new wheats for sustainable future
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New Wheatsfor a Secure,
Sustainable Future
Timothy G. Reeves, Sanjaya Rajaram,
Maarten van Ginkel, Richard Trethowan,
Hans-Joachim Braun, and Kelly Cassaday
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M aarten van Ginkel, head of bread w heat
breeding at CIM M YT, holds one of the
large-spiked w heats (right) that promise
to raise yields in w heats. On the lef t he
holds a normal w heat spike. (See page 7.)
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29
New Wheats for
a Secure, Sustainable
Future
Timoth y G. Reeves, Sanjaya Rajaram, Maar ten v an Ginkel,
Richard Trethow an, Hans-Joachim Brau n, and Kelly Cassaday*
* All au thors are staff of CIMMYT. T.G. Reeves is Director General; S. Rajaram is Director
of the Wheat Program; M. van Ginkel is Head , Bread Wheat Breeding; Richard
Trethow an is a Wheat Breeder; H.-J. Braun is a Wheat Breeder (based in Tur key); andKelly Cassaday is a Writer/ Editor. An earlier version of this paper w as presented at the
9th Wheat Breeding Assembly, 27 September-1 October, 1999, University of Southern
Queensland , Toowoom ba, Queensland , Australia.
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CIMMYT (www.cimmyt.mx or www.cimmyt.cgiar.org ) is an internationally fund ed, nonp rofit
scientific research and training organization. Head quartered in Mexico, the Center works w ithagricultura l research institutions worldw ide to improve the p rodu ctivity, profitability, and
sustainability of maize and wh eat systems for poor farmers in developing countr ies. It is one of 16
similar centers sup ported by the Consu ltative Group on International Agricultura l Research
(CGIAR). The CGIAR comprises about 60 partner countr ies, intern ational and regiona l
organizations, and private found ations. It is co-sponsored by the Food and Agriculture
Organ ization (FAO) of the United Na tions, the Interna tional Bank for Reconstru ction and
Developm ent (World Bank), the United Na tions Developm ent Programm e (UNDP), and th e United
Nations Environment Programme (UNEP). Financial support for CIMMYTs research agenda also
comes from m any other sources, includ ing foun dations, development ban ks, and pu blic and private
agencies.
CIMMYT supp orts Future H arvest, a public awareness campaign th at buildsund erstanding about th e importance of agricultura l issues and international
agricultura l research. Futu re H arvest links respected research institutions, influential p ublic figures,
and leading agricultural scientists to und erscore the w ider social benefits of improved agriculture
peace, prosperity, environmental renew al, health, and the alleviation of hu man suffering
(www.futureharvest.org).
Interna tional Maize an d Wh eat Imp rovem ent Cen ter (CIMMYT) 1999. Responsibility for this
publication rests solely with CIMMYT. The designations employed in the presentation of material
in this pu blication do not imp ly the expressions of any opinion w hatsoever on th e part of CIMMYT
or contribu tory organ izations concerning the legal statu s of any countr y, territory, city, or area, or of
its authorities, or concerning the delimitation of its frontiers or boun daries.
Printed in Mexico.
Correct citation: Reeves, T.G., S. Rajaram, M. van Ginkel, R. Trethow an, H -J. Brau n, an d K.
Cassa day. 1999.New Wheats for a Secure, Sustainable Future. Mexico, D.F.: CIMMYT.
Abstract: This paper reviews strategies used by CIMMYT and its partners to develop su stainable
wh eat prod uction systems for favored and marginal areas. These strategies aim to a chieve an
optimal combination of the best genotyp es (G), in the right environments (E), und er ap propriate
crop m anagem ent (M), and app ropriate to the needs of the people (P) wh o mu st implement and
man age them . The first section of the pap er presents new options for raising w heat yield potential
and discusses research on disease and stress tolerance, which is aimed at protecting yield p otential
in farmers fields (with special emp hasis on drou ght tolerance). Next, advances in dur um wh eatyield p otential are reviewed ; these advances may p rove particularly valuable in m arginal
environments. Other w heat research initiatives for ma rginal environments are d escribed as w ell.
This is followed by a review of the role of biotechnology in wheat improvemen t, research on w heat
quality, and initiatives in crop an d natur al resource managem ent research. The pap er conclud es
with a su mm ary of the latest data on th e global impa cts of wheat research and a discussion of
trends that could affect whether and how th is imp act is maintained.
ISBN: 970-648-040-4
AGROVOC descriptor s: Whea ts; Triticum; Ha rd w heat; Winter crops; Spr ing crops; High yield ing
varieties; Hybrids; Plant production; Production policies; Food production; Food security; Plant
breeding; Plant biotechnology; Nutrient improvement; Drought resistance; Pest resistance; Disease
resistance; Crop management; Resource management; Sustainability; Innovation adoption; Yield
increases; On farm research
Additional keywords: CIMMYT; Participatory research
AGRIS category codes: E14 Developmen t Economics and Policies; F30 Plant Gen etics and Breeding
Dewey decimal classificataion: 338.162ii
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Contents
iv Acknow ledgm ent s
1 New Wheats for a Secure, Sustainable Future
2 Agriculture: An Agent of Change
3 Prerequisites for Sustainable Agriculture
4 Breeding Wheats for Lasting Food Security
4 Options for Increasing Yield Potential
6 Gen e p ools of w in ter and sp rin g h exap loid w heats
6 In trogressin g sp rin g an d win ter wh eat gen e p ools
6 Ch in ese w heats: A w ellsp rin g of d iversity
6 Hybrid wheats7 Landraces
7 Improved plant ideotype
7 Phenological traits
7 Physiological traits
8 Synthetic w hea ts: Deliver ing diver sity to p lan t breeder s
8 Alien su bstitu tions and translocations
9 Protecting Yield Potential: The Role of Resistance to
Pathogens and Pests11 M oving beyond Marginal Yields in Marginal Environments
11 Breed ing for d rought tolerance
14 Higher yield ing durum wheats
15 Regional resea rch on w hea t for marg inal environments
16 Improvements in Wheat Quali ty
17 Biotechnology and Wheat Improvement: An Example ofCollaboration
18 Crop and Natural Resource M anagement Research
19 Improved input use efficiency
19 Bed planting systems
20 Farm er participatory research
21 Information Management Tools for Sustainable Systems
22 Conclusions
24 A n ew research parad igm for n ew research im p acts
24 The shape of things to come
27 References
ii i
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Acknowledgments
The authors are grateful to man y colleagues within CIMMYT who
contribu ted information for this pap er. Special thanks go to staff ofthe Wheat Program, as much of their research is d escribed here,
includ ing A. Mu jeeb-Kazi, I. Ortiz-Monasterio, J. Pea , W. Pfeiffer,
M.P. Reynolds, R.P. Singh, K.D. Sayre, and P. Wall. L. Harrington
and J. White of the N atural Resources Group , and A. McNab an d
D. Poland of Information Services, also generou sly provid ed
information for th is pap er. We than k the CIMMYT design section
for layou t and prod uction of the pu blication.
None of the work reported here would have been possible
withou t the continuining sup port of CIMMYTs investors, themem bers of the CGIAR. Amon gst those we p articularly than k our
core investors.
iv
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2
Agriculture: An
Agent of Change
The role of more prod uctive, profitable
maize and wh eat systems in fostering
food secur ity, generating local
employment, raising local incomes,
and thus alleviating poverty mu st not
be un derestimated. A recent report
(UNDP 1997) emp hasizes that
agricultural research is the central
means of achieving those goals:About th ree-quarters of the worlds
poorest people live in ru ral areas,
depend ent on agricultural activities
for their livelihood s. For these peop le,
pro-poor growth m eans raising
agricultu ral prod uctivity, efficiency,
and incomes. The report p oints out
wh y agricultu re can succeed w here
other initiatives migh t fail: Raising
the productivity of small-scale
agricultu re does more th an benefit
farmers. It also creates emp loyment on
the farm an d offand redu ces food
prices. The poor benefit most, because
about 70% of their consum ption is
food, mostly staples, and regular
sup plies and stable prices can greatly
redu ce the vulnerability of the poor.
Strong support to small-scaleagricultu re was at the core of the most
successful cases of pover ty
reductionsuch as China in 1978-85,
Malaysia since 1971, and Ind ia in the
early 1980s.
In these circum stances, the
challenges for researchand the
opp ortun ities to alleviate mu ch
hu man su fferingare clear. We will
have to develop the innovations that
make it possible for peop le to benefit
from m ore efficient, low-cost systems
for food prod uction. These systems
mu st fun ction w ithout m ining the
natu ral resources on which agriculture
dep end s. They are needed urgen tly in
favored as w ell as less favored
agricultu ral areas.In this paper, we review strategies
used by the International Maize and
Wheat Imp rovement Center
(CIMMYT) and its par tners to develop
sustainable wheat1 production
systems for favored an d m arginal
areas. These stra tegies aim to achieve
an op timal combination of the best
genotypes (G), in the rightenvironments (E), un der ap prop riate
crop m anagem ent (M), and
app ropriate to the needs of the peop le
(P) wh o mu st imp lement and manage
them (Reeves 1998, 1999). Each
variable in th is GxExMxP
sustainability equation is add ressed
in the sections that follow. After furth er
defining what w e mean by
sustainable technology, we:
Review new options for raising w heatyield poten tial.
Discuss research on d isease and stresstolerance, wh ich is aimed at
protecting yield p otential in farm ers
fields. We give special emp hasis to
drought tolerance.
Describe advances in du rum wh eatyield p otential wh ich may p rovepar ticularly valuable in marginal
environments.
1 In this paper we focus on strategies
related to wheat, although CIMMYTs
research mand ate encompasses maize as
well. We also give greater attention to
wh eat genetic improvem ent than to
crop and natu ral resource management
research, but readers shou ld be ad visedtha t CIMMYT engages in a great d eal of
crop and resource management
research, for w heat as w ell as maize. Fora general overview, see our annual
report, CIMMYT in 1998-99:Science to
Sustain People and the Environment.
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3
Provide an overview of other w heatresearch initiatives for marginal
environments.
Review the role of biotechnology in
wh eat improvement. Describe recent research on w heat
qua lity. For m any p oor farmers, an
increase in wh eat quality means a
correspond ing increase in income.
Briefly review recent initiatives incrop an d natural resource
management research in w heat.
We conclude by su mm arizing the
latest data on th e global impacts of
our w heat research and by d iscussing
trends that could affect wh ether and
how this imp act is maintained into
the future.
Prerequisitesfor Sustainable
Agriculture
To be susta inable, farm ing system s
mu st be biologically sensible,
economically viable, environmentallysound , socially acceptable, and
politically su pp ortable (Reeves 1998,
1999):
Sustainable farming systems m ust bebiologically sensible. For examp le,
the choice of crop(s), their
management, and the level of
intensification m ust be consistent
with the biophysical realities of the
farming system.
Sustainable farming systems m ust beeconomically viable at the farm and
national levels. Poor farmers cannot
invest in systems that w ill not
prod uce reasonable yields and (even
better) cash income, now and in the
future. At the national level, the
reality in most d eveloping countries
is that econom ic well-being and
developm ent are almost invariably
based on prod uctive and profitable
agriculture, the engine room of
subsequent industrialization.
Sustainable farming systems mu stbe environmentally soun d.
Economic success in agriculture
cannot come at the expense of our
soils, air, water, landscapes, and
indigenous flora and fauna.
Sustainable farming systems mu stbe socially acceptable. They m ust be
app ropriate to the people who,
relying on their own meager
resources, are responsible for
implementing and m anaging them.
The need for socially acceptable
systems imp lies the need for a better
und erstanding of farmer andcomm unity needs and values, as
well as better targeting of
technology to m eet local conditions.
Finally, sustainable farming systemsmu st be politically sup por table.
Political supp ort depend s largely on
successfully m eeting the first th ree
requirements of sustainability. If
econom ic growth is catalyzed by
agriculture within anenvironmentally sound , socially
acceptable framew ork, p oliticians
will continue to view agriculture as
justifying su pp ort.
All of these compon ents combine
to form the w hole: sustainable
agricultu re. If one is neglected, it can
seriously redu ce the rate and extent of
progress toward s sustainability and
food security.
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pattern s and their implications for
agricultu re. There is limited scope to
open n ew land for crop p roduction, and
there is an even more u rgent need to
protect land (in p articular, marg inalland) from inapprop riate uses. In recent
decades developing coun tries have
fortunately relied more on increased
yields than on an expansion of cropped
area to feed th eir pop ulations. Between
1961 and 1990, yield increases accounted
for 92% of the add itional cereal
produ ction in the d eveloping w orld
(Reeves, Pinstrup-And erson, and
Pand ya-Lorch 1997). When farm ers in
stable, high prod uction environments
obtain better yields, the need to intensify
prod uction in fragile agricultural
systems is redu ced , offering a mu ch
more sustainable app roach to meeting
long-term d emand for cereal prod uction
in developing coun tries.2 Because
higher y ield ing lines are frequen tly bred
to use inpu ts such as n utrients andwater m ore efficiently, higher yields are
not obtained a t a higher cost to the
environment. As our CIMMYT
colleague, Nobel Laureate Norm an
Borlaug, has said, The only w ay for
agricultu re to keep p ace with p opu lation
and alleviate world hu nger is to increase
the intensity of prod uction in those
ecosystems that lend themselves tosustainable intensification, while
decreasing intensity of produ ction in the
more fragile ecologies (Borlaug an d
Dowswell 1997).
The selection of segrega ting
pop ulations and consequent yield
testing of advan ced lines is param oun t
for iden tifying high yield ing, inp ut
responsive wheat genotypes. Theincrease in yield potential of CIMMYT
cultivars d eveloped since the 1960s is
show n in Figu re 1 (K. Sayre, per s.
comm.). The d ata d o not ind icate that
we are app roaching a yield p lateau,
and the p erformance of recently
released lines su ch as Attila an d
Baviacora, and ofLr19-derived Veery,
indicates that yield poten tial has beenfurther enhanced.
With y ield , a complex trait still
not w ell un derstood genetically or
ph ysiologically, the use of proven,
high yield ing sources, as well as
genetically d iverse germp lasm, will
continu e to be param oun t for
increasing yield potential. Genetic
diversity and the opp ortun ity for itsrecombination th rough crossing will
be imp ortant to break und esired
linkages an d increase the frequency
2 For example, if India were sudd enly
required to produce its current w heat
harvest u sing the technologies of 30
years ago, Indian farmers wou ld have tobring more than 40 million hectares of
add itional land into prod uction. The
wh eat varieties developed in the past
three decades were instrumen tal in
preventing d amage to areas that are not
well suited to agriculture.
10,000
9,600
9,200
8,800
8,400
1965 70 75 80 85 90 95Variety year of release
Grain yield kg/ha at 12% H20
Figure 1. Grain yield trend for semidwarf bread
wheat lines developed at CIMMYT since 1966,
under conventional planting, average for 1997,1998, and 1999 crop cycles at CIANO, Cd.
Obregn, Mexico.
Source: K.D. Sayre, CIMMYT.
Yield = -6.22*+104+36.05x(kg/ha/year)r2 = 0.772
Annual yield increase = 0.39%/year
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6
of desirable alleles. Futu re
breakthroughs in yield potential are
likely to come from such genetically
d iverse crosses. Examples are given
below, along with a d escription ofother efforts to raise both sp ring and
winter w heat yield p otential.
Gene Pools of Winter andSpring Hexaploid WheatsThe variability cur rently available
among spring and winter hexaploid
wheats is still extensive. New h igh
yield ing sources from w ithin theCIMMYT Bread Wheat Program and
from arou nd the world are iden tified
and intercrossed. For examp le, high
yield ing spring wh eat lines from South
Asia and China are regu larly
intercrossed w ith the h ighest yielding
lines identified in Mexico, followed by
selection for typ es sup erior to either
paren t, carrying all desirable genes.
Likewise elite w inter w heats are
intercrossed. Considerable progress
can still be mad e in this way as yield is
controlled by many genes and the
optimal combinations of these genes
for any particular environmen t may
not yet have been realized .
Introgressing Spring and
Winter Wheat Gene PoolsBy introgressing genetic variability
from w inter wheats, breeders have
considerably augmented the yield
potential of spring w heats. The Veery
wh eats, developed from crosses of
CIMMYT spring w heats and Russian
winter wheat, represented a quan tum
leap in spring wh eat yield an d w ide
adaptation du ring the 1970s and 1980s(CIMMYT 1986) (their cont ribu tion to
drough t tolerance is d iscussed later).
More recently, the spring bread wh eat
Attila, developed from crosses with
western European an d US winter
wheats, has rapidly gained ground on
the Indian subcontinent. New evidence
indicates that yield poten tial in w interwheat m ay also benefit from crosses
with high yielding spr ing wheats.
Chinese Wheats: AWellspring of DiversityBefore the mid-1980s, only a limited
amoun t of wheat germplasm from
outside China was available to
Chinese breeders. Since the mid-1980s, CIMMYT and Chinese
scientists have w orked together to
benefit from th e diversity in each
others wh eat germp lasm. More
than 100 Chinese varieties conta in
CIMMYT germp lasm, and u p to
20% of new CIMMYT spring wheats
have Chinese wh eats in their
ped igrees. Apart from its resistance
to biotic pests such as scab and
Karnal bun t, mod ern Chinese
germp lasm offers new alternatives
for raising the yield p otential of
wheat; yields of elite Chinese
wheats in China can exceed 10 t/ ha.
Hybrid WheatsThe expression of heterosis for yield in
wh eat can be high. Althou gh it has
been well documented, heterosis has
not been exploited commercially to
any great extent. Hybrids offer the
unique opp ortunity of combining
different gene p ools in th e prod uction
of the F1 hybr id. Because h eterosis is,
to some extent , a function of genetic
distance, CIMMYT is well positioned
to exploit this need for geneticdiversity. During th e past three years,
CIMMYT hybrids h ave p rodu ced
yields that are 15-20% higher th an
those of comm ercially grown cultivars
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in Mexico, and levels of heterosis of
a similar m aximu m size have been
reported . The difficulty of prod ucing
F1 seed in a cost-effective way
remains the g reatest limitation to th eexploitation of such hybrid s, but
CIMMYT breeders expect to resolve
this issue by introgressing
outcrossing traits.
LandracesMany high yield ing CIMMYT
wh eats have a considerable num ber
of landraces in their p edigrees. Acoefficient of parentage analysis
reveals that on average CIMMYT
advanced lines contain as man y as
50 land races in their gen etic history.
Breeding p rograms have still not
exploited a ll of the yield-controlling
genes available in landraces.
Landraces may also prov ide novel
sources of adaptation, wh ich w ill
allow breeders to select more stable,
high yielding lines. As yields
increase, consumer p references will
also turn to increased qu ality and
taste. Here, locally preferred
landraces can play a very new and
exciting role.
Improved Plant Ideot ypeCIMMYT breeders are u sing
increased know ledge of the
physiological bases of yield to d efine
a range of optimal wh eat plant
ideotypes. We are examining p lants
with large spikes, wh ich contain
man y grains per sp ikelet (see photo,
inside front cover). The op timization
of source-sink relationsh ips is also
being examined with a view toobtaining a better balance of grain-
filling characters. The h exaploid
wh eat and other gene pools are
being searched for examp les of
extreme expression of these
characters. We believe advances of
yield potential on th e order of at least
20% in optimu m conditions can still
be realized by fine-tun ing the source-sink relationships in w heat.
Phenological Trait sBy m anipulating p hotoperiod and
vernalization genes, we are
attemp ting to tailor genotyp es to
specific environments. Photoperiod
and vernalization genes optimize the
timing and d uration of flowering andgrain-filling, thereby influen cing th e
wh eat plants eventua l yield. New
and d ifferent sources of these genes
are being exploited throu gh the use of
high-latitud e germplasm from Central
Asia and Canada.
Physiological Traits
A strong bod y of eviden ce nowindicates that p hysiological traits may
complement early-generation
ph enotyp ic selection in w heat. Genetic
progress in increasing yield potential
is closely associated with increased
ph otosyn thetic activity (Rees et al.
1993). Photosynthetic activity as well
as yield potential have increased over
the p ast 30 years by som e 25%. These
find ings may have m ajor imp lications
for CIMMYTs future selection
strategy, since there is evidence that
wheat genotypes with h igher
ph otosynthesis rates have lower
canopy temp eratures, a characteristic
that can be measured easily, quickly,
and cheap ly. Canopy temperatu re
depression (CTD) is the cooling effect
exhibited by a leaf as transp irationoccurs. Canopy temperatu re
dep ression and stom atal condu ctance,
measured on sunny d ays during grain
filling, have show n a strong
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9
Protecting
Yield Potential:
The Role of
Resistance to
Pathogens and Pests
Over the p ast few d ecades, the gains
from breeding for disease resistance
are likely to have been at least asimpor tant as the gains from breeding
for increased yield potential (Byerlee
and Moya 1993). A recent su rvey of
wh eat breeders in developing
countries ind icated tha t among the
types of m aterials used in crossing
(includ ing the breeder s own ad vanced
lines, advan ced lines obtained from
other countries, wild relatives, and
land races), ma terials from CIMMYT
international nurseries are the most
frequently crossed in p ur suit of disease
resistance goals (Rejesus, van Ginkel,
and Smale 1996).
CIMMYTs global effort to breed
wh eats with diverse and du rable
resistance will protect global food
secur ity by redu cing th e incidence ofd isease epidemics. It will also protect
the environment and farmers incomes,
by redu cing d epend ence on pesticides
for disease and pest control. In
CIMMYTs target m ega-environments,
impor tant fungal d iseases of wh eat
caused by obligate pa rasites includ e
the ru sts (one or m ore of which are the
most economically impor tant d iseases
in most wh eat produ ction
environmen ts), pow dery m ildew, and
the bun ts and smu ts. Widespread
diseases caused by facultative fungal
parasites include septoria tritici blotch,
septoria nodorum blotch, spot blotch,
tan sp ot, head scab, and a suite of root
rots.The obligate parasites are highly
specialized, and significant variation
exists in the p athogen p opu lation for
viru lence to specific resistance genes.
The evolu tion of new virulence (races)
through migration, mu tation, and
recombination of existing viru lences
and their selection is m ore frequent in
rust and pow dery m ildew fun gi. Forthis reason, these diseases have
required constant vigilance and
attention from breeders. Physiological
races are also know n to occur for m ost
bunts and smuts, although evolution
and selection of new races is less
frequen t. Because m ost bunts an d
smuts are easily controlled by chemical
seed treatment, little effort is current ly
placed on breeding for resistance,
except for resistance to Karnal bun t.
Successful changes in pathogen races
are even less frequent in the facultative
parasites m entioned earlier.
Since wheat cultivars d erived from
CIMMYT germplasm are grow n over a
large area and are exposed to a variety
of pathogens und er cond itions thatmay favor disease developm ent, our
strategy has been to utilize resistance
sources that are as d iverse as possible
and have show n d urability. Genetic
diversity and durability of resistance
against diseases caused by path ogens
such as the ru st path ogens are vital for
long-term food security. Resistances
caused by race-specific genes become
ineffective in a shor t time (in five years
on average at th e global level and in
three years for leaf ru st, Puccinia
recondita, in Mexico). In contrast,
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cultivars w ith du rable resistance have
show n stable resistance for over 50
years at the global level. Consid er the
resistance to stem ru st (P. graminis).
McFadden in the US transferred theSr2 gene comp lex from a tetrap loid
emmer w heat to hexaploid bread
wheat in th e 1920s (McFad den 1930).
Borlaug in Mexico used this source of
resistance in h is breed ing p rogram in
the 1940s, and since then this gene, in
concert with several know n and
un known major and minor genes, has
formed the basis of durable resistance
to stem ru st in CIMMYT wheat
germplasm.
Following the lesson learnt from
stem ru st research, CIMMYTs w heat
breeding in the last three decades has
focused on u tilizing d iverse sources of
slow ru sting resistance to P. recondita
and yellow rust (P. striiformis). Genetic
analyses of d urable resistance indicate
that effective d isease control can be
achieved by combining from three to
five minor, slow ru sting genes in a
single cultivar. Such resistance is
expected to provide sufficient
protection to farm ers crop against all
biotypes over a long p eriod. Currently
we are also attempting to identify
molecular markers for each of the slow
rusting genes p resent in CIMMYTwheats. If this strategy is successful,
breeding p rograms w ill be able to
incorporate known combinations of
minor genes, develop a global strategy
for their deployment, and at the same
time enh ance genetic diversity in
farmers fields.
Recent an alysis of trials conducted
in north western Mexico confirms that
progress in p rotecting yield potential
through genetic resistance to leaf rust
is about th ree times as great asad vances in yield potential itself (R.P.
Singh and K.D. Sayre, pers. comm.).
The economic benefits of CIMMYTs
strategy of incorporating non-specific,
du rable resistance to leaf rust into
mod ern bread wh eats have been
estimated using d ata on resistance
genes identified in cultivars, trial data,
and area sown to cultivars in
northwestern Mexico. Even u nd er the
most conservative scenario, the gross
benefits generated in this region on
abou t 120,000 ha of w heat from 1970 to
1990 were US$ 17 million (in 1994 real
term s) (Smale et al. 1998). At th e globa l
level, wh ere a considerable area is
sown to cultivars carrying non-specific
resistance, the benefits mu st be
correspond ingly large.
Resistance to the d iseases caused
by facultative parasites, such as
Septoria tritici and Fusarium
graminearum, also involves genes th at
have additive effects. Tremendous
progress has been m ade at CIMMYT in
developing semidw arf wheats that
have ad equate resistance to Septoria
tritici. Sources contr ibut ing toresistance includ e w heats from France,
Brazil, China, and Russia. More
recently w e have identified synthetic
wheats (T. turgidum x T. tauschii)
possessing good resistance to septoria
tritici blotch. This new genetic
diversity is currently being transferred
to CIMMYT wheats.
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CIMMYT germ plasm in those
environments sup ports the mod el of
combining inpu t efficiency and inpu t
responsiveness.
Another piece of eviden ce is
Nesser, an advanced line with
superior performance in drou ght
conditions. Nesser was bred at
CIMMYT-Mexico and iden tified by
the CIMMYT Mediterranean program
located at the International Center for
Agricultu ral Research in th e Dry
Areas (ICARDA) in Syria. The cross
combines the high yielding CIMMYT
variety Jup ateco 75 and th e drou ght
tolerant Australian variety W3918A.
The performance of Nesser in the
dryland en vironments of WANA has
been widely pu blicized (ICARDA
1993), and the line is considered to
represent a un iquely drough t-tolerant
genotyp e. This line was selected a t
CIMMYT/ Mexico und er favorableconditions, and it carries a
combination of inpu t efficiency and
high yield respon siveness. In th e
absence of rust, its performance is
qu ite similar to th at of Veery S.
A breeding scheme to achieve the
combination of yield responsiveness
and drou ght tolerance in w heat is
presented in Table 5. This method is
supp orted by research on wh eat aswell as other crops, in w hich testing
and selecting in a range of
environments, includ ing well-irrigated
ones, has identified superior
genotypes for stressed conditions (see,
for example, Ehdaie, Waines, and Hall
1988; Duvick 1990, 1992; Bramel-Cox
et al. 1991; Ud din, Carver, and Clutter
1992; Zavala-Garcia et al. 1992; andCoop er, Byth , and Wood ru ff 1994). The
app roach results in the selection of
germplasm that is adopted by farmers
because it tran slates imp roved
environmental conditions into yield
gains. The trad itional methodology of
selecting on ly und er d rought
conditions and narrow ly relying on
land race genotypes does not m ove
yield levels significantly beyond th ose
usu ally obtained, and it does not
provid e the farmer with a bonus in
years w hen rainfall is higher.
Table 4. Grain yields (kg/ha) of selected w heat genotypes grouped by adaptation and
tested under mois ture regimes in the Yaqui Valley, Mexico, 1989/90 and 1990/91
Full Late Early Residual
Adaptation group irrigationa droughtb droughtc moistured
ME1 (Irrigated environment) 6,636 a 4,198 a 4,576 a 3,032 a
ME4A (Mediterranean Region) 6,342 b 3,990 ab 4,390 b 3,032 a
ME4B (Southern Cone, S. America) 5,028 c 3,148 bc 4,224 b 2,359 c
ME4C (South Asian Subcontinent) 4,778 c 3,245 bc 3,657 c 2,704 b
Source: Calhoun et al. (1994).
Note: Means in the same column followed by the same letter are not significantly
different at P=0.05.
a Received 5 ir rigations.
b Received 2 irrigations early, before heading.
c Received 1 irrigation for germination and 2 post-heading.d Received 1 irrigation for germination only.
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15
is an increase of more than 20% over
the previous generation of du rum
wh eats. Generally average yields of
duru m w heat in farmers fields in
northwestern Mexico are 6 t/ ha, andthe w orld average is 2-3 t/ ha. If these
recently tested w heats retain some of
their yield advantage in marginal
conditions, they may p rove to be a
valuable asset for breeding p rograms.
Regional Researchon Wheat for Marginal
EnvironmentsWest Asia and North Africa. About
one-third of the area planted to w heat
in the d eveloping world is located in
marginal environments plagued by
drough t and soil problems. These
problems are frequently exacerbated
by a lack of infrastructure and farmer
sup port services. Most of the w orlds
drou ght-prone w heat area is
concentrated in the WANA region
(Table 1). Wheat is the principal food
source for p eople in WANA, wh o on
average consum e more than 145 kg/
cap/ yr, one of the highest levels of per
capita consumption in the world .
CIMMYT efforts aimed at
improving wheat p roduction in
WAN A are conducted in conjun ction
with ICARDA. The CIMMYT/
ICARDA Joint Drylan d Wh eat
Program for West Asia and North
Africa seeks to increase wh eat
productivity by developing spring
bread and du rum wheats that are
better adap ted to the WANA region.
Wheats developed or identified by the
program are widely adap ted and
possess enhanced d isease and insect
resistance, as w ell as better tolerance to
the p revalent abiotic stresses. This is
wh y our p artners in the region
increasingly select them for use in their
own breeding programs. Farmer
adoption of CIMMYT- and CIMMYT/
ICARDA-der ived varieties in WANA
continu es to increase, with more than
90 wheat varieties released in 21countries in the region over th e past 10
years.
The Turkey/ CIMMYT/ ICARDA
International Winter Wheat
Improvem ent Program (IWWIP) based
in Ankara, Turkey, came into existence
11 years ago with the pu rpose of
generating winter w heats for
developing countries, particularly inthe WANA region. Over the past two
years, IWWIP has expand ed its
collaboration w ith winter w heat
programs in the developing w orld.
New research partnerships w ith
colleagues from Central Asia an d the
Caucasus hav e greatly increased th e
nu mber of cooperators.
The program is devoting particularattention to imp roving resistance to
yellow rust, wh ich is the m ost serious
winter w heat d isease in WANA. It
conducts trials using ar tificial
inoculation in An kara, Konya, and
Eskisehir (Turkey), Alepp o (Syria), and
Iran. It is also conducting research on
micronutrients aimed at identifying
zinc-efficient w heats to be used incrosses and alien m aterials that m ay be
poten tial sou rces of zinc efficiency. At
present, rye and triticale seem to be th e
best sources, bu t other a lien sp ecies are
also being tested at Turkeys ukurova
University.
Central Asia and the Caucasus. The
repu blics of Central Asia an d the
Caucasus are relatively diverse inclimate, agricultu ral p rodu ction, and
pop ulation. What these eight coun tries
(Armenia, Azerba ijan , Georgia,
Kazakhstan, Kyrgyzstan , Tad jikistan,
Turkmen istan, and Uzbekistan) have in
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17
1988; Ciaffi et al. 1992; Lafiandra,
Ciaffi, and Benedetelli 1993; William ,
Pea, and Mu jeeb-Kazi et al. 1993).
These alien gen es offer a poten tial
means of expanding the n um ber ofallelic var iants controlling proteins
with desirable quality effects in wh eat.
Several of the synthetic hexap loids
developed from accessions of d iploid
Triticeae sp ecies (T. tauschii, T.
boeoticum, T. monococcum, and T. urartu)
and d uru m w heat have been examined
in relation to grain cha racteristics
associated with end -use quality of
bread and du rum wh eats. The analyses
revealed that T. tauschii may be used
for substantially increasing the n um ber
of high molecular w eight glutenin
(HMWG) subu nits present in bread
wh eat (HMWG subun it comp osition is
implicated in the definition of gluten
strength in both bread w heat and
duru m wh eat) (Payne et al. 1981;
Pogn a et al. 1990).
We have also examined var iability
for quality (grain hard ness, protein
content, and SDS-sedimentation) as
well as the relationship betw een
quality and HMWG and low molecular
weight glu tenin (LMWG) subu nit
comp osition (SDS-PAGE) in 137
accessions ofT. dicoccon. Resu lts
confirm p revious find ings that T.dicoccon has m ore diverse genetic
var iability for alleles involved in the
synthesis of gluten-type proteins than
cultivated wheat. T. dicoccon should be
considered a good poten tial source for
improv ing gluten strength in bread
and du rum wheat.
In the past three years, the
frequency of high qu ality CIMMYT
bread w heats has increased
dram atically. A mod ification of the
crossing strategy, emphasizing high
quality parents, was imp lemented in
the ear ly 1990s. Quality testing of
advanced generation breeding
materials was increased over th e past
few years. Now th ese two strategies
have come to fru ition. In the nearfutu re, abou t 75% of CIMMYTs new
bread wheat germp lasm will be
competitive for quality standards in
the marketplace.
Biotechnology
and Wheat
Improvement: An
Example of
Collaboration
By d rawing on the p ower of
biotechnology, CIMMYT seeks to make
plant breeding more efficient an d, in
some cases, to improve wheat in ways
that have elud ed conventional
breeding ap proaches. The comparative
genetic map ping of cereal genomes has
identified a vast am oun t of conserved
linearity of gene ord er (Devos and
Gale 1997). This observation is likely toaccelerate the application of
quantitative trait loci (QTL) in w heat ,
as well as aid in the identification of
genes requ ired for introgression from
alien species. Given th e low num ber of
loci tagged at p resent in wh eat, the
problems related to d eveloping a h igh-
density map for w heat (Snap e 1998),
and the limited p rogress to identifyQTL for yield in wheat , we believe that
the imp act from th is linearity on wh eat
improvement will be significant.
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20
chopp ed an d left on the su rface of the
beds. The system h as several
advan tages for farmers and the
environment, includ ing:
Nitrogen can be app lied w hen andwh ere the wheat p lants can u se it
most efficiently. Yields im prove, and
nitrogen losses into the environment
are significantly redu ced.
Water conservation improves. Aswater for agriculture becomes more
scarce in the years to come, water
conservation p ractices w ill become
more important for farmers.
Researchers in South Asia and China
report a 30% savings in water u se
from u sing bed p lanting and
improved w eed control.
Weeds can be controlled bycultivating between the beds
redu cing costs and the need for
herbicide.
Residu es are returned to the soil
withou t burning, wh ich is beneficialto the environment.
The beds can be u sed cycle aftercycle. Farm ers avoid the financial and
environm ental costs of making
repeated p asses w ith a conventional
plow du ring land p reparation.
Prototype m achinery for this bed
planting system has been d esigned
and tested in Mexico and in Asia. The
prototyp es are mod ifications of
standard agricultural equipment an d
are expected to be affordable for poor
farmers. Mexican farmers reportedly
save 30% on their prod uction costs
wh en they use the bed p lanting
system. Some 10,000 farmers are
thou ght to u se the system in Mexico,
and the num ber of farmers who areusing bed planting is growing in South
Asia and China as well. In fact, in
par ts of China some farmers find the
technology so valuable that in the
absence of equ ipment they form the
beds by hand.
Farmer Part icipatoryResearchOver th e past few years, CIMMYT has
significantly increased its investment
in farmer par ticipatory research for
natu ral resource man agement (that is,
in the development of prod uctivity-
enhancing, resource-conserving
practices for maize and wh eat systems,
with beneficial impacts on soils, water,and agroecosystem d iversity). Farmer
participa tory research is a tool for a
pu rpose: the development of
sustainable practices that imp rove
resource quality w hile raising system
productivity. CIMMYT is moving
aggressively to mainstream the use of
this tool for these imp ortant en ds. For
example, in irrigated a reas in n orthern
Mexico, CIMMYT has long
collaborated w ith farmers in the
developm ent of the bed p lanting
systems described ear lier.
In Asia, CIMMYT works with th e
other m embers of the Rice-Wheat
Consortium for the Ind o-Gangetic
Plains to foster farmer experimentation
on reduced and zero tillage strategies
for establishing w heat after rice.
Farmer group s have assessed
alternative tillage and sowing
implements and wh eat establishment
strategies, and they have been
encouraged to develop their own
innovations and adap tations.
Minimum tillage practices are
spread ing in Bangladesh, and farmers
in the western pa rt of the Indo-Gangetic Plains are beginning to use
zero tillage. Farm ers report ear lier
sowing, higher yields w ith lower levels
of inp uts, and improved possibilities
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21
for diversifying cropping patterns
away from a continu ous rice-wheat
rotationwith num erous
agroecological benefits.
In Bolivia, we are collaboratingwith farmer groups to d evelop zero
tillage/ mu lch systems suitable for
smallholders (2-5 ha) in the high inter-
And ean valleys. These farmers
prod uce one crop of wh eat each year
in monoculture or in rotation w ith
potatoes, faba beans, peas, and / or
barley. Research focuses on evaluation
of straw cover to increase rainfall useefficiency. Results are extremely
encouraging: crop residu e retention
generally increases yields and redu ces
risk, two imp ortan t objectives for
Bolivias small-scale, subsisten ce
farmers. Researchers also participate
in a p roject to d evelop a small,
animal-drawn, no-till seed drill for
sowing cereals into surface residues,
and results are very positive
(CIMMYT 1999).
Information
M anagement Tools
for Sustainable
Systems
Researchers have always believed in
the value of sharing information m ore
widely, bu t the limitations of
information technology have not
made th is easy. CIMMYT now offers awid ening array of information
man agement tools to researchers in
man y d isciplines.
For examp le, the International
Wheat Information System (IWIS) is a
relational database available on CD
wh ich gives each genotyp e a unique
identifier and prov ides extensiveped igree and performan ce data. The
Genetic Resources Inform ation
Package (GRIP), designed in
conjun ction w ith Australian p artners,
allows IWIS users to locate seed
samp les in wheat germplasm stocks
in a nu mber of collections around the
world an d provides an abbreviated
version of the IWIS pedigrees. The
International Crop Information
System (ICIS) is a da ta management
tool that builds on IWIS. It contains
information on several crops in
ad dition to w heat . The core of ICIS is
a relational database structure that
stores data on plant genetic resources,
ped igrees, field and laboratory
evaluations (includ ing m olecular
information), and au xiliary d ata onlocations, institutions, and peop le.
Simple geograp hic information
functions are being incorporated into
ICIS, and a tool for expor ting d ata to
crop simu lation m odels is also und er
development.
One challenge to sharing
information more w idely is to
provid e access to cutting-edgegeographic information system (GIS)
tools for n on-GIS users, especially
those in Africa. African researchers
need spatially referenced d ata on
climate, soils, infrastructure, crop
distribution, and the natu ral resource
base, in par t to ascertain the extent to
wh ich th eir site-specific research may
have relevance to larger areas. TheAfrica Coun try Alman acs contain
such base data, along w ith the most
common ly requested map s, plus
search an d viewing tools, on a single
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compact d isc. Almanacs have been
developed for 12 African countr ies,5
some of which have requested follow-
on d emonstrations and training for
their research staff. Now all researcherscan have access to these powerful GIS
tools, not just a few sp ecialists in a
central office.
The Spatial Characterization Tool
(SCT) developed by CIMMYT and
Texas A & M Un iversity goes a long
way towards ad dressing the p roblem
of site specificity in n atu ral resources
management research. Site researcherscan now quickly perform site
similarity analysis, identifying areas
with environm ents resembling that of
their site. When applied to sites in
Bolivia, this an alysis un covered
environmentally similar areas within
Bolivia; in n eighbor ing coun tries (e.g.,
Chile, Brazil); with in the Am ericas
(e.g., Mexico); and even in oth er
regions of the wor ld (Ethiopia,
Lesotho). Scientists in these d iverse
locations find th at they hav e mu ch to
share about technology performance
and the consequences of techn ical
change for system p rodu ctivity and
sustainability.
These information management
tools help encourage researchintegration, explore the p rospective
performan ce of new technologies, and
overcome site specificity. However, like
all information m anagem ent tools, they
need data. A final challenge is how to
preserve, organize, and make available
to researchers the rich ar ray of da ta
often gen erated by research,
par ticularly in natu ral resource
managemen t research. CIMMYT is
developing an answ er to this set of
challenges: the Sustainable Farm ing
Systems Database (SFSD). Non-
governm ental organizations are using
the SFSD prototyp e to organizeinformation on the global experience
with green m anu re cover crops. As the
SFSD matu res, its u ses will be
virtu ally infinite.
Conclusions
The strategies we h ave just outlined
could m ake the d ifference between a
sustainable futu re, with food an d
economic opp ortun ity available for
the majority, and a future of scarcity,
with su rvival seriously comprom ised
for most people. Successful,
sustainable agricultu re can help create
the pu rchasing p ower and
emp loyment that w ill ensure food
secur ity and help erad icate poverty.
We believe that the risks of ignoring
agricultu ral developm ent w ill be far
higher than the risks of deciding to
create a su stainable futu re for us a ll.
The world has faced a similar
choice before, when a decision was
mad e to sow the new semidwarf
wheats in India in the hope that their
higher yields w ould p revent a famine
as great as the d evastating Bengal
famine of 1943. That d ecision
transformed agriculture and the way
that agricultural research w as
conducted. Today CIMMYT and its
pa rtners join forces in one of the
world s most ambitious endeavors:we p articipate in a global wh eat
improvem ent system that continues to
better th e lives of millions of poor5 Including three important wheatprod ucing nations: Ethiopia, Kenya,
and Zimbabwe.
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23
farmers and consum ers in
developing countries. The imp act of
that system is well documented
(Byerlee an d Moya 1993; Maredia
and Byer lee 1999; CIMMYT 1999). Inthe most recent p eriod, 1991-97,
almost 90% of the spring bread
wh eat varieties released by n ational
agricultu ral research systems had
CIMMYT ancestry (Figure 3).
Virtu ally all (98%) of the spring
du rum wh eats released by national
programs in 1991-97 had CIMMYT
ancestry (Figure 4). Farmers now
plant almost 80% of the developing
world s spring bread w heat area to
CIMMYT-related wheats (Figure 5).
CIMMYT crosses
(some re-selected by
NARSs), 56%
Figure 3. Ancestry of spring bread w heat
varieties released by national programs,
1991-97.
Source: CIMMYT wheat imp acts database.
NARS crosses with at
least one CIMMYT
parent, 28%
NARS crosses
with some
known
CIMMYT
ancestry, 5%
NARS
semidwarfs
with other
ancestry, 8%
Tall
varieties, 3%
CIMMYT
crosses, 77%
Figure 4. Ancestry of spring
durum wheat varieties
released by national
programs, 1991-97.
Source: CIMMYT wheat
impacts database.
NARS crosses w ith
at least one CIMMYT
parent, 19% NARS crosses
with some
known
CIMMYT
ancestry, 5%
Tall
varieties , 2%
100
80
60
40
20
0
ChinaIndia
OtherAsia
WANA
AllAsia
Sub-SaharanAfrica
LatinAmerica
Developingcountries
Figure 5. Area planted to spring bread
wheat in developing countries, 1997.
Source: CIMMYT wh eat impacts
database.
Percentage of total spring
bread wheat area
Unknown
Landraces
Tall wi th pedig ree
Other semidw arf
Any CIMMYTancestor
At least oneCIMMYT parent
CIMMYTcross
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A New Research Paradigmfor New Research ImpactsThese research impacts are reassuring,
but m uch remains to be done. When
our colleague N orman Borlaugaccepted the N obel Peace Prize for his
achievements in bringing abou t the
Green Revolution in w heat, he
cautioned th at the Green Revolution
has not transformed the world into
Utopia. None are more keenly aware of
its limitations than those wh o started it
and fough t for its success. . . . Above
all, I cannot emph asize too strongly the
fact that further p rogress depend s on
intelligent, integrated, and persistent
effort (CIMMYT 1970).
Borlaugs observation remains true.
If we are to m ake progress toward
sustainable food security, we m ust take
his advice and change the w ay we
plan, cond uct, and comm un icate about
research. We must b lend veryspecialized research d isciplines in
teams of scientists seeking ap prop riate
outcomes that have an immediate
imp act in farm ers fields. It is from
these fields that food sup plies mu st
come for the foreseeable futu re. The
farmer is the ultimate systems-oriented
operator, juggling biological, economic,
environm enta l, and social factors. In
such circumstances, isolated
interventions are of limited value at
best; all too often, they m ake th ings
worse.
These interventions will be based
on a new, integra tive research
parad igm that focuses on the elements
of the GXEXMXP equation mentioned
earlier: the best genotypes (G), in th e
right environm ents (E), un der
app ropriate crop man agement (M),
generating app ropriate outcomes for
people (P). Everyone who seeks to
foster sustainable agriculture in
developing coun tries shou ld recognize
the interdep end ence of these factors,
because m ost organizations by
themselves cannot contribute fully toeach asp ect of GXEXMXP. Partnerships
and consortia that assemble the best
possible teams to execute the GXEXMXP
app roach w ill und erpin the timely and
successful achievement of sustainable
farming systems and future food
security.
The Shape of Thingsto ComeGiven th ese requ irements, wh at w ill
agricultu ral research look like in the
new millenium ? Every member of the
international wheat improvement
systemand the farmers and
consumers w ho depend on itwill be
affected by changes in international
research in the year s to come. Which
forces are likely to shape the w ay tha t
research is doneeither by
contributing to or d etracting from the
integrative research parad igm we have
just described?
For decades, collaboration h as been
the mainsp ring of the international
wheat imp rovement system. None of
the achievements described in this
pap er could have been attained
withou t it. Gains from conventional
breeding will continu e to be significant
in the next two d ecades or more
(Duvick 1996), but these are likely to
come at a higher cost than in the past.
Research m anagers and p olicy makers
are increasingly concerned that the
very op en, collaborative netw orks that
have sustained the wh eat imp rovementsystem w ill become far m ore
circum scribed in coming years.
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