The Ionome–Hormone–Flavonoid Network Shapes Genotype-Dependent Yield Adaptation in Sugarcane

Sugarcane productivity varies widely among genotypes, but the biochemical traits underlying these differences remain poorly characterized. In this study, six contrasting sugarcane cultivars were profiled to investigate how ionomic, hormonal, flavonoid, and photosynthetic pigment signatures are associated with yield and sucrose accumulation. Morphological traits and field performance revealed marked genotypic variation, with ZZ14 and GL1215 achieving the highest yields and sugar content, while GT59 and GT60 performed less favorably. Multivariate analyses of ionomic data showed that potassium, magnesium, and calcium were consistently enriched in high-yield cultivars, whereas sodium, boron, and manganese were negatively associated with growth traits. Hormone profiling revealed that high-yielding genotypes utilize diverse strategies: while the high-yielding GL1215 achieved superior sugar content with the lowest levels of growth-promoting hormones, the LT1790 genotype, despite having the highest levels of these hormones, showed suboptimal yield due to a costly trade-off with its hyperactive defense system. Flavonoid analysis indicated that LT1790 contained the highest levels of Quercetin, rutin, and caffeic acid, suggesting enhanced antioxidant capacity, whereas GT59 preferentially accumulated chlorogenic acid. Canonical correlation analysis confirmed that nutrient balance and metabolite composition strongly correlated with plant height, stem diameter, and sugar concentration. Together, these results suggest that high-yield sugarcane genotypes achieve a superior metabolic balance, combining efficient nutrient uptake and robust antioxidant capacity with a favorable hormone profile that promotes strong growth without triggering a costly constitutive defense system.