Evaluation of SSR and SNP Markers for Molecular Breeding in Rice

Simple sequence repeats (SSRs) have been the marker of choice for rice molecular breeding due to the high level of polymorphism, technical simplicity and low cost. Recent advances in rice genomics have led to the discovery of abundant single nucleotide polymorphism (SNPs) which have enormous potential for rice molecular breeding. To assess both marker systems for molecular breeding in rice, SSR and SNP markers were evaluated on a set of 23 genotypes representing indica germplasm for their usefulness in molecular research and breeding program. Seven hundred SSR and sequence tagged sites (STS) markers and 384 SNPs were screened for polymorphism. Highly polymorphic markers based on polymorphic information content (PIC) values were identified, which will be useful for molecular breeding. Data was used to identify an “indica genotyping set” based on high level of polymorphism, chromosome position and marker quality which will provide kits of markers for marker assisted selection (MAS). Genetic diversity analysis using SSR data was more consistent with pedigrees compared to analysis with SNP data indicating that more than 384 SNPs are required when elite indica breeding material is used. The results also indicated that there were polymorphic “blind spots” for the fixed SNP set suggesting that SSRs could still be used to complement fixed-SNP genotyping platforms for some molecular breeding applications.