Insights into genetic diversity and population structure of Indian carrot (Daucus carota L.) accessions

Carrot (Daucus carota L.) is acknowledged as a highly valuable vegetable crop. Despite having high demand, limited breeding efforts have been made to develop the varieties and hybrids suitable to wider climatic conditions due to improper characterization of the available germplasm. An accession panel (AP) consisting of 144 accessions of five different root colors representing Asiatic and Western gene pools collected from different parts of India was utilized in the present study. This diverse AP was used to assess the population structure and genetic diversity from 80 polymorphic DNA markers distributed throughout the genome. Population structure, neighbor-joining (NJ) tree, and principal coordinate analysis (PCoA)-based diversity assessment divided the AP into three subpopulations/clusters. Greater than ninety percent polymorphism and the higher average polymorphic information content (͂> 0.50) coupled with higher gene diversity (He) indicating the broad genetic base of the population. Moderate to high F_st and gene flow (Nm) between the subpopulations revealed a moderate genetic differentiation among Indian carrot accessions owing to the highly outcrossing nature of carrot. Analysis of molecular variance (AMOVA) exhibited higher variation among individuals within the subpopulations (69.00%) or total populations (19.00%) than among the subpopulations (13%) as expected in the single Daucus species used here. The information obtained in the study would benefit the carrot breeders to explore the genetic diversity of the Indian carrots in the carrot breeding program for widening the genetic base and multi-color target trait improvement.