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

Dates: March 2002 to March 2006 -- Last meeting was held in Guatemala, April 2006.

Sponsors:  i)  United States - Israel Co-operative Development Research Program, The Agency for International Development, USA

                ii)  CONCYT (Consejo Nacional de Ciencia y Tecnologia), GT

   Investigators

Overall aim:

 Introduce molecular marker-assisted breeding technology into Guatemala using the development of locally adapted tomato cultivars resistant to whitefly-transmitted geminiviruses and other economically important pathogens as a model system.

Specific research objectives:

  1.   Introduce the principles of molecular marker-assisted breeding technology into a research program and into the M. Sc. Degree Program at Universidad de San Carlos, Guatemala City.

2   2.  Determine whether the markers used to map genes for resistance to TYLCV and ToLCV (Eastern Hemisphere geminiviruses) identify identical loci in the tomato breeding lines selected for resistance to the Guatemalan geminiviruses.

3  3.  Identify molecular markers linked to genes for resistance to whitefly-transmitted geminiviruses from Guatemala that are different than those in objective 2.

4  4.  Determine if the field-selected resistant tomato germplasm is resistant to all three tomato-infecting whitefly-transmitted geminiviruses in Guatemala.

     5.  Combine the independent sources of resistance to whitefly-transmitted geminiviruses and evaluate this  material in the field in Guatemala and Israel.

     6.   Use  molecular markers to combine genes for resistance to whitefly-transmitted geminiviruses    and other pathogens into improved resistant genotypes of tomatoes suited for    the Guatemalan market.

    Brief summary of results

Begomoviruses in Guatemala

Background - site and sources of resistance

Information on selection criteria; examples

Results of Field Evaluations for Resistance

March/April 2003 - Sanarate, GT

September 2003 - Sanarate, GT

Dec03/March04 - Sanarate, GT

July04/Oct04-Sanarate, GT

January05-April05 - Sanarate, GT and Antigua, GT

July05-Oct05 - Sanarate, GT and Antigua, GT

January06-April06 [Site under construction]

Breeding lines and Hybrids Developed with Begomovirus resistance

Marker-Assisted Selection 

    Tagging genes for begomovirus resistance

Development of PCR-based methods for detecting the Mi-1 locus for root-knot nematode resistance

        updated April 2006, Douglas P. Maxwell

[Projects on Breeding Tomatoes for Resistance]