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 different isolates 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. Tomato cultivars and rootstocks were screened by PCR-based co-dominant SCAR marker Mi23 for the zygosity states of the Mi-1 locus. All resistant tomato cultivars and the rootstock 'Comfort' were classified 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 isolates of Meloidogyne was assessed 8 and 16 weeks after inoculation with 3,000 nematode eggs for short and long growing periods, respectively. Nematode reproduction on resistant cultivars was similar or higher 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 and rootstocks responded as highly resistant (reproduction index < 10%) to all tested Meloidogyne isolates except for M. incognita A-11. Of the resistant genotypes inoculated with M. incognita A-11, in both experiments, the cultivars 'CrisoF and 'Adamsee were moderately resistant, whereas the rootstocks 'Beaufort' and 'Comfort' were highly resistant. 'Alsancak', 'Esin', 'Arazi', and 'King,kong' showed reduced resistance in the long growing period and responded as moderately resistant to M. incognita A-11. These findings showed that the resistance response of tomato cultivars and rootstocks to Meloidogyne isolates varies depending on the isolates of Meloidogyne or the length of the growing period.