Genetic diversity in cassava varieties (Manihot esculenta Crantz) under the agroecológicas conditions of Malanje

Abstract

The combined analysis of qualitative and quantitative variables has been pointed as a useful tool in the estimate of the genetic diversity among the varieties of a germoplasma collection. The objectivo of this study was to evaluate the genetic diversity of cassava varieties in the conditions agroecológicas of Malanje, Angola; starting from characters morfoagronómicos, for identification of divergent groups and carried of hybridization works and subsequent choice. They were appraised 10 quantitative characteristics and 12 qualitative in 40 varieties. The experimental design used was blocks of random with four repetitions. The width of the variation coefficients (CV), varied from 16,21% to 80,87%, they indicate variation among the results, presenting like this, a variability and heterogeneity of the varieties. The largest entropies were found in the variables, color of the stem (126), color of the terminal leaf (099), color of the cortex of the root, (095), ramification habit (088) and color of the peciolo (082). For the Method UPGMA, they were formed three groups basing on the analysis. Genetic variability exists starting from the morfoagronómicas characteristics in the appraised varieties. The qualitative descriptors that more contributes to the genetic divergence among the varieties are color expresses of the stem, color of the terminal leaf, color of the cortex of the root, ramification habit and peciolo color. The united analysis of quantitative and qualitative data provides larger efficiency in the knowledge of the existent divergence among the cassava varieties, and it allows carry future studies of hybridizations. The genotypes 29 (Malanje), 19 (Banana), 36 (Muringa), 39 (Gueti) were shown quite divergent of the others, being like this, selected as varieties of better answer.