About fifteen pathogens are now controllable by genetic resistance in tomatoes. The effectiveness of these resistances is highly variable, whether for their level of expression or their stability over time in the face of changes in the virulence of pathogens.

The varieties selected for their resistance to pests are mainly intended for sheltered crops, which are more frequently and severely parasitized. As their production potential is very high, the high price of seeds resulting from expensive breeding programs is easily accepted.

Certain resistances which have been demonstrated for a long time are only present in rare varieties. In the case of Pyrenochaeta lycopersici , the reason is complex; this resistance is partial and of recessive monogenic inheritance, and the “ ” pyl gene which controls it must be present in both parents of F1 hybrids. In addition, the practice of grafting on multiresistant rootstocks possessing in particular a high level of resistance to P. lycopersici decreases the interest in the selection of F1 hybrids resistant to this soil fungus.

Partial resistance to Phytophthora infestans , difficult to demonstrate by early selection tests, only interested few breeders. In addition, it relates to an aerial disease for which many effective fungicides are available on the market.

The other resistances, of limited use, are of particular interest to specific production areas (for example humid tropics for Ralstonia solanacearum ) or are the subject of relatively recent programs.

The availability of dominant monogenic resistances makes it possible to accumulate in F1 hybrids an increasing number of resistances: hybrids intended for sheltered crops generally offer 4 to 5 resistances, some accumulate up to 7. For field crops, fixed varieties have 2 to 4 resistors. More and more F1 hybrids of these different types of production have these resistances and contribute to the lasting protection of the tomato.

The available rootstocks are not very numerous and can be separated into 2 groups :
- F1 hybrids in the cultivated tomato type with several resistances to borne diseases including partial resistance to soil- Pyrenochaeta lycopersici ;
- interspecific F1 hybrids between cultivated tomato and Lycopersicon hirsutum . These hybrids have a strong root system that endures lower temperatures than the cultivated tomato. Lycopersicon hirsutum , native to the Andean heights, also offers a high level of dominant resistance to Pyrenochaeta lycopersici .