Transmission efficiency of Fusarium oxysporum f.sp. cepae in bulbs of shallot (Allium cepa L. group aggregatum)

Fusarium oxysporum f. sp. cepae (Foc) in bulb is a source of inoculum for Fusarium basal rot disease of shallot. This research aimed to determine the transmission efficiency of Foc carried by bulb of shallot to plants and the relationship between shallot variety and soil origin with the efficiency of pathogen transmission. This research used two varieties of shallots ‘Batu Ijo’ and ‘Bima’, with six different seed lots. The bulbs of shallot were tested for seed health using the blotter test and growing on test methods and tested for transmission efficiency on several sources of soil. The results showed a correlation between the infection of Foc in the bulbs of shallot and the incidence of basal rot on shallot plants. The results also showed a relationship between plant varieties and soil properties on the efficiency of Foc transmission to shallot bulbs. Shallot varieties that are resistant to Fusarium basal rot disease have lower transmission efficiency of Foc bulbs compared to susceptible varieties. In addition, based on the results of the study showed that soil with higher nitrogen content, clay content and soil microorganism populations in soil from Samosir were related to increased soil suppression against Fusarium basal rot disease so that it can reduce the efficiency of Foc transmission of shallot bulbs.