Genome-wide diversity analysis to infer population structure and linkage disequilibrium among Colombian coconut germplasm

Abstract

Genetic diversity and relatedness of accessions for coconut growing in Colombia was unknown until this study. Here we develop single nucleotide polymorphisms (SNPs) along the coconut genome based on Genotyping by Sequencing (GBS) with the goal of analyze the genetic diversity, population structure, and linkage disequilibrium (LD) of a diverse coconut panel consisting of 112 coconut accessions from the Atlantic and Pacific coasts of Colombia. A comprehensive catalog of approximately 40,000 SNPs with a minor allele frequency (MAF) of > 0.05 is presented. A total of 40,614 SNPs were found but only 19,414 anchored to chromosomes. Of these, 10,338 and 4606 were exclusive to the Atlantic and Pacific gene pools, respectively, and 3432 SNPs could differentiate both gene pools. A filtered subset of unlinked and anchored SNPs (1271) showed a population structure at K = 4, separating accessions from the Pacific and Atlantic coasts that can also be distinguished by palm height, as found in previous studies. The Pacific groups had a slow LD decay, low Fixation Index (Fst) and low nucleotide diversity (π), while the Atlantic group had slightly higher genetic diversity and faster LD decay. Genome-wide diversity analyses are of importance to promote germplasm conservation and breeding programs aimed at developing new cultivars better adapted to the region.