Selection of somaclonal variants of the cultivar ‘Prata-Anã’ for resistance to Fusarium oxysporum f. sp. cubense race 1

Abstract

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-Anã’ resistant to Fusarium wilt by inducing somaclonal variation. ‘Prata-Anã’ 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-1), Thidiazuron (TDZ, 1 ml L-1), and Paclobutrazol (PBZ, 10 ml L-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.

Pre-selection of banana somaclones resistant to Fusarium oxysporum f. sp. cubense, subtropical race 4

“…Therefore, this study shows that genetic variation occurred and that defense responses were activated in the T-1P7 and T-2P1 somaclones, which were based on barriers that are related to pathogen penetration. A similar result was obtained by Ferreira et al (2020) , with the isolate of Foc CNPMF 218A used to select and evaluate resistant Prata-Anã (AAB) banana somaclones; the authors considered the absence of pathogen structures in the root tissues as an indication that the pathogen did not successfully penetrate these tissues, because resistant somaclones probably developed physical and/or chemical barriers to block penetration.…”

“…Since plants that were not submitted to the culture medium containing TDZ and PBZ (control) were susceptible to Foc under greenhouse conditions and this did not happen to plants that were submitted to this treatment, it is possible to infer that somaclonal variation was induced in the Grand Naine cultivar. Likewise, Ferreira et al (2020) obtained banana somaclones of the Prata-Anã (AAB, Pomme subgroup) cultivar resistant to Fusarium wilt by inducing somaclonal variation and testing with the CNPMF 218A isolate, representative of STR4. The plant regulators added to the growth medium at certain concentrations or in combination with other growth regulators, really can affect the rate of somaclonal variation because they increase the process of cell division (Gao et al, 2010).…”

“…Treatment based solely on somaclonal variation induction without the addition of FA was not effective for obtaining Grand Naine banana plants resistant to the Foc. This result may be associated with the low number of early multiple shoot clumps used in the in vitro multiplication process (35), as most studies use a higher number of plants, considering that the induction of variation occurs at low percentages ( Ferreira et al, 2020 ; Hwang and Ko, 2004 ).…”

Improvements in the Resistance of the Banana Species to Fusarium Wilt: A Systematic Review of Methods and Perspectives

“…In a recent study, tests with these Cavendish banana somaclones in northern Mozambique revealed that GCTCV-119 was more resistant to FOC TR4, but GCTCV-218 produced better bunches [ 5 ]. Another recent study obtained, through different combinations of plant regulators in a culture medium, two somaclones of the cultivar Prata-Anã, namely T2-1 and T2-2, which presented resistance to FOC race 1 in a greenhouse, characterizing an important result for the banana cultivation in Brazil since the pathogen FOC R1is present in most banana plantations and this cultivar is preferred by Brazilian consumers [ 153 ].…”

Inoculation Methods to Determine Resistance of Phalaenopsis amabilis (L.) Regeneratded from Irradiated Protocorms to Dickeya dadantii

“…Breeding and variety development is a method to obtain disease-resistant plants. Breeders design a mutant superior using various techniques like somaclonal variations (Ferreira et al, 2020), mutation induction (Jeong et al, 2017), and transgenic plants (Chen et al, 2019). Mutation induction through physical and chemical mutagens is widely used in Phalaenopsis amabilis (Raihanun, 2017;Mohammadi et al, 2020;Putri et al, 2021;Azis et al, 2021).…”