Submitted to: Tomato Genetics Cooperative
Publication Type: Research Notes
Publication Acceptance Date: November 15, 2009
Publication Date: November 23, 2009
Citation: Mejia, L., Garcia, B.E., Fulladolsa, A.C., Sanchez-Perez, A., Havey, M.J., Maxwell, D.P. 2009. Effectiveness of the Ty-3 Introgression for Conferring Resistance in Recombinant Inbred Lines of Tomato to Bipartite Begomoviruses in Guatemala. Tomato Genetics Cooperative. 59:42-47.
Management of begomovirus-incited diseases on tomatoes in Guatemala continues to be a challenge and there continues to be a need to better understand the genetics of resistance to begomoviruses. In this study, the resistant line, Gh13, was crossed with the susceptible line, HUJ-VF, that lacked the Ty-1 and Ty-3 resistance genes, and F2 plants were selfed to create the recombinant inbred lines (RILs). These RILs were scored for the presence of the Ty-3 introgression with PCR primers on chromosome 6. RILs were evaluated for virus phenotype in field trials in Guatemala. The 41 RILs with the Ty-3/Ty3 introgression were divided into three groups: resistant (DSI =3.0, 9 RILs), moderately resistant (DSI 3.1 – 4.0, 7 RILs), and susceptible (DSI =4.1, 25 RILs). As expected, only RILs that had the Ty-3 introgression were resistant or moderately resistant. However, the low number of highly resistant RILs was unexpected. These genetic studies stress the complex nature of resistance to begomoviruses, and although molecular markers may be useful in development of begomovirus-resistant inbreds, thorough field testing remains a must.