Quantification of sorgoleone and assessment of root morphological traits in diverse sorghum accessions

Sorghum exhibits strong allelopathic potential via root exudation of sorgoleone, a lipid benzoquinone. Quantitative differences in sorgoleone production among landraces and varieties, and their links to root morphology, remain insufficiently resolved. This study evaluated eight accessions grown under soil-free conditions, with sorgoleone extracted from 10 days old roots and root traits were quantified. Microscopy confirmed active secretion of hydrophobic droplets from root hairs in all genotypes. Significant genotypic variation (p < 0.05) was recorded for root fresh weight, dry extract and sorgoleone concentration (0.87-6.96 mg g^-1 root fresh weight). Landraces, especially 'Red Sorghum', produced more sorgoleone than varieties, whereas 'K12' was lowest. Correlation analysis showed negligible association between sorgoleone content and gross root morphology, indicating root hair-specific metabolism. These results suggest sorgoleone production is genetically regulated, largely independent of total root biomass, and that high-producing landraces offer promising resources for sorghum-based bioherbicide development and sustainable weed management.