Haiyan Wei

Silicon is an essential element for enhancing the yield, quality and lodging resistance of rice, which are mainly applied through a base application or foliar application during critical growth stages in current practice. The effect of foliar application of water-soluble silicon fertilizer at different growth stages on rice yield, quality and lodging resistance were studied to screen the optimal spraying period that enhances both high yield and lodging resistance. The experiment used “Nanjing9108 and Nanjing5718” as test materials; three treatment combinations were established, corresponding to the following spraying periods: tillering stage + elongation stage (Si1), tillering stage + elongation stage + grain-filling stage (Si2), elongation stage + grain-filling stage (Si3). Applying with plain water served as the control (CK). The results showed that a foliar application of silicon fertilizer significantly increased rice yields, with the Si2 treatment yielding the best results, increasing the yields of the NJ9108 and NJ5718 by 4.82–5.70% and 4.02–5.29%, respectively, over the two-year period. Foliar silicon fertilization significantly enhanced stem wall thickness and shortened the length of the basal internodes, thereby enhancing the lodging resistance of rice. The lodging resistance of the second basal internodes by 5.52–7.79% for NJ9108 and 4.80–7.15% by NJ5718, while that of the third basal internodes increased by 3.42–4.97% and 5.67–6.76%, respectively. In addition, silicon application treatments exhibited enhanced N uptake at maturity with increases of 6.19–13.56% and 5.37–13.86%, respectively. N use efficiency increased with the number of silicon applications. Silicon application during the grain-filling stage effectively delayed leaf senescence, providing sustained photosynthesis to support dry matter accumulation during the mid-to-late growth stages and further facilitating nitrogen transport and utilization. In summary, the synergistic application of silicon fertilizer during the tillering, elongation, and grain-filling stages is the most effective strategy for achieving the dual objectives of high yield and lodging resistance.

A comprehensive management framework integrating environmental and agronomic factors is critical for stable and resource-efficient rice production. The primary objective of this study was to develop an optimization framework for transplanted rice in Jiangsu Province, China, using a Generalized Additive Model (GAM). The framework was used to quantify the inter-annual stability of optimized management schemes and assess their sensitivity to future climate scenarios. The study evaluated the model’s generalization capability using two cross-validation strategies: Leave-One-Year-Out (LOYO) and Leave-One-Site-Out (LOSO). By predicting the yield of each candidate, the scheme maximizing yield was selected as the annual optimal management practice. Validation results demonstrated robust generalization capabilities across both spatial and temporal dimensions, with the model achieving an R² of 0.66 and an RMSE of 836 kg ha⁻¹ in LOSO validation, and an R² of 0.61 and an RMSE of 848 kg ha⁻¹ in LOYO validation. Analysis of the optimized schemes revealed that transplanting date and seedling age functioned as relatively stable planning benchmarks across years, whereas inter-annual adaptation was achieved primarily through adjustments in planting density and nitrogen inputs. Beyond yield prediction alone, this framework translates interpretable GAM response surfaces into spatially differentiated management prescriptions and highlights both soil-conditioned variable-rate strategies and the distinction between stable and adaptive management components under future climate scenarios.

To investigate the differences in carbon and nitrogen metabolism between superior and inferior grains of southern soft and non-soft japonica rice and their relationships with appearance quality, the metabolic characteristics and appearance quality of superior and inferior grains during the grain-filling stage were compared between the two rice types. The results showed that, compared with non-soft japonica rice, the activities of AGPase and GBSS in superior grains of soft rice were significantly lower, whereas the activities of SSS, SBE, and DBE were significantly higher. The amylose content decreased by 32.68–44.72%, while amylopectin increased by 7.27–10.73%. The limitation in carbon metabolism was more pronounced in inferior grains, and the non-structural carbohydrate content was 9.33–17.33% lower than that in superior grains. In terms of nitrogen metabolism, GS activity decreased whereas GOGAT activity increased in superior grains, resulting in a 6.28–8.38% increase in protein content. The protein content of inferior grains was 1.75–6.44% higher than that of superior grains. In addition, the chalky grain rate and chalkiness degree of superior grains in soft rice were 79.00–481.03% higher than those in non-soft japonica rice, while the increases in inferior grains ranged from 67.51% to 136.31%. Correlation analysis indicated that the chalky grain rate of superior grains was positively correlated with starch content during the early grain-filling stage, whereas the chalkiness degree of inferior grains was positively correlated with protein content. These results suggest that differences in carbon and nitrogen metabolism between grain positions are closely associated with the formation of appearance quality.

This study investigates the material foundations underpinning the variations in appearance quality among different types of japonica rice and within differ

The effects of nitrogen (N) application rates and N topdressing at different leaf growth stages on the yield, N absorption, and utilization of japonica rice cultivar Nanjing 9108 were studied to screen the optimal N management mode for high yield and high N use efficiency. A field experiment was conducted from 2023 to 2024, with nine N regulation treatments (94–351 kg ha⁻¹) established through dynamic allocation of basal, tillering, and topdressing fertilizers. The results showed that with the increase of N application rate, the yield and N use efficiency of Nanjing 9108 first increased and then decreased. At a total N application rate of 270 kg ha⁻¹, the N6 treatment (basal N + tiller N + topdressing at the 13th leaf stage) demonstrated optimal overall performance, achieving the highest yield and N use efficiency. Topdressing at the 13th leaf stage (coinciding with young panicle differentiation) promoted spikelet differentiation and large panicle formation, increasing grains per panicle by 2.36–2.20% compared to other treatments under the same N rate. The N6 treatment exhibited enhanced N uptake and utilization: N accumulation increased by 39.27–67.12% during the elongating to heading stage and by 7.14–62.24% during heading to maturity, while N apparent efficiency and agronomic efficiency rose by 3.51–14.68% and 29.22–58.25%, respectively. At heading, the proportion of high-effective leaf area in N6 was 1.52–7.05% higher than in N4, N5, and N7 treatments, accompanied by a slower leaf area decay rate. These traits provided sustained photosynthetic support for dry matter accumulation in mid-to-late growth stages. Consequently, dry matter accumulation in N6 increased by 5.85–33.44% (elongating to heading) and 0.42–26.98% (heading to maturity), leading to a yield advantage of 3.8–17.2% over other treatments. In summary, the N management strategy combining basal, tiller, and 13th-leaf topdressing at 270 kg ha⁻¹ is most effective for achieving both high yield and high N efficiency in Nanjing 9108.

Mounting labor shortages and rising operational costs are threatening the sustainability of mechanized rice production in Southern China, underscoring the urgent need for innovations that reduce labor inputs during nursery preparation and transplanting. To address these challenges, this study developed an innovative double-blanket seedling tray measuring 120 cm in length—twice that of a conventional tray. Based on this design, experiments were conducted to identify suitable lightweight substrates capable of producing cohesive and structurally stable double-blanket rice seedling mats. Two lightweight substrates—crop straw boards and matrix cotton—were evaluated in comparison to traditional nursery soil. Results demonstrated that, when combined with the nutrient solution “Miao Zhuang Feng”, both lightweight substrates significantly improved seedling quality, transplanting performance, and final yield. Notably, the fresh weight of double-blanket seedlings grown on lightweight substrates was comparable to single-blanket seedlings cultivated in soil while being 47.46% lighter than double-blanket seedlings raised with soil. To optimize double-blanket seedling mat formation and transplanting quality, five seeding densities (300, 360, 420, 480, and 540 g/tray) and four seedling ages (10, 15, 20, and 25 d) were tested using crop straw board as the substrate. The results revealed that optimal combinations varied by condition: 480 and 540 g/tray were suitable for 15-day-old seedlings, 420 g/tray for 20-day-old seedlings, 360 g/tray for 20~25-day-old seedlings, and 300 g/tray for 25-day-old seedlings. Compared with single-blanket seedlings, the double-blanket approach reduced the number of trays required per hectare and the total seedling cultivation and transportation cost by 57.97% and 16.67%. Furthermore, increasing the seeding density from 300 to 360, 420, 480, and 540 g/tray led to additional reductions of 16.31%, 26.24%, 34.75%, and 41.13%, respectively—substantially lowering labor requirements for tray handling and seedling feeding during transplanting.

Lodging is one of the key limiting factors in achieving high wheat yield. The application of plant growth retardants (PGRts) is regarded as an effective practice to prevent lodging. For accurate PGRt selection and the establishment of stable, high-yield production plans, it is essential to make clear the regulation strategies for lodging resistance and yield in PGRts. Field experiments were conducted at two test sites. At the initial jointing stage of wheat, Chlormequat Chloride (CCC) or Uniconazole (S₃₃₀₇) was sprayed. Compared with the control (CK), spraying CCC or S₃₃₀₇ significantly reduced the culm lodging index (CLI) and decreased the lodging rate from 7.1% to 15.6%. CCC was more capable of adjusting plant morphology (reducing plant height and second internode length and increasing stem diameter), while S₃₃₀₇ was more effective in enhancing breaking strength. The contents of GA, IAA, and zeatin nucleoside (ZR) and the activities of lignin-related enzymes (TAL and CAD) were significantly correlated with different stem indicators and CLI. Compared with CK, the yield after spraying CCC or S₃₃₀₇ increased by 6.5% and 6.0%, respectively. CCC mainly enhanced the yield by increasing grain weight per spike and the SPAD value of leaves, while S₃₃₀₇ mainly did so by increasing the number of spikes and the effective leaf area. Moreover, carbon metabolism-related enzymes (Rubisco, SS, and SPS) were significantly positively correlated with the yield. The enzyme activity of CCC was higher at the heading stage, while that of S₃₃₀₇ was higher at the filling stage. Hence, spraying CCC or S₃₃₀₇ can significantly enhance lodging resistance and yield. The optimal PGRts should be selected based on the climate and the growth stage of the wheat.

This study investigates the material foundations underpinning the variations in appearance quality among different types of japonica rice and within different grain positions, thereby providing a theoretical basis for enhancing the quality of soft rice varieties. The experimental results indicate that relative to non-soft rice, soft varieties demonstrate markedly higher levels of chalkiness and reduced transparency in both grain classifications. Structural analyses indicate that soft rice grains, particularly the inferior ones, exhibit lower amylose content along with higher proportions of small starch granules and Fa chains, alongside enhanced crystallinity and short-range order. These characteristics compromise the crystalline integrity and amplify light scattering. Furthermore, the protein network in soft rice is characterized by increased levels of albumin and glutelin, a reduction in prolamin content, and a transition towards α-helix and random coil structures. These changes suggest a diminished integration of starch and protein and introduce spatial limitations. The compounded defects across multiple scales in starch and protein structures are more accentuated in inferior grains, leading to enhanced porosity and optical heterogeneity within the endosperm. This synergistic degradation of starch and protein architectures emerges as the primary mechanism responsible for the relatively poor appearance quality of soft rice.

Objective: This study aims to establish a scientific basis for improving rice quality by investigating the relationship between variations in eating and appearance quality and the starch and protein content in soft and non-soft rice varieties.Methods: Two soft rice varieties, Nanjing 5718 and Nanjing 9108, were compared with two non-soft rice varieties, Huaidao 5 hao and Huajing 5 hao. The study focused on eating and appearance quality, starch and protein content, and how these factors varied between superior and inferior grains within each variety.Results: Compared to non-soft rice, soft rice has some disadvantages in appearance quality, which is characterized by high chalky grain rate and chalkiness degree, and large differences in appearance between superior and inferior grains. This is mainly due to the low proportion of high grain weight grains, low amylose content, abnormal development of starch structure, and large protein bodies with high globulin and glutenin content, which destroys the close accumulation of starch particles, resulting in increased light scattering, increased chalkiness, and reduced transparency. Although the appearance quality of soft rice is not outstanding, its eating quality is extremely excellent, which is embodied in good appearance, high viscosity, good balance, high taste value and low hardness. This superior performance may be due to the high proportion of amylopectin in soft rice, which helps to improve the overall taste. In contrast, the amylose content of non-soft rice is higher, which leads to the increase of rice hardness and the decrease of viscosity. In addition, the gelatinization property of soft rice starch is more favorable, which makes the starch dissolve more in the cooking process, so as to further improve its eating quality.