Evaluation of Resistance to Fusarium oxysporum f. sp. raphani in Radish Germplasm

Abstract

: Identification of Fusarium oxysporum f. sp. raphani and investigation on fusarium wilt development by isolates and inoculation methods were conducted to establish a screening method for fusarium wilt - resistance in radish ( Raphanus sativus L.) germplasm. Pathogenicity of F. oxysporum f. sp. raphani isolate, Heonggye-1 and Heonggye-2, to radish plants was confirmed by seedling test. Radish seedlings were inoculated by root-dipping and soil-drenching with or without root-wounding. For Heonggye-1 isolate, mean disease indexes were 4.13 and 3.91 by root-dipping and soil-drenching with root-wounding, respectively, but those were 1.87 and 1.88 without root-wounding. For Heonggye-2 isolate, mean disease indexes were 3.83 to 4.37 regardless of inoculation methods. Two-hundred sixty accessions of radish germplasm collected from 9 countries of Asia and Europe were evaluated for fusarium wilt-resistance by soil-drenching with root-wounding with Heonggye-2 isolate. Fifty-four resistant accessions with higher than 70% of the percentage of resistant seedlings in accession (P R ) and lower than 20% of the percentage of susceptible seedlings in accession (P S ) was found. Eighteen susceptible accessions with lower than 20% of P R and higher than 50% of P S were selected. These accessions could be used as breeding and research materials after re-evaluation of disease-resistance and characterization of agronomical traits.