Resistance Response of Tomato Cultivars and Rootstocks Carrying the Mi-1.2 Gene to Isolates of Meloidogyne arenaria, M. incognita, and M. javanica at Two Different Growing Periods

The reaction of four tomato cultivars and four rootstocks, carrying the Mi-1.2 gene, to differentisolates of Meloidogyne arenaria (4 isolates), M. incognita (2 isolates), and M. javanica (2 isolates)were determined in pot experiments conducted in a non-temperature controlled greenhouse. Tomatocultivars and rootstocks were screened by PCR-based co-dominant SCAR marker Mi23 for thezygosity states of the Mi-1 locus. All resistant tomato cultivars and the rootstock ‘Comfort’ wereclassified as heterozygous resistant (Mimi), whereas the rootstocks ‘Arazi’, ‘Beaufort’, and ‘Kingkong’were homozygous resistant (MiMi) at the Mi-1 locus. The response of resistant genotypes to isolatesof Meloidogyne was assessed 8 and 16 weeks after inoculation with 3,000 nematode eggs for shortand long growing periods, respectively. Nematode reproduction on resistant cultivars was similar orhigher than on resistant rootstocks for all tested Meloidogyne isolates in the short period experiment(p ˂ 0.05), but not in the long period experiment. In both experiments, all tomato cultivars androotstocks responded as highly resistant (reproduction index ˂ 10%) to all tested Meloidogyneisolates except for M. incognita A-11. Of the resistant genotypes inoculated with M. incognitaA-11, in both experiments, the cultivars ‘Crisol’ and ‘Adamset’ were moderately resistant, whereasthe rootstocks ‘Beaufort’ and ‘Comfort’ were highly resistant. ‘Alsancak’, ‘Esin’, ‘Arazi’, and‘Kingkong’ showed reduced resistance in the long growing period and responded as moderatelyresistant to M. incognita A-11. These findings showed that the resistance response of tomatocultivars and rootstocks to Meloidogyne isolates varies depending on the isolates of Meloidogyne orthe length of the growing period.