Insight into root system architecture of buckwheat through genome-wide association mapping-first study

Buckwheat, a valuable nutraceutical crop, is predominantly cultivated in low-input marginal farming systems and faces productivity challenges due to abiotic stresses, including drought. Roots play a crucial role in stress tolerance and nutrient acquisition. This study aimed to comprehensively investigate the root system architecture (RSA) of 117 buckwheat genotypes, including Fagopyrum esculentum and Fagopyrum tataricum, using phenotypic and genomic analyses. Plants were grown under controlled conditions, and root traits were analyzed using high-resolution scanning and image analysis. Phenotypic analysis revealed significant variability in root traits, with F. tataricum displaying superior RSA attributes compared to F. esculentum. Genome-wide association studies identified 73 significant quantitative trait loci (QTLs) associated with 27 traits, primarily related to RSA. High-density genotyping using the genotyping-by-sequencing approach enabled the identification of single nucleotide polymorphism and candidate genes within a 100-kb region surrounding these QTLs. Correlation analyses highlighted key traits such as root surface area, root volume, and branching frequency, which influence stress tolerance. This pioneering study provides valuable insights into the genetic basis of RSA in buckwheat. Identified QTLs and candidate genes offer potential for marker-assisted breeding to develop drought-resilient, high-yielding buckwheat varieties. These findings contribute to improving buckwheat's productivity and stress adaptation, supporting its role in sustainable agriculture and global food security.