02279naa a2200181 a 450000100080000000500110000800800410001910000140006024500590007426000090013350000100014252017210015270000150187370000140188870000200190270000140192277301610193616375232009-02-19       2008    bl uuuu     u00u1 u    #d1 aALVES, A.  aCurrent status of the Embrapa wild Manihot collection.  c2008  aS5-4.  aWithin Manihot gender, with around 98 documented species, only one is the cultivated cassava (M. esculenta Crantz), considered one of the most important staple foods in the human diet in the tropics. Brazil, which is considered the main center of cassava origin, has the largest genetic diversity, dispersed all over the country. Embrapa has used the cultivated cassava germplasm banks as the main source of variability for the cassava breeding program in Brazil. To allow the utilization of wild species useful genes for improving cultivated cassava, the establishment and enlargement of a wild species collection at Embrapa/CNPMF has been the main objectives of two projects, funded by Embrapa and Generation Challenge Programme. In the last four years, a collection has been field established with wild accessions obtained from the following sources: 1) sexual seeds and cuttings of wild accessions from CENARGEN's collection; 2) cuttings from a collection of the 'Universidade Federal do Reconcavo da Bahia'; 3) wild genotypes existing at Embrapa/CPATSA; 4) several collection expeditions accomplished in semi-arid ('caatinga') and savanna ('cerrado') ecosystems. Currently, the collection has around 920 accessions of 18 cassava wild relatives, maintained, mainly, under field condition. Also, a seed bank of around 40,000 sexual seeds from wild species has been preserved. In this wild germplasm, the following preliminary studies are being carried out: 1) evaluation for resistance to drought, pests and diseases; 2) crossing compatibility between wild and cultivated species; 3) cytogenetics, production and viability of pollen grains, and 4) molecular markers screening for resistance to pests and diseases.1 aMENDES, R.1 aSILVA, A.1 aCARVALHO, P. de1 aCOSTA, I.  tIn: SCIENTIFIC MEETING OF THE GLOBAL CASSAVA PARTNERSHIP, 1., 2008, Ghent. Cassava: meeting the challenges of the new millennium. Ghent:: IPBO, 2008. p. 81.