Lodging has limited yield and potential of increasing yield in rice. Lodging could be minimized by increasing the mechanical or physical strength of the rice culm. Silicon (Si) is associated with sturdiness and rigidity. Therefore, the objectives of this experiment were to evaluate the effects and optimum rate of Si application to improve yield, growth, and lodging resistance of MR219, a popular rice variety in Malaysia. Si, in the form of fertilizer, was applied at the onset of reproductive stage as topdressing. All Si-treated plants showed an increase in number of tillers, number of spikelets per panicle, number of effective tillers, percentage of filled spikelets, and weight per panicle in Si-treated plants as compared to control. Lodging resistance was higher in plants treated with Si as shown by bending parameters. Si-treated plants showed significant increase in flag leaf area, chlorophyll content, and Si content.

Lodging is a phenomenon that affects most of the cereal crops including rice, Oryza sativa. This is due to the fragile nature of herbaceous plants whose stems are non-woody, thus affecting its ability to grow upright. Silicon (Si), a beneficial nutrient is often used to toughen and protect plants from biotic and abiotic stresses. Deposition of Si in plant tissues enhances the rigidity and stiffness of the plant as a whole. Silicified cells provide the much needed strength to the culm to resist breaking. Lignin plays important roles in cell wall structural integrity, stem strength, transport, mechanical support, and plant pathogen defense. The aim of this study is to resolve effects of Si on formation of microstructure and regulation of cinnamoyl alcohol dehydrogenase (CAD), a key gene responsible for lignin biosynthesis. Besides evaluating silicon, paclobutrazol (PBZ) a plant growth retartdant that reduces internode elongation is also incorporated in this study. Hardness, brittleness and stiffness were improved in presence of silicon thus reducing lodging. Scanning electron micrographs with the aid of energy dispersive x-ray (EDX) was used to map silicon distribution. Presence of trichomes, silica cells and silica bodies were detected in silicon treated plants. Transcripts of CAD gene was also upregulated in these plants. Besides, phloroglucinol staining showed presence of lignified vascular bundles and sclerenchyma band. In conclusion, silicon treated rice plants showed an increase in lignin content,silicon content and formation of silicified microstructures.

Silicon, a quasi-essential element that is often associated with rigidity and hardiness is an alleviator of biotic and abiotic stresses. Lodging affects the ability of plants especially cereal plants such as rice, Oryza sativa to grow upright, thus reducing yield and increasing harvesting costs. Bending or lodging resistance could be increased by strengthening the rice culm. Here, we tested stage and method of silicon application, each with three levels of treatments to find the right combination to enhance yield and lodging resistance in MR219, a popular rice variety in Malaysia. Application of silicon at the onset of reproductive stage via topdressing improved agronomic and physiological parameters. Plants applied with Si at the reproductive stage by means of topdressing showed a significantly higher leaf area. Number of tillers, weight per panicle and weight of 100 grains were significantly higher when silicon was applied as topdressing at the reproductive stage. Number of spikelets per panicle was significantly higher when silicon was supplied as topdressing or soil incorporation. Percentage of filled spikelets was significantly higher when silicon supplementation was done as topdressing at either reproductive or maturity stages. Mode of application which favoured the increase in soluble lignin and neutral detergent fiber was topdressing and soil incorporation. Meanwhile, cellulose and acid detergent lignin was highest when silicon was applied at the reproductive and maturity stages. Application of silicon at the reproductive stage by means of topdressing was effective in improving growth, yield and stem strength of the rice plant since the method has higher retention time and has residual effect. Foliar application was deemed unsuitable as it can only be applied in minimal amount while showing a temporary effect.

Rice which belongs to the grass family is vulnerable to water stress. As water resources get limited, the productivity of rice is affected especially in granaries located at drought prone areas. It would be even worse in granaries located in drought prone areas such as KADA that receives the lowest rainfall in Malaysia. Spermine (SPM), a polyamine compound that is found ubiquitiosly in plants is involved in adaptation of biotic and abiotic stresses. The effect of SPM on growth,grain filling and yield of rice at three main granaries namely, IADA BLS, MADA and KADA representing unlimited water, limited water and water stress conditions respectively, were tested during the main season. Additinally, the growth enhancer was also tested during off season at KADA. Spermine increased plant height, number of tillers per hill and chlorophyll content in all three granaries. Application of SPM improved yield by 38, 29 and 20% in MADA, KADA and IADA BLS, respectively. Harvest index showed 2.6, 6 and 16% increases at IADA BLS, KADA and MADA, respectively in SPM treated plants as compared to untreated. Except for KADA which showed a reduction in yield at 2.54 tha⁻¹, SPM improved yield at MADA, 7.21 tha⁻¹ and IADA BLS, 9.13 tha⁻¹ as compared to the average yield at these respective granaries. In the second trial, SPM increased the yield to 7.0 and 6.4 tha⁻¹ during main and off seasons, respectively, indicating that it was significantly higher than control and the average yield reported by KADA. The yield of SPM treatments improved by 25 and 33% with an increment of farmer’s income at main and off seasons, respectively. Stomatal width was significantly higher than control at 11.89 µm. In conclusion, irrespective of the tested granaries and rice variety, spermine mediated plots displayed increment in grain yield.

Rice (Oryza sativa L.) is the most important staple food in the South-east Asian region as a dominant portion of global rice supply is produced and consumed here. Rice plant is a high silicon (Si) accumulator. Constitutive deposition of Si in the form of “phytoliths” offers the plant resistance against various pests, pathogens and stresses, and enhances growth and development. In this study, two sources of Si namely calcium silicate (CaSiO₃) and rice husk ash (RHA) were comparatively evaluated for their bio-fertilizing efficiencies on rice plants cultivated under a glasshouse condition. In addition, we added manganese (Mn), as a form of supplemental nutrient and tested it in combination with the two Si sources. A two-factorial pot experiment with Malaysian rice varieties (MR219 and MR253) and Si-based treatment combinations [NPK only (control), NPK + RHA, NPK + CaSiO₃, NPK + RHA + manganese (Mn) and NPK + CaSiO₃+Mn] indicated that soil amendment using both, a renewable and nonrenewable Si compound (with and without Mn) significantly improved the rice yield-related components and yield as compared to the control (Si-free treatment) at P < 0.05. At 100 day after planting (harvest stage), the grain yield per experimental pot (MR219 and MR253 rice varieties) treated with RHA (with and without Mn) showed no significant difference to the plants treated with CaSiO₃ (with and without Mn). Our findings suggest that RHA, an excellent renewable source fetched from rice production system offers an environmentally sound solution for effective Si-based fertilization of rice plants (Malaysian varieties).