Genome-Wide Association Study of Gossypium arboreum Resistance to Reniform Nematode

The Gossypium arboreum germplasm collection is an important source of resistance to reniform nematode (RN, Rotylenchulus reniformis), which is a serious root pathogen of upland cotton in the United States. To understand the genetic basis of RN resistance of G. arboreum, a genome-wide association study was performed using 246 G. arboreum accessions and 7,220 single nucleotide polymorphic (SNP) sequences generated from genotyping-by-sequencing. Fifteen SNPs distributed over 8 chromosomes were identified to be significantly associated with RN resistance. A set of genes containing or physically close to these SNPs were proposed as candidate genes for RN resistance. Significantly associated SNPs identified from this study can serve as potential important tools in marker-assisted breeding of upland cotton with improved RN resistance. Genetic structure and functional analysis of RN resistance candidate genes will contribute to the understanding of the molecular mechanisms of resistance.