Penggunaan Asam Fusarat Dalam Seleksi in Vitro Untuk Resistensi Abaka Terhadap Fusarium Oxysporum F.sp. Cubense

Abstract

The USAge of fusaric acid (FA) in vitro selection of abacaresistant to Fusarium Oxysporum f. sp. cubenseWilt Fusarium disease caused by Fusarium oxysporum Schlechtf.sp. cubense (E.F. Smith) Snyd & Hans (Foc) is one of the major diseasesof Musa sp. including abaca, and it could decrease 20-65% fiberproductivity. One of the method to solve this problem is utilization ofabaca resistant clones. In vitro selection using fusaric acid (FA) asselective agents is an effective method to produce abaca resistant clones toFoc infection. Culturing abaca embriogenic calli (EC) and shoots on MTmedium containing various FA concentrations was used to determine FAinhibition effects. Sub-lethal concentration was defined as one inhibiting >90% proliferation of abaca EC and shoots. In vitro selection to identify FAinsensitive SE was conducted using FA sub-lethal concentration.Following plantlet regeneration and acclimatization, the regenerated abacalines were grown in the glasshouse for testing against Foc using detachedleaf dual culture test. The objectives of this study were to (1) evaluategrowth inhibition of abaca EC and shoots by FA, (2) determine sub-lethalconcentration of FA, (3) identify FA insensitive variants of abaca somaticembryos (SE) through in vitro selection followed by plantlet regeneration,and (4) evaluate resistance of regenerated plantlets against Foc infection.Results of the experiment showed FA inhibited abaca EC and shootsgrowth while sub-lethal concentration of FA was 50 mg/l. Following invitro selection, 85 plantlets of Tangongon and 28 of Sangihe-1 wereregenerated from FA insensitive SE. The original Tangongon genotypewas very susceptible against Foc infection. Meanwhile, among three Foctested lines derived from Tangongon, two lines were considered resistantand one was slightly susceptible. However, resistance against Foc ofvariants derived from Sangihe-1 have not been evaluated in thisexperiment due to the plantlets were not strong enough to be acclimatized