Parasitism Of Solanum Torvum By Meloidogyne Hapla Populations From Japan

Solanum torvum, a wild Solanum species, is widely used as a rootstock and is known for its resistance to several pathogens and pests including root-knot nematode (RKN, Meloidogyne spp.). Virulence to S. torvum was observed in several Meloidogyne species such as M. hapla, but M. hapla populations isolated from Japan have not been tested for parasitism. We performed inoculation assays on S. torvum cultivars and control plants (S. melongena, eggplant; S. lycopersicum, tomato) inoculated with Japanese M. hapla populations, and we then evaluated the host suitability based on the eggmass number. The assays were carried out using nursery plants in small plastic pots. The first assay revealed that S. torvum cultivars that are commercially available in Japan were susceptible to M. hapla. In the second assay, three M. hapla populations obtained from geographically distant areas produced a number of eggmasses on S. torvum roots. The S. torvum cultivars were all resistant to M. incognita, as a control species of Meloidogyne, in both assays. Our examination of the number of eggs per eggmass of M. hapla demonstrated that the values of S. torvum under inoculation of two M. hapla populations were significantly lower than those of S. lycopersicum, implying some difference in the fecundity of M. hapla depending on the host plants. The series of experiments revealed the virulence and reproductivity of Japanese M. hapla populations to S. torvum, posing a potential risk that S. torvum cannot suppress RKN damage in agricultural fields under infestation of such Meloidogyne species.