Diversity: the spice of life

Sarah J. Hearne, s.hearne@cgiar.org

Cowpea seed collection, IITA genebank. Photo by IITA.
Cowpea seed collection, IITA genebank. Photo by IITA.

Cowpea is an important grain legume cultivated globally in the tree-scattered open grasslands of the tropics and subtropics. In Africa, these characteristic savanna regions are the “birthplace” of cowpea. The center of diversity of wild cowpea (where you find the most variation) is in southern and southeastern Africa; the center of diversity of cultivated cowpea is in West Africa (Padulosi 1993).

As a crop, cowpea is generally grown for its dry grain used for human and animal consumption, and green pods consumed as vegetables, and also for the fiber for textiles from the long peduncles or stalks (West Africa). It is a versatile plant and is used as a green manure, a dual-purpose crop in mixed cropping systems, and alone as a forage crop for livestock. The leaves are also eaten as a vegetable in parts of East Africa and in Senegal; in Sudan and Ethiopia, the roots are eaten as well.

IITA holds more than 15,000 accessions of cultivated cowpea in its genebank collection. These accessions form an invaluable resource for conservation and improvement. To be able to fully use such a collection, it is important to characterize the materials to enable the selection of the best materials for various purposes, such as crop improvement for high yield, better agronomic traits, drought tolerance, or disease resistance.

To help characterize IITA’s global cowpea collection, Institute scientists undertook a study funded by the Generation Challenge Program. This included defining a core collection from the thousands of accessions held in the IITA genebank, characterizing the molecular diversity of this collection, and defining a smaller reference collection to enable the wider use of these important genetic resources. Seeds of the core collection accessions were virus tested and have been made available for distribution.

A core collection is a subset of accessions that are representative of the diversity of the entire collection. These core collections are needed as they provide a smaller, more manageable number of materials from which meaningful conclusions reflecting the wider collection can be made. A core collection of 2,062 accessions was derived from the 15,000 accessions in the IITA genebank, based on information held on each accession within the genebank database. The core collection contains accessions from many countries but with more from West, East, and Central Africa—the cradle of cowpea diversity.

Cowpea collection sites
Cowpea collection sites

The core collection was then subjected to further study. Molecular markers, signposts present in the DNA of all living things, were used to look for variation among the accessions in the laboratory. Using the resulting data, scientists were able to describe the molecular diversity of the accessions and identify which accessions were more like one another and those that were not. As a result, clusters of accessions that were similar to one another could be identified. Altogether, nine such clusters were identified in the cowpea core collection.

The core collection is an important resource, but it is simply too large for many users of the genebank to apply in studies, such as screening for desired traits (perhaps disease resistance) in a systematic manner. It was therefore necessary to define from the core a smaller collection of accessions, called a reference collection. The reference set of 374 accessions was defined using the clusters identifed in the molecular characterization. The reference collection is representative of the molecular diversity and descriptive diversity of the core and the entire collection.

As soon as the definition of the cowpea reference collection was publicized the genebank received many requests for the materials. The reference collection has been used widely by IITA scientists and our many partners and genebank clients in studies looking at drought, pest and disease tolerance, and in further studies of molecular diversity. The robustness of the collection was confirmed during some of these studies when comparisons of the reference collection with those from other institutes indicated that there was no novel molecular diversity present in the other collections investigated.

Padulosi, S. 1993. Genetic diversity, taxonomy, and ecogeographic survey of the wild relatives of cowpea (V. unguiculata). PhD thesis. University of Louvain La Neuve, Belgium.

A classical approach to saving life’s variety


The beginning of the tragedy to come wasn’t so clearly understood, but it became more visible as scientists studied the demise of the dinosaurs and came to consider, over the centuries, the reduction of species. The destructive trend is clear and fast encroaching on domesticated plants and wild animals alike, putting some species such as the whales and panda bears on the endangered list and threatening food security.

Consequently the world is losing biodiversity at rates not seen before.

In Nigeria, for instance, the country has lost some 6.1 million hectares or 35.7% of its forest cover since 1990. Worse, Nigeria’s most biodiverse ecosystems—its old-growth forests—are disappearing at an even faster rate. Since 2000, Nigeria has been losing an average of 11% of its primary forests every year, twice as fast as in the 1990s.

Adeniyi Jayeola, a Senior Lecturer in plant systematics, Department of Botany and Microbiology, University of Ibadan, says, “The deterioration we find worldwide today is unprecedented. Unless we act together, and quickly too, we may sooner than later induce a global ecological crisis far beyond the control of any technology. It is a multi-faceted challenge requiring all hands to be on deck.”

Areas visited in Nigeria in particular and the world in general have shown that man has demonstrably failed to accord the environment the respect it deserves, whether this is the air, sea, or land.

Consequently, out of more than 10,000 species in the past people today depend on only 12 species for 80% of all their food.

To stem the loss of biodiversity, in 2002, 10 years after the Convention on Biological Diversity (CBD), 193 nations participating in the treaty had agreed to “achieve by 2010 a significant reduction of the current rate of biodiversity loss at the global, regional, and national level as a contribution to poverty alleviation and to the benefit of all life on earth.”

This year, parties are converging to take stock of the journey so far but the general assumption is that more action needs to be taken.


What is biodiversity worth?
As the world prepares to take a retrospect on set targets, we can, however, no longer expect nature to provide us with a free lunch. Efforts to protect natural resources could depend on our putting a price tag on the goods and services they provide us. The United Nations Environment Programme’s 2007 Global Environment Outlook 4 report states that the pollination of crops by honeybees alone is worth US$2−8 billion, and the global herbal medicine market was worth US$43 billion back in 2001.

In addition, the tropical forests provide a whole variety of leaves, fruits, barks, roots, and nuts which form the mainstay of the modern pharmaceutical industry. We depend totally on the variety of life for our food security. The loss of biodiversity therefore presents us with one of the toughest puzzles, and concrete steps are needed to slow down the tide.

Innovative approaches to contain biodiversity loss
Despite the decline in species, which are currently disappearing at 50–100 times the natural rate, a regenerated forest on IITA’s campus in Ibadan has proved that indeed we can restore nature if we so desire. The forest, located on the west bank in IITA, sits on 350 ha of land and was initiated from abandoned farmland.

Forty three years after its establishment, this swathe of securely protected trees stands out as one of the least disturbed patch of forest in Nigeria with floristic characteristics ranking almost at par with a natural forest. The regeneration of the forest has brought appeal from the scientific community as researchers are seeking to uncover and understand the variation in plant species, composition, and structure of a forest regrowing from abandoned farmland and the causes of the variation.

David Okali, Chair, Nigerian Environmental Study/Action Team, who plans to do the study on the IITA forest with other colleagues, says such long-term studies are rare. The results on the rate of growth will be used in calculating directly the rate of carbon storage in the forest.
As the world marks the International Year of Biodiversity, Okali says deliberate efforts to conserve nature are important to stem biodiversity loss, stressing that the reestablishment of the IITA forest presented a good scenario for conservation.

Apart from forest regeneration, Okali says local communities could adopt other initiatives to curtail the loss of biodiversity. These include a return to traditional practices that made it a taboo for people to cut some species of trees or kill sacred animals. Also traditionally regulating hunting practices, and planting and protecting shade-providing fruit trees that adorn the village squares will help.

The success of the regenerated forest at IITA has reinforced the possibility that the opportunity is still within our reach.

Based on this experience, it is clear that the plan by parties to the CBD to create a global network of terrestrial and of marine protected areas can be done if there is the will and the means. How this will happen and funded is a question that all Governments must answer.

The butterflies of IITA

Robert Warren, robertdavidwarren@yahoo.co.uk

Charaxes imperialis. Photo by IITA.
Charaxes imperialis. Photo by IITA.

IITA boasts a wide range of butterflies. Knowledge about the diversity of these species, however, is incomplete. For instance, a preliminary survey conducted from 2002 to 2009 has confirmed the presence of 149 butterfly species. The actual number could fall somewhere in the range of 250 to 400.

A survey carried out in a directly equivalent location (Olokomeji Forest Reserve) in the late 1960s found 267 species, with quite limited collecting inputs (estimated total >450). A more complete survey at Agege, near Lagos in southwestern Nigeria, found more than 380 species. This location is in the moist evergreen forest zone, and is fairly comparable to the secondary nature of the IITA forest.

Completing a survey at IITA would yield information useful for conservation. The fact that the IITA forest is small and now isolated would allow the assessment of pressures on extinction. Despite the enormous destruction of West African forests to date, records show that butterfly extinction has yet to occur when viewed on a regional scale.

While the primary consideration for survival will be the presence of the host plants, there is also a consideration of the range required for survival. Knowledge of the total species population within IITA and specific species present could be likely to provide answers on the cut-off point where the range is too small for survival of certain species groups.

The IITA forest is also an important conservation target itself because of its location. It is quite possibly the westernmost representative of semi-deciduous forest on this scale before the Dahomey gap. Attempts to locate equivalent forests within Nigeria to the west of IITA, guided by satellite imagery, yielded only one small, unprotected patch (5 km west of Tapa). Forest reserves have all but disappeared. Several butterfly species (e.g., Liptena ilaro, Euriphene kiki, Axiocerses callaghani) found near IITA have not been seen elsewhere, pointing to the biogeographical importance of such habitats. If results eventually show that the IITA forest is indeed too small to allow the survival of all the species that should be present in an equivalent forest type, it will nonetheless remain an important refuge.

Display cases of all but a handful of the 149 species observed to date have been donated to IITA to promote further interest.* A specimen of the very rare species Melphina noctula was found at IITA (there are only three in the Natural History Museum), and has been donated to the African Butterfly Research Institute in Nairobi, Kenya.

An in-depth study of the IITA butterflies would be of international interest and importance because very few such surveys have been completed in Africa. Comparison with our knowledge of the fauna of western Nigeria could shed light on the importance of a forest such as IITA’s for the long-term survival of species. It could be one of the localities proposed for studying the survival of the butterflies between now and 2100. Finally, it could show if new species are added as the forest matures from its secondary status over time.

*Specimens were collected, identified, mounted, and donated recently by the author to IITA. These are currently on show at the IITA International School in Ibadan, Nigeria. The author is a buttefly expert who came to Nigeria at the age of 4 months. He has been surveying butterflies all over Nigeria and also at IITA since 2002.

The state of Nigeria’s forests

David Ladipo, ladipoolajide@yahoo.com

The IITA forest. Photo by K. Lopez, IITA.
The IITA forest. Photo by K. Lopez, IITA.

Nigeria is blessed with a large expanse of land and variable vegetation, but this important resource is not sustainably used or managed. Many rural dwellers in the past have treated our forest resources as inexhaustible.

Today the story is different. The average rural dweller now realizes that the forest is “finished,” but poverty continues to force people to exploit even the relics of remaining forests.

The Federal Government has, over the years, attempted to generate baseline data on the state of our forests including their use. These studies have provided data for a better understanding of the state of forest resources, the rate of environmental degradation, and the rate of forest depletion.

They also emphasize that present-day forest cover is under pressure as a result of human activities such as agricultural development where vast lands are cleared without conservation considerations, large-scale peri-urban housing project development, fuelwood generation, uncontrolled forest harvesting including poaching for logs and poles, and urbanization.

Pterocarpus soyauxii (local name: Silk-cotton) in IITA. Photo by J. Peacock, IITA.
Pterocarpus soyauxii (local name: Silk-cotton) in IITA. Photo by J. Peacock, IITA.

In Nigeria, deforestation or loss of vegetation or the selective exploitation of forests for economic or social reasons is very common. In most areas major losses have been recorded in vegetation, forest complexity (diversity), or in germplasm (quality).

The deforestation rate in the country is about 3.5% per year, translating to a loss of 350,000–400,000 ha of forest land per year. Recent studies show that forests now occupy about 923,767 km2 or about 10 million ha. This is about 10% of Nigeria’s forest land area and well below FAO’s recommended national minimum of 25%. Between 1990 and 2005 alone, the world lost 3.3% of its forests while Nigeria lost 21%.

In addition, some state governments are removing the protected status from forest estates without regard for the environment. The State Forest Departments have been unable to curtail the spate of requests to establish large-scale oil palm plantations in forest estates. The unfortunate impression that has thus been created is that the forest estate exists as a land bank for other sectors as demands continue nationwide.

As the forests are exploited, so too is the biodiversity. Plant and animal genetic resources are also lost with this important genetic resource, vital for breeding in future. Conserving the wild relatives of cultivated crops is also needed.

What factors continue to threaten biodiversity and contribute to poverty? These include deforestation, desertification, habitat alteration, invasive alien species (plants and animals) importation, poor land management (fire and agricultural systems + grazing), climate change, unilateral development decisions, poor political accountability, and poor budget allocation, release, and implementation.

Young Milicia excelsa (Iroko). Photo by J. Peacock.
Young Milicia excelsa (Iroko). Photo by J. Peacock.

We cannot afford not to conserve our forests and thus lose the vital ingredients of rural development. The situation is getting worse every day and the need for forest conservation and restoration is becoming critical.

With the new National Forestry Policy and the National Document on Biodiversity Conservation Action Plan, a new approach is needed now on forestry resources conservation in Nigeria. Enforcement and a community approach will produce positive results.

All stakeholders need to understand that biodiversity is critical to the maintenance of a healthy environment. Its role is enormous in meeting human needs while maintaining the ecological processes upon which our survival depends. Biodiversity not only provides direct benefits such as food, medicine, and energy; it also affords us a “life support system.”

Biodiversity is required for the recycling of essential elements. It is also responsible for mitigating pollution, protecting watersheds, and combating soil erosion. Controlling deforestation will ensure that biodiversity exists and can help reduce the impacts of climate change and thus act as a buffer against excessive variations in weather and climate. It can then protect us from catastrophic events.

Increasing our knowledge about biodiversity can transform our values and beliefs. Knowledge about biodiversity is valuable in stimulating technological innovation and providing the framework for sustainable development. Let us protect our forests as a start.

Edition 4, March 2010

Biodiversity and NRM
Biodiversity conservation is key
Insect biodiversity for NRM
Why manage noncrop biodiversity
A research park for Africa
Unlocking the diversity of yam
Cassava: improver of soils
Participatory yam conservation strategies
Smart NRM approaches
DNA barcodes for pathogens
A new food security crop?

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African yam bean: a food security crop?

Daniel Adewale, d.adewale@cgiar.org

Read the Ukranian translation by Martha Ruszkowski

Diversity in color, color pattern, structure, texture, brilliance, etc. of African yam bean seeds. Photo by D. Adewale, IITA.
Diversity in color, color pattern, structure, texture, brilliance, etc. of African yam bean seeds. Photo by D. Adewale, IITA.

Biodiversity assures the evolutionary continuity of species. The collection and conservation of diversity within species are a safeguard against the loss of germplasm. They provide a buffer against environmental threats and assure continual and sustainable productivity. Global food security is becoming shaky with increasing dependence on a few major staple crops. This has resulted in an alarming reduction not only in crop diversity but also in the variability within crops.

The conservation and maintenance of agrobiodiversity of neglected and underutilized plant species such as African yam bean (AYB) in seed banks aim at contributing to food security and preventing a potential food crisis. Increasing the use of underutilized crops is one of the better ways to reduce nutritional, environmental, and financial vulnerability in times of change (Jaenicke and Pasiecznik 2009); their contribution to food security is unquestionably significant (Naylor et al. 2004, Oniang’o et al. 2006). Among other things, the consumption of a broader range of plant species ensures good health and nutrition, income generation, and ecological sustainability.

Potentials of African yam bean
The plant (Sphenostylis stenocarpa) is one of the most important tuberous legumes of tropical Africa. It is usually cultivated as a secondary crop with yam in Ghana and Nigeria. A few farmers who still hold some seed stocks, especially the white with black-eye pattern, plant it at the base of yam mounds in June or July. The crop flourishes and takes over the stakes from senescing yam. It flowers and begins to set fruits from late September and October. The large bright purple flowers result in long linear pods that could house about 20 seeds.

The seed grains and the tubers are the two major organs of immense economic importance as food for Africans. This indigenous crop has huge potential for food security in Africa. However, there are cultural and regional preferences. In West Africa, the seeds are preferred to the tubers but the tubers are relished in East and Central Africa (Potter 1992). The crop replaces cowpea in some parts of southwestern Nigeria (Okpara and Omaliko (1995). Researchers (Uguru and Madukaife 2001) who did a nutritional evaluation of 44 genotypes of AYB reported that the crop is well balanced in essential amino acids and has a higher amino acid content than pigeon pea, cowpea, and bambara groundnut.

Tuber yield per stand of AYB accession TSs96 at Ibadan, 2006. Photo by D. Adewale, IITA.
Tuber yield per stand of AYB accession TSs96 at Ibadan, 2006. Photo by D. Adewale, IITA.

Apart from the use of soybean as an alternative to animal protein, protein from other plant sources is not often exploited. The protein content in AYB grains ranged between 21 and 29% and in the tubers it is about 2 to 3 times the amount in potatoes (Uguru and Madukaife 2001, Okigbo 1973). AYB produces an appreciable yield under diverse environmental conditions (Anochili 1984, Schippers 2000). Another positive contribution of the crop to food security is the identification of the presence of lectin in the seeds, which could be a potent biological control for most leguminous pests.

Although the vast genetic and economic potentials of AYB have been recognized, especially in reducing malnutrition among Africans, the crop has not received adequate research attention. Up to now, it is classified as a neglected underutilized species or NUS (Bioversity 2009). Devos et al. (1980) stressed that the danger of losing essential germplasm hangs over all cultivated food crop species in tropical Africa, especially those not receiving research attention. The quantity and availability of AYB germplasm is decreasing with time. At one time, Klu et al. (2001) had speculated that the crop was nearing extinction; its inherent ability to adapt to diverse environments (Anochili 1984, Schippers 2000) may have been responsible for its continual existence and survival. Nevertheless, scientists think that the genetic resources of AYB may have been undergoing gradual erosion.

IITA keeps some accessions of the crop, but otherwise, its conservation in Nigeria is very poor and access to its genetic resources is severely limited. Seeds of AYB seem to be available in the hands of those who appreciate its value, i.e., the elderly farmers and women in a few rural areas in Nigeria. The ancient landraces in the hands of local farmers are the only form of AYB germplasm; no formal hybrid had been produced as yet.

Improvement of the crop is possible only when the intraspecific variability of the large genetic resources of the species is ascertained. The genetic resources of AYB need to be saved for use in genetic improvement through further exploration in tropical Africa and for conservation.

African yam bean plant showing mature pods ready for harvest. Photo by Daniel Adewale, IITA.
African yam bean plant showing mature pods ready for harvest. Photo by Daniel Adewale, IITA.

Understanding AYB
Eighty accessions (half of the total AYB collection under conservation in the IITA genebank) were assessed for diversity using morphological and molecular methods. Thirty selected accessions were further tested in four ecogeographical zones in Nigeria to understand their productivity and stability. The breeding mode was also studied.

Findings show that each of the 80 accessions of AYB has a unique and unmistakable genetic entity, promising to be an invaluable genotype as a parent for crop improvement. Morphologically, two groups have evolved: the tuber forming and the nontuber forming.

Grain yield differed among individual accessions and across the four agroecologies. The average grain yield across the four diverse environments in Nigeria (Ibadan, Ikenne, Mokwa, and Ubiaja) was ~1.1 t/ha; however, grain yield at Ubiaja was well above 2 t. Most agronomic and yield-determining traits had high broad sense heritability and genetic advances, assuring high and reliable genetic improvement in the species. AYB is both self fertilizing and an outcrosser; the latter trait is exhibited at about 10%.

The good news is improvement through hybridization is possible within the species.

Anochili, B.C. 1984. Tropical Agricultural Handbook. Pages 48–50 in Food Crop Production. Macmillan Publishers, London, UK.

Bioversity International. 2009. http://www.bioversityinternational.org/scientific_information/themes/neglected_and_underutilized_species/overview.html [25 February 2010].

Devos, P., G.F. Wilson, and E. Delanghe. 1980. Plantain: Genetic resources and potential in Africa. Pages 150–157 in Genetic Resource of Legumes in Africa edited by Doku, E.V. Proceedings of a workshop jointly organized by the Association for the Advancement of Agricultural Science in Africa and IITA, Ibadan, Nigeria, 4–6 January 1978.

Jaenicke, H. and N. Pasiecznik. 2009. Making most of underutilized crops. LEISA Magazine, 25(1):11–12.

Klu, G.Y.P., H.M. Amoatey, D. Bansa, and F.K. Kumaga. 2001. Cultivation and uses of African yam bean (Sphenostylis stenocarpa) in the Volta Region of Ghana. The Journal of Food Technology in Africa 6:74–77.

Naylor, R.L., W.P. Falcon, R.M. Goodman, M.M. Jahn, T. Sengooba, H. Tefera, and R.J. Nelson. 2004. Biotechnology in the developing world: a case for increased investment in orphan crops. Food Policy 29:15–44.

Okigbo, B.N. 1973. Introducing the yam bean (Sphenostylis stenocarpa) (Hochst ex. A. Rich.) Harms. Proceedings of the first IITA Grain Legume Improvement Workshop, 29 October–2 November 1973, Ibadan. Nigeria. pp. 224–238.

Okpara, D.A. and C.P.E. Omaliko. 1995. Effects of staking, nitrogen and phosphorus fertilizer rates on yield and yield components of African yam bean (Sphenostylis stenocarpa). Ghana Journal of Agricultural Science 28:23–28.

Oniang’o, R.K., K. Shiundu, P. Maundu, and T. Johns. 2006. Diversity, nutrition and food security: the case of African leafy vegetables in Hunger and poverty: the role of biodiversity. Report of an International Consultation on the role of biodiversity in achieving the UN Millennium Development Goal of freedom from hunger and poverty edited by Ravi, S.B., I. Hoeschle-Zeledon, M.S. Swaminathan, and E. Frison. Chennai, India, 18–19 April 2005. M.S. Swaminathan Research Foundation, Chennai, India. pp. 83–100.

Potter, D. 1992. Economic botany of Sphenostylis (Leguminosae). Economic Botany, 46: 262-275.

Schippers, R.R. 2000. African indigenous vegetables: An overview of the cultivated species. Natural Resources Institute/ ACP-EU Technical Centre for Agricultural and Rural Cooperation, Chatham, UK. pp. 89–98.

Uguru, M.I. and S.O. Madukaife. 2001. Studies on the variability in agronomic and nutritive characteristics of African yam bean (Sphenostylis stenocarpa Hochst ex. A. Rich. Harms). Plant Production and Research Journal 6:10-19.

Participatory strategies of conserving yam biodiversity in Bénin

A. Dansi (adansi2001@gmail.com), C. Lusty (charlotte.lusty@croptrust.org), R. Asiedu (r.asiedu@cgiar.org), R. Hall, and R. Vodouhè (r.vodouhe@cgiar.org)

Yam (Dioscorea spp.) is an important tuber crop in Bénin. Its production is intensive in Collines (Center), Donga and Borgou (North), but marginal in Atakora (Northwest), Plateau (Southeast), and in Alibori (far north). Four species are cultivated (D. alata, D. cayenensis-rotundata complex, D. dumetorum, and D. bulbifera). Among these, the native African D. cayenensis-rotundata complex remains the most important, preferred, and widely cultivated.

Yam tuber seeds of different accessions ready for transport to IITA genebank for ex situ conservation. Photo from Alexandre Dansi, IRDCAM.
Yam tuber seeds of different accessions ready for transport to IITA genebank for ex situ conservation. Photo from Alexandre Dansi, IRDCAM.

Yam production in Bénin is seriously hampered by numerous constraints including pest and disease pressure, poor soil, and changing climate. Strategic use of existing genetic diversity is thus an appropriate option for addressing these constraints in an affordable and sustainable way. For this diversity to be well studied, conserved, and used, the International Foundation for Science (IFS), Gatsby Charitable Foundation (UK), IITA, Bioversity International, and more recently the Global Crop Diversity Trust (GCDT) sponsored several research projects in Bénin between 1997 and 2009. Within the framework of these projects, different yam germplasm collection surveys have been conducted that led to a unique collection of 1,017 accessions conserved in the field by Crop, Aromatic and Medicinal Plant Biodiversity Research and Development Institute (IRDCAM) in northern Bénin.

The landraces collected were fully documented (origin, agronomic traits, and technological characteristics) and a database was constructed. With the help of farmers, the collected landraces have been fully characterized based on plant morphology and classified into 210 morphotypes. The equivalence of the diverse vernacular names that cause confusion among users has been clearly established. The geographical distribution of the morphotypes, together with genetic diversity analysis, led to the identification of four different zones of diversity. These are Zone 1: Atakora (far Northwest); Zone 2: Bariba cultural area (Northeast); Zone 3: Donga (Northwest); and Zone 4: South-Center.

Yam germplasm collection points. Courtesy of GIS Lab, IITA.
Yam germplasm collection points. Courtesy of GIS Lab, IITA.

Analysis at the community level within each of these four zones revealed the high yam diversity in Bénin in Zone 2 (20–82 varieties per village; 40 on average) and in Zone 3 (13–48 varieties per village; 24 on average). Zone 1 (8–27 varieties per village; 17 on average) and Zone 4 (6–51 varieties per village; 20 on average) had less diversity. Early maturing (double-harvested) varieties dominate Zones 1 and 4, while Zone 3 is dominated by late-maturing (single-harvested) varieties. Both late- and early maturing landraces appeared in almost equal proportions across villages in Zone 2.

Within each of the four diversity zones and at community level, several varieties are disappearing or being abandoned. High rates of genetic erosion (32–48% on average) were recorded almost everywhere. This highlights the necessity and urgency of developing strategies to conserve the existing diversity both in situ and ex situ for use by present and future generations. With the financial support of GCDT, Bénin yam germplasm is already fully regenerated and safely duplicated in IITA’s Genetic Resources Center at Ibadan (Nigeria) where it will be conserved both in vitro and in a field bank.

The causes of the ongoing genetic erosion are diverse (technological, biotic, abiotic, and cultural) and vary in relative importance according to production zones. In the far Northwest (Zone 1), for example, environmental factors, particularly poor adaptation to climate change and susceptibility to poor soils, are the most important. In the Northeast (Zone 2) susceptibility to pests and diseases and cultural beliefs are the principal reasons.

To compensate for the loss in diversity and cope with the environmental (biotic and abiotic) constraints, farmers use different strategies to exploit the existing diversity. In the dry zone of Atakora where climate change is more perceptible, farmers adopt new varieties to adapt production to actual local conditions that are characterized by increasing frequency of drought. They also alter the timing of planting and other agronomic practices. In central Bénin, farmers increasingly neglect D. cayenensis rotundata varieties in favor of those of D. alata since these are better adapted to current agroecological conditions (poor soil, pest and disease pressure, low rainfall, etc.).

To assist farmers with this option for using the genetic diversity, a program for intensive variety exchanges between villages and producers in different diversity zones was launched in 2009 within the framework of the GCDT project. Of 20 to 30 participating villages in each zone, 15 villages have already received new varieties (40 to 50 per village). This year, 15 other villages will also benefit from this program.

Alexandre Dansi (right) and some farmers from Tchakalakou (North Bénin) in a discussion during the participatory yam characterization and classification exercise. Photo from Alexandre Dansi, IRDCAM.
Alexandre Dansi (right) and some farmers from Tchakalakou (North Bénin) in a discussion during the participatory yam characterization and classification exercise. Photo from Alexandre Dansi, IRDCAM.

The exchanges have been conducted, taking into account the preference criteria determined for each zone. This exchange of varieties is a strategic way of conserving diversity on-farm through utilization. It has a multidimensional importance that includes strengthening yam production, food security, poverty alleviation; improvement of household income generation; strengthening diversity, conservation, and use; and improvement of sociocultural conditions of rural women. The results will rapidly become more evident in Zone 1.

In the northern part of this zone negatively affected by climate change, only one to two varieties out of eight to ten are tolerant of drought. The weather is suitable for the production of dry yam chips, which are in high demand and more expensive than fresh yam, but the late-maturing varieties used for this purpose were almost absent. In the south of the zone (Toucountouna and Natitingou region) dominated by lowlands, flooding is a challenge and only a few varieties were reported to be tolerant of high soil moisture.

We believe that by using, through exchanges, a large number of the Bénin yam varieties available, farmers in these regions will have a chance to find at least 50 that will be suitable for their local conditions. A strong network of yam producers in Bénin is actually being organized by IRDCAM to sustain the effort. The farmers highly appreciate the effort.

Cultivated yam are all domesticated from wild relatives co-evolving with the cultivated forms via gene flows. Because these species are sources of useful genes, participatory strategies have also been developed to preserve their diversity in situ while encouraging the domestication process developed by farmers.

Dominique Dumet: Safeguarding agrobiodiversity for the future

Dominique Dumet showing seeds, IITA genebank. Photo by J. Oliver.
Dominique Dumet showing seeds, IITA genebank. Photo by J. Oliver.

As the head of IITA’s Genetic Resources Center (GRC), Dominique Dumet says she is something between a curator and an administrator. She is involved in conservation (field bank, seed bank, and in vitro bank, which includes cryopreservation for clonal crops), checking inventory, improving processes and workflows, transferring technology, and computerizing the system. In addition, she is involved in recruiting staff and selecting students, germplasm distribution and acquisition, research in plant genetic resources, staff management, research project development and proposal writing, and communication to donors on special projects and about germplasm at IITA during scientific meetings.

She is primarily interested in ex situ conservation and particularly low temperature biology and its application to conservation systems (cryopreservation, sanitation). She has an overview of all domains of germplasm conservation and takes part in various research projects as a collaborator to “add value to the germplasm.” She no longer considers herself a researcher, since she spends most of her time administering the genebank and planning or writing proposal or reports. This International Year of Biodiversity, she explains what GRC plans in support of promoting biodiversity conservation.

Why is biodiversity conservation important? What are your priorities?
Our work is very important. We try to reduce the rate of irreversible loss in the biological diversity that is used in agriculture. All conservation aspects are important, but maybe the conservation sensu stricto comes first if we have to choose as we have a responsibility towards the international community and if we do not work well, all may suffer from our mistakes.

What do you like about working in Africa? In your field of specialization?
I am proud of my job. I hope I contribute to improving the well being of the poorest even if for one iota. I also like being in an environment very different to the one in which I grew up.

In vitro biology and cryopreservation in particular is my field of specialization. Cryopreservation fascinates me as I find it amazing that we can stop the life of a tissue and bring it back again whenever we want to do so. In the frozen stage, all biochemical or biological processes stop—that means that everything stops moving at one moment—and then the magic of life makes it start again so long as physical and chemical parameters are adequate (cooling and thawing temperature, osmotic pressure, light, growth regulators, etc.).

What are your challenges and constraints at work?
The challenges are to maintain the bank at international standards and to keep all the accessions alive. Some constraints include unforeseen requests which make us work under pressure as we still have our routine activities, and new concepts that make our system obsolete.

Collection recording with barcode inventory system, IITA genebank. Photo by O. Adebayo, IITA.
Collection recording with barcode inventory system, IITA genebank. Photo by O. Adebayo, IITA.

How do you make the many visitors to GRC understand and appreciate what you are doing?
I give information on the basic concepts of diversity, I explain why we need to conserve it ex situ (out of the natural environment) because of the genetic erosion taking place in the field. Then I explain how we maintain it via seeds or field and in vitro banks, depending on the crop. I also show some examples of diversity, e.g., cowpea seed collection and the variation observed at seed coat. I provide some background on the gaps in the collection based on GIS. And I generally conclude with the International Treaty and access to plant genetic resources for food and agriculture (PGRFA).

Please cite some concrete steps being taken by IITA in biodiversity conservation.
IITA was involved in collecting genetic resources as early as the 1970s so we do have a long history in investing in biodiversity conservation. Many collecting missions have been organized and germplasm has been also acquired from many national collections. The majority of the collections have now been described at agromorphological level, but we are still working on it for maize, for example. We have to characterize any new accessions coming into the bank.

Recently we organized a meeting and survey to develop the cowpea global conservation strategy (Trust-funded). We will have the same strategy developed for yam in 2010 (we are also organizing the Trust-funded expert meeting for this). We are developing more efficient conservation processes such as cryopreservation (this lowers costs but also limits genetic variation during storage). We are fingerprinting the collections of clonal crops to identify germplasm at accession level. This will further guide our collecting missions.

Do you think governments everywhere are serious about biodiversity conservation?
That depends on the country. The richer ones certainly take more serious action—but the poorest (or the less organized) do not have this ‘luxury’. I think all understand the value of biodiversity but as it is a long-term investment to store and as the return on investment is not guaranteed, countries either ignore it or do little about it.

What is the state of agrobiodiversity in Africa?
It is not too bad, compared to other continents—my view on this is that Africa has not yet undergone its Green Revolution (but this opinion may be controversial). However, things may change very quickly, especially now that Africa is seen as a big field where agriculture can take off. Somehow, if we are successful in producing high-yielding crops the adoption rate of such high potential crops may quickly wipe away natural diversity, including (but not only) the landraces (varieties developed by farmers over thousands of years). When the elite genotype replaces older varieties it makes the low performing one obsolete and it increases the rate of planting (as it can generate higher revenue). We have to be vigilant about this since we, as breeders of improved varieties, are partly responsible. There is a conflict of interest between agriculture intensification and conservation of biodiversity.

Do farmers understand the need to conserve seeds or genetic resources for future generations?
In general I would think they are the first one to know about biodiversity but they may not be aware of the amplitude of the “erosion” of species.

Some are already organized in community based genebanks and there are participatory conservation projects within the CGIAR but I do not know enough about the topic. This may be an important complementary approach, but participatory conservation may be difficult to sustain. Besides in community based conservation, the incentive is cultural preference. That means only materials of immediate interest for the farmers are kept.

Bambara groundnut seeds. Photo by J. Oliver, IITA.
Bambara groundnut seeds. Photo by J. Oliver, IITA.

What is the status of IITA’s seed shipment to Svalbard in Norway?
We had planned on sending more than 20,000 accessions of cowpea and its relatives, bambara groundnut, maize, and soybean in the next few years. Cowpea makes up the majority of the accessions that we are sending. There is a bit of deviation from the original plan but we are more or less on track.

Being the lead person in agrobiodiversity conservation in the Institute, how do you plan to mark the UN International Year of Biodiversity?
We plan to raise awareness about biodiversity among the youth, i.e., high school students and adults in the local community. We will organize quiz contests, tree planting activities, excursions to the IITA forest and to the genebank; produce information materials (videos, flyers, handouts) and set up roaming exhibits and posters.

We also plan to organize seminars and a field or biodiversity/community day for students, farmers, and residents in the local community. We will be coordinating with partners from the University of Ibadan, local schools, Alliance Française, and other organizations, such as the National Center for Genetic Resources and Biotechnology, Nigeria Institute of Horticulture, and University of Abeokuta.

What would be your message to colleagues about biodiversity conservation?
Don’t just conserve; educate as well.

Robert Asiedu: Advancing the development of Africa through science

Robert Asiedu. Photo by IITA.
Robert Asiedu. Photo by IITA.

Robert Asiedu is a plant breeder, whose main research interest is on tropical root and tuber crops, especially yam and cassava. From the International Maize and Wheat Improvement Center (CIMMYT) he joined the Root and Tuber Improvement Program of IITA in 1989. His initial research was on cassava and its wild relatives but he spent most of his time on yam research. He has held various leadership or management roles in IITA since 1991. He is Director, Research for Development (R4D), West Africa, and Program Director, Agrobiodiversity and Root and Tuber Systems Programs. In this interview, he talks about research on root and tuber systems, and on agrobiodiversity initiatives.

What inspires you at work?
The potential to advance the development of Africa through agricultural research is a major inspiration for me. IITA offers an excellent platform for achieving this so it is a great pleasure and a privilege to work here.

What do you like about your work as director?
I enjoy the broader opportunities and challenges the position offers to contribute to the development of the subregion through science.

How do you feel about IITA’s work in West Africa and in those areas that you are in charge of as program director?
West Africa is the subregion in which the Institute has worked longest. It is fascinating to reflect on the changes in our modes of operation and interaction with partners in response to the changes in our environment. We have done well so far but there is still a
lot to do.

What is your work philosophy?
To do the best I can every time.

You talk about yam as being a “part of man”. What is so special about yam?
My thoughts on the links between man and yam are based on several fascinating articles by anthropologists and ethnobotanists that I have read on the subject. From West Africa through the Caribbean to the Pacific region, yam is respected and celebrated through major annual thanksgiving festivals in areas where it is cultivated as a staple.

How is progress on IITA’s R4D on roots and tubers/ Agrobiodiversity?
The R4D work on tropical root and tuber crops continues to focus on genetic improvement, crop and pest management, food science and technology, and agroenterprise development.

For yam, improved options for the mass production of affordable and healthy seeds are a major component of our agenda. We have been investigating nutrient use efficiency and the role of mycorrhizal fungi in yam mineral nutrition. The research on food science/technology is focused on understanding the functional properties required in yam tubers and products for household and industrial purposes, development of new competitive products from yam, and screening of germplasm for textural and nutritional attributes.

We continue to improve on our efficiency and effectiveness in conserving the germplasm of banana/plantain, cassava, cowpea, maize, soybean, and yam. Core collections and reference sets are being defined. These collections are characterized using molecular tools and several are being preserved in the form of DNA available for delivery to requestors. Documentation of information has been improved and are now available online. There has been a significant increase in the accessions of clonally propagated crops that are preserved in vitro, in addition to the field banks.

What are the challenges in working on roots and tubers? Agrobiodiversity?
The limited history of research on the tropical root and tuber crops, such as cassava and yam, has left huge gaps in the knowledge of their basic biology. This affects the pace of advancement in research, compared to that of other major staple crops. This is exacerbated by the limited pool of researchers on these crops worldwide. Research funding is very low compared with the importance of these crops in sub-Saharan Africa.

In Agrobiodiversity, the major challenges are the lack of clarity in the interpretation of various international conventions, increasing protectionism in the sharing of crop germplasm, and the apparent lack of international agreements governing the status of collections of nonplant taxa.

What can you advise colleagues?
We should constantly keep our focus on the status, needs, and expectations of those who will benefit from our work.

How could we make the partnership with national programs, donors and policymakers, the private sector, or the growers work better?
Successful partnerships are built on good foundations. Establishing partnerships involve the joint setting and common understanding of the objectives, sharing of responsibilities, and clarity of roles. Periodic and objective assessment of progress is necessary, followed by effective action on the findings. There should be mutual respect and trust in the relationship as well as regular, effective, and open communication. It is important to monitor the changing circumstances of the various partners, including institutional and policy environments, and the needs of some partners for capacity building to play their roles effectively. Good cooperation also depends on fairness in acknowledging the contributions of partners and equity in sharing results, credits, or benefits.

How would you assess IITA’s efforts in agrobiodiversity conservation?
IITA has played and continues to play a key role in conserving germplasm of staple crops, underutilized crop species, and nonplant taxa that are important to African agriculture. Most national programs in sub-Saharan Africa have difficulty in providing the facility and personnel required for long-term conservation of these materials, especially the clonally propagated crops. The duplication of national collections of selected crops in our genebank is a major contribution to the assurance of long-term security. IITA works with a range of partners to continually improve the methods of preservation and characterization of the conserved germplasm.

How can we promote agrobiodiversity conservation among our audiences?
We can increase information dissemination using the print and electronic media and stakeholder consultative workshops to highlight the benefits of sustaining diversity in the food and farming systems and hence in the genetic resources on which these depend. The long-term conservation of nonplant genetic resources, such as beneficial insects and bacteria, requires even more explanation. Taking advantage of our political neutrality and links with relevant international agencies, we can engage in more consultation with policymakers in Africa to allow more freedom in making new collections of germplasm and facilitating international exchange.

Scott Miller: Guardian of life

Scott Miller, Undersecretary for Science, Smithsonian Institution and Chair, Executive Committee, Consortium for the Barcode of Life. photo courtesy of S. Miller.
Scott Miller, Undersecretary for Science, Smithsonian Institution and Chair, Executive Committee, Consortium for the Barcode of Life. photo courtesy of S. Miller.

As Deputy Undersecretary for Science at the Smithsonian Institution (SI), Scott Miller helps oversee the work of SI’s science units, including the National Museum of Natural History, National Zoological Park, Smithsonian Tropical Research Institute, and others. He is also Chair of the Executive Committee of the Consortium for the Barcode of Life (CBOL), and Co-Chair of the US Government Inter-Agency Working Group on Scientific Collections, where he works on science capacity building activities on national and international scales. He maintains an active research program in the systematics and ecology of moths, and the application of that information to conservation and agricultural issues in New Guinea and Africa.

How did you become interested in biodiversity?
I grew up fascinated by nature as a child, and was able to get involved early in insect research projects at a local natural history museum, leading to a career in biodiversity. As I gained a broader perspective, I became especially concerned about helping developing countries to develop the capacity to manage their biodiversity wisely. They lead to my work in Africa.

What will the International Year of Biodiversity achieve?
This is an important opportunity to raise the profile of biodiversity issues. But we have to remember that our reliance on biodiversity is constant, and so must be our attention to understanding and wise management.

Most ecological studies show that biodiversity is declining at an alarming rate worldwide. Could you comment on this?
I agree that biodiversity is being degraded at an alarming rate. While the exact rate can be debated, it is clearly not sustainable.

What is the value of lost biodiversity?
We need much better economic models and data for biodiversity and ecosystem services, but some studies give an idea of the economic importance [Costanza et al. 1997, Pimentel et al. 2000]. One-third of global crop production relies on insect pollinators, valued at some US$ 117 billion. Natural biological control is valued at some $400 billion. Soil arthropods that maintain soil fertility provide trillions of dollars in value to agriculture.

How can Africa reduce the loss of biodiversity?
Action is needed at all levels, from wise government policies, enlightened management of industries that use natural resources, through the empowerment of local people to conserve and benefit from their own natural resources. Wise management requires understanding biodiversity, and valuing conservation to maintain the benefits to society over the long term. The economies of most African countries are based on natural resources, and sustainable development requires wise management. I have always been impressed by the “Working for Water” program in South Africa as a model for integrating landscape scale conservation, invasive species management, economic development and job creation, but there are many other success stories across Africa.

You worked in the International Center for Insect Physiology and Ecology (icipe) in Kenya some time ago. Tell us about your experiences in conservation and sustainable development.
My time in Kenya was a tremendous learning experience for me, and I hope I was able to help build programs that will have lasting impact. I am still involved in Kenya through collaborations with icipe, Mpala Research Centre, and the National Museum. We tried to help local people understand the value of their biodiversity, how to restore degraded landscapes, and how to benefit from the biodiversity resources. Among other things, I was involved in an integrated conservation development project at Kakamega Forest in western Kenya that involved many synergetic components. These included strengthening forest management, replanting degraded lands, reducing the use of wood as fuel (through promoting efficient cooking stoves), developing sustainable income sources (especially “low tech” uses of natural products, and ecotourism), providing microfinance facilities, and enhancing the accessibility of health care and family planning.

What do you think of IITA’s efforts in agrobiodiversity conservation/sustainable agriculture?
Historically, IITA has played a very important role in agrobiodiversity conservation efforts. While some of those efforts remain strong, I am concerned that financial pressures threaten some of them, such as the collections that support biological control research and application in insects and fungi. The institutional infrastructure for understanding biodiversity is very weak in West and Central Africa, and as an international organization, IITA can play a vital role in filling the gap, and building national capacity. I am pleased to see IITA’s leadership in the CGIAR study of biomaterial collections beyond plant germplasm, which recognizes these collections as Global Public Goods.

Do you see the investment in conservation well spent?
IITA’s investment has been critical in the past, and needs to be enhanced to support future agricultural development and pest management. Climate change will bring new challenges to agriculture in Africa, and crop germplasm will be crucial, as well as knowledge of crop relatives, pest organisms, and beneficial organisms. The native forest on IITA’s Ibadan campus is an important biodiversity resource, and the protection that IITA has provided it for many years has been an important service.

What is the contribution of insect diversity to agriculture?
Insects provide vital ecosystem services to agriculture, including pollination, biological control of pests, and the maintenance of soil fertility. A recent study on the impact of CGIAR research in Africa (Maredia and Raitzer 2006) found that 80% of the impact (valued at $17 billion) resulted from four biocontrol programs using insects and mites. All those programs had to solve significant taxonomic problems (e.g., understanding the biodiversity) before they became successful, underscoring the importance of research and documentation.

How does the Consortium for the Barcode of Life contribute to the conservation and protection of biodiversity?
DNA barcoding is a species diagnostic system using short sequences of DNA (www.barcoding.si.edu), and the Consortium is an international organization promoting the development of standards and the building of the reference library of sequences. Understanding species, being able to identify them, and being able to communicate about them are basic to managing and using biodiversity. Thus, CBOL contributes through allowing fast and accurate identifications in difficult situations such as the immature stages of plant pests, the wood or roots from medicinal plants, or parts of butchered wildlife or fish in the illegal trade.

CBOL works closely with organizations with similar interests, such as BioNET INTERNATIONAL and the Global Taxonomy Initiative of the Convention on Biological Diversity. We are communicating with organizations such as the International Plant Protection Convention to help establish formal protocols for the DNA-based identification of agricultural pests.