Submitted to: Symposium Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 4/20/2007
Publication Date: 5/20/2007
Citation: Maxwell, D.P., Mejia, J., Scott, J.W., Havey, M.J. 2007. Geminivirus Management: Disease Resistance. The 5th International Geminivirus Symposium & 3rd International ssDNA Comparative Virology Workshop [abstract]. Available: http://www.ufv.br/dfp/virologia/op2007/index_files/Abstract%20book,%205th%20IGS%20and%203rd%20IssDNACVW.pdf Interpretive Summary:
Technical Abstract: Begomoviruses are a major constraint for tomato production in many parts of the subtropic and tropics; and the most efficient way to increase tomato production is to use resistant cultivars in association with an IPM program. The Middle East (MERC) and a Guatemalan (CDR) project involved involved development of begomovirus-resistant hybrids for the local markets. Begomoviruses identified in the Middle Eastern countries were TYLCV, TYLCV-mild, and TYLCSV. Seven begomoviruses were identified in Guatemala. Local germplasm or commercial hybrids were used as parental lines and crosses were made with begomovirus-resistant lines having introgressions from S. habrochaites (Hebrew University of Jerusalem), S. peruvianum (Volcani Center), and S. chilense (University of Florida). In field trials in Guatemala, the virus pressure was severe and growth conditions were marginal. Crosses of begomovirus resistant parents were made with susceptible lines. For the habrochaites resistance, there was a dominant component, whereas the resistance from peruvianum and chilense were recessive with these conditions. When virus pressure was lower, the chilinse resistance had a dominant component. F1 populations from crosses of lines with habrochaites resistance with lines having resistance from another species exhibited the highest level of resistance. Since pyramiding loci from different wild species might broaden resistance against a more diverse range of begomoviruses, efforts were initated to detect the three loci assicated with begomovirus resistance (Ty-1, Ty-2, and Ty-3 loci) in breeding lines developed in Guatemala. GenTropic Seeds S. A. was formed in Guatemala to produce and market hybrids at prices similar to those of the begomovirus-susceptible hybrids commonly grown. The hybrid, Llanero, with roma-shaped fruits has a high level of resistance to begomoviruses in Guatemala and Egypt.