02345naa a2200217 a 450000100080000000500110000800800410001910000150006024500760007526000090015150000100016052016820017070000150185270000170186770000160188470000170190070000140191770000170193170000180194877301610196616375422009-02-19       2008    bl uuuu     u00u1 u    #d1 aFUKUDA, W.  aBreeding cassava for enhancement of carotenoid, iron and zinc contents.  c2008  aS7-9.  aThe goal of this project is to improve the nutritional quality of cassava varieties for provitamin A, Fe and Zn contents, in the HarvestPlus program. Initialy, a total of 1800 cassava accessions from the germplasm bank at Embrapa Cassava & Tropical Fruits, were screened. Total carotenoid content in one-year old roots of the 72 landraces selected ranged from 0.63 to 15.51 ug.g-1 (fresh weight). It was observed that accessions with higher total  carotenoid contents also presented elevated HCN levels. Based on, the low cyanogenic potential required for cassava consumption as boiled roots (where carotenoid retention is higher), 7 landraces with total carotenoid concentrations ranging from 1.50 to 4.49 ug.g-¹ were selected as parents. In the first generation (228 genotypes), hybrids with total carotenoid increment of more than 100% in relation to the parents were identified. Total carotenoid levels in the population ranged from 0.87 to 10.47 ug.g-¹. Analyses of beta-carotenes revealed an approximated, but not linear relation with the total carotenoid contents. In the second generation (136 hybrids) additional increment of total carotenoid contents with respect to the first was verified, reaching the maxim concentration of 12.41 ug.g-¹. Regarding Fe and Zn contens, the 72 yellow landraces initially selected as well as all the hybrids of two generations were evaluated by atomic absorption. Keeping low HCN and hight and high total carotenoid concentrations as priority, hybrids with more than 10 ug.g-¹ of total carotenoids and high levels of Zn and Fe were selected. These hybrids are currently under agronomical evaluations to be recommended as varieties.1 aSANTOS, V.1 aOLIVEIRA, L.1 aPEREIRA, M.1 aCEBALLOS, H.1 aNUTTI, M.1 aCARVALHO, J.1 aDITA, MIGUEL.  tIn: SCIENTIFIC MEETING OF THE GLOBAL CASSAVA PARTNERSHIP, 1., 2008, Ghent. Cassava: meeting the challenges of the new millennium.Ghent:: IPBO, 2008. p. 106.