Genetic diversity analysis using SSR markers for high temperature tolerance in tomato (Solanum lycopersicum L.)

Molecular characterization of selected 22 tomato genotypes (Solanum lycopersicum L.) under high temperature stress condition was assessed using 25 simple sequence repeat (SSR) markers. Out of the 25 markers used 22 primers showed amplification, 15 SSRs were monomorphic and 7 were polymorphic. Polymorphism information content (PIC) value of the markers ranged from 0.58 to 0.65 with an average value of 0.6. The highest PIC value was shown by SSR 96(0.65). Phylogenetic tree was constructed based on Jaccard's similarity coefficient using the unweighted pairgroup method with arithmetic mean (UPGMA) using NTSYSpc cluster analysis software. Cluster analysis divided the twenty-two genotypes into four clusters. SSR marker analysis and cluster analysis were able to differentiate the genotypes into; tolerant, moderately tolerant, susceptible and genotypes which show mixed characteristics. Genetic maps currently available in tomatoes have a limited number of SSR markers that are not uniformly distributed across the genome, so this study helps our fundamental understanding in identification of molecular markers linked to high temperature tolerance in tomato.