Evaluation of tomato resistance to Meloidogyne incognita in Heilongjiang Province

Root knot nematode (Meloidogyne spp.) is one of the most important pathogens in tomato (Solanum lycopersicum L.). By screening M. incognita resistance in 21 tomato cultivars collected from Heilongjiang Province, plant of each tomato cultivar was inoculated with 1 000 eggs in greenhouse. The results showed that VFNT as a resistant control was immune to M. incognita, only two tomato cultivars, Hongchuntao and Shuiguofanqie displayed low disease indices with 12 and 20, respectively, and nematode was not able to reproduce in Hongchuntao with less number of egg masses and RF (eggs reproduction factor/plant) in Shuiguofangqie, demonstrating that the two cultivars were resistant to M. incognita. Further, cultivars Hongchuntao and Shuiguofanqie were susceptible to M. hapla as VFNT with great disease indices, egg masses and RF, suggesting that the two cultivars contain Mi-1 gene as VFNT does. The results provide valuable materials for controlling southern root knot nematode disease by using resistance cultivars. Most tomato cultivars sold in the markets with high susceptibility to root-knot nematodes would be a great challenge for tomato root knot nematode management.