Genotyping-by-Sequencing Analysis for Determining Population Structure of Finger Millet Germplasm of Diverse Origins

Finger millet [ (L.) Gaertn.] is grown mainly by subsistence farmers in arid and semiarid regions of the world. To broaden its genetic base and to boost its production, it is of paramount importance to characterize and genotype the diverse gene pool of this important food and nutritional security crop. However, as a result of nonavailability of the genome sequence of finger millet, the progress could not be made in realizing the molecular basis of unique qualities of the crop. In the present investigation, attempts have been made to characterize the genetically diverse collection of 113 finger millet accessions through whole-genome genotyping-by-sequencing (GBS), which resulted in a genome-wide set of 23,000 single-nucleotide polymorphisms (SNPs) segregating across the entire collection and several thousand SNPs segregating within every accession. A model-based population structure analysis reveals the presence of three subpopulations among the finger millet accessions, which are in parallel with the results of phylogenetic analysis. The observed population structure is consistent with the hypothesis that finger millet was domesticated first in Africa, and from there it was introduced to India some 3000 yr ago. A total of 1128 gene ontology (GO) terms were assigned to SNP-carrying genes for three main categories: biological process, cellular component, and molecular function. Facilitated access to high-throughput genotyping and sequencing technologies are likely to improve the breeding process in developing countries, and as such, this data will be very useful to breeders who are working for the genetic improvement of finger millet.