02547naa a2200145 a 450000100080000000500110000800800410001910000260006024501120008626000090019852020660020770000180227370000210229177300890231216518112004-04-05       1998    bl uuuu     u00u1 u    #d1 aCARVALHO, L. J. C. B.  aGenetic diversity of cassava (Manihot esculenta crantz) in a germplasm collection assessed by rapd markers.  c1998  aAbstract: Cassava germplasm individuals from collection representing different agroecological habitas of Brazil was assessed by RAPD markers. Fifty nine cassava accessions representing the World core collection and seven agroecological habitats in one of the center of diversity of cassava were used. Phenetic analysis discriminated nine distinct clusters from Colombia, two clusters from Brazil and five clusters of distinct habitats in Brazil. None of other representative individuals from the other countries showed distinct clusters. This structures represents the genetic diversity of cassava germplasm in the World Core Collection, and confirms the high genetic diversity different regions in Brazil. It is also inferred that land races originated from Cerrados, Litoral, and Sub Tropics are well represented in the World Core Collection, but not the other habitats. Degree of genetic diversity within individuals indicated higher values for nucleotide diversity (2.7%) in the Brazillian collection than in the World Core Collection (2.1%). From the different habitats of cassava in Brazil, it is possible to distinguish three major source of genetic diversity. One, the Cerrados area, with limited diversity (0.6% of nucleotide diversity per site in the genome), a second source of variation with high genetic diversity in Caatinga and Humid tropics regions, and a third source of variation with intermedian genetic diversity in Sub tropics, Litoral, and Semi Arid regions.Divergence between the different habitats varied from 0.3% between Brazil and Cuba, but 0.6% between Brazil and Malaysia. Accessions from Cuba are more close to accessions from Colombia then the other countries.The highest divergente between genetic materials from different habitats is observed between Wide adapted land races in Brazil and individuals from Malaysia, and between Litoral habitat in Brazil and Malaysia. This indicates that the germplasm in Malaysia show substantial differences from the one in Brazil, and may be provenance from different region in South America.1 aSCHAAL, B. A.1 aFUKUDA, W. M. G.  tRevista Brasileira de Mandioca, Cruz das Almasgv. 17 p.13, nov., 1998., Suplemento.