Avaliação de pragas e doenças na adaptabilidade e estabilidade de genótipos de mandioca no sul e centro do país

Abstract

A trial was carried out in the field of the Agrarian Station of Umbeluzi located in the agro-ecological zone no. to evaluate pests and diseases in the adaptability and stability of cassava genotypes in both environments. The design used was randomized complete blocks (DBCC), with three replicates (blocks) and 12 treatments that consisted of the genotypes Mz0430920, Umbelúzi 2, Clone1, Manguiza 2 (local), R.macia, Mz04045, Clone 3, Mz040248, Mistura 1 (cream), Chinhembwe, Umbelúzi 6 and Clone 4. The study variables were density of the pest population, level of infestation and average attack rate of pests and diseases and total root yield. The collected data were subjected to analysis of variance, assumption of normality of residues (Shapiro Wilk test), assumption of homogeneity of residues (Breusch - Pagan test), means comparison test (Fisher-Hayter), correlation and multiple regression between the total root yield and population density, level of infestation and average attack rate of pests and diseases, at a significance level of 5%. The separate analyzes, the joint analysis to estimate the genotype and environment interaction, and the multiple linear correlation and regression used the STATA version 10.1 statistical package. The estimate of the adaptability and stability of the genotypes was based on the GGEbiplot method using the GenStat version 14 statistical package. The pests that attacked the genotypes in the Umbelúzi field were the cassava mealybug, green mite and elegant grasshopper, and the diseases were the African mosaic of cassava, bacterial burning and brown stain. In the Dondo field, the plague was the cassava mealybug and the disease was the African mosaic of the cassava. Pests and diseases did not influence the total root yield of the genotypes in both Umbelúzi and Dondo environments. The genotypes Umbluzi6 and Chinhembwe were stable with general adaptation, thus being recommended for cultivation in both environments. The genotypes Mz04045, Clone 4 and Mz0430920 were unstable with specific adaptation, thus being recommended for cultivation in the Dondo environment (TRADUÇÃO NOSSA )