Genetic diversity of Amaranthus species from the Indo-Gangetic plains revealed by RAPD analysis leading to the development of ecotype-specific SCAR marker.

Genetic diversity and relationships among 6 Amaranthus species from 8 phytogeographic regions of the Indo-Gangetic plains were analyzed using a random amplified polymorphic DNA (RAPD) marker. RAPD primers yielded a total of 262 amplicons, ranging from approximately 250 to approximately 3000 bp in size with an average of 13.1 amplicons per primer, of which 254 amplicons (96.94%) were polymorphic. The genetic similarity coefficient among all the Amaranthus species ranged from 0.16 to 0.97 with a mean similarity coefficient of 0.56, indicating that variation existed in the genetic diversity of different populations. In the unweighted pair group method with arithmetic average dendrogram, populations of the same species clustered together. A unique 1371-bp RAPD band specific for Amaranthus gangeticus (syn. tricolor) of a particular phytogeographic region was converted to a sequenced characterized amplified region (SCAR) marker. The translated marker sequence showed homology with hemagglutinin protein. This SCAR marker is potentially useful for germplasm conservation and identification of amaranth ecotype.