Selection of Descriptors in a Morphological Characteristics Considered In Cassava Accessions By Means Of Multivariate Techniques

Abstract

An experiment was conducted to determine the selection of morphological descriptors in cassava crop by multivariate techniques with the aim of optimizing the use of this technique in order to provide reliable, useful information for the program of genetic improvement and conservation of the species. The phenotypical characterization was performed in 200 genotypes, using 35 descriptors. These genotypes came from Embrapa Cassava and Tropical Fruits, located in the municipality of Cruz das Almas-BA. 19 qualitative and 16 quantitative variables were used. The selection of descriptors was performed by means of principal components analysis (quantitative) and entropy (multi-categories). The efficiency of elimination was analyzed by a comparative study between the components formed, taking into account all the 35 descriptors. Namely, root length and diameter, number of roots per plant, root weight per plant, starch content and HCN in the root, distance between leaf scars, number of stems from the manioc cuttings mother, height of the first branch, length of the middle lobe and the petiole. Color was measured in various places, namely in the film from root; root bark without film, stem, petiole and color of terminal branches. The form of the lobe was also measured It was concluded that the disposal of 57% of descriptors caused no loss of information, however, it minimized the costs and streamlined the management of collections of germplasm of cassava.