Resistance of a BC₁ line (‘Reikodai 1 go’) derived from hybridization between the common fig, Ficus carica, and a wild congener, F. erecta to different strains of Ceratocystis ficicola

抄録

‘Reikodai 1 go’ is a BC₁ line derived from the interspecific hybridization of the common fig, Ficus carica, with a wild fig, F. erecta that has resistance to Ceratocystis canker caused by Ceratocystis ficicola. We have confirmed that ‘Reikodai 1 go’ possessed the same resistance to Ceratocystis canker as F. erecta by an inoculation experiment in a previous study using only one strain of C. ficicola collected in Kure City (Hiroshima Prefecture). However, we are uncertain if the rootstock can be utilized for different strains of C. ficicola because the resistance level of ‘Reikodai 1 go’ to other strains is unknown. Therefore, we carried out inoculation experiments with different strains of the fungi using cuttings of ‘Reikodai 1 go’ and a susceptible common fig cultivar ‘Houraishi’. In addition to the Kure city strain, we employed C. ficicola strains collected in Fukuyama City (Hiroshima Prefecture), Habikino City (Osaka Prefecture) and Buzen City (Fukuoka Prefecture). By 30 days, all ‘Houraishi’ cuttings were dead, but all ‘Reikodai 1 go’ cuttings were still alive regardless of the origin of the fungi. Quantitative PCR showed that the amount of C. ficicola DNA was limited in ‘Reikodai 1 go’ cuttings relative to those in ‘Houraishi’ cuttings, regardless of the fungal origin. These results indicate that ‘Reikodai 1 go’ would be utilized anywhere in Japan.