Development of local pink tomato varieties resistant to TSWV using molecular markers

Tomato is the most produced vegetable type in the World. Virus diseases are the leading diseases that limit tomato production in the world and in our country. Tomato spotted wilt virus comes first among these diseases. TSWV causes a decrease in quality and yield due to deformations in fruit structures. Chemical and biological control methods are insufficient in the fight against TSWV. The most effective metod to combat this virus is to use disease-resistant varieties. The known gene for resistance against TSWV is the Sw-5 gene, a dominant gene. The aim of this Master's Thesis study is to develop new varieties of domestic pink tomatoes that are resistant to TSWV. In the study, two red tomato lines resistant to TSWV and ''Nazlı F1'' pink tomato variety, which has been used for many years, are used as plant materials. Hybrids made with breeding lines known to be genetically resistant whit the sensitive parent were self-pollinated for 6 generation and tested by mechanical inoculation method. Molecular testing method was applied only in plants at the F2 and F6 stage. Two SCAR molecular markers (NCSw-003, NCSw-012) associated with the Sw-5 gene were used in molecular testing. Pink tomatoes carrying the resistant allele of the molecular marker were also found to be resistant by mechanical inoculation method. As a result, tomatoes carrying the molecular marker associated with the Sw-5 gene were observed to be resistant to TSWV, but tomato plants that did not carry this molecular marker were found to be sensitive to TSWV. In this study, it has been demonstrated that molecular markers can be used successfully in the development of TSWV resistant pink tomato lines.