To conserve or not to conserve?

IITA maintains more than 15,000 accessions of cowpea in its genebank. Photo by IITA.
IITA maintains more than 15,000 accessions of cowpea in its genebank. Photo by IITA.

Crop improvement through breeding and biotechnology is one way of tackling the challenges of feeding the world. Conservation of genetic resources is an important component of crop improvement, providing a pool of materials for the researchers to draw from.

IITA’s Genetic Resources Center (GRC) created in 1975, maintains over 28,000 accessions of six main staple crop collections that are available to food and agriculture researchers worldwide working on crop improvement. They are cowpea or “black-eyed pea” (Vigna unguiculata L.), maize (Zea mays L.), soybean (Glycine max (L.) Merr.), cassava (Manihot esculenta Crantz), yam (Dioscorea spp.), and banana (Musa spp.).

Over 50% of the collection is made of cowpea collected from 89 countries, mainly in Africa, and other Vigna spp. It is also the most shared, with 54 of all the germplasm materials being distributed.

Ex situ conservation in IITA genebank: medium-term storage, 5 °C. Photo by IITA.
Ex situ conservation in IITA genebank: medium-term storage, 5 °C. Photo by IITA.

Since 1985, IITA has distributed germplasm of cowpea and its wild Vigna relatives for genetic improvement research to institutions in sub-Saharan Africa, Asia, USA, and South America. This has contributed to the development of new cultivars or varieties currently adopted by rural farmers in the regions.

The effectiveness of the distribution system from the genebank, the use of the distributed germplasm, and conservation costs were assessed in a study conducted by Victor Manyong, Dominique Dumet, and A.T. Ogundapo from IITA and D. Horna from the International Food Policy Research Institute. Likewise, the impact of the conservation of germplasm of cowpea and wild relatives was examined to justify the conservation efforts.

Methodology
Questionnaires were e-mailed to partners who had collected germplasm from GRC between 1975 and 2009 to determine the ease of accessing material and their use. To estimate the cost of conserving a unit of the two crops, the Decision Support Tool (DST) developed by IFPRI was used.

Ex situ conservation in IITA genebank: medium-term storage, in vitro. Photo by IITA.
Ex situ conservation in IITA genebank: medium-term storage, in vitro. Photo by IITA.

Only about 13% of the beneficiaries responded but they accounted for about 84% of the accessions distributed to beneficiaries in West Africa, Asia, East Africa, Europe, and North America.

No responses were received from beneficiaries in Australia, the Caribbean, Central Africa, the Middle East, North Africa, South Africa, and South America. This may partly have been due to lack of updated contact details in the genebank’s electronic database. This needs to be improved for future feedback surveys.

Use of cowpea and wild Vigna germplasm
The study findings show that most of the distributed cowpea and wild Vigna accessions were used for breeding followed by activities in agronomy and biotechnology research. However, in many cases, they had multiple uses, such as breeding, biotechnology, and agronomy.

Between 2001 and 2005, about 76% of the accessions were used for various agricultural research activities and were found adaptable to different agroecological zones, from forest to the savanna in the tropics and subtropics. Derived, Sudan, and Sahel savannas were recognized as the adaptable agroecological zones for the cultivation of cowpea and wild Vigna.

Ex situ conservation in IITA genebank: long-term storage, −196 °C. Photo by IITA.
Ex situ conservation in IITA genebank: long-term storage, −196 °C. Photo by IITA.

The majority of the users of the germplasm found it easy (32%) to very easy (68%) to get the material from the genebank. Only a few experienced difficulties. These included the inability of the genebank to supply the required quantities (3% of accessions), poor collaboration with NARS and universities (3%), long bureaucratic procedures to acquire germplasm (2%), and improper documentation of the passport database of accessions (1%).

Desired traits
High yield and pest resistance were the two traits desired by the majority of agricultural researchers who made requests, irrespective of their specialization. Other desired traits included compatibility to cross with other accessions, seed color and size, nutritive value, palatability and attractiveness, drought tolerance, nematode resistance, early flowering, and storability.

Moreover, many were satisfied with the accessions they received. Findings show that 68% of the accessions received by agronomists met their desired traits, 76% for food technologists, but only 3% for breeders where the main issue was the low level of resistance to pests and diseases. However, the breeders recorded 100% satisfaction in the exploitation of accessions for seed color, seed size (good), and compatibility with crossing. Likewise, 95% satisfaction was achieved on high seed yield and 74% on the combination of high yield and pest resistance by some of the breeders.

Cost of conservation
The structure cost of the genebank in the DST has four categories: capital, quasi-fixed, variable labor input, and variable nonlabor input. Capital inputs include infrastructure, such as germplasm storage and genebank facilities, and equipment for field operations and offices.

Ex situ conservation: field genebank, IITA. Photo by IITA.
Ex situ conservation: field genebank, IITA. Photo by IITA.

Using 2008 as a reference year, US$358,143 and $28,217 was spent annually on the conservation and management of cowpea and wild Vigna. The capital cost took the major share of the costs, followed by quasi-fixed costs for scientific staff, nontechnical labor, and nonlabor supplies and consumables. Each accession cost about $72 for cowpea and only about half of that for wild Vigna. A large share of the expenditure, $28,537, went into the regeneration of 2,228 accessions of cowpea, at an average cost of approximately $12.81 per accession.

Cowpea germplasm is regenerated in the screenhouse to produce high quality germplasm, with considerations of purity and sanitation, hence the relatively high cost per accession. Seed health testing ($13.94/accession) and distribution ($22.63/accession) were the other high costs.

One way to reduce these costs is by increasing the number of accessions, thus lowering the unit cost. Also, upgrading and expanding the current infrastructure to improve the efficiency of the genebank were recommended.