Genetic purity of a seed lot represents the degree of true to type of the variety and its yield potential. In India, certified seed production is done by generation system of seed multiplication by registered institutes, private sectors and also by farmers. Hence, monitoring genetic purity at each stage of seed production becomes necessary. The traditional Grow Out Test for assessing seed genetic purity fail to distinguish the several new cultivars which have been produced from hybridization between members of a genetically very close elite group, besides a time consuming method. To overcome this complexity the present investigation was undertaken to identify variety specific SSR markers for the major rice varieties in seed chain of Tamil Nadu and explore the advantage of molecular markers over morphological markers in seed purity testing.
In this study, eighty eight primers showed polymorphism and 36 primers recorded PIC value more than 0.5 among the thirteen rice varieties analyzed. The number of alleles generated by a polymorphic loci varied from 2 - 6 with an average of 2.7 alleles per locus. Variety specific markers were identified for the varieties ADT 37, ADT 43, ADT 46, ASD 16, Bhavani, CO 49, CR 1009, IR 50 and Improved White Ponni. The validation of variety specific markers RM 163 and RM 331 clearly identified the off types present in the seed lot of the ADT 37 and ASD 16 respectively, giving a clear scope for use of SSR markers in genetic purity assessment of rice varieties.