Tomato breeding for resistance to Tomato spotted wilt virus (TSWV): an overview of conventional and molecular approaches

The disease caused by Tomato spotted wilt virus (TSWV) belongs to the most destructive diseases of tomato all over the world. Therefore, tomato has been subjected to many breeding efforts, including the incorporation of resistance to the virus. Recently emerged approaches, ideas and technologies could affect the future direction of the virus resistance breeding. In particular molecular techniques have provided opportunities in the form of linked molecular markers to speed up and simplify the selection of host resistance genes. Transformation of an inbred tomato line with the TSWV nucleoprotein gene cassette resulted in high levels of resistance to TSWV that have been retained in the hybrids derived from the parental tomato line. These and other techniques offer great opportunities for improving the virus resistance and, therefore, it is time to reconsider the future direction of resistance breeding in tomato. The effort has been made to review available sources of resistance, conventional breeding methods, marker-assisted selection, pathogen-derived resistance and transgenic resistance approaches in this paper.