Desenvolvimento e caracterização de variantes somaclonais de bananeira resistentes à murcha de Fusarium

Abstract

Bananas play a crucial role in the diet of millions of people and are a source of income for thousands of families in various countries. In Brazil, the state of São Paulo stands out as the largest producer, followed by Bahia and Minas Gerais. Banana plants of the Prata subgroup, such as ‘Prata-Anã,’ ‘Gorutuba,’ and ‘Catarina,’ are the main genotypes cultivated in the country, forming the basis of Brazilian production and representing approximately 70% of the cultivated area, mainly for domestic consumption. Fusarium wilt, caused by the fungus Fusarium oxysporum f. sp. cubense (Foc), is recognized as one of the most devastating diseases for banana cultivation worldwide. Tropical Race 4 (TR4) destroys banana plantations in all environmental conditions, while Subtropical Race (SR4) causes damage when plants are subjected to some stress in subtropical environmental conditions. Consequently, banana breeding programs worldwide have used various technologies to generate new resistant genotypes. In this context, the initial aim of this work was to conduct a systematic review on the role of somaclonal variation in plant breeding. A protocol was created and rigorously followed to meet the guidelines established in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The analysis of the 219 selected articles revealed that the number of subcultures and plant growth regulators are the main sources of in vitro somaclonal variation. The systematic review also gathered information on morphological changes in the generated somaclones and tools for their identification, enriching the knowledge of this technique. This work also aimed to induce in vitro somaclonal variation in Prata Catarina banana plants to select somaclones resistant to Foc Isolate 229. Thirteen resistant somaclones were selected from the two tested treatments. Histological and histochemical evaluations may indicate the activation of post-formed resistance mechanisms. Molecular analyses indicated no genetic differences between the somaclones and the commercial plant, suggesting that commercial agronomic characteristics were not affected. In conclusion, this work gathers information on the technique of somaclonal variation and its contributions, offering new sources of resistance to Fusarium wilt for the banana breeding program.