High-throughput phenotyping coupled with elemental mapping identifies biomarkers for yield and biofuel purity in sweet sorghum

The increasing demand for sustainable biofuels requires high-yielding and easily processable feedstocks; however, the bioenergy potential of sweet sorghum ( Sorghum bicolor L. Moench) remains underexploited due to limited understanding of the interactions among its morphological, physiological, biochemical, elemental, and thermal characteristics. This study employed an integrated high-throughput phenotyping and multi-trait analytical framework to identify robust biomarkers for yield and biofuel quality under diverse nutrient management strategies. Ten treatments, including conventional NPK, nano-NPK, zeolite, press-mud, and bio-neem, were evaluated using a randomized block design with the variety SSV-84. Traits related to plant phenology, yield components, juice quality, elemental composition (EDX), and thermal stability (TGA) were systematically assessed. Among the treatments, T6 combining 75% recommended fertilizer with zeolite (1.5 t ha⁻¹), press-mud (15 t ha⁻¹), and bio-neem (5 kg ha⁻¹) consistently outperformed others, significantly ( p ≤ 0.05) increasing grain yield by 56%, ethanol concentration by 30%, and extract weight by 74% over the control. EDX analysis showed enhanced nitrogen accumulation with reduced trace metals, while TGA revealed improved thermal stability with a multistage degradation profile and a decomposition temperature of approximately 294 °C. Multivariate analyses (PCA, k-means, hierarchical clustering, and chord correlation) confirmed strong associations between T6 and yield- and quality-related characteristics. These findings establish a scalable framework for the early identification of superior bioenergy phenotypes and demonstrate that integrating organic amendments with reduced inorganic inputs can simultaneously enhance agronomic performance, juice quality, and biomass processability, indicating a strategic progression toward a sustainable bioeconomy.