Evaluation of tomato germplasm for resistance to geminiviruses in Sanarate, GT

         Luis Mejia, Universidad de San Carlos, Project leader

Chocolate Spot Disease of Tomato in Guatemala:

    This problem was first brought to our attention a couple years ago.  Little is known about its causal agent or agents.  In March 2003, Mejia and Maxwell observed the following symptoms on a 35-day-old planting of Elios in the Salama Valley, GT.  Kits from Agdia were used to detect Tobacco streak virus, Tomato spotted wilt virus, and polyviruses.  The plant below was negative and also negative for begomoviruses, when this sample was hybridized with a general probe (M. K. Nakhla).   Incidence in this recent planting was nearly 100%. 

    Elios with chocolate symptoms, 35 days after transplanting.

Tomato cultivars have a differential response as noted by Luis Fernando Orellana, AgroVida at Salama, GT.  In a recent field trial in Salama, GT, Llanero 7  did not have chocolate spot symptoms.  Llanero 7 is a hybrid for begomovirus resistance from a GF1 (L. hirsutum resistance for begomoviruses) x a commercial tomato breeding line made by Dr. Favi Vidavski, Hebrew University of Jerusalem.  Growers have commented that Marina is more resistant than Elios.

Licda. Margarita Palmieri at Universidad del Valle de Guatemala is studying this disease.

[Back to Field Tests, March 03] [Breeding tomatoes for resistance to geminiviruses in Guatemala]