mozambique 1,015 17 17 1 18 18 94

Zambia 763 5 5 72 77 77 6

Cote d’Ivoire 691 14 42 4 18 46 88

Ghana 465 16 48 0 16 48 91

Benin 454 9 27 1 10 28 61b

Uganda 389 30 70 10 40 80 0

Togo 296 7 18 3 10 21 81

Burkina Faso 216 15 70 2 17 72 48

Cameroon 200 20 67 1 21 68 72b

Mali 170 36 50 0 36 50 27

Lesotho 145 12 12 70 82 82 15

Burundi 124 5 20 0 5 25 81

Senegal 117 100 100 0 100 100 100

Swaziland 84 0 0 90 90 90 0

Total 13,304 11 26 23 34 49 33

1992 estimates 13,008 17 25 43

a Min = area usually based on seeds sales; max = area based on surveys or breeder’sestimates

b Mostly germplasm from ITTA that includes CIMMYT backgroundc Excludes over 1 million ha of maize, not covered by the survey in Zaire, Angola, Somalia,

Madagascar, and Namibia

Source: Byerlee and Heisey (1996)

The first major success story with hybrid maize was its rapid uptake by smallholders inKenya in the early 1970s (Gerhart, 1975). The Kenyan success story has been repeatedamong smallholders in several other countries of Eastern and Southern Africa in the1980s, especially Zimbabwe, Lesotho, Swaziland, Zambia and South Africa. However,until recently, research on hybrid maize had less impact in some countries, particularlythe mid-altitude areas of Tanzania and Malawi (Friis-Hansen, 1989; Kydd, 1989).

The overall adoption of improved maize germplasm is relatively greater in Eastern andSouthern Africa than in Western and Central Africa (Figure 4). Almost a hundredpercent of the improved germplasm adopted in Western and Central Africa is OPVs, incontrast to the widespread adoption of hybrids in Eastern and Southern Africa. This isbecause maize research programs in Western and Central Africa, unlike the hybridresearch programs in many Eastern and Southern African countries, focused explicitly

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on small farmers from the beginning. With active research collaboration and exchangeof germplasm with IITA and CIMMYT, several of these OPV programs had notablesuccesses in the 1980s. Especially notable is the rapid adoption of improved maizevarieties in the savanna areas of Western Africa, particularly Nigeria, and importantmaize growing regions in Ghana, Zaire, Senegal, Mali and Ethiopia (Byerlee andHeisey, 1996).

0

20

40

60

80

100

West & Central Africa East & Southern Africa

Per

cen

tLocalsOPVsHybrids

Figure 4. Percent area sown to maize hybrids and improved OPVs by sub-regionsin Africa. 1992.

The dominance of hybrids in Eastern and Southern Africa and OPVs in other regionscan also be attributed to the ecological differences in the maize growing areas of theseregions. In most of the Eastern and Southern African countries, the dominant maizegrowing ecology is located in mid- or high-altitude areas where hybrid materials weredeveloped for commercial farmers. In other regions of Africa, improved OPVs aremore important than hybrids, partly because in these areas the dominant ecology formaize is tropical lowland and hybrid materials were unavailable for this ecology untilrecently.

Despite the regional differences within Africa, the overall record of adoption ofimproved maize germplasm is impressive. The overall rate of adoption of improvedmaize varieties in the early 1990s was estimated to be about 42% of the total maizearea in Africa, quite comparable to the estimated figures of 42% in Asia and 39% inLatin America (Figure 5).

10

2013

27

17 29

14

6358 59

0

20

40

60

80

100

Africa Asia Latin America

Per

cen

t A

rea

Locals

OPVs

Hybrids

Figure 5. Adoption of improved maize varieties by developing regions, 1992

The adoption of improved maize germplasm has had a significant impact on maizeproduction in Africa. For hybrids, most estimates suggest that yield gains over localunimproved material, under farm conditions, have averaged at least 40% in favoredareas (Smale and Heisey, 1994; Pomela, 1993). In dry areas, the evidence suggests thathybrids provide at least a 30% yield gain (Rohrbach, 1989; Lopez-Pereira and Morris,1994). The yield gain of OPV is less; according to one estimate it is about 14-25%over local materials in tropical areas (Morris et al., 1992). Applying these yield data tothe estimated area planted to improved germplasm in Africa (Table 4), the overallyield gain from the adoption of improved germplasm alone is estimated to be 12-14%(Byerlee and Heisey, 1996).

In addition to the yield gains, yield stability has been enhanced by the release ofdisease resistant varieties, especially those that have resistance to the maize streakvirus, which has become a major disease of maize in Africa, affecting some 60% ofthe maize area in recent years (Diallo et al., 1990). In some cases, resistance to streakvirus is the main explanation for the yield superiority of improved varieties over localmaterials (Low and Waddington, 1990).

In addition to the documented adoption and yield impacts of maize improvementresearch, several studies have also assessed country-specific impacts of maize researchand calculated the rates of return (RORs) to investment in maize research. Theseassessments generally find positive RORs across different regions of Africa (AppendixA). In countries where, in the past, research has not had very significant impactsrelative to the efforts put in, such as Malawi and Uganda, the more recent estimateshave been encouraging, suggesting that these investments are finally paying-off. Forexample, Uganda’s lack of significant impact to date is a direct consequence of thepolitical problems of the 1970s and early 1980s. However, projecting their expectedfuture research benefits yield positive and high rates of return.

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3.2. Sorghum and Millet

Sorghum and millet are the second and third most important cereal crops in Africa,respectively. They are grown in the harsh semi-arid tropics of Africa where inadequaterainfall and lack of irrigation make production of other cereal crops difficult to sustain.

A general impression is that research to improve sorghum and millet has generallylagged worldwide because they are not grown as food crops in the developed world. InAfrica, they are considered as "poor man’s crops." In the past decade or two, therefore,activities of international donor-sponsored research programs, such as ICRISAT andINTSORMIL-CRSP, have increased in the region and been a major source of researchsupport to African NARSs attempting to improve sorghum- and millet-basedtechnologies. However, despite their importance in African agriculture, little is knownabout the extent of the research effort by African NARSs to improve sorghum andmillet technologies.

Impacts of Sorghum and Millet Research

The available evidence on the release and adoption of improved sorghum and milletvarieties in Africa is still very limited. Research programs are under increasingpressure to increase the adoption of these varieties and quantify their impacts, if theyare to continue to receive donor and government support for their research. Tables 5and 6 provide the preliminary estimates of the adoption of improved sorghum andmillet varieties in Eastern and Southern Africa. The evidence suggests that theadoption of improved sorghum and millet varieties has been significant in someSouthern African countries, notably, in Zimbabwe and Zambia. However, unlike othercereal crops, much of the adoption of improved sorghum and millet varieties infarmers’ fields has occurred in recent years, suggesting that the years of research andcollaboration with IARCs on these crops are finally bearing fruit. Further, much of theadoption in Southern Africa, in recent years, resulted from the concerted efforts ofnational and international research programs to disseminate improved varietiesthrough drought relief programs (Rohrbach and Rutiro, 1996).

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Table 5: Adoption of improved sorghum and millet varieties in Southern Africa, 1996

Country Sorghum Millet Sorghum Millet

Total area

(000 ha)a

Percent estimated area planted toimproved varieties in 1995/96

Angola Botswana Lesotho Malawi Mozambique Namibia South Africa Swaziland Tanzania Zambia Zimbabwe

110834242

37613

1551

66342

132

99609

43150

210

25932

204

924

210

40

7750

23630

017

00

2325

00

<16325

a Area estimates correspond to 1992-94 average for sorghum and 1996 for millet.b FAO data for Angola does not distinguish sorghum and millet; it is assumed that sorghum

makes up half of the area and production reported here.

Source: FAOSTAT (1995), ICRISAT estimates (1996)

Table 6: Adoption of improved sorghum and millet varieties in Eastern Africa, 1996

CountryTotal area of

crop 1995(000 ha)

Year of firstsignificantdiffusion

Area estimated to be plantedto improved varieties

1995/96(000 ha)

Area of expectedcoverage(000 ha)

SORGHUM Burundi Ethiopia Kenya Rwanda Sudan Tanzania Uganda

54970120

676300

690265

1990199019941988198219921980

1730107060 5

20

352045

150134125

50

MILLET Tanzania 376 1996 -- 200

Source: ICRISAT estimates, 1996.

There is, however, a growing skepticism among donors about the impacts of sorghumand millet research on food production in Africa, especially in Western Africa. Theconventional wisdom (which is gaining increasing acceptance) is that there is littlepotential for substantial impacts from research on the traditional crops of Africa,especially sorghum and millet. A recent TAC (Technical Advisory Committee) reportasserted that there have been no impacts of sorghum and millet research in WesternAfrica (CGIAR/TAC, 1995). The report was also very pessimistic about any likelyfuture effects of this research. This report, however, did not include recent evidence ofincreased adoption of a number of ICRISAT-bred sorghum varieties by farmers inseveral countries. An update of on-farm diffusion of NARS-ICRISAT sorghum and

13

millet varieties in Western African countries in the spring of 1996 (Table 7) can befound in Sanders (1996). Sanders also noted several positive signs of increasing butstill very limited impacts of sorghum and millet research in Western Africa from theseestimates. He further noted (a) the extension of the sorghum variety, S-35, fromCameroon into Chad; (b) the diffusion of new millet cultivars in Senegal since the1980s and, more recently, in Mali; and (c) a major effort by a seed company and a beercompany to diffuse new sorghum cultivars, including a hybrid, in Nigeria. However,no mention was made of the fact that improved sorghum and, to some extent, milletvarieties have also been widely adopted in Nigeria.

Table 7: Release and diffusion of improved NARS-ICRISAT sorghum and milletvarieties in West Africa

Variety Country Area of Adoption Source

SORGHUM:

S-35 ChadCameroonNorthern Nigeria

Firm data not currentlyavailable

N/A

Framida GhanaTogoCote d’IvoireBurkina Faso

Firm data not currentlyavailable

N/A

ICSV 400 NigeriaMali

4,800 ha20 to 30 % adoption

For Guinness breweryICRISAT field study

ICSV 1049ICSV 1002

Burkina Faso Firm data not currentlyavailable

N/A

ICSH 89002 NG Nigeria 10 tons of seed sold (1992-1995)

Estimates of Premier Seed Co.(hybrid sorghum)

SEPON 82SRN39NAD1

Niger 15,000 to 16,000 ha Projectedadoption rate

Mazzucato and Ly (1994);Diffusion study in progress forcurrent estimates

MILLET:

BG 8735 Chad 30,000 ha Breeders’ estimate

ITMV 8001 Chad 10,000 to 20,000 ha Breeders’ estimate

ITMV 8001IBMV 8004

Senegal 10,000 to 30,000 ha Breeders’ estimate

Toroniou C-1 Mali Diffused near the Cinzanastation

N/A

P3KOLLOHKPCIVT

Niger 35,000 to 40,000 ha Mazzucato and Ly (1994)

Source: Adapted from Sanders (1996)

The yields of sorghum and millet increased at an annual rate of 0.7% and 1.0%,respectively, from 1971 to 1991. However, unless there is also a fairly rapid increaseof input use, especially of inorganic fertilizers, and a rapid increase in the supply ofquality seeds, the adoption of new varieties of sorghum and millet has only very smallimpacts on yields and incomes. Under the dry conditions of Sahelian countries likeNiger, improved millet varieties are estimated to increase yields by 22% or about 200-

14

500 kilograms/hectare (Mazzucato and Ly, 1994). At the extreme, striga-resistantsorghum varieties are estimated to increase yields by 59% in the striga-affected regionsof Africa (Aghib, 1996).

The available evidence on returns to investments in sorghum and millet improvementresearch, indicate that the results are mixed (Appendix A). The negative ROR reportedfor Niger’s joint millet, sorghum and cowpea research investments is because of thelower yield potential of these crops. Niger’s extremely harsh and variable climatediscourages farmers from replacing their traditional varieties that give lower butassured yields each year with improved varieties which may yield higher in good yearsbut perform poorly in bad years. Thus, during the severe droughts of 1985 and 1988many farmers reverted to traditional varieties of millets and cowpeas, reducing thetotal area under improved varieties from the peak adoption percentage of 20% in 1984to less than 12% by 1991 (Mazzucato and Ly, 1994). However, projecting the benefitsto the year 2011 on the assumption that adoption is no higher than it was in 1991,gives a positive return, in the range of 2-21% annually, to millet, sorghum andcowpeas research in Niger. In contrast, the overall returns to sorghum research inCameroon was estimated to be about 1% for the period 1979-88 (Sterns and Bernsten,1994). The improved variety, S-35, the only successful direct transfer from India intoWestern Africa, out-yielded local varieties in years when the onset of the rainy seasonwas late and/or total rainfall was below average. Hence, the benefits from thedevelopment of S-35 in Cameroon were limited to drought years (which occur in oneout of every three years, based on historical predictions) thus lowering the overallreturns to sorghum research (Sterns and Bernsten, 1994).

The higher returns to other sorghum/millet research programs reported in Appendix Aare attributed to the following successful varieties: (a) Hageen Dura-1 in the irrigatedregions of the Sudan, grown under higher levels of fertilizer inputs and bettermanagement practices; (b) SV-2 in the semiarid communal areas of Zimbabwe; (c)Okashana-I in the northern millet production strip of Namibia; and (d) striga-resistantsorghum variety, P9401-8, which is expected to avert yield losses by more than 50%across the ten countries of Eastern and Western Africa.

The basic conclusion from these ROR studies is that returns to research are marginalwhen sorghum/millet is grown in a very difficult environment without any use of otherinputs. But returns are quite high and comparable with other commodities when theshift to new sorghum/millet varieties is also accompanied by an increase in otherinputs, especially in better environments where input use is less risky.

3.3. Rice

Rice, a relatively new and minor crop in Africa, is becoming increasingly important. Inthe face of rapidly growing demand, there is widespread interest in increasingproduction. Today, rice is grown to some extent in nearly every country in Africa.Although Madagascar is a leading rice producer in Africa, Western African countriesdominate in terms of their share in total rice production.

15

Compared to other cereal crops, rice research programs have been limited in number,resources and scope. Rice research by colonial powers began in Africa in the 1920s,mainly in Western African countries (Dalrymple, 1986). Although some breeding wasdone in the projects supported by British and French governments, rice improvementresearch in Africa largely consisted of making selections from lines and varietiesdeveloped outside Africa. Strategic and applied research aimed at developing new ricetechnologies within Africa is relatively recent. Today, the major players in riceresearch in Africa are the national programs, research institutions from northerncountries (especially French institutes), and IARCs (WARDA, IITA and IRRI).Research by all these institutions, however, has been marked by discontinuities duringthe last decade (Matlon et al., 1996).

Continent-wide estimates of the research effort on rice are not easily available.However, for the 17 countries in Western Africa, Matlon et al. (1996) estimated a totalof 95 FTE researchers in public research programs in 1990. The research intensitymeasured by the number of researchers per million tons of rice production comes toabout 15 researchers, which is about the same as for wheat improvement research.Rapid staff turnover and inadequate operational budgets, which are characteristicfeatures of many African NARSs, have further limited the effectiveness of most riceresearch programs. The overall rice research efforts in Africa have been furtherdampened by the closing down of IITA’s rice program in 1990, and WARDA’s deep-water rice project in Mali in 1986 and research on mangrove swamp rice in 1993(Matlon et al., 1996).

Indicators of Research Success and Impacts of Rice Research

Because of the lack of comprehensive information on the adoption of rice varieties inall parts of Africa, the discussion on impacts of rice research will be limited toWestern Africa. It is estimated that in Western Africa alone, more than 100 varietieshave been released, either in the form of direct transfers from IRRI and WARDA orindirect transfers resulting from the use of IARC materials in further crossing activities(Matlon, 1995).

The adoption of improved rice varieties is estimated to be about 55% of the total ricearea in Western Africa (Table 8). The success of rice improvement research has beengreatest in irrigated ecosystems, where it is estimated that 97% of the rice area iscurrently sown to improved varieties. Significantly less progress has been achieved inupland ecosystems where traditional varieties continue to dominate. However, overalladoption in irrigated and lowland rainfed ecologies is higher than in Asia.

16

Table 8: Rice varietal adoption in West Africa, by ecology

Ecology % total area % total production% area improved

varieties

Rainfed uplands 40 27 39

Rainfed lowlands 38 36 68

Irrigated 12 27 97

Mangrove 4 5 19

Deepwater 7 5 10

All 100 100 100

Source: Matlon (1996)

While the adoption of improved rice varieties in Asia had already reached 40% by1980, it was less than 15% in Africa in 1983 (Herdt and Capule, 1983). Thus, unlikeAsia, where adoption of improved rice varieties began in the mid-1960s and triggeredthe Green Revolution, most adoption in Africa has occurred in the last 13 years. In themangrove eco-system, the extensive data available suggest that improved rice varietieshave been introduced only in the last ten years, and uptake of rice has beenimpressively rapid. A survey of farmers in Sierra Leone and Guinea found thatbetween 1986 and 1990, the percentage of farmers growing improved rice varieties inSierra Leone increased from 17% to 56%, and in Guinea from 0% to 17% (Table 9).The adoption rate in the mangrove rice system of The Gambia is also quite impressive.

Table 9: Adoption of improved varieties in mangrove rice eco-system

Country/year of estimate % area under-improvedvarieties

% farmers using improvedvarieties

The Gambia, 1996 53 91

Senegal (Casamance), 1996 NA 14-100

Guinea-Bissau, 1996 14-16 NA

Guinea, 1992 9 17

Sierra Leone, 1992 22 53

Sierra Leone, 1995 51 100

Source: Various studies cited in Matlon (1996)

Studies examining the adoption pattern of rice varieties indicate that technology-specific characteristics are much more important than farmer-specific characteristics(such as a farmer’s exposure to new technology, educational level, and size of farmholding) in driving the adoption of improved varieties in Africa (Adesina and Zinnah,1992; Edwin, 1995, 1996; Sedi and Adesina, 1996; Willis, 1996; and Ojehomom etal., 1996 cited in Matlon et al., 1996). Among these, post-harvest factors such asthreshing and starch content feature prominently.

17

The major source of an annual 3.5% growth rate in rice production from 1971 to 1991,was the expansion of the cultivated area, which grew at a little over 2.5% annually.During this period, rice yields increased only about 1.0% per year (Figure 2). Today,despite the rapid adoption of improved varieties, the average rice yields in Africa isonly 40% of the world mean. The gap between the current average yields realized infarmers’ fields and the potential yields in Western Africa range from 0.3 tons/hectarein deep-water/floating rice eco-systems to more than 2 tons/hectare in irrigated humideco-systems (Matlon et al. 1996).

Despite these discouraging yield figures, there is evidence of the potential impacts ofintroducing new varieties in several countries. For example, improved rice varieties inthe mangrove eco-system are reported to yield in excess of 2.4 tons/hectare. Thesevarieties out-yielded the best local materials by nearly 35% under low-input farmermanagement.

There are several studies which go beyond simply assessing adoption; they alsoattempted to evaluate the economic impact of increased production due to improvedvarieties. Adesina and Zinnah (1992) (cited in Matlon et al., 1996) concluded thatadoption of improved rice varieties in mangrove regions generated a total of $12million worth of economic benefits for Sierra Leone over the period 1986-90, and $0.4million for Guinea over the same five-year period. Studies evaluating the impact ofimproved rice varieties estimate the rates of return to mangrove rice in Western Africato be in the range of 18-26% (Appendix A). Based on rather conservative estimates ofthe potential substitution of existing improved varieties in Senegal by the newintroductions from WARDA, Fisher et al. (1995) estimated an internal rate of return(IRR) for rice research in the range of 50-65%.

3.4. Wheat

In the last few decades, African countries have been confronted by a rapidly increasinglevel of wheat consumption and importation mainly because of increasing urbanizationand partly due to policy distortions favoring wheat consumption (Tanner and Mwangi,1992). However, in terms of area and production, wheat is only the fifth mostimportant cereal crop in Africa after maize, sorghum, millet and rice. It is grown on anestimated 2.3 million hectares, with more than a third grown in Ethiopia and the restscattered among some 12-15 countries, mainly in Eastern, Central and SouthernAfrica.

Compared to other developing regions, the total resources devoted to wheat research inAfrica, measured by number of researchers and research expenditure, are quite modest(Table 10). In most of the growing countries, wheat research is handled by a multi-disciplinary group of scientists, addressing breeding, pathology, crop management andsocio-economic issues. The smaller NARSs cannot afford to commit more than one ortwo researchers to wheat research. Private sector involvement in wheat improvementresearch is limited to a few countries, such as Tanzania, Zimbabwe and Zambia. Onaverage, wheat research programs per country in Africa employ 4 FTE scientistscompared with 11 in Latin America and 142 in Asia. However, wheat researchintensity in Africa measured by number of researchers and expenditures per ton of

18

wheat is almost four times higher than the developing country average, reflecting thesmaller wheat area and the inability to capture economies of size in wheat research.Although a few large countries, such as Ethiopia, Sudan and Kenya, have active wheatbreeding programs, most small countries depend on testing and screening wheatgermplasm from other sources, especially from CIMMYT.

Table 10: Wheat research inputs in Africa and other developing regions, early 1990s

Region

Number of wheatimprovementresearchers

(FTE)

Wheatresearchersper country

Number ofresearchersper M t of

wheat

Researchexpenditure per ton

of wheat(1990 PPP$)

AfricaMiddle-east and North AfricaAsiaLatin America

39344719133

3.328.9

120.012.8

18.4 7.4 4.3 6.8

2.100.970.250.84

Source: Bohn and Byerlee (1993)

Indicators of Research Success

One indication of the success of the testing and wheat breeding efforts in Africa wasthe release of more than 140 improved wheat varieties (mostly semi-dwarfs) from1966 to 1990 (Table 11). During this period, the number of releases per country peryear averaged 0.7 in Africa, which was about one-third the rate in Asia and LatinAmerica, but of the same order of magnitude as in the Middle-East and North Africaregion. On average, the number of varieties released per million hectares of wheat areain Africa is estimated to be about 5 per year, which is more than twice the rate in otherdeveloping regions. As a result of these research efforts, African farmers, today, haveaccess to a steady stream of improved wheat varieties.

Table 11: Number of wheat varieties released and releases per million hectares in Africaand other developing regions.

Region Total releasesa

(1966-90)Releases per million ha

per yearAverage releases per

country per year

Africa 141 4.9 0.7Middle-east and North Africa 212 0.8 0.7Asia 312 0.4 2.1Latin America 551 2.2 2.1

Source: Byerlee and Traxler (1995)a Includes only spring wheat varieties, which occupies almost 100% of the wheat

area in Africa and more than 70% of the total wheat area in the developing world.

Although the number of varieties released in Africa is quite impressive, almost 85% ofthe varieties released during 1966-90 were direct transfers from CIMMYT, and about12% were based on crosses by NARSs using CIMMYT germplasm (Table 12). Thus,the tendency to use direct and indirect transfers from CIMMYT is greater in Africathan in any other region.

19

Table 12: Sources of new wheat varieties in Africa and other developing regions

RegionDirect transferfrom CIMMYT Adaptive

crossOther Total

(percentage)

Africa 85 12 4 100

Middle-east andNorth Africa

68 21 12 100

Asia 34 42 24 100

Latin America 57 29 14 100

Source: Byerlee and Moya (1993)

Impacts of Wheat Research

Wheat is often cited as an agricultural research success story that triggered the GreenRevolution in the irrigated areas of Asia and Latin America. Today, more than 80% ofthe wheat area in Asia and Latin America is cultivated under the high-yielding semi-dwarf varieties (Byerlee and Moya, 1993). The adoption of improved wheat varietiesin Africa (although impressive in relation to other food crops) is the lowest in thedeveloping world, covering a little more than 50% of the cultivated wheat area. Thisindicates the difficult agro-ecological environments under which wheat is produced inAfrica. Technical constraints, including weeds, soil erosion, soil acidity and drainageproblems in Africa require wheat varieties with special characteristics to ensure theiradaptation and adoption by farmers.

On average, wheat crop management practices in Africa are at a lower level than inother regions, as indicated by the lower adoption rate of improved varieties, low ratesof adoption of fertilizer and other modern inputs, and the relatively small areas underirrigation (Tanner and Mwangi, 1992). An encouraging factor, however, is that theadoption of improved semi-dwarf wheat varieties has steadily expanded over the lasttwo decades, achieving an accelerated increase in adoption of almost 3% per year(adding about 30 thousand hectares per year) in the late-1980s (Figure 6).

Low use of inputs in Africa has resulted in very low wheat yields, averaging about 1.5tons/hectare compared to 2.4 tons/hectare in other developing countries in the early1990s. The adoption of improved semi-dwarf varieties is estimated to contribute ahigh of 25% yield increase over traditional tall varieties in the irrigated areas and about10% in drought-prone areas. The yield effects of replacing traditional tall varietieswith improved semi-dwarf varieties in the rainfed environments that characterize mostof the wheat growing regions in Africa is estimated to be about 20% (Byerlee andTraxler, 1995). In addition to this, the continued adoption and replacement of modernvarieties contribute an estimated 1.2% per year yield gains due to research efforts ingenetic improvement and maintenance of disease resistance. In Africa, the estimatedyield gains from varietal replacement attributed to wheat improvement researchcontributed more than half the total average increase in farm yields (1.6%/year) in thepast two decades (Byerlee and Moya, 1993).

20

5

22

32

52

0

20

40

60

80

100

1970

Per

cen

t o

f ar

ea (

%)

1970 1977 1983 1990

Source: Byerlee and Moya (1993)

Figure 6. Adoption of semi-dwarf wheat varieties in Africa from 1970 to 1990

The yield effects due to the adoption of improved wheat varieties is estimated tocontribute about 150,000 tons of additional wheat production in Africa during the1977-90 period. This generated an estimated annual economic surplus of US$ 30million (measured in $ 1990) by the late 1980s (Byerlee and Moya, 1993). However,almost half of this surplus is attributed to CIMMYT’s research in the form of directand indirect transfers. The internal rate of return to wheat improvement research inAfrica, after accounting for the share of CIMMYT’s cost of wheat research, isestimated to be about 23%. In comparison with the estimated RORs of 91% in SouthAsia, 82% in Latin America and 71% in the Middle-East and North Africa,investments on wheat improvement research in Africa have yielded lower returns, buthave nonetheless been economically profitable (Byerlee and Traxler, 1995). Theseresults are in congruence with the country-level estimation of 33% ROR to wheatresearch investment in Kenya, the third largest wheat producer in Africa (AppendixA).2

One of the reasons for the relatively lower ROR on wheat improvement research inAfrica is the smaller size of wheat production environments and the resulting relativelyhigh research intensities. In fact, what the aggregate ROR figures do not show is theunderlying inefficiencies of many wheat research programs targeted at smallerenvironments. Despite the evidence of research spill-ins from CIMMYT in the form ofdirectly transferable, adapted wheat varieties, many research programs devoteresources to establish a breeding program aimed at developing new varieties.According to Maredia and Byerlee (1996) out of eight wheat research programssurveyed in Africa, four were found to be “relatively inefficient” because they were

2 A first of its kind impact assessment study in South Africa, noted in Appendix A, shows

the returns to investment (IRR) on wheat aphid control research program in the range of35-43% (Marasas et al., 1997). These high rates of return are attributed to 5 improvedresistant varieties released by the ARC-SGI (Agricultural Research Council-Small GrainInstitute), which covered almost 20% of the wheat area in the Central and Eastern FreeState region of South Africa within two years after the first variety was released in 1993.The yield advantage of these improved wheat varieties was estimated to be in the range of0.02 to 0.3 t/ha over the susceptible varieties that farmers use in that region.

21

concentrating on adaptive breeding rather than screening imported varieties. Twoprograms had negative net profitability on wheat research investment because the sizeof wheat production in their mandate region was too small to justify the research costs.These results indicate that there is considerable scope for increasing the efficiency ofwheat research resources by consolidating research programs and shifting the emphasisof research programs from adaptive breeding research to testing foreign varieties.

3.5. Other Food Crops in Africa

There are many other crops, including legumes (e.g., cowpeas, beans, groundnut), androots & tubers (e.g., cassava, yams, potatoes), which are immensely important foodcrops in Africa, both in terms of production and caloric contribution to African diets.However, the available evidence of research impacts on these food crops is scanty, notonly in Africa but also in other parts of the developing world.

Some of these crops have been labeled “orphan crops,” since little interest was shownby colonial powers and, initially, by the international donor community to improvethem. However, this has changed in the last few decades when they became themandated research crops of many IARCs (e.g., IITA, ICRISAT, CIAT, CIP) and afocus of some donor-supported collaborative research programs in Africa (e.g., Bean-Cowpea CRSP).

The table in Appendix A presents a summary of RORs to research for cowpeas andpotatoes. Although, the available evidence on impacts is scanty both in terms of cropand geographic coverage, it is nonetheless tangible, especially the impacts of beanresearch in Eastern and Central Africa. The available evidence is discussed below.

Impacts of Bean Research in Eastern and Central Africa

Common beans (Phaseolus vulgaris) are grown on more than 3.5 million hectares inAfrica. They are cultivated for subsistence and, increasingly, as a cash crop by manyfarmers, most of them women. For many rural and urban consumers in Africa, beansprovide the least expensive source of calories and protein. Although bean yields inAfrica have increased modestly during recent years, the rate of increase in productionstill lags behind population growth. The full realization of this crop’s potential tocombat hunger and poverty requires a major research effort aimed at overcoming keyconstraints.

Although a precise figure on research resources devoted to beans is not available, beanimprovement research is becoming increasingly important at both the national andinternational levels. For several years, the national bean research programs in Africahave been developing various technologies, including: high yielding, stress tolerantvarieties; pest management strategies; and soil fertility amendments to address beanproduction constraints and increase yields.

As a result of these increased efforts, the national programs in Africa have released 42new bean varieties since 1984. Nineteen of these were breeding lines developed atCIAT headquarters, and another 23 were selected in Africa based on CIATintroductions (CIAT 1996, p. 9). In Tanzania, for example, a total of 11 varieties have

22

been released for production (Madata et al., 1998). Grain yields of these releasedvarieties evaluated in farmers fields range from 1.1 to 1.9 tons/hectare, substantiallyabove the average yields of 0.5 to 0.7 tons/hectare of traditional bean varieties (Madataet al., 1998).

A review of the dissemination and adoption of new bean technologies in eight Easternand Central African countries in 1992-96 revealed that approximately 69 improvedbean varieties were widely available to farmers in these countries through formal andinformal seed channels (David, 1997). Only a few of these improved varieties wereavailable to farmers a decade ago; and at least 23 of the 69 varieties were released orfirst disseminated to farmers between 1992 and 1996 (David,1997). No comprehensiveinformation is yet available on the adoption and impact on crop production due to theadoption of new bean varieties. Recent adoption studies by Sperling et al. (1994) andHoogendijk and David (1997), however, report wide adoption of climbing beanvarieties in Rwanda and Uganda. In Mbale district, Uganda, an estimated 45% to 88%of farmers surveyed reported using improved bean varieties (Hoogendijk and David,1997). The 1992-93 study by Sperling et al. (1994) documented more than 40% offarmers cultivating improved bean varieties in Uganda. In terms of area, 10-20% of thetotal bean area in Rwanda in the early 1990s was planted to 20 improved climbingbeans introduced five years earlier. The study concluded that “the use of improvedclimbing beans annually brings 31 to 66 thousand additional tons of beans forRwanda, equivalent to an extra US$ 8 to 15 million in income to Rwandan farmers”(Sperling et al. 1994, p.8).

Impacts of Cowpea Research in Western Africa

Cowpeas, which most likely originated in West Africa, are now found throughout theworld. The principal production areas are Nigeria and Niger, with approximately one-half of world cowpea production (Sanders, 1994). Even though the cowpea area andproduction in other West African countries are relatively small, cowpeas are veryimportant in this region, both as a nutritional food source for the farm household andfor improving the cropping system by providing the fertility and other benefits of acereals-grain legumes rotation.

Research on cowpeas and the establishment and maintenance of cowpea germplasmwas probably first carried out in the early 1950's at the Federal West AfricanAgricultural Research Station at Bambey, Senegal (Bingen et al., 1988). At present,the largest cowpea research program in the region is probably in Nigeria. However,several NARSs including Senegal, Mali, Burkina Faso, Niger, Ghana and Cameroonalso have active cowpea research programs, with 1-3 FTE researchers (Lowenberg-DeBoer, Personal Communication). In addition to the efforts of NARSs, IITA, donor-supported collaborative networks (e.g., CRSP) and NGOs play an important role indeveloping and promoting the use of improved cowpea varieties in this region.

Cowpea breeding research in this region is mainly focused on developing resistancefor striga, field insects (aphids, thrips), storage insects (bruchids) and diseases. Thisresearch has had substantial successes in the introduction of new early maturingcowpea varieties in Western and Central Africa. In Ghana a new variety, Vallenga,

23

released in 1987, has been introduced on more than 20,000 hectares in the north,raising farmers’ yields to approximately one ton per hectare. The introduction of anearly maturing cowpea variety in northern Senegal in 1985 doubled the area sown tocowpeas and increased the national production from the previous fifteen year averageof 17,800 metric tons. to 66,000 tons in that year (Schwartz et al., 1990). Diffusion of8 new cowpea varieties in Burkina Faso was estimated to reach almost 100% of thecowpea area by 1992 (Sanders, 1994)..

The estimated yield differentials between improved and traditional cowpeas varygreatly depending on the production techniques. In Niger and Cameroon, the yieldadvantage was estimated to range from 25-46% depending on the region (Sterns andBernsten, 1994; Mazzucato and Ly, 1994).The yield advantage of the most recentISRA releases in Senegal, is about 40% over older improved varieties in on-farmtrials. Increases are larger with phosphate application and pest management.

The available evidence on economic rate of returns to cowpea research show thatimprovement research on this crop has ranged from as low as 3% in northernCameroon to as high as 32-92% in Senegal (Appendix A), suggesting that research andtechnology transfer activities in cowpeas have contributed to increased productivity ofthe agricultural sector in several countries.

The benefits of cowpea research are also in the form of gains due to maintaining yieldsover time in an increasingly difficult environment. It was estimated that, as a result ofthe development and diffusion of improved resistant varieties, about 25 to 50% inyield loss was averted (Sanders, 1994). For Burkina Faso and Mali, Sanders estimatedthat the annual benefits to maintaining farmers’ yields ranged from $0.8 to $4.8million per year between 1984 and 1992, using the most conservative assumption of25% yield decline in the absence of new varieties.

There are, however, other impacts of cowpea improvement research that are notquantifiable with the ROR measure. Notable among these is the impact on householdfood security by increasing the supply of fresh green-pods in the “hungry season.” Theearly harvest of cowpea grain and fresh green pods made possible by improved, earlymaturing varieties helps to alleviate the household food constraint faced early in theseason. In Senegal, for example, it was estimated that about 17.5% of total cowpeaproduction was consumed as fresh green pods. Another benefit of cowpea research notincluded in most ROR studies is the decline in storage losses of dried cowpeas.Recognizing the importance of post-harvest losses of cowpeas, the research agenda inseveral countries have shifted the breeding strategy to develop varieties resistant tostorage pests, such as bruchids, but also to develop new storage methods andtechniques to reduce grain losses. An impact assessment of progress in Cameroonshows an approximately 6% ROR for cowpea storage research if the technology isused only in northern Cameroon. However, if these technologies are extended andadapted to other Western African countries the ROR would be almost 50%(Lowenberg-Deboer, personal communication).

24

Impacts of Potato Research in Eastern and Central Africa

Potato is an important cash crop in the highlands of Eastern and Central Africa, grownon about 110,000 hectares. Beginning in the late 1960s and early 1970s, the increasingsupport for potato crop improvement has translated into the release of high yielding,disease-resistant varieties in the highlands of Burundi, Zaire, Rwanda and Uganda.Since 1980, more than 12 varieties have been released in the region, including 10 inBurundi alone. These improved varieties have been rapidly and widely diffused to thesmallholder farmers that grow potatoes in the region. By 1993, the total area underthese improved varieties was estimated to exceed 55,000 hectares, which is about 50%of the potato-growing area in this highland region. These improved, disease-resistantpotato varieties are estimated to yield 2.8 tons/hectare (or 40%) more than the averageyields of traditional varieties of 7.0 tons/hectare.

Given the high adoption rate and significant yield improvement in a period of less than15 years, the investment in potato research and extension in the highlands of Easternand Central Africa has been immensely profitable, with a ROR of 84% (Appendix A).The net benefits stream of potato improvement research in this region reached $10million annually in the late 1980s and early 1990s.

4. SUMMARY AND CONCLUSIONS

While progress has been uneven among countries, the scientific capacity of AfricanNARSs is greater than at any previous time, and more African farmers now haveaccess to a steady stream of improved technologies. This success is the result ofseveral developments: (a) increased financial support for NARSs from internationaldonors and national governments in the past three decades, (b) investments by NARSsin human capital development; and (c ) germplasm sharing through a network ofnurseries coordinated by IARCs and regional collaborative research programs. Theresearch efforts in Africa, today, are generally comparable to those in other developingregions, both in terms of number of researchers and their qualification. However, thesmall size of many African countries, combined with considerable diversity inenvironmental conditions, complicates the process of designing efficient research andextension systems. Because of the small size of most countries in Africa, IARCs andvarious regional networks have and will continue to play a major role in developingimproved agricultural technologies for African farmers.

In recent years, as a result of the growing donor pressure to demonstrate researchimpacts, an increasing number of studies have been conducted to document impactsand estimate RORs to research investment in Africa. These studies provide tangibleevidence of the increasing availability of improved varieties of major food crops tofarmers in Africa, increased food production in regions where adoption has occurred,and positive returns to research investment. They indicate that agricultural research inAfrica has had productivity-increasing impacts. The widespread adoption of improvedmaize, wheat and rice varieties is especially noteworthy, with more than 50% of thearea planted under these improved cereal crops by the early 1990s.

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As a result of the growing body of evidence, the impacts of agricultural research inAfrica can no longer be denied. The generation and diffusion of: improved, higher-yielding maize OPVs in Western Africa and hybrids in Eastern and Southern Africa;higher-yielding wheat in Eastern and Southern Africa; hybrid sorghum in Sudan; semi-dwarf rice for irrigated regions in Western Africa; early maturing cowpeas in WesternAfrica; and disease-resistant potatoes in the Eastern and Central African highlands arenow cited as outstanding success stories of technological change in food cropproduction in Sub-Saharan Africa.

There are however several qualifications to the crop improvement research successstory described in this paper. First, the results are patchy or uneven, by country andover time. The information available for the major legume and roots & tuber crops isnot sufficient to permit extrapolation. Second, despite the introduction of newvarieties, the resulting yield impacts have been less than expected, especially in thecase of crops grown under adverse conditions and without the use of external inputs.

Further, while returns to research (and extension) investments are reported to be quitehigh, the performance is variable across countries and crops. Food crops grown inregions dominated by commercial farmers, under irrigated conditions using fertilizersand better management practices, provided higher returns than crops grown in regionswhere the main change is only a shift to new varieties. The results also reflectconsiderable variability by country as a result of differences in agroclimatic factors,and the policy environment -- which can affect the supply of seeds and other inputs,and the continuity and stability of research investments. Finally, the increasingavailability of improved varieties is a necessary but not a sufficient condition forincreasing agricultural productivity. The adoption of improved varieties of food cropsthat respond to a package of purchased inputs, such as improved seed and fertilizer, isstrongly conditioned by the policies that affect input supply and prices, and the marketplace.

Crop improvement research in Africa can thus be regarded as a qualified success story.There are many important issues, both in and outside the agricultural research systemthat will need to be addressed if agricultural research is to continue to be a catalyst formodernizing African agriculture. These include: the size of NARSs, commodityresearch programs, relative emphasis on testing versus breeding, allocation ofresources to different research activities (crop improvement versus crop managementversus natural resource management) and geographic regions (high versus lowpotential areas), and low salaries and consequent high turnover among scientists.There is considerable potential for improving the efficiency of research systems. A keyto these improvements is to improve coordination among NARSs and for them tocontinue to increase their collaboration with regional and international organizations.It is also important for the NARSs to strengthen their research and analytical capacityfor more impact assessment work. The results of such work can influence theformulation of agricultural policy, and guide the development of a national agriculturalresearch agenda to enhance the impact of research on agricultural productivity.

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Appendix A

Summary of Rates of Return Studies for Africa by Major Food CropsAuthor(s) and date of study Location and years covered ROR (%)

Maize:Karanja, 1990Mazzucato, 1992Howard, Chitalu and Kolonge, 1993Boughton and de Frahan, 1994Smale and Heisey, 1994Kupfuma, 1994Quedraogo and Illy, 1996Sanders, 1994

Kenya, 1955-88Kenya, 1978Zambia, 1978-91Mali, 1969-91Malawi, 1977-92Zimbabwe, 1932-90Burkina Faso, 1982-93Ghana, 1968-91

40-60%58-60%84-90%135%63-64%44%78%74%

Sorghum and Millet:Mazzucato and Ly, 1994a

Sterns and Bernsten, 1994b

Ahmed, Masters and Sanders, 1995b

Sanders, 1994b

Anandajayasekeram, et al., 1995ab

Anandajayasekeram, et al., 1995bd

Aghib, 1996c

Niger, 1975-911975-2011Cameroon, 1979-98Sudan, 1979-92Cameroon, 1980-92Zimbabwe, 1980-99Namibia, 1988-99Eritrea, Ethiopia, Ghana, Mali, Niger, Mozambique, Rwanda, Senegal, Somalia and Sudan, 1985-2009

<02-21%1%53-97%2%22%11%

56%

Wheat:Makau, 1984Byerlee and Traxler, 1995Makanda and Oehmke, 1995Marasas, et al., 1997

Kenya, 1922-80Africa, 1973-90Kenya, 1921-90South Africa, 1980-2005

33%23%12%35-43%

Rice:Tré, 1995Seidi, 1996Fisher et al., 1995

Sierra Leone, 1976-2010Guinnea-Bissau, 1980-94Senegal, 1995-2004

18-21%26%66-83%

Other Food Crops:

CowpeaSchwartz, Sterns and Oehmke, 1993Sterns and Bernsten, 1994

Senegal, 1980-85Cameroon, 1979-98

32-92%15%

PotatoRueda et al., 1996 East and Central African highlands, 1978-93 84%

Source: For detailed citations, see references.

a Estimate includes joint investment on sorghum, millet and cowpeasb Estimate for sorghum research onlyc Estimate specifically for striga resistant sorghumd Estimate for millet research only

29

REFERENCES

Adesina, A.A. and Zinnah, M.M. 1992. “Using Farmers’ Perceptions to Re-OrientVarietal Technology Development Strategies: Case Study of Mangrove SwampRice in West Africa” Paper presented at the Rockefeller Foundation SocialScience Fellows Meeting, CIMMYT, Mexico, November 9-13, 1992.

Aghib, A.J. 1996. “The Economic Impact Assessment of the World VisionInternational - Purdue University Striga Resistant Sorghum Initiatives” Reportprepared for World Vision International. West Lafayette: Purdue University.

Ahmed, M.M., Masters, W.A. and Sanders, J.H. 1995. “Returns from Research inEconomies with Policy Distortions: Hybrid Sorghum in Sudan” AgriculturalEconomics, 12: 19\83-92.

Anandajayasekeram, P., Martella, D.R., Sanders, J.H., and Kupfuma, B. 1995a “CaseStudy 1, Zimbabwe, Sorghum: Impact of SV-2" Chapter 10 in Report on theImpact Assessment of the SADC/ICRISAT Sorghum and Millet ImprovementProgram: Volume I. Gaborone, Botswana: SACCAR.

Anandajayasekeram, P., Martella, D.R., Sanders, J.H., and Kupfuma, B. 1995b. “CaseStudy 2, Namibia, Pearl Millet: Impact of Okashana-I” Chapter 11 in Reporton the Impact Assessment of the SADC/ICRISAT Sorghum and MilletImprovement Program: Volume I. Gaborone, Botswana: SACCAR.

Bingen, J.R. Hall, A.E., and Ndoye, M. 1988. “California Cowpeas and Food Policyin Senegal” World Development 16(7): 857-865.

Boughton, D. and de Frahan, H.B. 1994. Agricultural Research Impact Assessment:The Case of Maize Technology Adoption in Southern Mali, MSU InternationalDevelopment Working Paper No. 41. East Lansing: Department ofAgricultural Economics, Michigan State University.

Byerlee, D. and Heisey, P. 1996. “Past and Potential Impacts of Maize Research inSub-Saharan Africa: A Critical Assessment” Food Policy, 21(3): 255-77.

Byerlee, D., and Moya, P. 1993. Impacts of International Wheat Breeding Research inthe Developing World, 1966-1990. Mexico, D.F.: CIMMYT.

Byerlee, D. and Traxler, G. 1995. “National and International Research in the Post-Green Revolution Period: Evolution and Impacts” American Journal ofAgricultural Economics 77 (May): 268-278.

30

CIAT. 1996. The African Bean Exchange: Patterns of Sharing. pp. 10. Cali: CIAT.

CIMMYT. 1992. 1991-92 CIMMYT World Maize Facts and Trends: Maize ResearchInvestment and Impacts in Developing Countries. Mexico, D.F.: CIMMYT.

CGIAR Technical Advisory Committee. 1995. Report of the Panel on CGIARCommitments in West Africa. Washington, D.C.: Food and AgriculturalOrganization of the United Nations.

Dalrymple, D.G. 1986. Development and Spread of High-Yielding Rice Varieties inDeveloping Countries. Washington, D.C.: USAID, Bureau of Science andTechnology.

David, Sonii. 1997. Dissemination and Adoption of New Technology: A Review ofExperiences in Bean Research in Eastern and Central Africa, 1992-1996.Network on Bean Research in Africa Occasional Publications Series No 21.Kampala, Uganda: CIAT.

Diallo, A.O., Edmeades, G.O., Tang, C.Y., Deutsch, J.A., and Bjarnason, M. 1990.“Breeding Strategies to Overcome Constraints and Increase MaizeProductivity in Sub-Saharan Africa” In B. Gebrekidan (ed.) MaizeImprovement, Production, and Protection in Eastern and Southern Africa:Proceedings of the Third Eastern and Southern Africa Regional MaizeWorkshop. Nairobi, Kenya: CIMMYT.

Edwin, J. 1995. “The Adoption of Improved Mangrove Rice in the Brumpeh RiverArea of Sierra Leone” WARDA Rice Economics Task Force PreliminaryReport.

Edwin, J. 1996. “The Adoption of Improved Rice Varieties in Inland Valley Swampsin Kambia and Port Loko Districts of Sierra Leone” WARDA Rice EconomicsTask Force Preliminary Report.

Fisher, M.G., Fall, A.A., and Sidibe, M. 1995. The Future Impact of Rice Research inthe Senegal River Valley. Draft Paper. Dakar: ISRA/BAME.

Friis-Hansen, E. 1989. Seeds of Wealth, Seeds of Risk? The Vulnerability of HybridMaize Production in Southern Highlands of Tanzania. CDR Project Paper88.2. Copenhagen: Center for Development Research.

Gerhart, J. 1975. The Diffusion of Hybrid Maize in Western Kenya, Research Reportfor CIMMYT. Mexico, D.F.: CIMMYT.

Gryseels, G. and Anderson, J.R. 1991. “ International Agricultural Research” in P.G.Pardey, J. Roseboom and J.R. Anderson (eds.) Agricultural Research Policy:

31

International Quantitative Perspectives. New York: Cambridge UniversityPress.

Herdt, R.W. and Capule, C. 1983. Adoption, Spread, and Production Impact ofModern Rice Varieties in Asia. Los Banos, The Philippines: IRRI.

Hoogendijk, M., and David, S. 1997. Bean Production Systems in Mbale District,Uganda, with Emphasis on Varietal Diversity and the Adoption of NewClimbing Varieties. Network on Bean Reserach in Africa, OccasionalPublications Series No 20. Kampala, Uganda: CIAT.

Howard, J., Chitalu, G.M., and Kalonge, S.M. 1993. The Impact of Investment inMaize Research and Dissemination in Zambia, Part I: Main Report, MSUInternational Development Working Paper No. 39/1. East Lansing: Departmentof Agricultural Economics, Michigan State University.

Karanja, D.D. 1990. The Rate of Return to Maize Research in Kenya: 1955-88,Unpublished M.S. Thesis. East Lansing: Department of AgriculturalEconomics, Michigan State University.

Kupfuma, B. 1994. The Payoffs to Hybrid Maize Research and Extension inZimbabwe: An Economic and Institutional Analysis. Unpublished M.S.Thesis. East Lansing: Department of Agricultural Economics, Michigan StateUniversity.

Kydd, J. 1989. “Maize Research in Malawi: Lessons from Failure” Journal ofInternational Development 1: 112-144.

Lopez-Pereira, M.A. and Morris, M. 1994. Impacts of International Maize BreedingResearch on the Developing World, 1966-1990. Mexico, D.F.: CIMMYT.

Low, A.C. and Waddington, S.R. 1990. “On-Farm Research on Maize ProductionTechnologies for Smallholder Farmers in Southern Africa: CurrentAchievements and Future Prospects” In B. Gebrekidan (ed.) MaizeImprovement, Production, and Protection in Eastern and Southern Africa:Proceedings of the Third Eastern and Southern Africa Regional MaizeWorkshop. Nairobi, Kenya: CIMMYT.

Madata, C.S., Mushi, C.S., Ampofo, J.K.O., and Kirkby, R.A. 1998. Beans: The“Meat” of Rural and Poor Urban Households. Background paper prepared forSPAAR Week 1998, Arusha, Tanzania.

Makanda, D.W. and Oehmke, J. 1995. The History of and Returns to Kenya WheatResearch, Department of Agricultural Economics Staff Paper No. 95-54. EastLansing: Michigan State University.

32

Makau, B.F. 1984. Measurement of Economic Returns to Wheat Research in Kenya,Unpublished M.A. Thesis. Nairobi: University of Nairobi, Kenya.

Marasas, C., Anandajayasekaram, P., Tolmay, V., Martella, D., Purchase, J., andPrinsloo, G. 1997. Socio-Economic Impact of the Russian Wheat AphidControl Research Program. Gaborone, Botswana: SACCAR.

Maredia, M.K., and Byerlee, D. 1996. “Determining the Efficiency of Research in thePresence of International Spillovers: Wheat Research in DevelopingCountries” Draft paper. East Lansing: Department of Agricultural Economics,Michigan State University.

Matlon, P., Randolph, T., and Guei, R. 1996. Impact of Rice Research in West Africa.Paper presented at the International Conference on the Impact of RiceResearch, Bangkok, Thailand, 3-5 June, 1996.

Mazzucato, V. 1992. Non-Research Policy Effects on Rate of Return to MaizeResearch in Kenya: 1955-88, Unpublished M.S. Thesis. East Lansing:Department of Agricultural Economics, Michigan State University.

Mazzucato, V. and Ly, S. 1994. An Economic Analysis of Research and TechnologyTransfer of Millet, Sorghum, and Cowpeas in Niger, MSU InternationalDevelopment Working Paper No. 40. East Lansing: Department ofAgricultural Economics, Michigan State University.

Morris, M., Clancy, C. and Lopez-Pereira, M.A. 1992. “Maize Research Investmentand Impacts in Developing Countries.” Part I of 1991-1992 CIMMYT MaizeFacts and Trends: Maize Research Investment and Impacts in DevelopingCountries. Mexico, D.F.: CIMMYT.

Oehmke, J.F. and Crawford, E.W. 1996. “The Impact of Agricultural Technology inSub-Saharan Africa” Journal of African Economies 5(2): 271-92

Ojehomom, V.E.T., Olaniyan, G.O., Ojehomon, O. 1996. “Rice Varietal Adoption inthe Inland Valley of Niger State of Nigeria” WARDA Rice Economics TaskForce Preliminary Report.

Ouedraoga, S. And Illy, L. 1996. Evaluation de l’Impact Economique des CordonsPierreux: Cas du Plateau Central au Burkina Faso” Mimeo. Ouagadougou:INERA.

Pardey, P.G., Roseboom, J., and Anderson, J. (eds.) 1991. Agricultural ResearchPolicy: International Quantitative Perspectives. New York: CambridgeUniversity Press.

33

Pardey P.G., Roseboom, J. and Beintema, N.M. 1997. Investments in AfricanAgricultural Research. World Development 25(3): 409-423.

Pomela, M.E. 1993. “Adoption of New Maize Production Technology on SmallFarms in Lesotho” In P. Heisey and S. Waddington (eds.), Impacts of On-farmResearch. Proceedings of a Workshop on Impacts of On-Farm Research inEastern and Southern Africa, Lilongwe and Harare: CIMMYT.

Rohrbach, D. 1989. The Economics of Smallholder Maize Production in Zimbabwe:Implications for Food Security. MSU International Development Paper No.11.East Lansing: Department of Agricultural Economics, Michigan StateUniversity.

Rohrbach, D. and Killian Mutiro. 1986. Formal and Informal Channels of Sorghumand Pearl Millet Seed Supply in Zimbabwe. Paper presented at National SeedPolicy Workshop, July 30-31, 1996, Harare, Zimbabwe.

Rueda, J.L., Ewell, P.T., Walker, T.S., Soto, M., Bicamumpaka, M., and Berrios, D.1996. “Economic Impact of High-Yielding, Late-Blight-Resistant Varieties inthe Eastern and Central African Highlands” In T.S. Walker and C.C. Crissman(eds.) Case Studies of the Economic Impact of CIP-Related Technologies.Lima, Peru: International Potato Center.

Sanders, J.H. 1994. “Economic Impact of the Commodity Research Networks ofSAFGRAD,” in J.H. Sanders, T. Bezuneh and A. Schroeder (eds.) ImpactAssessment of the SAFGRAD Commodity Networks. Washington D.C.:USAID/Africa Bureau.

Sanders, J.H. 1996. “Measuring Impacts of Sorghum/Millet Technologies in Sub-Saharan Africa” Paper presented at the INTSORMIL Principal InvestigatorsConference in Lubbock, Texas, September 21-22, 1996.

Schwartz, L. Sterns, J., and Oehmke, J. 1990. Impact Study of the Bean/Cowpea CRSPfor Senegal. East Lansing: Michigan State University.

Schwartz, L., Sterns, J., and Oehmke, J. 1993. “Economic Returns to CowpeaResearch, Extension, and Input Distribution in Senegal” AgriculturalEconomics 8:161-71.

Seidi, S. 1996. “An Economic Analysis of Rice Research, Extension and SeedProduction in Guinea-Bissau: Preliminary Evidence from the case of SwampMangrove rice” WARDA Rice Economics Task Force Preliminary Report.

Seidi, S. and Adesina, A.A. 1996. “Farmers’ Perceptions and Adoption of NewAgricultural Technology: Analysis of Modern Mangrove Rice Varieties inGuinea-Bissau” Quarterly Journal of International Agriculture, forthcoming.

34

Smale, M. and Heisey, P. 1994. “Maize Research in Malawi Revisited: An EmergingSuccess Story?” Journal of International development, 6(6): 689-706.

Smith, J., Barau, A.D., Goldman, A., and Mareck, J.H. 1994. “The Role ofTechnology in Agricultural Intensification: The Evolution of Maize Productionin the Northern Guinea Savanna of Nigeria” Economic Development andCultural Change 42(3): 537-554.

Sperling, L., Scheidegger, U., Buruchara, R., Nyabyenda, P., and Munyanesa, S. 1994.Intensifying Production Among Smallholder Farmers: The Impact of ImprovedClimbing Beans in Rwanda. CIAT Africa Occasional Publication SeriesNo.12. Butare, Rwanda: CIAT/RESAPAC.

Sterns, J.A. and Bernsten, R.H. 1994. Assessing the Impact of Cowpea and SorghumResearch and Extension in Northern Cameroon, MSU InternationalDevelopment Working Paper No. 43 East Lansing: Department of AgriculturalEconomics, Michigan State University.

Tanner, D.G., and Mwangi, W. 1992. “Current Issues is Wheat Research andProduction in Eastern, Central and Southern Africa: Constraints andAchievements” In: D.G. Tanner and W. Mwangi (eds.) Seventh RegionalWheat Workshop for Eastern, Central and Southern Africa. Nakuru, Kenya:CIMMYT.

Tre, J.P. 1995. The Rates of Return to Mangrove Rice Research in West Africa,Unpublished M.S. Thesis. West Lafayette: Purdue University.

Willis, R. 1996. “Modeling the Adoption of Improved Varieties of Mangrove Rice inthe Western Region of The Gambia” WARDA Rice Economics Task ForcePreliminary Report.