Resistance of N - and Me -gene Carrying Peppers ( Capsicum annuum ) to California Isolates of Meloidogyne incognita and M. floridensis

Pepper cultivation is encumbered by infections of Meloidogyne spp. Resistance against M. incognita in N-gene and Me-gene carrying pepper cultivars has been reported, but their effects on M. floridensis need further characterization. Eight pepper cultivars were inoculated with eggs of Meloidogyne incognita race 3 and M. floridensis from California. In greenhouse experiments, root-galling and nematode reproduction were evaluated on the following bell pepper cultivars: M. incognita-susceptible ‘Baron’, N-gene resistant: ‘Carolina Wonder’, ‘Charleston Belle’, ‘Celaya’, ‘Ocelot’, ‘Triple5’, and two Me-gene resistant pepper rootstock cultivars: ‘Bedrock’ and ‘Foundation’. In inoculation experiments with second-stage juveniles (J2), root penetration and subsequent development of M. incognita and M. floridensis in susceptible ‘Baron’, ‘Carolina Wonder’, and ‘Bedrock’ were determined at different time intervals. When examining the reproductive potential on the eight cultivars, M. incognita caused significant root-galling and reproduced abundantly (>10-fold) only on the susceptible cultivar. In contrast, M. floridensis induced significant root-galling and reproduced abundantly (>10-fold) both on the susceptible and on all five N-gene resistant peppers. The two cultivars with Me-gene resistance remained virtually free of galling and inhibited egg production classifying them as highly resistant to both Meloidogyne species. More M. incognita J2 penetrated the roots of susceptible pepper than of the N-gene or Me-gene pepper cultivars. Development of M. incognita into third- and fourth-stage juveniles, or female stage was only observed in the susceptible cultivar. Equal numbers of M. floridensis J2 penetrated the roots of the susceptible, the N-gene, and the Me-gene cultivar, but development beyond the second stage occurred only in the susceptible and the N-gene cultivar. The results showed that the N-gene in pepper confers resistance to M. incognita, but not to M. floridensis whereas the Me-gene confers resistance to both species. Identification of the nematode populations in production fields is crucial to design nematode management schemes using host plant resistance.