Effects of the <I>Mi-1, N</I> and <I>Tabasco</I> Genes on Infection and Reproduction of <I>Meloidogyne mayaguensis</I> on Tomato and Pepper Genotypes


  • J. A. Brito
  • J. D. Stanley
  • R. Kaur
  • R. Cetintas
  • M. Di Vito
  • J. A. Thies
  • D. W. Dickson


Capsicum annuum, bell pepper, resistance, root-knot nematodes, Solanum lycopersicum, sweet pepper.


Meloidogyne mayaguensis is a damaging root-knot nematode able to reproduce on root-knot nematode-resistant tomato and other economically important crops. In a growth chamber experiment conducted at 22 and 33øC, isolate 1 of M. mayaguensis reproduced at both temperatures on the Mi-1-carrying tomato lines BHN 543 and BHN 585, whereas M. incognita race 4 failed to reproduce at 22øC, but reproduced well at 33øC. These results were confirmed in another experiment at 26 ñ 1.8øC, where minimal or no reproduction of M. incognita race 4 was observed on the Mi-1-carrying tomato genotypes BHN 543, BHN 585, BHN 586 and `Sanibel', whereas heavy infection and reproduction of M. mayaguensis isolate 1 occurred on these four genotypes. Seven additional Florida M. mayaguensis isolates also reproduced on resistant `Sanibel' tomato at 26 ñ 1.8øC. Isolate 3 was the most virulent, with reproduction factor (Rf) equal to 8.4, and isolate 8 was the least virulent (Rf = 2.1). At 24øC, isolate 1 of M. mayaguensis also reproduced well (Rf ≥ 1) and induced numerous small galls and large egg masses on the roots of root-knot nematode-resistant bell pepper `Charleston Belle' carrying the N gene and on three root-knot nematode-resistant sweet pepper lines (9913/2, SAIS 97.9001 and SAIS 97.9008) carrying the Tabasco gene. In contrast, M. incognita race 4 failed to reproduce or reproduced poorly on these resistant pepper genotypes. The ability of M. mayaguensis isolates to overcome the resistance of tomato and pepper genotypes carrying the Mi-1, N and Tabasco genes limits the use of resistant cultivars to manage this nematode species in infested tomato and pepper fields in Florida.