Avaliação genotípica de acessos de mandioca no Amazonas e estimativas de parâmetros genéticos

Abstract

The present study reports the evaluation of genotypic demandioca 250 hits in the State of Amazonas, to the characters commercial yield, starch content in the roots, amount of rotten roots, number of roots per plant, root length and diameter, and features also estimates of genetic parameters (heritability and genetic correlations) that allow us to infer the genetic control and level of genetic variability present in the material evaluated. Methodology was employed REML / BLUP. It was found that the germplasm collection presents considerable genetic variability, except for starch content. Thus, there are good prospects for genetic improvement. The low heritability of verified individual plots (2% to 18%) are consistent with the quantitative and polygenic nature of these characters. The improvement of these characters is fully possible and can be performed efficiently by adopting an appropriate number (5 to 20) repetitions of the experiments. Genetic correlations between production of commercial roots and its component traits (amount of rotten roots, number of roots per plant, length and diameter of roots) amounted to - .12; 0.33; 0.23 and 0.35, respectively, all significant by t test. Thus, the commercial production of roots is positively correlated with the diameter and length of roots and the number of roots per plant. On the other hand, is negatively correlated to the amount of roots rotted. This paper describes the genotypic evaluation of 250 cassava accessions in the state of Amazonas to the characters commercial yield, starch content in the roots, amount of rotten roots, number of roots per plant, length and diameter of roots and also presents estimates genetic parameters (heritabilities and genetic correlations) that allow us to infer the genetic control and level of genetic variability present in the material evaluated. Methodology was employed REML / BLUP. It was found that the germplasm collection presents considerable genetic variability, except for starch content. Thus, there are good prospects for genetic improvement. The low heritability of verified individual plots (2% to 18%) are consistent with the quantitative and polygenic nature of these characters. The improvement of these characters is fully possible and can be performed efficiently by adopting an appropriate number (5 to 20) repetitions of the experiments. Genetic correlations between production of commercial roots and its component traits (amount of rotten roots, number of roots per plant, length and diameter of roots) amounted to -0.12; 0.33; 0.23 and 0.35, respectively. Thus, the commercial production of roots is positively correlated with the diameter and length of roots and the number of roots per plant. On the other hand, is negatively correlated to the amount of roots rotted.