Correlations Among Grain Mold Severity, Seed Weight, and Germination Rate of Sorghum Association Panel Lines Inoculated With Alternaria alternata, Fusarium thapsinum, and Curvularia lunata

Abstract

The sorghum association panel was evaluated for grain mold severity, seed weight, and germination rate. The 377 accessions were inoculated with Alternaria alternata alone, a mixture of A. alternata, Fusarium thapsinum, and Curvularia lunata, and untreated water-sprayed control during 2010, 2013-2015 growing seasons at the Texas AgriLife Research Farm, Burleson County, Texas. Each accession was evaluated at least twice. Across accessions, Spearman’s rank correlation was performed for non-parametric correlation analysis for grain mold severity, seed weight, and germination rate. There were significant negative correlations between grain mold severity with seed weight and germination rate for the individual treatment and when combined. A significant positive correlation between seed weight and germination rate was observed. The results indicated that higher grain mold severity reduces both sorghum seed weight and germination rate whether deliberately inoculated with fungal pathogens or naturally infected. It can be argued that correlations from this study were more robust due to a large number of accessions from all major sorghum races used and may represent the true association among the three parameters for this pathosystem. Thus, the use of grain mold-resistant lines, resulting in sound seeds and higher germination rates is recommended.

A Genome-Wide Association Study of Seed Morphology-Related Traits in Sorghum Mini-Core and Senegalese Lines

“…Furthermore, recent studies identified potential linkages between sorghum seed morphology traits and host resistance against fungal pathogens. Significant negative correlations between grain mold severity and seed weight in sorghum were identified in a recent study [39]. Similarly, Ahn et al [29] identified correlations between seed morphology traits (circularity and the distance between IS and CG) and the formation of spots on seedling leaves.…”

Identification of pleiotropic loci mediating structural and non-structural carbohydrate accumulation within the sorghum bioenergy association panel using high-throughput markers

“…The remaining loci, including a locus on Chr6 and three loci on Chr9) were minor. A highly significant locus on Chr2 (Chr2: 71718582) corresponding to a candidate gene (Sobic.002G353800), which encodes the homeodomain-leucine zipper (HD-Zip) transcription factor family that plays a vital role in plant development and morphogenesis as well as responses to biotic and abiotic stresses ( Prom et al., 2021 ). Interestingly, only a single genomic region on Chr5 (52 Mb) was co-localized between these traits (FW and DW).…”

Multi-Trait Genome-Wide Association Studies of Sorghum bicolor Regarding Resistance to Anthracnose, Downy Mildew, Grain Mold and Head Smut

“…Sorghum pathologists have been applying GWAS to identify defense-related genes in sorghum against various fungal diseases, and the studies successfully mined various sources of sorghum resistance in univariate frameworks [ 10 , 11 , 12 , 13 , 15 , 20 , 28 ]. Examples of candidate defense-related genes through univariate GWAS include F-box domain, helix–loop–helix DNA-binding domain, K05280-flavonoid 3’-monooxygenase, leucine-rich repeat, MADS-box protein, MYB transcription factor, oryzalide A biosynthesis, pentatricopeptide repeat, selenium binding protein and xyloglucan endotransglucosylase [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 28 ]. In addition to univariate GWAS, recent studies have extensively applied multivariate GWAS, identifying new sources of SNPs associated with various traits of interest.…”

“…Prom et al [ 12 , 17 ] evaluated 377 lines from the Sorghum Association Panel (SAP) for grain mold resistance by inoculating them with either A. alternata alone; a mixture of A. alternata , Fusarium thapsinum and Curvularia lunata ; or untreated water as a control group at the Texas A&M AgriLife Research Farm, Burleson County, Texas. Based on the phenotypic data, a univariate GWAS with over 79,000 SNP loci from a publicly available genotype was conducted by sequencing dataset for the SAP lines [ 18 ] using the TASSEL version 5.2.55 [ 19 ] association mapping software to identify chromosomal locations associated with differences in the grain mold response.…”

“…In sorghum pathology, multiple subsets of sorghum populations, including the Sorghum Association Panel (SAP), the Sorghum Mini Core Collection and the Senegalese sorghum population, have been screened against various sorghum diseases such as anthracnose, downy mildew, grain mold and head smut. Still, these studies were performed in a univariate framework [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. The studies measured multiple disease-related traits in the three different populations, and both single-nucleotide polymorphism (SNP) data and phenotypic data are publicly available.…”