Genome-wide association analysis of cotton salt stress response-related sites

Soil salinization is the main abiotic stress factor affecting agricultural production worldwide, and salt stress has a significant impact on plant growth and development. Cotton is one of the most salt-tolerant crops. Its salt tolerance varies greatly depending on the variety, growth stage, organs, and soil salt types. Therefore, the selection and utilization of excellent salt-tolerant germplasm resources and the excavation of excellent salt-tolerant salt and salt resistance genes play important roles in improving cotton production in saline-alkali soils. In this study, we analysed the population structure and genetic diversity of 144 elite Gossypium hirsutum cultivar accessions collected from around the world, and especially from China. Illumina Cotton SNP 70K was used to obtain genome-wide single-nucleotide polymorphism (SNP) data for 149 experimental materials, and 18,432 highly consistent SNP loci were obtained by filtering. PCA (principal component analysis) indicated that 149 upland cotton materials could be divided into 2 subgroups, including subgroup 1 with 78 materials and subgroup 2 with 71 materials. Using the obtained SNP and other marker genotype test results, under salt stress, the salt tolerance traits 3d\_Germination\_potential, 3d\_Bud\_length\_drop\_rate, 7d\_Germination\_rate, 7d\_Bud\_length\_drop\_rate, 7d\_Germination\_weight, 3d\_Bud\_length, 7d\_Bud\_length, relative\_germination\_potential, Relative\_germination\_rate, 7d\_Bud\_weight\_drop\_rate, Salt tolerance index 3d\_Germination\_potential\_index, 3d\_Bud\_length\_index, 7d\_Bud\_length\_index, 7d\_Bud\_weight\_index, and 7d\_Germination\_rate\_index were evaluated by genome association analysis. A total of 27 SNP markers closely related to salt tolerance traits and 15 SNP markers closely related to salt tolerance index were detected. At the SNP locus associated with the traits of the bud length decline rate at 7 days, alleles Gh\_A01G0034 and Gh_D01G0028 related to plant salt tolerance were detected, and they are related to intracellular transport, membrane microtubule formation and actin network. This study provides a theoretical basis for the selection and breeding of salt-tolerant upland cotton varieties. ### Competing Interest Statement The authors have declared no competing interest.