NEW SOURCES OF GENETIC-RESISTANCE TO RACE-3 OF FUSARIUM-WILT OF TOMATO

Wild Lycopersicon accessions were screened for resistance to race 3 of Fusarium oxysporum f. sp. lycopersici. Of the accessions examined, only L. hirsutum (LA 1777) and L. parviflorum (LA 2133) consistently failed to develop wilt symptoms after inoculation. Resistances in these two accessions were analyzed genetically. Results from these analyses suggested that the resistances were not monogenic dominant or monogenic recessive and, therefore, genetically different from the resistance observed previously in L. pennellii (LA 716). Resistance in L. parviflorum (LA 2133) controlled by two independent recessive genes. We propose that genes involved in the resistances expressed in L. hirsutum (LA 1777) and L. parviflorum (LA 2133) be tagged with molecular markers and incorporated along with resistance genes derived from L. pennellii (LA 716) into commercial cultivars. This stacking of resistance genes could delay the appearance of new races of economic importance.