TITLE:  Molecular Marker-Assisted Breeding for Resistance to Whitefly-Transmitted Geminiviruses Infecting Tomato in Guatemala

Past History:  Dr. Luis Mejia started a breeding program in 1998 for resistance to begomoviruses at a site in Eastern Guatemala near Sanarate.  This site was selected, as it had an extremely high whitefly population year around and inoculum for the tomato begomoviruses was always present.  Germplasm was collected from various breeding programs, which were focused on resistance to Tomato yellow leaf curl virus in the Mediterranean region or Tomato leaf curl virus in Asia.  In all cases, begomovirus resistance had been introgressed from wild tomato species.  From H. Laterrot, INRA, in France, three populations were obtained, and at least one of these populations had been field tested in Jordan.  The population with introgressions from L. pimpinellifolium and L. peruvianum (designed Pimpertylc J-13) was the most useful of these.  Other sources were i) hybrids (FAVI 9, FAVI 12, FAVI 13) with introgressions from L. hirsutum (Phytopathology 88:910-914) and line TY52  homozygous for  the Ty1 gene from L. chilense (Theor. Appl. Genet. 88:141-146) from H. Czosnek and F. Vidavski, the Hebrew University of Jerusalem, ii) two lines, TY198 and TY197, with introgressions from L. peruvianum from Moshe Lapidot and colleagues, Volcani Center (Plant Dis. 81:1425-1428; J. Amer. Soc. Hort. Sci. 123:1004-1006), iii) line H24 from P. Hanson, AVRDC, with introgressions from L. hirsutum (J. Amer. Soc. Hort. Sci. 125:15-20), and iv) several lines from J. Scott, University of Florida, with introgressions from L. chilense (J. Amer. Soc. Hort. Sci. 126:462-467).  In all cases, these lines or hybrids had moderate to high levels of viral resistance to a particular begomovirus species.

[Projects on Breeding Tomatoes for Resistance]