Development and Utilization of DNA Markers to Assess Genetic Diversity of Proso Millet (Panicum milliacum) Germplasm.

Proso millet (Panicum milliacum) is one of the oldest dryland cereals with high WUE, short season and drought adaptability which is currently grown as an alternative crop in USA, Africa and Asia. Though there is great advancement in genomics, however, genomic resources in proso millet are very limited. Comparative genomics using syntenic similarity and transferability of the SSR markers among the cross species is cheapest way to develop large numbers of DNA markers and other genomic tools in proso millet. The objectives of the present report are (1) to develop SSR markers using cross-species genomic resource, (2) to determine the genetic diversity among proso millet germplasm. We used SSR primers from switchgrass, wheat, rice, barley and oat to develop DNA markers for proso millet. Total of 68 proso germplasm from 28 countries were used for genetic diversity analysis using SSR markers developed. We screened total 379 SSR primers (308 markers from switch grass, 25 markers from proso BAC library, 21 markers from rice, 15 markers from wheat, 9 markers from oat and 1 marker from barley) and developed new 201 SSR markers in proso millet. Highly polymorphic and transferable cross-species SSR markers were validated for reproducibility. Total 120 SSR markers amplified 730 different alleles in 68 germplasm. Genetic distance matrix was created using NTSYS 2.2 to generate dendogram and principal component analysis (PCA) to evaluate the genetic diversity among the proso germplasm. Both UPGMA and PCA analysis grouped proso germplasm into four clusters which was in support to their origin. To the date this will be the first report to publish these many SSRs in proso millet with genetic diversity analysis. Marker developed in this study will be helpful for linkage map construction, mapping agronomic traits and future molecular breeding efforts in proso millet.