Combining Fruit Quality and Late Blight Resistance in Tomato

Late blight caused by Phytophthora infestans is a devastating disease of tomato (Solanum lycopersicum L.). Three genes, Ph-1, Ph-2 and Ph-3, have been identified to confer resistance to this disease. Among these, a combination of Ph-2 and Ph-3 is effective to confer resistance to the available races of Phytophthora infestans. While there are some tomato breeding lines with combined Ph-2 and Ph-3 genes, they do not have the genes that confer other fruit quality traits that are in high demand in the market including the dark-red gel color conferred by the ‘crimson’ gene. There is also commercial interest in tomato breeding lines with the ripening inhibitor (rin) gene combined with the crimson gene. Our objective was to combine late blight resistance genes and fruit quality related genes (crimson and rin) into a single tomato line. An F2 population from NC 2CELBR x NC 2rinEC was generated and inheritance and segregation analysis was performed. The Ph-2 Ph-3, crimson and rin genes were found to segregate as single genes. Several single plants with Ph-2, Ph-3, crimson and rin genes were selected at the homozygous state for field evaluation of horticultural traits in the next generation. These lines will also be evaluated for lycopene content, a highly desirable trait. Combination of these traits in tomato breeding lines should lead to a superior tomato hybrid.