Confirmation of hybridity in DOGR hybrids of onion (Allium cepa L.) using SSR markers

Molecular identification and hybrid purity testing in nine onion hybrids along with their seven parental lines was conducted at ICAR-Directorate of Onion and Garlic Research, Rajgurunagar, Pune (Maharashtra). Four out of ten microsatellite (SSRs- Simple Sequence Repeats) markers were found to be polymorphic. All four polymorphic markers revealed polymorphism between the male and female parents of one or more hybrids and was utilized for their hybridity testing. ACM016, ACM033 and ACM078 have been identified as the three diagnostic markers for testing the genetic purity of all the nine onion hybrids included in this study viz.; DOGR Hy-1, DOGR Hy-2, DOGR Hy-3, DOGR Hy-4, DOGR Hy-5, DOGR Hy-6, DOGR Hy-7, DOGR Hy-8 and DOGR Hy-50. These 10 SSR loci amplified a total 28 alleles in 9 hybrids and 7 parents with 2-4 alleles per loci. The average number of alleles per loci was found to be 2.8. The highest polymorphism information content (PIC value) was observed to be 0.7137 for the marker ACM093 and the three potential markers ACM016, ACM033 and ACM078 with PIC value 0.5874, 0.5949 and 0.6628, respectively were the best markers that could be used to differentiate the parental lines and utilized for hybridity testing. This study showed that SSR are reliable and effective molecular marker capable of detecting genetic purity of onion hybrids.