Resistance to Tomato spotted wilt virus introgressed from Lycopersicon peruvianum in line UPV 1 may be allelic to Sw-5 and can be used to enhance theresistance of hybrids cultivars

The breeding line UPV 1 developed from the PE-18 accession of Lycopersicon peruvianum collected in Huallanca, Ancash, Peru, shows resistance to TSWV. Mechanical inoculation and thrips transmission were used to study the inher itance of TSWV resistance of this line. UPV 1 resistance is controlled by a dominant gene. The penetrance of this resistance gene was complete in mech anical inoculation and incomplete when thrips transmission was used. Linkag e tests between the resistance genes of lines UPV 1 and RDD ( Sw-5), indica ted allelism. A molecular analysis using a SCAR marker tightly linked to Sw -5 also supported this hypothesis. In heterozygotes the level of resistance expressed in UPV 1 is higher than that expressed in RDD ( Sw-5), indicatin g that the resistance from UPV 1 may be of higher value for the development of commercial hybrids.