Interação de antracnose e bacteriose em genótipos de mandioca

Abstract

Anthracnose (Colletotrichum gloeosporioides f. sp. manihotis) and bacterial blight (Xanthomonas phaseoli pv. manihotis) in cassava are diseases of economic importance in Brazil and in the world, due to their high prevalence in commercial areas, causing high yield losses. Therefore, the objective of this work was to evaluate the severity of anthracnose and bacterial blight , as well as their interaction, genotypes reactions and agronomic traits and their consequences. Two field experiments were carried out in the 2019/2020 and 2020/2021 seasons, with 157 accessions at the Experimental Farm of UFGD and 96 accessions in an area at the Federal University of Grande Dourados, respectively. There was an experiment in pots with cultivar CS01, with five treatments (inoculation with Xanthomonas only, inoculation with Xanthomonas and after 15 days with Colletotrichum, inoculation only with Colletotrichum, inoculation with Colletotrichum and after 15 days with Xanthomonas and without inoculation) with four replications. A positive and significant correlation was observed for anthracnose and bacterial blight , in which the 2019/2020 crop presented, through the area under the disease progress curve (AACPD) and maximum disease index (IDMax), values of 0.50 and 0.83, respectively, and in the 2020/2021 harvest, values of 0.34 and 0.74 for the same indicators. In the 2019/2020 crop, in the Dourados region, a significant negative correlation was observed in relation to disease and productivity only in associations between anthracnose (AACPD and/or IDMax) and total root weight. Among the commercial accessions, five commercial accessions behaved with greater resistance to anthracnose and bacterial blight for AACPD and IDMax, being: BRS Dourada, BRS Formosa, IAC-90, IAC-576 and Mani Branca showed moderate resistance to bacterial blight and anthracnose.