RAPD MARKERS BASED GENETIC DIVERSITY ANALYSIS OF ONION (ALLIUM CEPA) GERMPLASM

Onion is one of the most popular spice crop, which is used for seasoning wide range of dishes as well as folk medicine. Assessment of genetic diversity helps to use the onion germplasm as breeding materials for its improvement. Molecular marker based diversity assessment is more powerful, rapid and reliable compared to morphology based genetic diversity assessment. Thirty eight onion germplasm were characterized by using 10 random amplied polymorphic DNA (RAPD) markers for estimating genetic diversity within the germplasm. The germplasm exhibited wide range of variability which could be used in cross breeding for getting superior F1 generation. Out of 10 primers, four gave polymorphism among onion germplasm. Genetic diversity of 38 germplasm was analyzed using variation at 34 RAPD loci, of which 91.89% were polymorphic. The highest pair wise genetic distance was 1.046 and the lowest was 0.056. The mean gene diversity among all the germplasm was 1.54 and Shannon's information index was 0.3188. The UPGMA dendrogram, based on Nei`s genetic diversity showed 6 clusters. The frequency of polymorphic loci ranged from 0.0263 to 1.0000, indicates that there exists a wide genetic diversity among the germplasm and corroborated the usefulness of RAPD markers for estimating genetic diversity in onion.