Caracterização molecular de acessos de mandioca açucarados e não açucarados

Abstract

Emphasis has been given lately to cassava accessions that accumulate free sugars in their storage roots, besides starch, such as the commercial cultivars. These accessions are popularly known as sugary cassavas or "mandiocabas", and present a high potential for the use in ethanol biofuel production. Nevertheless, this germplasm was not yet sufficiently studied regarding its genotypic variability, which is of fundamental importance for its conservation and use in genetic improvement. The objective of this work was to characterize, via RAPD marker, 14 sugary and non-sugary cassava accessions. Within Laboratory conditions, the accessions were evaluated by using 12 RAPD primers. Afterwards, the matrix of genetic dissimilarity among the acessions was estimated by using the complement of Jaccard index. The primer generated 131 RAPD markers, among which 73% were polymorphic, highlightening the existence of genetic variability and efficiency of the RAPD technique. The most similar accessions were BGMC 1207 and BGMC 1209, both sugary ones, and the least similar, the sugary accession BGMC 1219 and the cultivar BGMC 436. The accessions were divided into four groups, the first group was composed by the 10 sugary accessions, the second group consistecs of two local non-sugary accessions, the third and fourth groups were composed by the improved accessions BGMC 753 and BGMC 436. The results obtained reveal the existence of high genetic variability among the evaluated accessions and differed the sugary accessions from local non-sugary and the non-sugary commercial cultivars.