Detection of the Ty-3 introgression and related introgressions:
A co-dominant SCAR marker, P6-25F2/R5, is available. See: Ji et al. 2007. Co-dominant SCAR markers for detection of the Ty-3 and Ty-3a loci from Solanum chilense at 25 cM of chromosome 6 of tomato. Tomato Genetics Cooperative Report 57:25-28.
This SCAR marker will also detect the introgression from S. chilense LA1969, designed Ty-3b as the PCR fragment is slightly larger than the one for Ty-3a.

Recent report on Ty-3 introgression: 2011 Plant and Animal Genomes XIX conference,
http://www.intl-pag.org/19/abstracts/P05g_PAGXIX_437.html

Abstract reports that Ty-3 lies between Ty-M1 at 20.2 cM and cLEG-31-P16 at 22.1 cM and germplasm with an introgression less than 80 kb has been developed.

PDF file online: L. Mejia et al. 2011. Wild tomato introgressions that confer resistance to begomoviruses in Guatemala. International conference on Solanaceae: Resistance breeding technologies, genetics, and genomics, Chiang Mai, Thailand, 17-19 Feb. 2011. (http://www.sol-symposium2011.com/)

http://www.sol-symposium2011.com/sci/17-10.pdf