Due to the harmful potential and existence of numerous races of lettuce downy mildew (Bremia
lactuca
e Regel), several
countries carry out the monitoring of these races through the use of differential cultivars of lettuce (
Lactuca sativa
L.) The
identification of resistance to other important diseases in these cultivars would be of great value for the lettuce’s breeding,
allowing the simultaneous selection for diseases. Among soil pathogens, the most important are the root-knot nematodes
(Meloidogyne spp.) due their damage and difficulty of control. Thus, the present work evaluated the resistance of these
differential cultivars (C-Set) against the two most important nematode species for the crop, M. javanica and M. incognita.
The experiment was conducted in a completely randomized design, with eight replicates and initial population of 1000
eggs and juveniles. The evaluations were performed by the criteria of reproduction factor and reproduction index, 75 d
after inoculation. Data were submitted to ANOVA and averages were compared by the Scott-Knott test (p < 0.05). All
cultivars are considered susceptible to M. incognita by the reproduction factor, ߵArgelès’, ߵBedford’, ߵDesign’ and ߵGrand
Rapids’ are considered as slightly resistant by the reproduction index. However, to M. javanica ߵArgelès’, ߵKibrille’,
ߵBalesta’, ߵColorado’, ߵDesign’, ߵBartoli’, and ߵNunD/m
15’ are classified as resistant by the reproduction factor and very
resistant by the reproduction index, and can be used as resistance source for simultaneous selection to downy mildew and
this species of nematode.