Published by the Sustainable Agriculture Programme of the
International Institute for Environment and Development
Plants, Genes and
the Relevance of
Michael P Collinson
GATEKEEPER SERIES No. 30
The Gatekeeper Series of the Sustainable Agriculture Programme is produced by the
International Institute for Environment and Development to highlight key topics in the field
of sustainable agriculture. The Series is aimed at policy makers, researchers, planners and
extension workers in government and non-government organizations worldwide. Each paper
reviews a selected issue of contemporary importance and draws preliminary conclusions of
relevance to development activities. References are provided to important sources and
background material. The Swedish International Development Authority and the Ford
Foundation fund the series.
Angelique Haugerud is Assistant Professor of. 'h,iii, '"l'. Yale University, Box 2114 Yale
Station, New Haven, Connecticut 06520, U SA and Michael P Collinson is Science Adviser in
the CGIAR Secretariat, 1818H St. NW, Washington DC 20433. US A.
This is an abbreviated version of a paper by the authors entitled "Plants, genes and people:
improving the relevance of plant breeding in Aifrica ". which appeared in Experimental Agricul-
ture (1990), Volume 26, pp 341-362. Experimental Agriculture is published by Cambridge
University Press. We are gratefid fbr permission to reproduce parts of this article.
GATEKEEPER SERIES NO. SA30
2 GATEKEEPER SERIES NO. SA30
PLANTS, GENES AND PEOPLE:
IMPROVING THE RELEVANCE OF
Plant breeding dominates international agricultural research, accounting for some 50% of the
budgets of the International Agricultural Research Centres. Recent innovations in breeding
programmes for developing nations highlight differences in selection criteria between farmers
and scientists, and among farmers themselves. Scientists' and farmers' assessments of new crop
varieties diverge, not because farmers lack formal scientific knowledge, but because scientists
often fail to use farmers' knowledge and to accommodate their constraints. Farmers' own cultivar
preferences vary according to characteristics such as farm size, family structure, gender, wealth,
and market opportunities.
Overlooking both types of divergence in breeding criteria carries the twin risks of releasing new
crop varieties farmers do not adopt, and rejecting germplasm farmers find valuable. Ignoring the
differences can also mean a breeding programme's new cultivars reach only a narrow range of
farmers. This paper addresses ways to reduce such risks.
Plant Breeding and the IARCs in Africa
In Africa, the International Agricultural Research Centres (IARCs) have spent more per head,
hectare and tonne of food, with less to show (as yet) for the effort than elsewhere. Africa's position
in the world economy, its diverse environments, economies and sociopolitical systems all contrast
sharply with the conditions of the Asian 'Green Revolution'. Communications, food transport
costs, the means to distribute agricultural inputs on time, water availability, soils and climatic
conditions are all less favourable in Africa than in Asia. Foreign exchange to import chemicals
and fertilizers is scarce, and both foreign and domestic terms of trade often work against
agriculture. African farmers diversify their economic pursuits and limit their dependence on
uncertain markets and government services.
Wheat and rice, Asia's food staples, are luxuries in Africa, yet staples such as sorghum, millet,
cassava, chickpeas and cowpeas have only recently received research attention from both national
programmes and IARCs, as have regions with poor soils and low and unreliable rainfall.
Africa's national research institutions often retain the orientations of western agricultural
education (Collinson, 1988). University agricultural curricula are still centred on large fields,
machines, straight lines and intensive management. These biases threaten the long-term
sustainability of African agricultural systems, and limit the relevance of national and interna-
tional research. Relevance is also jeopardised by a single-discipline focus, narrow peer group
evaluation, unquestioning adherence to inherited breeding strategies, and inadequate exposure of
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plant breeders to small farmers' circumstances.
Traditional western agricultural curricula, for example, discount inter-cropping, though many
plant scientists today recognize that insufficient research has been done on possible positive
interactions of species and cultivars planted in mixtures (Altieri, 1985; Willey 1979). Comple-
mentary effects involving the uptake of soil nutrients or water, for example, are poorly
understood, as is the degree to which crop and cultivar mixtures may slow the spread of pathogens
and pests. Yet intercropping research in Africa is often considered a retrograde step.
Attempts in the last decade to institutionalise processes for agricultural researchers (both national
and international) to learn directly from farmers, and for farmers themselves to do more than react
to scientists' proposals have been dominated by various types of farming systems research (FSR)
(Byerlee et al., 1982; Collinson, 1985, 1988; DeWalt, 1985; Horton, 1986; Merrill-Sands, 1986;
Norman et al. 1982; Rhoades, 1985; Eicher and Baker, 1982; Hildebrard, 1981). Though the term
FSR itself has become controversial, its basic principles are of lasting importance. These include:
- the need for close collaboration among technical scientists (both physical and biological) and
the usefulness of multi rather than single-commodity approaches (since farmers themselves
pursue multiple enterprises and evaluate technical innovations in any one crop in the context
of the systems they operate);
and explicit recognition that the farmer and other agents in the food system are the primary
clients of agricultural research, and that farmers' current production systems must be
understood in order to design and assess on-farm and on-station experimental programmes
intended to improve production.
The less effective alternative has been for researchers to seek the optimal way to grow crops and
to expect farmers to adjust to these requirements. When scientists' selections of new crop varieties
are based solely on features of the natural environment (such as rainfall, soils and temperatures),
farmers may reject the high-yielding varieties scientists most admire. More than maximum yield,
African cultivators often favour yield stability, short maturation periods, suitability for intercrop-
ping, storability and particular taste or cooking characteristics.
How African Farmers Use Cultivar Diversity
Breeding programmes have rarely exploited small farmers' sophisticated knowledge of differ-
ences among cultivars, and their use of these differences in cropping strategies. Cultivators
classify varieties, and value particular characteristics, for different purposes. They often manage
a combination of cultivars in the production process, and multiply or eliminate varieties as they
evaluate their performance over time (Brush et al, 1980; Conklin, 1988).
Farmers themselves are expert experimenters with new plant materials (Johnson, 1971; Ninez,
1984; Rhoades, 1987; Richards, 1985). When testing promising new plant genotypes, scientists
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can improve the relevance of their research by drawing upon farmers' own informal methods of
experimenting with unfamiliar cultivars and practices. Farm innovators over thousands of years
have enabled the human population to double ten times since agriculture began, including eight
doublings before industrialisation and the use of fossil fuels:
The human population expanded as traditional agricultural societies learned to domesticate
animals, select crop varieties, manage weeds and insects, and enhance nutrient recycling. Both
ecosystems and social systems were modified to sustain improved agricultural technologies.
The transformations occurred through experimentation, fortuitous mistakes, and natural selec-
tion (Norgaard, 1985).
African farmers are less likely than scientific breeders to seek a single best cultivar for any given
crop. Instead, an accepted new cultivar usually joins other valued genotypes of the same crop in
a farmer's fields. Mixed stands (of cultivars as well as species) are conventional. Plant breeders
can ease their own task by combining groups of relatively compatible traits into different cultivars
in the knowledge that farmers will readily manage more than one.
Yield stability in Africa, unlike that in industrial economies, depends on a patchwork of many
different varieties planted on the same farm, rather than on a continuous supply of new cultivars
(Plucknett and Smith, 1986). In the West, rapid evolution of new races of pathogens prompts a
frequent turnover of cultivars of such crops as wheat, for which the average lifespan of a new
variety in northwestern US is only five years (Plucknett and Smith, 1986). Wheat mixtures have
recently been rediscovered as a means of managing pathogens. The biological hazards of genetic
homogeneity in the US are demonstrated by the speed with which Florida's citrus crop succumbed
to citrus canker bacterial infection in the mid-1980s, and by the devastating southern corn leaf
blight in 1970. In 1983, for example, 86% of Florida's commercial orange harvest consisted of
just three varieties, while two-thirds of its grapefruit crop was made up of a single strain
In developing countries, cultivar specialisation may increase short-term profits for a few large
farmers, but threaten the long-term environmental and economic sustainability of production.
The IARCs can help national programmes to reduce the likelihood of epidemics caused by
breakdown of monogenic resistance in popular cultivars.
In addition to epidemiological reasons for monitoring cultivar specialisation in Africa, the local
relevance of breeding agendas depends upon understanding farmers' everyday strategies of
cultivar diversification. Some maize and potato examples illustrate this point.
How Rwandan Farmers Use Potato Cultivar Diversity
Farmers in Rwanda recognize several dozen different potato varieties, which they distinguish
according to plant and tuber traits, as well as agronomic and culinary characteristics. Most grow
three to eight different cultivars at once. They mix cultivars within fields, and use variability in
traits such as the length of the growth cycle, dormancy (time elapsed between physiological
maturity and sprouting), disease resistance (particularly late blight), tolerance of rainfall excesses
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and deficits, and dry matter content (which affects taste and storability) to manage the vagaries
of both nature and the market (Scott, 1988; Durr, 1980, Poats, 1981).
Since most potato varieties introduced into Rwanda before the late 1970s were from a relatively
narrow genetic base (European-adapted Solanum tuberosum), cultivar diversity provides less
protection against environmental hazards than in the crop's Andean homeland. Nonethless,
Rwandan farmers do use the available diversity to help reduce their production, consumption and
marketing risks, and to spread labour requirements and food supplies more evenly across the
annual cycle. Cultivar mixtures allow the use of staggered harvests and varied growth cycles,
which permit farmers to extend the period of fresh food and cash availability.
Distinctions between 'traditional' and 'modem' varieties, always problematic, are quickly
blurred in Rwanda, where potatoes have only been grown for about a century, and where in recent
decades dozens of cultivars have been introduced, from Europe and South America in particular.
The four most frequently grown potato cultivars in Rwanda (Montsama, Sangema, Gashara, and
Muhabura) have diverse origins. Agricultural research institutions introduced Montsama and
Sangema into Rwanda from Mexico in the 1970s, and Gashara from Europe a number of decades
ago. Farmers and traders probably brought Muhabura into Rwanda from Uganda. Montsama,
Muhabura and Sangema were multiplied and distributed by the Rwandan national potato research
programme (PNAP) in the late 1970s and early 1980s.
Farmers rate these four popular cultivars as having distinctly different maturity and dormancy
periods, water content, cooking time, storability, late blight resistance, market acceptability,
response to moisture stress, and suitability for intercropping (Haugerud, 1988). The variety
Muhabura, for example, though disliked for its taste and poor storability, is appreciated for its
short dormancy. Farmers appreciate Sangema for its taste, market acceptability, yields under
good rainfall, and late blight resistance (which Rwandan farmers equate with good yield under
heavy rain), though they appreciate less its long dormancy and long growth cycle.
The degenerated cultivar (degeneration refers to accumulation of viruses) Gashara would have
been abandoned long ago if disease resistance and yield were farmers' sole decision criteria.
Many farmers continue to cultivate Gashara, however, because of its short growth cycle, short
cooking time, short dormancy, and good taste (low water content). The continued popularity of
this cultivar suggests one neglected strategy for current breeding and germplasm screening. We
return later to this and other implications of the farm survey work for germplasm screening in
East African Farmers' Use of Maize Cultivar Diversity
Farmers recognize in maize, as in potato cultivars, important differences in taste, texture,
storability, marketability, disease and pest resistance, and response to moisture stress. At least
nine possible end uses, many of them simultaneously relevant on a single farm, help to determine
the maize genotypes east African farmers prefer. The crop may for example, be consumed at
home green or dry brewed for beer, or sold green or dry. In addition, the plant and grain may be
used green at various stages of maturity, or dry as food for livestock. Cultivar mixtures in maize,
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a sexually-reproduced, allogamous species, behave differently from those in an inbred, vegeta-
tively-propagated crop such as potatoes. The 'purity' of individual cultivars planted in field
mixtures is less in an outbreeder such as maize, while the possibilities for farmers themselves to
improve the crop through rustic forms of recurrent selection are greater.
As in the case of potatoes, many farmers plant both early and late maturing maize cultivars in
order to manage seasonal food gaps, to meet varied end uses of the crop, and to manage
environmental hazards (uncertain rainfall, diseases, pests). Maize farmers in parts of Zambia, for
example, plant traditional short-term cultivars (100-120 days) early in the season to obtain food
and because they taste better as green maize than do the later-maturing hybrids SR52 and ZH1
(170 days), which are produced mainly for sale. Zambian farmers give priority to the planting of
traditional varieties, which delays planting of the hybrids that require a 170-day season; 25% of
the hybrids are planted with only 125 remaining days of rain. When asked whether an improved
120-day cultivar would be useful to them, 96% of the farmers thought it would, and 63%
mentioned the advantage of early food (CIMMYT, 1978).
In Zimbabwe, farmers in Mangwende use maize varieties with differing times to maturity to
manage the variable timing of the rains. An October start to the rainy season results in first
plantings of SR52, a 170-day variety with high yield potential. If farmers have to replant because
of early drought, or delay planting because of late onset of the rains, they switch to shorter-cycle
cultivars such as R201 or R200 (both 135-140 days). Multiple plantings are common, and late
plantings of R201 or R200 extend into January. Late plantings help to insure against losses in the
crop planted earlier and allow a spread of oxen use over a longer period (Shumba, 1985).
The relative economic value of maize stover and grain also affects farmers' choice of cultivar. In
Somalia, there is a market for maize stalks that have been cut and dried. In land-scarce central
Kenya, some farmers prefer to plant a proportion of their land to the 600-series maize hybrids,
rather than the 500-series recommended for the zone, because its larger plant structure provides
more biomass for stall feeding of dairy cattle, a major source of cash for many households.
Farmers in the densely-settled parts of western Kenya show the same interest in maize stover.
Both green plant material and dry maize stover are important sources of cattle feed, and proposals
for two adaptive experimental programmes have been identified (Wangia, 1980). One was to
examine the increase in maize plant density needed to increase fodder production without
sacrificing grain yields in both the long and short rains. The second was to examine the effects
on grain and fodder yields of alternative times of picking the leaves and tops of maize when green.
Breeding Implications of Farmers' Cultivar Diversification
In industrialized economies, field mechanisation and consumer markets favour genotypic and
phenotypic uniformity. Standardised plants and products are less relevant to Africa's resource-
poor farmers. Crop breeding in Africa can benefit from the comparative advantage of the skilled
labour of small farmers in handling cultivar diversity, and in giving detailed attention to
individual plant types. Understanding decisions about the adoption of new cultivars requires
knowledge of farmers' present diversification strategies. This is not to suggest that scientists
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cannot stimulate changes in existing cropping patterns or husbandry practices, or that farmers will
adopt only those new cultivars that are higher-yielding replicates of currently popular varieties.
Rather, researchers must consider carefully the costs and risks farmers face, before investing time
and money in developing particular types of new cultivars.
Balancing Yield and Maturity Period as Selection Criteria
Conventional varietal selection based on yield favours later-maturing cultivars, given the
correlation of yield and period of photosynthetic intake. Farmers, however, may adopt shoter-
term varieties in agroclimatic zones where long-duration cultivars offer higher biomass and
yields. The rationale for such a choice becomes apparent once the scientist's analytical
framework shifts from the individual cultivar to a multi-crop and multiple season perspective.
Rather than assume farmers will accommodate any maturity period in a high-yielding cultivar,
breeders must first assess local constraints on maturity periods and then select for high yields
within locally appropriate maturity classes.
Although farmers are skilled at managing cultivar diversity, including multiple maturity periods,
even minor departures from current types can have wide ramifications for cash flow and food
security. If land is scarce, for example, adoption of a longer-maturing cultivar may mean an
unaffordable delay in the planting of another essential food staple on the same plot. A new variety
may require earlier planting or harvesting of a previous season's crop on the same land. It may
compete for scarce labour at critical points in the production cycles of other crops. A later-
maturing cultivar may introduce a constraint in the family consumption calendar if its longer
period in the field coincides with a period when food substitutes are unavailable. It may introduce
a family cash constraint if delayed harvest prolongs a period of cash shortage. In short, single-
crop or commodity research programmes cannot ignore other crops and enterprises that compete
for farmers' land, labour and cash resources, and that help farmers meet their food and cash needs.
Under conditions of bimodal rainfall and land scarcity, single season yields may be less important
to small farmers than annual productivity. In this situation farmers may choose to plant the
combination of cultivars that gives the best yields in two growing seasons, rather than a single
cultivar that gives the best yield in one season but precludes a second crop the same year and
therefore forces the farmer to purchase food on an expensive pre-harvest market. Some examples
from areas where land is scarce and rainfall bimodal illustrate these points.
Maize Maturity Classes in Western Kenya
Farming systems research has highlighted the disadvantage of the highest-yielding hybrids in
western Kenya's densely settled, high rainfall zone. The long maturation period of the high-
yielding 600-series Kitale hybrids makes it difficult to plant a second maize crop. The hybrids
are planted in March and not harvested until mid-September. Because rainfall is unreliable from
December to February, the late-standing 600-series crop leaves only 100 days for replanting with
a second maize crop in the last months of the year. The second maize crop is essential to poorer
families who have little land because maize prices in July and August, before the new long rains
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harvest, often reach three or four times the post-harvest prices. Unless they plant a second crop,
small farmers are forced to buy maize for food at high prices and then, for lack of cash, or because
they have mortgaged the crop to buy food earlier, they are forced to sell their crop at low post-
harvest prices. Such food purchases take precedence over input purchases from their limited cash
In recognition of farmers' need to secure a second crop, new on-farm experimental research began
to reconsider cultivar recommendations. Trials were designed to compare the performance of
maize varieties in the 130-to 180-day range in the long (March to August) and short (August to
December) rainfall periods and to identify the varietal combination that gives the best production
over the two seasons (Collinson, 1985).
Potato Maturity Classes in Rwanda
Farmers in Burundi rejected a new late-maturing (220-day), high-yielding maize variety although
it yielded 20 to 40% more than cultivars released previously (Zeigler, 1986) because they had to
wait six weeks longer to harvest it, so that the new variety did not permit a good second pea crop.
Field trials based on farmers' traditional practices showed that the higher yields of the late-
maturing maize cultivar occurred at the expense of family food security and nutritional balance,
since it did not fit into the complex local system of intercropping maize and beans and relay
cropping maize with peas. The late maize also had less stable yields.
In such a situation, selecting a new cultivar on the basis of single crop yield trials (rather than the
mixed cropping and relay cropping actually practised by local farmers) may result in the release
of a cultivar that is incompatible with farmers' needs and limitations, and that actually decreases
their nutritional and economic well-being.
Maize Maturity Classes in Burundi
In Rwanda the most densely populated country in sub-Saharan Africa extreme land scarcity,
bimodal rainfall, and late blight all affect farmers' potato maturity class preferences. Rainfall
distribution permits double, and in some zones multiple, cropping of potatoes. Late blight
increases with the spread of frungal spores in heavy rain, and farmers' traditional means of coping
with the disease is to plant late in the rainy season. Although higher-yielding, later-maturing
(120+ days) potato cultivars resistant to late blight became locally available in the late 1970s, by
the mid-1980s few fanners chose to rely on them. Short-duration cultivars allowed them greater
flexibility in managing very scarce land resources, in dealing with uncertain rainfall distribution,
and in managing food and cash needs.
For example, some farmers in the northern volcanic soils zone intercrop potatoes (planted in
April/May and harvested in August/September) with maize (planted in May and harvested in
January). After the potato harvest, they plant beans in the same maize field in September and
harvest them in December and January. The longer the cycle of the potato crop, the more difficult
it becomes to get the bean relay crop planted in time to catch the short rains.
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Most farmers prefer either short-duration cultivars alone (70-90 days), or a mixture of early,
medium and late cultivars (Haugerud, 1988). One rationale for the mixed strategy is that short-
cycle cultivars, by filling food and cash gaps, enable some farmers to grow long-cycle varieties
as well. Wealthier farmers with large land holdings can devote more land to late cultivars. Given
the nearly universal demand for some early cultivars, the Rwandan germplasm screening and seed
production programme, which had previously emphasised late cultivars, recently increased the
emphasis on short-duration cultivars. Previously, the programme had taken insufficient account
of the multi-crop and multiple-season framework in which farmers decide what cultivars to adopt.
Defining Appropriate Experimental Conditions
Efforts to match the conditions of resource-poor farmers in experimental fields are controversial.
Should varietal selection on the research station be conducted under husbandry conditions beyond
the reach of most African farmers? Identification of superior genotypes is more difficult under
low input conditions, where heterogeneity makes it difficult to apply equal selection pressure over
an entire plant population. More experimental replications are requried, since differences in
productivity may be small and statistical error large. Adjusting on-station research to farmers'
practices and priorities can complicate experimental design and analysis. Classic experimental
methodology, however, has its own shortcomings. Both conscious and unconscious decisions by
crop scientists produce more favourable crop environments on research stations than in farmers'
fields, and lead breeders to select genotypes that respond well to favourable environments
(Maurya et al, 1988; Simmonds, 1984).
One problem is to identify the changes to farmers' practices and priorities which it is reasonable
to expect them to adopt. The yield is in part due to circumstances beyond farmers' control (eg.
whether fertilizer or irrigation water arrives on time), as well as to farming practices that make
good biological, nutritional sense. Small farmers may use low inputs for a number of reasons: the
mix of production, consumption, and marketing priorities within the farming system; limited cash
resources; inadequate personal influence to obtain inputs; and limited capacity to risk high losses.
Small cultivators operate multiple enterprises as an integrated system, which requires compro-
mises in management, and therefore productivity, of any one constituent enterprise. Traditional
mixed cropping is a further dimension of this systems context with its own implications for
Another way in which germplasm screening can take greater account of the diversity of actual
farm conditions is to decentralise screening by the earlier release of promising material to farmers
for testing in on-farm trials, as in a successful rainfed rice breeding programme in India (Maurya
et al, 1988).
When scientists define treatment and non-experimental variables for cultivar selection, they
manipulate management practices such as time of planting, soil fertility, water availability,
chemical protection against diseases and pests, intercropping, relay cropping, cultivar mixtures,
crop rotation and plant spacing. The more explicitly they take such decisions from a knowledge
of farmers' practices, and the less tied they are to traditional textbook experimental design, the
more useful research results are likely to be. Some illustrations follow.
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Time of Planting and Maize Performance
Maize yields are substantially reduced each day that planting is delayed after the onset of rains
Acland (1971) reported reductions of 55-110 kg ha-1 for each day planting was delayed in
Kenya's Rift Valley Province, and as much as 170 kg ha -1 d-1 in the Eastern and Central
Provinces, where the season is shorter. Labour and draught power constraints, however, lead
many small farmers to continue to plant maize for two or even three months after the start of the
rains. Contrary to conventional wisdom that late planting demonstrates small farmers' irration-
ality, scientists now recognize that labour and power constraints limit farmers' ability to plant at
the 'optimal' time. Indeed, the appropriate variety for small farmers will often be 20-30 days
quicker maturing than the breeders' preferred full-season cultivar. In addition, some cultivars
intentionally avoid planting early in order to reduce the risks from hazards such as uncertain
rainfall or diseases and pests associated with rainfall. Interest has therefore grown in the effects
of late planting on varietal choice, and in the selection of cultivars adapted to small farmers'
Fertilisers and Maize
Agronomic recommendations aimed solely at yield maximisation underestimate the importance
of yield stability and hazard management to resource-poor farmers. Improved maize cultivars
tested without fertilizers in on-farm trials in Malawi, for example, were more than twice as
unstable as local maize. With fertilizer, yield stability improved for both local and improved
maize, though the latter remained significantly less stable than the local maize (Hildebrand and
Poey, 1985). Farmers also limit their use of purchased inputs such as fertilisers when they fear
damaging losses from environmental hazards. Producers in southern Zimbabwe, for example,
apply a basal dressing of compound fertilizer after rather than before the maize crop emerges, in
order to reduce their losses from poor germination (Shumba, 1985).
Experimental Conditions and Potato Varietal Selection in Rwanda
One potato research programme in Rwanda owes its success in part to the screening of germplasm
without fertilisers or fungicides. The programme recognized early that most farmers' only
commercial inputs would be occasional seed purchases; since degeneration rates (accumulation
of viruses) are low in the highlands, farmers can multiply their own seed for five to ten years. In
order to benefit the minority of farmers who can afford other inputs, scientists in the Rwanda
programme also carry out separate fungicide trials and train extension officers in their use.
In its first five years Rwanda's low-input screening programme introduced six improved cultivars
whose yields without chemical inputs were two to five times the previous national average
(PNAP, 1984, 1985). Germplasm sources for the improved cultivars included South America,
Mexico and Europe. Two previously introduced cultivars which the programme re-released in
1980 were found in all the country's major potato producing regions in 1985. In nearly two-thirds
of 360 potato fields observed in 1985, either Montsama or Sangema occupied the largest area
(Haugerud, 1988). As about half of all potato fields are intercropped with maize, beans, sorghum,
colocasia and sweet potatoes.
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On-station trials began to consider the comparative performance of the improved cultivars in
these various crop associations. Trials of potatoes intercropped with maize in 1987 showed that
land equivalent ratios increased with increasing plant densities, even when plant densities of
associated crops were those normally used in pure stands (7.2 potato plants and 8.0 maize plants
per square metre; preliminary results are reported by Jeroen Kloos in the 1987 CIP regional
progress reports). Trials to test the performance of field mixtures of improved potato cultivars
were also recommended, after farm surveys showed that most farmers grow three to five different
potato cultivars at once, most of their fields being planted with cultivar mixtures.
Participatory Breeding Research
It is easy to assert that defining appropriate varietal screening priorities and experimental
conditions require frequent and direct communication both between farmers and researchers and
between researchers of different disciplines (economists, anthropologists, breeders, agronomists,
phytopathologists, soil specialists). Few biological scientists, however, are trained in techniques
to elicit and to apply knowledge from farmers (Richards, 1985; Brokensha et al. 1980).
Although it sounds straightforward for scientists to learn from farmers, and to convene groups
or panels or innovator workshops, how to do this is rarely part of scientists' training, and good
methods are anyway not well known. Nor has discussion of such methods penetrated the harder
professional literature (Chambers and Jiggins, 1985).
After a decade of rhetoric about feedback of farmers' problems to extension workers and
scientists, a large gap remains between the ideal and the reality., Innovations in both training and
methods are required to bridge this gap. To the usual on-station and on-farm trials, and formal
and informal surveys must be added less familiar approaches such as panels of farmers who
regularly meet with and advise scientists, one-shot group interviews, the training of scientists in
role reversal, workshops with innovative farmers, and village meetings in which farmers decide
on the design of on-farm trials. Farmers included in the design of on-farm trials can "contribute
to defining evaluation criteria, before researchers [have] screened out most of the options by
fixing the experimental design" (Ashby, 1986). When setting up on-farm variety trials, scientists
can begin by asking farmers how they themselves would test a new cultivar on their own land
(Biggs, 1988). In addition, researchers can track farmers' own innovations, which take them
beyond the limitations of reductionist methods of on-station trials, as they adapt new cultivars to
complex intercropping, rotation and agroforestry practices, and as they exploit diverse microen-
vironments (Chambers and Jiggins, 1985). Large-scale formal surveys, with their well-known
problems of data reliability, sampling biases, logistical costliness, and lengthy processing
requirements, are also increasingly replaced by less formal and more innovative techniques. In
such attempts, team work, rather than 'lone ranger' research (Robert Rhoades' term) increases the
credibility of results.
Farmer Participation in On-Station Germplasm Screening
Normally when on-station germplasm plots were harvested in Rwanda's national potato research
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programme, the entire research team (breeder, agronomist, pathologist, anthropologist) were
present to select by consensus genotypes to keep for further stages of testing and multiplication.
In a novel initiative, farmers were invited to make their own selections from the station fields, and
to explain their reasoning to scientists. Researchers found that they had previously assumed too
narrow a range of local acceptability in traits such as tuber colour, size, shape and uniformity.
Whereas some researchers, for example, had for years favoured red-skinned clones, farmers
found red, white and pruple skins all to be acceptable. The only skin types farmers strongly
rejected were russets, which they believed to be diseased.
In other words, the scientists were more conservative than the farmers, and their misconceptions
led to unnecessary rejection of some potentially useful potato germplasm. Formal farm surveys
of existing varieties and preferences confirmed these findings. Incorporating farmers into on-
station germplasm screening can produce useful information at little cost.
Participatory research, then, can become a two-way flow that both takes scientists to farmers'
fields and brings farmers to the scientists' fields. CIAT's bean research programme in Rwanda
subsequently adopted this approach. Female bean seed experts now participate in on-station bean
varietal assessment (Sperling, 1988). Women farmers (since they rather than men tend the crop)
visit on-station germplasm trials at two or three critical points in bean growth (at flowering and
formation of pods, at maturation, and at harvest). Also valuable to both the scientists and visiting
farmers are the observations of station field labourers (themselves usually small farmers) who see
the scientists' trials through the entire crop cycle. In the Rwandan potato research programme,
local scientists knew that some station labourers were both very keen observers of experimental
germplasm, and experimenters with promising plant material on their own farms. These labourer-
farmers were among those who assessed potato germplasm in the exercise mentioned. This
technique is a useful complement to farmer-managed trials in farmers' fields.
Plant breeders cannot respond to every quirk of farmers' circumstances. Their task becomes more
complicated, costs increase, and progress slows as the number of selection criteria increases.
Breeders require general guidelines based on accurate prior identification and ranking of cultivar
traits that particular categories of producers and users find important, discarding less relevant
screening criteria, and assessing farmers' capacities to change existing practices. Crop breeding
is a long-term investment; decisions taken at the outset have implications for many years to come.
If farmers in Africa, Asia and Latin America are to influence agricultural research more directly,
researchers and extensionists need better incentives and improved ability to address farmers'
needs. Skills to bridge the social distance between 'authoritarian' scientists and 'deferential'
farmers are essential, so that "when farmers experiment with low fertilizer applications to find out
what works and pays best for their conditions", researchers will see them as experimenters rather
than as "deviants who do not adopt recommended practices" (Chambers and Jiggins, 1985; Ashby,
Social science skills are often underutilised in the design and analysis of on-station and on-farm
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farmer participation: a strategy for rice breeding in rainfed areas of India. Experimental
Merrill-Sands, D. 1986. Farming systems research: clarification of terms and concepts. Experi-
mental Agriculture 22,87-104.
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Savannah. Boulder, Colorado, Westview Press.
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Poats, S. 1981. La pomme de terre au Rwanda: resultats preliminaire d'une enquete de
consommativa. Bulletin Agricole du Rwanda ND 14, 82-91.
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Systems in Mangwende, a High Potential Area in Zimbabwe. Research Report No 5. FSRU, DR
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Scientific Research Division, Ministry of Agriculture.
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GATEKEEPER SERIES NO. SA30
1. Pesticide Hazards in the Third World: New Evidence from the Philippines. 1987.
J.A. McCracken and G.R. Conway.
2. Cash Crops, Food Crops and Agricultural Sustainability. 1987. E.B. Barbier.
3. Trees as Savings and Security for the Rural Poor. 1988. R.J.H. Chambers.
4. Cancer Risk and Nitrogen Fertilisers: Evidence from Developing Countries. 1988.
J.N. Pretty and G.R. Conway.
5. The Blue-Baby Syndrome and Nitrogen Fertilisers: A High Risk in the Tropics?
1988. J.N. Pretty and G.R. Conway.
6. Glossary of Selected Terms in Sustainable Agriculture. 1988. J.A. McCracken and
7. Glossary of Selected Terms in Sustainable Economic Development. 1988.
E.B. Barbier and J.A. McCracken.
8. Internal Resources for Sustainable Agriculture. 1988. C.A. Francis.
9. Wildlife Working for Sustainable Development. 1988. B. Dalal-Clayton.
10. Indigenous Knowledge for Sustainable Agriculture and Rural Development. 1988.
D.M. Warren and K. Cashman.
11. Agriculture as a Global Polluter. 1989. J.N. Pretty and G.R. Conway.
12. Evolution of Agricultural Research and Development Since 1950: Toward an
Integrated Framework. 1989. R.E. Rhoades.
13. Crop-Livestock Interactions for Sustainable Agriculture. 1989. W. Bayer and A.
14. Perspectives in Soil Erosion in Africa: Whose Problem? 1989. M. Fones-Sondell.
15. Sustainability in Agricultural Development Programmes: The Approach of
USAID. 1989. R.O. Blake.
16. Participation by Farmers, Researchers and Extension Workers in Soil Conservation.
1989. S. Fujisaka.
GATEKEEPER SERIES NO. SA 30
17. Development Assistance and the Environment: Translating Intentions into Practice.
1989. M. Wenning.
18. Energy for Livelihoods: Putting People Back into Africa's Woodfuel Crisis. 1989. R.
Mearns and G. Leach.
19. Crop Variety Mixtures in Marginal Environments. 1990. J. Jiggins
20. Displaced Pastoralists and Transferred Wheat Technology in Tanzania. 1990. C. Lane
and J.N. Pretty.
21. Teaching Threatens Sustainable Agriculture. 1990. R.I. Ison.
22. Microenvironments Unobserved. 1990. R. Chambers.
23. Low Input Soil Restoration in Honduras: the Cantarranas Farmer-to-Farmer Extension
Programme. 1990. R. Bunch.
24. Rural Common Property Resources: A Growing Crisis. 1991. N.S. Jodha
25. Participatory Education and Grassroots Development: The Case of Rural Appalachia.
1991. J. Gaventa and H. Lewis
26. Farmer Organisations in Ecuador: Contributions to Farmer First Research and Develop-
ment. 1991. A. Bebbington
27. Indigenous Soil and Water Conservation in Africa. 1991. Chris Reij
28. Tree Products in Agroecosystems: Economic and Policy Issues. 1991. J.E.M. Arnold
29. Designing Integrated Pest Management for Sustainable and Productive Futures. 1991.
Michel P. Pimbert
30. Plants, Genes and People: Improving the Relevance of Plant Breeding. 1991.
Angelique Hangerud and Michael P. Collinson
Copies of these papers are available from the Sustainable Agriculture
Programme, IIED, London (2.50 each inc. p and p).
GATEKEEPER SERIES NO. SA 30
The Sustainable Agriculture Programme
The Sustainable Agriculture Programme of IIED promotes
and supports the development of socially and environ-
mentally aware agriculture through research, training,
advocacy, networking and information dissemination.
The Programme emphasises close collaboration and con-
sultation with a wide range of institutions in the South.
Collaborative research projects are aimed at identifying
the constraints and potentials of the livelihood strategies
of the Third World poor who are affected by ecological,
economic and social change. These initiatives focus on
indigenous knowledge and resource management; par-
ticipatory planning and development; and agroecology
and low external input sustainable agriculture.
The refinement and application of Participatory Rural
Appraisal methods is an area of special emphasis. The
Programme is a leader in the training of individuals from
government and non-government organizations in the
application of these methods.
The Programme supports the exchange of field experi-
ences and research through a range of formal and informal
publications, including RRA Notes, aimed at practitioners
of Rapid and Participatory Rural Appraisal, and the Gate-
keeper Series, briefing papers aimed at policy makers. It
receives funding from the Swedish International Develop-
ment Authority, the Ford Foundation, and other diverse
International Institute for
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