Selection of somaclonal variants of the cultivar 'Prata-Ana' for resistance to Fusarium oxysporum f. sp. cubense race 1/Selecao de variants somaclonais da cultivar 'Prata-Ana' para resistencia a Fusarium oxysporum f. sp. cubense raca 1

The banana tree is one of the most cultivated fruit globally; however, some diseases significantly affect its production, such as Fusarium wilt. The most appropriate measure for controlling this disease in areas with inoculum pressure is the use of resistant cultivars. Therefore, this study aimed to generate banana somaclones of the cultivar 'Prata-Ana' resistant to Fusarium wilt by inducing somaclonal variation. 'Prata-Ana' stem apexes were established in vitro in MS culture medium and, on a monthly basis, subcultivated in AIA and adenine sulfate supplemented MS medium with added plant regulators: 6-benzylaminopurine (BAP, 4 ml [L.sup.-1]), Thidiazuron (TDZ, 1 ml [L.sup.-1]), and Paclobutrazol (PBZ, 10 ml [L.sup.-1]). The treatments were: T0: no regulator, T1: BAP, T2: TDZ, T3: PBZ, T4: BAP + TDZ, T5: BAP + PBZ, T6: TDZ + PBZ, and T7: BAP + TDZ + PBZ. After the twelfth subculture, the regenerated plants were planted in boxes containing sterile soil infected with Fusarium oxysporum f. sp. cubense, and evaluated after 90 days for resistance to the pathogen. Somaclonal variants T2-1 and T2-2, generated in Treatment 2, with TDZ, were selected as resistant. This result is promising for the launch of a new Fusarium race 1-resistant banana variety. Index terms: Biotechnology; Tissue culture; Musa sp.; Somaclonal variations; Fusarium wilt. A bananeira e uma das frutiferas mais cultivadas no mundo; entretanto, algumas doencas tem afetado sua producao, como a murcha de Fusarium. Em areas onde ha pressao de inoculo, a medida mais adequada no controle da doenca e a utilizacao de cultivares resistentes. Diante disso, o objetivo deste trabalho foi obter somaclones de bananeira da cultivar 'Prata-Ana' resistentes a murcha de Fusarium pela inducao de variacao somaclonal. Para isso, apices caulinares de bananeira 'Prata-Ana' foram estabelecidos in vitro, em meio de cultura MS. Em seguida, foram transferidos e subcultivados mensalmente para meio MS, suplementado com AIA e sulfato de adenina, acrescidos de diferentes combinacoes de reguladores: 6-benzilaminopurina BAP (4 ml.[L.sup.-1]), Thidiazuron TDZ (1 ml.[L.sup.-1]) e Paclobutrazol PBZ (10 ml.[L.sup.-1]). Os tratamentos foram: T0: sem regulador; T1: BAP; T2: TDZ; T3: PBZ; T4: BAP + TDZ; T5: BAP + PBZ; T6: TDZ + PBZ; 7: BAP + TDZ + PBZ. As plantas regeneradas, apos o decimo segundo subcultivo, foram posteriormente plantadas em caixas d'agua contendo solo esteril e infestado com Foc, e aos 90 dias foram avaliadas quanto a