Location: Tropical Crops and Germplasm ResearchTitle: Genetic diversity, population structure and anthracnose resistance response in a novel sweet sorghum diversity panel
Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/10/2022
Publication Date: 1/13/2023
Citation: Cuevas, H.E., Vermerris, W., Knoll, J.E., Prom, L.K. 2023. Genetic diversity, population structure and anthracnose resistance response in a novel sweet sorghum diversity panel. Plant and Animal Genome Conference. 01/13-18/2023.
Technical Abstract: The sweet sorghum collection of the USDA-ARS National Plant Germplasm Systems (NPGS) encloses ~2,500 accessions and is the primary source of genetic diversity for the development of new sweet sorghum varieties for biofuel production. Anthracnose, caused by the fungal pathogen Colletotrichum sublineolum, is a prevalent disease in warm and humid sorghum cultivation regions. The identification of novel anthracnose-resistance sources present in sweet sorghum germplasm is necessary for the development of new resistant sweet sorghum cultivars. Therefore, we established a sweet sorghum diversity panel (SWDP) of 272 accessions that includes landraces from 22 countries, advanced breeding materials, and represents ~15% of the NPGS sweet sorghum collection. Genomic characterization of the SWDP identified 171,954 SNPs with an average of one SNP per 4,071 kb. Population structure analysis revealed that SWDP could be stratified into four populations and one admixed group, and this population structure could be aligned to sorghum racial classification. Results from a two-year replicated trial of the SWDP for anthracnose resistance response in Texas, Georgia, Florida, and Puerto Rico showed 27 accessions to be resistant across locations, while 145 accessions showed variable resistance response against local pathotypes. Genome-wide association study employing the BLINK model identified multiple genomic regions associated with anthracnose resistance. We found that a 44.6 kb genomic region at the top of chromosome 8 was associated with resistance response observed in Georgia, Texas, and Puerto Rico. Candidate gene analysis within this region revealed that most of the genes encode protein domains associated with fungal resistance genes.