03019nam a2200205 a 450000100080000000500110000800800410001910000200006024500940008026003190017452021760049365000120266965000120268165000210269365000130271465000350272770000170276270000200277970000140279918672792022-08-22       2010    bl uuuu     u00u1 u    #d1 aALVES, A. A. C.  aResponse of cassava genotypes to different micropropagation media.h[electronic resource]  aIn: ANNUAL MEETING [OF] THE ASSOCIATION FOR THE ADVANCEMENT OF INDUSTRIAL CROPS, 22., 2010, Fort Collins. 2010 new crops: exploring diversity and preserving our future: program and abstracts. Fort Collins: Association for the Advancemente of Industrial Crops, 2010. 12 p. Edited by T. A. Isbell, D. A. Dierigc2010  aCassava is one of the most important staple foods in the human diet in the tropics, where it ranks fourth as a source of energy, after rice, sugar cane and maize. Since it is a vegetative propagated crop, the use of in vitro propagation is very important to preserve the germplasm free of pest and diseases and to multiply the germplasm for exchange purpose. Several protocols for in vitro cassava micropropagation have been used, in which the main results were large differences in the performance of different accessions to a specific medium. The establishment of a culture medium efficient for a large number of genotypes remains one of the great challenges. The objective of this study was to evaluate the performance of contrasting cassava genotypes under different culture media in order to achieve the best results for establishing a comprehensive protocol for cassava micropropagation. Six cassava genotypes with contrasting performance under in vitro cultivation were submitted to ten different culture media, with different combinations and concentrations of hormones (IAA, NAA, BA, GA) and adenine sulfate. For each genotype and medium, apical and axillary node explants, from approximately two month old in vitro cultures, were placed in six magenta vessels; three vessels with apical nodes and three vessels with axillary nodes (five explants/vessel). After six weeks, the responses of plants were evaluated by: number of nodes, roots, leaves and stems; leaf area; length and fresh weight of roots and shoots; and the presence of callus. The genotypes showed different performance with significant growth difference among the different media and dependent on the type of explants. In general, the apical explants grew faster and produced more biomass in the roots and shoots. The different behavior of genotypes can be attributed to the fact that they are adapted to diverse ecosystems, they have different genetic structure (native and improved varieties) and because of the contrasting levels of hormones (NAA, BA and GA) and amino acid (adenine sulfate) used. The use of cassava genotypes adapted to stressful environments has helped in proposing at least  acassava  aManihot  amicropropagation  aMandioca  aMelhoramento Genético Vegetal1 aSCHNIBBE, J.1 aJENDEREK, M. M.1 aELLIS, D.