Researchers utilized multi-locus GWAS to uncover key QTNs and candidate genes associated with agronomic and yield-related traits in Ethiopian sorghum landraces, providing valuable insights for genomics-assisted breeding of resilient, high-yielding varieties.
Keywords: Agronomic traits, Candidate genes, Genetic diversity, ML-GWAS, Quantitative trait nucleotides, Sorghum bicolor
Ethiopia, recognized as a center of origin and genetic diversity for sorghum, presents a rich resource for advancing sorghum breeding programs. The extensive variation among Ethiopian landraces offers valuable insights into the genetic architecture underlying complex traits such as yield, which is influenced by multiple morphological, phenological, and physiological factors. Genomics-assisted breeding (GAB) approaches, particularly genome-wide association studies (GWAS), have emerged as vital tools for dissecting such polygenic traits. Sorghum’s moderate linkage disequilibrium and self-pollinating nature make it especially well-suited for high-resolution mapping. Researchers from Addis Ababa Science and Technology University, Injibara University, Swedish University of Agricultural Sciences and Purdue University applied multi-locus GWAS (ML-GWAS) models, including mrMLM, FASTmrMLM, and others, to identify quantitative trait nucleotides (QTNs) and candidate genes associated with agronomic and yield-related traits in 216 Ethiopian sorghum landraces, aiming to enhance breeding efficiency and crop resilience.
The analysis revealed substantial genetic and phenotypic diversity, with strong trait correlations and significant marker-trait associations. Days to flowering exhibited high heritability (h² = 0.7) and genetic advance, suggesting strong potential for selective breeding, while grain yield showed low heritability, highlighting environmental influence. Among the 351,692 SNP markers initially identified, 50,165 were selected for GWAS, resulting in the detection of 176 QTNs, notably on chromosomes 1, 5, and 8. Key candidate genes such as Sobic.001G196700, Sobic.002G183400, and Sobic.005G176100 were linked to flowering time and stress responses, while others like Sobic.003G324400 and Sobic.004G178300 influenced plant height and seed weight. These findings underscore the importance of integrating ML-GWAS approaches in sorghum improvement, paving the way for the development of climate-resilient, high-yielding varieties through marker-assisted selection.
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The study analyzed 216 sorghum landraces, improved varieties, and checked cultivars collected from various agro-ecological zones in Ethiopia. Phenotypic data were gathered over two cropping seasons, focusing on traits such as days to flowering, days to maturity, plant height, seed number per plant, grain yield, and thousand seed weight.
Using multi-locus Genome-Wide Association Studies (ML-GWAS) models, the research identified 176 QTNs associated with the studied traits. Notably, significant QTNs were found on chromosomes 1, 2, and 3, particularly influencing days to flowering and plant height.
The analysis pinpointed several candidate genes linked to agronomic traits. For example:
Associated with flowering time:
- Sobic.001G196700 (similar to Prolyl carboxypeptidase like protein, putative, expressed)
- Sobic.002G183400 (hypothetical protein)
Associated with stress response:
- Sobic.005G176100 (mannose-6-phosphate isomerase)
Associated with plant height and seed weight
- Sobic.003G324400 (hypothetical protein)
- Sobic.004G178300 (hypothetical protein)
Reference:
Getahun A, Alemu A, Nida H, Woldesemayat AA. Multi-locus genome-wide association mapping for major agronomic and yield-related traits in sorghum (Sorghum bicolor (L.) moench) landraces. BMC Genomics. 2025 Mar 28;26(1):304. PMID: 40155810. doi: 10.1186/s12864-025-11458-4. Read more