Thursday, August 11, 2016
Georgia Ballroom (Sheraton Hotel Atlanta)
Verticillium wilt, caused by Verticillium dahliae, is an important disease of spinach (Spinacia oleracea L.) grown for seed production.
Furthermore, when the pathogen is introduced into other areas, it will affect other crops because of its seedborne nature. The most economical method of controlling this disease in most crops, including spinach, is through the use of genetic resistance. The objective of this research was to conduct molecular association analysis for Verticillium wilt resistance in spinach. A total of 95 USDA spinach accessions were evaluated for resistance to Verticillium wilt in this study. Significant genetic variance of Verticillium wilt disease resistance was observed among the 95 spinach accessions with a wide range of disease severity scores from 0.3 to 3.0 on a scale of 0-4. Eight genotypes (NSL 81328, NSL 92513, PI 169675, PI 174960, PI 176774, PI 179588, PI 204732, and PI 204735) showed a highlevel of resistance to Verticillium wilt with disease severity scores of 1 or less. Genotyping by sequencing (GBS) was conducted and approximately 0.5 million SNPs were discovered from the 95 spinach genotypes. After filtering, 2,878 SNPs were used for genetic diversity and association analysis. Two well-differentiated genetic populations and admixtures were postulated in the spinach panel by STRUCTURE 2.3.4 and MEGA 6. Association analysis for Verticillium wilt resistance was done using single marker regression (SMR), general linear mode (GLM), mixed linear mode (MLM), compressed mixed linear model (cMLM), and enriched compressed mixed linear model (EcMLM) using QGene, TASSEL, and GAPIT. Seven SNP markers (AYZV02052660_2183, AYZV02064249_10266, AYZV02112284_14543, AYZV02123399_146, AYZV02145765_3277, AYZV02199578_156, and AYZV02278250_41) were identified to be strongly associated with Verticillium wilt resistance where LODs ranged from 2.53 to 4.69 and R-squared values from 9.4 – 18.5% for these SNP markers. These markers may be useful tools in molecular spinach breeding to select Verticillium wilt resistance through marker-assisted selection.
Furthermore, when the pathogen is introduced into other areas, it will affect other crops because of its seedborne nature. The most economical method of controlling this disease in most crops, including spinach, is through the use of genetic resistance. The objective of this research was to conduct molecular association analysis for Verticillium wilt resistance in spinach. A total of 95 USDA spinach accessions were evaluated for resistance to Verticillium wilt in this study. Significant genetic variance of Verticillium wilt disease resistance was observed among the 95 spinach accessions with a wide range of disease severity scores from 0.3 to 3.0 on a scale of 0-4. Eight genotypes (NSL 81328, NSL 92513, PI 169675, PI 174960, PI 176774, PI 179588, PI 204732, and PI 204735) showed a highlevel of resistance to Verticillium wilt with disease severity scores of 1 or less. Genotyping by sequencing (GBS) was conducted and approximately 0.5 million SNPs were discovered from the 95 spinach genotypes. After filtering, 2,878 SNPs were used for genetic diversity and association analysis. Two well-differentiated genetic populations and admixtures were postulated in the spinach panel by STRUCTURE 2.3.4 and MEGA 6. Association analysis for Verticillium wilt resistance was done using single marker regression (SMR), general linear mode (GLM), mixed linear mode (MLM), compressed mixed linear model (cMLM), and enriched compressed mixed linear model (EcMLM) using QGene, TASSEL, and GAPIT. Seven SNP markers (AYZV02052660_2183, AYZV02064249_10266, AYZV02112284_14543, AYZV02123399_146, AYZV02145765_3277, AYZV02199578_156, and AYZV02278250_41) were identified to be strongly associated with Verticillium wilt resistance where LODs ranged from 2.53 to 4.69 and R-squared values from 9.4 – 18.5% for these SNP markers. These markers may be useful tools in molecular spinach breeding to select Verticillium wilt resistance through marker-assisted selection.