Adding Value to Cassava Genetic Resources Conserved at CIAT-Part I: A Review of Fifty Years of Collection, Conservation, Characterization and Distribution.

内容摘要

Improved varieties strengthen cassava's roles as both a food security staple and a versatile industrial raw material across the tropical regions where it is produced. In support of this effort the International Center for Tropical Agriculture (CIAT) curates the world's largest cassava germplasm collection at its Cali, Colombia, research center. Since the first collection expeditions in 1969, a primary focus was to assemble and conserve the diversity from the crop's center of origin in the American tropics. Later additions expanded representation from Asia and Africa as secondary centers of diversity. The collection now consists mainly of landraces (about 5000 accessions), bred lines from CIAT (375) and from partner institutions (253), and related wild Manihot (377 accessions from 23 species or subspecies). Landrace diversity originated and evolved almost entirely through occasional farmer selections from seed-derived plants, which were subsequently conserved clonally over many generations. Secure ex situ conservation, first as a field collection and then in a slow-growth in vitro system, gave priority to pathogen testing and reliable culture and exchange methods. Cryopreservation research is ongoing to achieve added security and efficiency. CIAT extensively characterizes accessions through morphological, biochemical and molecular criteria. As a core goal, the collection has been a foundation for genetic improvement of the crop globally. This paper provides perspectives on the future management and use of the collection in the context of the recently established Future Seeds genebank facilities in Colombia, and new tools and technologies that support more effective conservation, evaluation and use.