Controle genético da resistência do tomateiro 'yoshimatsu' à Ralstonia pseudosolanacearum e Ralstonia solanacearum

Abstract

The bacterial wilt in the tomato crop is a disease that has local, national and world importance. This disease is difficult to control and can cause damage that can compromise the entire crop. Genetic resistance within integrated management is the primary measure of bacterial wilt control. In this sense, the knowledge of the genetic control of resistance in breeding programs tends to improve the efficiency in its planning and in the choice of the best method to be adopted. The objective of this thesis was to study the genetic control of resistance of 'Yoshimatsu' tomato to Ralstonia pseudosolanacearum and Ralstonia solanacearum. In the first stage two experiments were conducted with Yoshimatsu, IPA-7 and the F1, F2, RC11 and RC21 generations, using a randomized block design with four replicates. In the second stage two experiments were conducted with 43 progenies F2:3 and their parents with the same experimental design of the first stage. At each stage the two species of the R. solanacearum complex were inoculated in independent experiments. The incidence and severity of bacterial wilt were evaluated by means of a descriptive scale of notes at 10 and 20 days after inoculation. Genetic control of the resistance of tomato 'Yoshimatsu' to R. pseudosolanacearum involves two genes of greater effect with independent segregation of additive effects only, plus polygenes with additive and dominance effects, in which resistance is associated with recessive alleles. On the other hand, the genetic control of the resistance of the tomato 'Yoshimatsu' to R. solanacearum involves two genes of greater effect with independent segregation of additive effects and dominance, plus polygenes with additive and dominance effects, in which resistance is also associated To recessive alleles. In this study, the selection of plants resistant to R. pseudosolanacearum and R. solanacearum is indicated mainly at 20 days after inoculation.