Abstract
Resistance of tomato plants cvs. Momotaro and Kyouryokubeiju grafted onto three root-stocks: Solanum sisymbriifolium, S. torvum and S. toxicarium to Pseudomonas solanacearum and Meloidogyne incognita was investigated.
Own-rooted 'Momotaro' plants are highly susceptible to all of the five strains (I to V) of Pseudomonas solanacearum, whereas own-rooted S. toxicarium is completely resistant to all five strains. This resistance persists when S. toxicarium is grafted with scions of 'Momotaro'. Seedlings of S. sisymbriifolium on its own roots are resistant to strain HI, whereas those of S. torvum are resistant to strains I, II and V. When S. torvum is used as a rootstock, the combination, 'Momotaro'/S. torvum becomes susceptible to strain V. S. sisymbriifolium and S. torvum are susceptible to other strains but they become even more susceptible when used as rootstocks for 'Momotaro'. However, the strain-specific resistance of these three species to bacterial wilt is not affected by the susceptible factors of the tomato scion.
'Kyouryokubeiju' and 'LS-89' are highly susceptible to M. incognita, whereas S. toxicarium and S. torvum are resistant. Small nodules were observed on roots of S. sisymbriifolium but nematode maturation and egg production was not observed. High resistance of these Solanum species to M. incognita persisted when they were used as rootstocks of 'Kyouryokubeiju'.
