Host status of cultivated plants to Meloidogyne hispanica

Abstract

The reproduction of a Meloidogyne hispanica isolate from Portugal was evaluated in 63 plant species/cultivars, in pot assays at 25 ± 2.0°C, on the basis of root gall index (GI) and reproduction factor (Rf = final/initial egg density) at 60 days after inoculation. Cultivars of aubergine, bean, beetroot, broccoli, carnation, corn, cucumber, French garlic, lettuce, melon, onion, parsley, pea, potato, spinach, and tobacco and two of cabbage were susceptible (3 ≤ GI ≤ 5; 1.15 ≤ Rf ≤ 262.86). Cabbage cv. Bacalan, cauliflower cv. Temporão and pepper cv. Zafiro R2 were hypersusceptible or poor hosts (Rf < 1; GI > 2) and pepper cvs. Aurelio and Solero were resistant (0.0 ≤ GI ≤ 0.4; 0.00 ≤ Rf ≤ 0.03). The response of the pepper cultivars and the Mi-1 resistant tomato cv. Rossol was also conducted in pots using two inoculum levels and four temperatures, three growth chamber (25 ± 2.7°C, 29.3 ± 1.8°C and 33.6 ± 1.2°C) and one outdoors (24.4 ± 8.2°C). At 24.4 ± 8.2°C and 25 ± 2.7°C, the reproduction on the resistant tomato was significantly lower compared to the susceptible cv. Easypeel. At all temperatures, resistance was evident for the pepper cultivars, despite the fact they were not found to contain any of the Me1, Me3, Me7 and N genes. The eggs obtained on cv. Aurelio at 33.6 ± 1.2°C were used to get a selected resistance breaking isolate of M. hispanica that was able to reproduce on the three pepper cultivars. Our results suggest that the initial M. hispanica isolate is a mixture of virulent and avirulent individuals. The pepper cultivars tested, have potential to reduce M. hispanica populations in agro-ecosystems under certain conditions, but they should be used as a part of an integrated management strategy in order to prevent the development of virulent populations.