Comparative analysis of genetic diversity of 8 millet genera revealed by ISSR markers

The genetic diversity among different millet genera is not very well known; therefore, an investigation was undertaken with Inter Simple Sequence Repeats (ISSR) markers to ascertain the possibility of using these DNA markers to reveal the genetic relationships among different millet genera/species. Twelve out of 30 screened ISSR primers amplified successfully, and a total of 258 bands were scored for all 69 millet accessions, with a high level of polymorphism being detected. Nei's genetic distance among all accessions varied from 0.0241 to 0.3786, and from 0.0163 to 0.1476 at the genera level, respectively. The Shannon's index was estimated as 0.9689. The Neighbour joining (NJ) tree created, using the UnWeighted Neighbor-Joining method and Dice’s dissimilarity coefficient, grouped all 69 millet accessions into eight clusters, indicating that the majority of accessions of a given genus tend to group together. The ISSR markers revealed the close relatedness between the Eragrostis and Panicum genera, as well as between Eragrostis and Pennisetum; while the greatest distance was found between the Coix and Setaria genera. Such a determination of relatedness is useful for a better understanding of the difficult relationships among the different millet genera, which are generally considered to be a complex group.