Identification of random amplified polymorphic DNA (RAPD) marker of Ph-3 gene for late blight resistance in tomato

Late blight is a highly destructive disease of tomato worldwide. Host resistance is the most effective method for disease control. The application of molecular markers is an efficient way to identify host resistance for breeding programs. In this study, bulked segregant analysis (BSA) was used to search for random amplified polymorphic DNA (RAPD) markers linked to the late blight resistance gene Ph-3, using an F 2 population (147 individuals) derived from a cross of tomato lines CLN2037 (resistant) and T2-03 (susceptible). Two hundred and thirty decamer primers with arbitrary sequences were chosen for polymerase chain reaction amplification. One RAPD marker CCPB272-03740 (primer sequence GGTCGATCTG) was found to be tightly linked to the resistance gene Ph-3 and was located 5.8 cm from the resistance gene. Marker CCPB272-03740 is the first marker of gene Ph-3 based on PCR reaction. Key words : Tomato, late blight, random amplified polymorphic DNA (RAPD) marker, gene Ph-3.