S21 - Session P2 - Selection of diploid and tetraploid banana hybrids resistant to Pseudocercospora fijiensis

Authors: Edson Perito Amorim *, Zalmar Gonçalves, Fernando Haddad, Vanusia Amorim, Claudia Ferreira

Black Sigatoka, a disease caused by the fungus Pseudocercospora fijiensis , can lead to 100% banana ` and plantain yield loss in the absence of chemical control, which in turn can increase the production cost by 30%, impact health and contaminate the environment. The development of resistant cultivars is the focus of many banana breeding programs and is an alternative to the use of fungicides, providing sustainable banana production under organic systems. Crossing improved diploids with susceptible commercial cultivars is the most widespread strategy used. In this study, we evaluated 23 improved diploids, seven tetraploids and two commercial cultivars in the presence of P. fijiensis . Four selection criteria were considered: i) mean disease severity index (ID); ii) area under the disease progress curve (AUDPC) estimated over the total period of the experiment, only in summer and only in winter; iii) the emission of bunches; and iv) harvesting of bunches. With an analysis based on genotypes + genotypes by environments (GGE) we established that the selection of genotypes was more effective in the winter, and the evaluation of four leaves no. 3 emitted after six months of growth was efficient at differentiating the resistant and susceptible genotypes. Three improved diploids exhibited qualitative resistance and two exhibited quantitative resistance. The tetraploid hybrid CNPMF0906 (AAAB, Prata-type) and the commercial cultivar BRS Princesa (AAAB, Silk type), showed quantitative resistance and can be used by banana producers. We indicate that the guidelines adopted for the selection of genotypes resistant to black Sigatoka should include methodologies that reduce the evaluation time, in addition, we discuss new sources of resistance to the disease and the influence of its genetic inheritance in future crosses aiming to develop cultivars adapted to organic production.