Fig 2.

Model-based populations in association panels consisted of 268 USDA GRIN germplasm accessions: (a) Delta K values for different numbers of populations (K) assumed in analysis completed with the STRUCTURE software. (b) Classification of 268 spinach accessions into two populations using STRUCTURE Version 2.3.4, where the numbers on the y-axis show the subgroup membership, and the x-axis shows the different accession. The distribution of accessions into different populations is indicated by the color coding and shape (Cluster 1, Q1, is red round shape; Cluster 2, Q2, is green squared; Cluster 3, Q3, is blue triangle; Cluster 4, Q4, is yellow diamond; and Cluster 5, Q5, is purple triangle). (c) Maximum Likelihood (ML) tree of the 268 spinach accessions drawn in MEGA 6. The color code for each population is consistent in the (b) and (c), and the empty black square represents accessions aligned with the admixture cluster or population, in 268 USDA GRIN spinach germplasm accessions.