FUSARIUM SPECIES FROM AN INDONESIAN GENOTYPE OF FOXTAIL MILLET SEEDS

Abstract

As a generalist pathogen in cereals, Fusarium spp. become the most threatening fungi which can conduct its saprogenesis by infecting seeds. Determination of fungal identity and the yield loss risk is needed to modify the effective controlling strategies. However, there is no report on implementing methods for controlling Fusarium spp. on foxtail millet (Setaria italica L. Beauv.). This research was undertaken from July to September 2020 and November to December 2021 under ambient laboratory conditions to identify and evaluate the pathogenicity of seed-borne Fusarium species in foxtail millet. One hundred colonies of seed-borne fungi were isolated from foxtail millet genotype ICERI-6 which was dominated by Fusarium spp. Morphological characterization by observing the structure of colonies and microscopical features indicated that the six isolates (Fu1–Fu6) were identical to Fusarium solani, F. chlamydosporum, F. oxysporum, F. equiseti, F. proliferatum, and F. graminearum, respectively. Molecular identification for the 5.8s rDNA target gene with ITS1 and ITS4 primers has confirmed that the Fusarium spp. were determined as mentioned species. Pathogenicity test using potato dextrose agar medium showed that the germination percentage of seed inoculated by Fusarium spp. was only 1.2% on average at 7 days after incubation. These species led to germination failure as the seeds were covered by fungal mycelia. Seeds that could escape from germination failure performed necrotic spots on the seedlings. These abnormalities would contribute to low productivity in the field. The study has implication in controlling seed-borne disease and that resistant variety breeding becomes important issues to be addressed for future research.