Abstract Understanding the processes that have led to the recent prevalence of necrotic genotypes in PVY populations is an important challenge for research programs studying this virus. Non-necrotic PVY O-139, necrotic PVY N-605 and point mutated versions of PVY N-605 (PVY KRED, PVY KR and PVY ED), were used in mixtures to inoculate two Nicotiana hosts which express ( N. tabacum cv. Xanthi) or not ( N. clevelandii) necrosis symptoms in response to infection by PVY N group members. The comparison during serial passage experiments of proportions of PVY genotypes produced in mixed infected plants with those of the inocula was used to describe: (i) complementation between PVY KR and PVY N and between PVY KRED and PVY O genotypes; (ii) exclusion of the PVY KRED genotype, previously described as fitter, during mixed infections in the presence of one of the less fit PVY N, PVY ED and PVY KR genotypes and (iii) the prevalence of the non-necrotic PVY KR genotype in the presence of PVY N parental sequence. These results indicate that the role of both A/G 2213 and A/C 2271 nucleotides in the fitness of PVY genotypes depends on other genetic information in the viral genome that has not yet been identified. Moreover, the collected data indicate that mutation of the nucleotide 2213 in the PVY N-605 sequence could lead to the prevalence, both in N. tabacum cv. Xanthi and in N. clevelandii, of the non-necrotic PVY KR genotype.