Abstract: In the greenhouses of the Region of Murcia, pepper is being monocultured for morethan two decades. Meloidogyne incognita is a major soil pathogen. Rootstocks harbouringresistance genes are an alternative to chemical control to mitigate the effects of the nematode. Todetermine the influence of the interaction between this new genetic material nature of somepopulations of parasitic nematodes to investigate the behavior of the reiteration of root stockcarrying resistance genes to M. incognita particularized in the gene Me7. For four consecutiveyears, in four greenhouses, has followed the evolution of virulence of populations to this gene,comparing grafted plants carrying this gene with ungrafted plants susceptible to the nematode,grown in soil without disinfecting. We found differences in the interaction between plants graftedon rootstocks that carry Me7 gene and nematode population, between greenhouse and betweenyears. In three greenhouses we found nematode population infesting grafted plants (Me7) thesame level that ungrafted plants, when these plants were grown in the same soil during 2 or 3consecutive years. This didn’t happen in other greenhouse.