The ICRISAT Genebank serves as a world repository for the collection of germplasm of the five mandate crops – sorghum, pearl millet, chickpea, pigeonpea and groundnut; and six small millets – finger millet, foxtail millet, little millet, kodo millet, proso millet and barnyard millet. With over 120,000 germplasm accessions assembled from 144 countries, it is one of the largest international genebanks. Several landraces now conserved in the ICRISAT genebank have disappeared from their natural habitats in Africa and Asia. The collection serves as insurance against genetic erosion and as a source of resistance to diseases and pests, tolerance to climatic and other environmental stresses, and improved quality and yield traits for crop improvement.
The majority of the collection is seed producing and essentially orthodox in nature. Seed conservation has a vital role in preservation of genetic variability as it is simple to handle, cost-effective and has the capability of maintaining genetic stability over long periods of time. The conserved germplasm has been characterized (98.9% of the collection) for important morpho-agronomic characteristics.
The active collection of the genebank, stored at 4°C and 30% RH, is a basic source for distribution and utilization. The base collection is maintained at –20°C in vacuum packed aluminum foil pouches at 3-7% seed moisture content. Base collections ensure long-term viability of material (more than 50 years) as a security to the active collection. In addition, ICRISAT has committed to place the FAO-designated germplasm (111,000 accessions) at the Svalbard Global Seed Vault in Norway as safety backup. 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.
The genebank collection (94.8%) placed in-trust with FAO of the United Nations has become an important source of diversity available to researchers in both public and private sectors throughout the world. For example, between the years 1975 and July-2012, the ICRISAT genebank has distributed over 20,000 samples of its mandate crops and small millets to users in 146 countries beside an equal number of samples to ICRISAT scientists. The ICRISAT genebank has restored several thousands of germplasm to the source countries when requested. Examples are Botswana (362 sorghum accessions), Cameroon (1827 sorghum and 922 pearl millet), Ethiopia (1723 sorghum and 931 chickpea), India (44,723 accessions of five mandate crops and six small millets), Kenya (838 sorghum and 332 pigeonpea), Nigeria (1436 sorghum), Somalia (445 sorghum), Sri Lanka (71 pigeonpea) and Sudan (977 sorghum and 594 pearl millet). The genebank has promoted testing and release of its germplasm directly as superior varieties. So far, 75 accessions have been released as 96 cultivars contributing to food security in 39 countries.
Exiguous use of germplasm has been observed in breeding programs mainly due to lack of information on economic traits. Core collections (10% of entire collection) and mini core collections (10% of the core or 1% of entire collection) have been developed for all mandate crops and finger millet, foxtail millet and proso millet to enhance use of germplasm in breeding programs. We have used core and mini core collections to identify genetically diverse trait specific germplasm for resistance to abiotic and biotic stresses, and for agronomic and quality traits for use in breeding programs to develop broad based cultivars. Molecular characterization of core/mini core collections have helped in understanding genetic diversity and population structures. Genotype based reference sets of genetically diverse 200-400 accessions (depending upon the crop) have been established. Seeds of mini core collection and reference sets are available for use by the global research community following the standard material transfer agreement (SMTA) under the International Treaty on Plant Genetic resources for Food and Agriculture (ITPGRFA).
Within the frame-work of the ITPGRFA, the genebank ensures that the assembled germplasm is maintained in a safe, secure and cost-effective manner and distributed to all bonafide users for utilization in crop improvement. The collections are maintained under long-term conditions, monitored regularly, and regenerated with appropriate plant population and pollination controls to ensure genetic integrity.
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