Evaluation of onion varietal identity using SSR markers

Seven open-pollinated varieties of onion were evaluated for varietal identity using SSR primers. Pooled samples of 100 seeds were used to generate a representative profile of the population. Fifty EST-SSR primers were used and 21 were polymorphic among the varieties. Eight primers were found to have a PIC value more than 0.5 and are sufficient to discriminate all seven varieties. The genetic similarity (GS) value ranged from 0.77 to 0.92. The highest similarity was observed between varieties Bhima Raj and Bhima Red. As they are multi-allelic in nature, SSR primers have the ability to distinguish even within close groups. Amplification of unique alleles was also observed in six varieties and these could be of use in establishing varietal identity in close groups of varieties and for quality analysis during seed production.