Understanding how environmental factors modulate starch structure and functionality in sorghum is critical for optimizing its application in the food processing and fermentation industries. In this study, two sorghum cultivars with distinct starch types—Liaonian 3 (LN3, waxy) and Liaoza 82 (LZ82, non-waxy)—were cultivated across four major ecological regions in China to systematically investigate the combined effects of temperature and precipitation on grain composition, starch molecular structure, and processing properties. Comprehensive analyses, including scanning electron microscopy, molecular weight profiling, chain-length distribution, crystallinity, molecular order, and thermal/pasting behaviors, demonstrated that precipitation is the predominant environmental factor driving starch biosynthesis and structural assembly. High precipitation levels promoted amylopectin accumulation, shorter chain formation, increased branching degree, and higher crystallinity and molecular order, ultimately enhancing starch thermal stability and paste consistency. Genotypic differences further modulated starch structural patterns and environmental responsiveness, with LN3 consistently exhibiting higher amylopectin content, crystallinity, double-helix proportion, and gelatinization enthalpy compared to LZ82. Correlation analyses revealed genotype-dependent regulatory relationships linking environmental cues to starch structure and processing functionality. These findings provide a comprehensive framework elucidating the environmental regulation of starch structure–function relationships in sorghum, offering theoretical insights for climate-resilient breeding and functional starch development.

Drought stress is one of the most critical abiotic stresses restricting global crop production, and sorghum plays an important role in arid and semi-arid areas due to its inherent drought tolerance compared to many other cereals. However, significant variation in drought tolerance exists among different sorghum genotypes, which provides an opportunity to dissect the underlying mechanisms. In this study, a drought-tolerant sorghum line (LNR-6) and a drought-sensitive line (LR-2381) were used for comparative analysis. Plants were grown under two water regimes: well-watered conditions (CK, soil water content maintained at 40%) and drought stress (soil water content reduced to 24%). Integrated transcriptomic and non-targeted metabolomic analyses were conducted to investigate the physiological and molecular mechanisms underlying sorghum drought tolerance. Phenotypic analysis showed that drought stress significantly reduced plant height and chlorophyll content in the drought-sensitive genotype, whereas the drought-tolerant genotype showed only minor changes. Transcriptome analysis identified several enriched functional categories of differentially expressed genes between the two genotypes under drought stress. Among them, genes associated with limonene and pinene degradation, photosynthesis, and photosynthesis-antenna proteins were significantly enriched and may be involved in drought-response regulation. Metabolomic analysis revealed significant accumulation of flavonoids and phenylpropanoids under drought conditions. KEGG pathway enrichment further indicated that flavone and flavonol biosynthesis, flavonoid biosynthesis, and phenylpropanoid biosynthesis were the most significantly enriched metabolic pathways. Overall, these findings enhance our understanding of the coordinated transcriptional and metabolic responses underlying drought tolerance in sorghum.

Phosphorus fertilization can regulate starch accumulation and quality in cereal grains, but its effects on sorghum starch remain insufficiently understood. This study investigated sorghum cultivar Liaoza 82 under four phosphorus levels: 0, 40, 80, and 160 kg P₂O₅ ha⁻¹. Phosphorus application significantly affected starch accumulation and the activities of starch biosynthesis-related enzymes, including AGPase, GBSS, SSS, and SBE. Moderate phosphorus, particularly 80 kg P₂O₅ ha⁻¹, increased amylose content, granule size, molecular weight, amylopectin branching degree, and medium-to-long amylopectin chains, whereas the highest phosphorus treatment weakened these effects and caused granule surface depressions. Although the A-type crystalline pattern was unchanged, phosphorus modified crystallinity, short-range order, thermal properties, solubility, swelling power, and pasting behavior. Within the phosphorus range investigated, P2 produced a favorable combination of selected structural and thermal characteristics, including lower crystalline order and lower gelatinization temperature and enthalpy, whereas some pasting parameters were highest under P3. These findings indicate that phosphorus fertilization alters sorghum starch structure and functionality, with the response depending on the specific starch characteristic evaluated.

Slightly saline–alkali soils represent an important but underutilized land resource in northern China, and optimizing planting patterns is essential for improving sorghum productivity under such marginal conditions. This study aimed to evaluate the effects of wide–narrow row spacing combined with different planting densities on the canopy structure, photosynthetic performance, and grain yield of brewing sorghum. A field experiment was conducted from 2022 to 2024 at the Yulin Experimental Station in Shaanxi Province, China, using the brewing sorghum cultivar Liaonuo 16. Four planting treatments were established: wide–narrow row spacing (80/60 cm) with three planting densities (105,000, 112,500, and 120,000 plants ha⁻¹) and uniform row spacing (60 cm) with 112,500 plants ha⁻¹ as the control. Wide–narrow row spacing combined with higher planting density significantly improved canopy structure and light interception. The treatment with 120,000 plants ha⁻¹ increased light interception in the middle and lower canopy layers during flowering and grain filling by 8.7% and 25.58%, respectively, and enhanced total canopy light interception by 3.33% and 1.96%. Moreover, the leaf area index and photosynthetic capacity were improved, resulting in a 10.1% increase in grain yield compared with the uniform row spacing treatment. Wide–narrow row spacing combined with a planting density of 120,000 plants ha⁻¹ effectively optimizes canopy structure and enhances sorghum productivity in slightly saline–alkali soils, providing a practical cultivation strategy for improving resource use efficiency in marginal farmlands.