Bananas, a staple food globally and a key agricultural commodity, face a severe threat from the fungus Fusarium oxysporum f. sp. cubense (Foc), significantly impacting production. Genetic improvement to develop resistant cultivars stands out as a crucial strategy to mitigate this disease. This study focused on assessing and recommending enhanced diploid banana varieties for resistance against Foc subtropical race 4 (ST4) and Foc race 1 (R1). Twenty-four improved diploids developed by Embrapa, Brazil, underwent evaluation. Utilizing a scale for internal symptoms at 90 days after inoculation, genotypes were categorized from highly resistant to highly susceptible based on the internal symptom index. The diploid M53 exhibited high resistance to Foc R1 and resistance to Foc ST4, while only the diploid CNPMF 0534 demonstrated complete resistance to both R1 and ST4, with resistance to the latter likely associated with penetration, primarily due to the presence of callose. These findings provide valuable insights for banana and plantain breeding programs, offering selected diploids for crossbreeding with commercial cultivars to develop new, resistant genotypes against Foc.

Bananas, a staple food globally and a key agricultural commodity, face a severe threat from the fungus Fusarium oxysporum form specialis cubense (Foc), significantly impacting production. Genetic improvement to develop resistant cultivars stands out as a crucial strategy to mitigate this disease. This study focused on assessing and recommending enhanced diploid banana varieties for resistance against Foc subtropical race 4 (ST4) and Foc race 1 (R1). Twenty-five improved diploids developed by Embrapa, Brazil, underwent evaluation. Utilizing a scale for internal symptoms at 90 days post-inoculation, genotypes were categorized from highly resistant to highly susceptible based on the internal symptom index. The diploid M53 exhibited high resistance to R1 and resistance to Foc ST4, while only the diploid CNPMF 0534 demonstrated complete resistance to both R1 and ST4, with resistance to the latter likely associated with penetration. These findings provide valuable insights for banana and plantain breeding programs, offering selected diploids for crossbreeding with commercial cultivars to develop new, resistant genotypes against Foc.

Banana production is affected by several pests and diseases, of which Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), is notable. Despite the different control measures and management used to contain Fusarium wilt, the development of resistant cultivars has been the best approach to combating this disease. This study explores a biotechnological approach with the potential to induce somaclonal variation using the plant growth regulators Thidiazuron (TDZ) and paclobutrazol® (PBZ) in the banana cultivar ‘Grand Naine’ (Cavendish, AAA), and proposes a greenhouse pre-screening based on inoculation bioassays with Foc, using the commercial cultivar Grand Naine as a susceptible control. The somaclonal variants showed 3.5% of highly resistant plants, which were immune to Foc inoculation in the first round of tests. Of these, thirteen (43.3%) maintained their resistance response when subjected to a second test in an experiment with replicates. In addition, histological analysis of roots demonstrated the absence of pathogen structures, such as hyphae, conidia, or chlamydospores, within the tissues of these somaclones. This study provides Cavendish somaclones that have never before been generated and pre-selected under greenhouse conditions. These somaclones will be further evaluated for agronomic and market potential, as well as for validation of resistance stability, with the aim of future recommendation to farmers and use in breeding programs.