Genebank activities

Conserving Genetic Resources

Genetic diversity created through natural and human selection over millennia, and complemented by the diversity present in wild relatives of crop plants, provides the raw material for improving crop productivity to meet food-security needs of the rapidly growing global population. Genetic variation, once considered unlimited, is fast eroding as modern varieties replace traditional cultivars over large areas, and natural habitats are destroyed. Genetic diversity must be conserved, both to combat new pests and diseases that emerge from time to time, and to produce better-adapted varieties to changing climatic and environmental conditions. One of ICRISAT’s major objectives is conservation of germplasm, for which it has established a genebank that serves as a world repository for the collection of germplasm of the five ICRISAT mandate crops: sorghum, pearl millet, chickpea, pigeonpea, groundnut; and six small millets: finger millet, foxtail millet, little millet, kodo millet, proso millet and barnyard millet.

Assembling the germplasm

With over 119,700 germplasm accessions assembled from 144 countries through donations and collection missions, the ICRISAT genebank is one of the largest international genebanks. Major donors to the collection are the national programs in Cameroon, Ethiopia, France, India, Iran, Nigeria, Sudan, Uganda, and the United States; organizations; individual research workers; and generous farmers of many nations. Also, ICRISAT scientists conducted over 200 collection expeditions to collect several landraces on the verge of extinction, braving difficult terrain, hostile environments, and harsh conditions. The collection provides both insurance against genetic erosion and a source of tolerance to diseases and pests, climatic and other environmental stresses, improved grain quality and yield traits for crop improvement. Several landraces now conserved in the ICRISAT genebank have disappeared from their natural habitats in Africa and Asia. Examples are the Hegari, Zerazera, and Kurgis landraces of sorghum once present in the Gezira, Kasala and Blue Nile provinces of Sudan.

Collecting germplasm also provides rich opportunities for cooperation between ICRISAT and national programs. Collection is always done jointly with national/international organizations. The samples are initially characterized and regenerated in the source country and germplasm is acquired under Material Acquisition Agreements. All exotic germplasm that finds its way into the ICRISAT genebank at Patancheru, India is examined by the Indian national plant quarantine system before it is released.

Characterizing New Germplasm

All newly acquired germplasm is first characterized for a set of recognized descriptors. These include stable botanical (qualitative) characters and a few agronomic and grain quality traits. Examples of some major identifiable traits are early seedling vigor, number of days needed to flower and mature, plant height, stem thickness, tillering, leaf size, number of seeds per pod, seed size and color, and grain yield.

After the initial characterization, germplasm accessions are evaluated and screened by multidisciplinary teams of ICRISAT and national program scientists. These teams assess the potential and usefulness of germplasm lines for specific circumstances. Typically, these include abiotic stress tolerance, disease and pest resistance, and quality characteristics. After several years of detailed scientific evaluation and screening, new genetic stocks are identified for use in crop improvement as new sources of breeding material for desirable characteristics. Germplasm sets were evaluated for agronomic performance over locations jointly with NARS scientists in Burkina Faso, Canada, China, Ethiopia, India, Indonesia, Japan, Kenya, Namibia, Nepal, Thailand, Ukraine, USA and Vietnam. The results of joint evaluations have led NARS scientists to better understanding of the germplasm conserved in the ICRISAT genebank.

Hundreds of such genetic stocks have already been identified and are being used by ICRISAT and NARS scientists throughout the world. Through participation in such evaluation-identification exercises, many national program scientists have been trained in plant characterization. This gives them the skill to identify new genetic stocks and enhances their ability to manage germplasm in their national crop improvement programs.

Maintaining the Collection

ICRISAT Genebank ensures continued germplasm availability for crop improvement. Seed storage under controlled environmental conditions – low temperature and low relative humidity – prolongs seed viability and eliminates the need for frequent regeneration of germplasm, which is expensive and involves risk to genetic integrity. The conservation of germplasm in genebanks in the form of seeds requires that the integrity of the material conserved be maintained to the highest standard over prolonged periods of time. A short-term storage, maintained at 18-20ºC and 30-40% relative humidity, is used to hold seeds while they are dried and prepared for medium- and long-term storage. Five medium-term storage rooms maintained at 4ºC and 20-30% relative humidity help conserve seed samples for 20-25 years. Four long-term storage units at -20ºC conserve the seeds dried to 5-7% moisture content and hermetically sealed in aluminum foil packets for more than 50 years.

Germplasm accessions that do not produce adequate seed for conservation (such as wild species of groundnut and pearl millet), are maintained as live plants in a botanical garden and green houses.

Germplasm samples for conservation are multiplied mainly during the postrainy season to get better quality seed. To minimize genetic drift, an adequate number of plants are grown and sampled equally in constituting new seed stocks. Genetic integrity is maintained by pollination control while regenerating cross-pollinating crops such as sorghum, pearl millet, and pigeonpea. Pre-storage deterioration in seed quality is minimized by harvesting promptly when maturity is reached.

Ensuring Germplasm Safety

Svalbard Global Seed Vault, Norway

ICRISAT’s genebank is designed to withstand natural disasters. For further safety, the long-term conservation collection is duplicated in other genebanks. Duplicates of a large portion of chickpea germplasm are conserved at the International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria; and pearl millet, groundnut and small millets at the ICRISAT Regional Genebank, Niamey, Niger. The Svalbard Global Seed Vault (SGSV) located in the remote Arctic Svalbard Archipelago, Norway, has been established to preserve unique duplicate samples of seeds held in genebanks worldwide. The Seed Vault provides an insurance against the loss of seeds in genebanks, as well as a refuge for seeds in the case of large scale regional or global crisis. ICRISAT has committed to place in the SGSV the FAO-designated germplasm of its mandate crops and small millets.

Access to Germplasm

Distribution of germplasm and related information is fundamental to ICRISAT’s mission of increasing crop productivity and food security. To ensure unrestricted access of the world community, ICRISAT placed its germplasm collections under the auspices of the Food and Agricultural Organization of the United Nations (FAO) in 1994. Under the terms of the agreement with the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA), ICRISAT supplies germplasm through standard material transfer agreement (SMTA).

Using the Collection

Documentation is essential in good genebank management to allow efficient and effective use of germplasm. ICRISAT too ensures information access to its genebank by participating in the CGIAR’s System-wide Information Network for Genetic Resources (SINGER). The SINGER database is an information source of the collections of genetic resources maintained around the world. This searchable database has information on the identity, origin, and characteristics of the accessions in ICRISAT’s genebank http://singer.grinfo.net.

Supply of Germplasm

Germplasm requests, primarily for use in crop improvement research, are processed by selecting for particular qualities against information stored as passport information or the evaluation database in computers. Hundreds of germplasm accessions are tested annually by ICRISAT scientists for use in developing new varieties and hybrids for the semi-arid tropics. Several thousand accessions of germplasm have been restored to their country of origin upon request. Examples are Botswana (362 sorghum accessions), Cameroon (1827 sorghum and 922 pearl millet), Ethiopia (1723 sorghum and 931 chickpea), India (44,701 accessions of five mandate crops and six small millets), Kenya (838 sorghum and 332 pigeonpea), Nigeria (1436 sorghum), Somalia (445 sorghum), and Sri Lanka (71 pigeonpea).

With the erosion of genetic diversity available on farm, the ICRISAT genebank has become a major source of diversity available to plant breeders for crop improvement. Between the years 1975 and 2008, the ICRISAT genebank has distributed about 700,000 samples of its mandate crops and small millets to users in 144 countries. Several of these samples have been tested and 66 accessions were directly released as cultivars in 44 countries contributing to food security. Thousands of other samples are being used as raw materials in breeding programs as desirable sources of new agronomic traits for crop improvement.

Core and Mini core collections

A large gap exists between availability and actual utilization of the germplasm materials. Limited use of germplasm has been observed in breeding programs, mainly due to lack of information on economic traits. Core collections (representing 10% of the entire collection) and mini core collections (10% of core collection, ie, 1% of the entire collection) have been developed at ICRISAT to enhance use of germplasm in breeding programs globally. The core and mini core collections were evaluated to identify genetically diverse trait specific germplasm for resistance to abiotic and biotic stresses, agronomic and quality traits for use in breeding programs to develop broad based cultivars.

The revolution in molecular biology, bioinformatics, and information technology has provided the scientific community with tremendous opportunities for solving some of the world’s most serious agricultural and food security issues. Molecular characterization of composite sets of germplasm, that include core or mini core collections, have helped in understanding genetic diversity and population structures in each species. The molecular characterization details on ICRISAT germplasm sets are available through www.generationcp.org. Genotype based reference sets of genetically diverse 300 accessions have been established at ICRISAT. Seeds of mini core collection and reference sets are available for use by the global research community.

Germplasm adoption

To augment resources for the long-term availability of funds for the conservation, characterization and distribution of germplasm for the benefit of agriculture and food security for humanity, ICRISAT has come up with innovative idea of adopting germplasm, first by ICRISAT staff members themselves, and then moving to non-traditional donors for adoption. ICRISAT believes that more and more such philanthropists will come forward to adopt these priceless resources for the benefit of humanity.

Making a Long-term Impact

ICRISAT has been highly successful in assembling and conserving germplasm as part of the global effort for the conservation of biodiversity. The greatest impact is in conserving the germplasm and making diverse material readily available for use in crop improvement globally, including the semi-arid tropics. ICRISAT’s Genetic Resources Unit continues to assemble germplasm from unexplored areas of diversity, and makes it freely available for use in crop improvement for the benefit of humankind.

Germplasm is basic to crop improvement programs for sustainable agriculture. Our strategic research on core and mini core collections, and identification of new diverse sources will enhance the use of germplasm in breeding programs, aimed at producing agronomically superior cultivars with a broad genetic base. Molecular characterization of mini core and trait-specific subsets will further reveal the usefulness of germplasm accessions in allele mining. Another dimension of breeder requirements is agronomic desirability of the germplasm lines. This helps in maintaining or even improving the agronomic performance of breeding lines while enhancing the traits of importance. Thus our aim is to identify the trait-specific, genetically diverse and agronomically superior germplasm lines for use in crop improvement programs to develop high yielding cultivars with a broad genetic base.

For further information Contact:

Dr H D Upadhyaya
Assistant Research Program Director-Grain Legumes and
Principal Scientist and Head Gene Bank
ICRISAT
Email: h(dot)upadhyaya(at)cgiar(dot)org