Submitted to: Tomato Genetics Cooperative
Publication Type: Research Notes
Publication Acceptance Date: October 2, 2008
Publication Date: October 20, 2008
Citation: Garcia, B.E., Teni, L.R., Sanchez, A., Barillas, A.C., Montes, L., Melgar, S., Keuler, N., Salus, M., Havey, M.J. 2008. Effectiveness of the Ty3 introgression for conferring resistance in F3 families of tomato to begomoviruses in Guatemala. Tomato Genetics Cooperative. 58:22-28.
Begomoviruses have been the main cause of losses in tomato production in many subtropical and tropical regions and breeding begomovirus-resistant tomato hybrids has become a principle focus for control. Resistance genes from Solanum chilense and Solanum habrochaites have been introgressed into S. lycopersicum (Hanson et al., 2000; Scott et al., 1995; Vidavsky and Czosnek, 1998). One breeding line, Gh13, was selected from the hybrid, FAVI 9. Molecular marker studies showed that Gh13 had an introgression in chromosome 6 from 20 to 32 cM and that this introgression was identical to the introgression for Ty3. Homozgous ty3 plants yielded a 320-bp fragment and homozygous Ty3 plants gave a 450-bp fragment. The ratio of ty3/ty3:Ty3/ty3:Ty3/Ty3 was 18:29:17, which fits the expected 1:2:1 ratio . Homozygous plants were allowed to self pollinate. DSI scores for 42 days after transplanting in Guatemala were averaged for each entry for each block and analyzed by an ANOVAs. The average DSIs for F3 families with the Ty3 introgression and those without the Ty3 introgression were 2.0 and 4.5, respectively, indicating that the Ty3 marker genotype significantly explains the DSI value (resistant or susceptible).