Rice is an important diet source for the majority of the world’s population, and meeting the growing need for rice requires significant improvements at the production level. Hybrid rice production has been a significant breakthrough in this regard, and the floral traits play a major role in the development of hybrid rice. In grass species, rice has structural units called florets and spikelets and contains different floret organs such as lemma, palea, style length, anther, and stigma exsertion. These floral organs are crucial in enhancing rice production and uplifting rice cultivation at a broader level. Recent advances in breeding techniques also provide knowledge about different floral organs and how they can be improved by using biotechnological techniques for better production of rice. The rice flower holds immense significance and is the primary focal point for researchers working on rice molecular biology. Furthermore, the unique genetics of rice play a significant role in maintaining its floral structure. However, to improve rice varieties further, we need to identify the genomic regions through mapping of QTLs (quantitative trait loci) or by using GWAS (genome-wide association studies) and their validation should be performed by developing user-friendly molecular markers, such as Kompetitive allele-specific PCR (KASP). This review outlines the role of different floral traits and the benefits of using modern biotechnological approaches to improve hybrid rice production. It focuses on how floral traits are interrelated and their possible contribution to hybrid rice production to satisfy future rice demand. We discuss the significance of different floral traits, techniques, and breeding approaches in hybrid rice production. We provide a historical perspective of hybrid rice production and its current status and outline the challenges and opportunities in this field.

An extremely hazardous heavy metal called cadmium (Cd) is frequently released into the soil, causing a considerable reduction in plant productivity and safety. In an effort to reduce the toxicity of Cd, silicon dioxide nanoparticles were chosen because of their capability to react with metallic substances and decrease their adsorption. This study examines the processes that underlie the stress caused by Cd and how SiO₂NPs may be able to lessen it through modifying antioxidant defense, oxidative stress, and photosynthesis. A 100 μM concentration of Cd stress was applied to the hydroponically grown wild rice line, and 50 μM of silicon dioxide nanoparticles (SiO₂NPs) was given. The study depicted that when 50 μM SiO₂NPs was applied, there was a significant decrease in Cd uptake in both roots and shoots by 30.2% and 15.8% under 100 μM Cd stress, respectively. The results illustrated that Cd had a detrimental effect on carotenoid and chlorophyll levels and other growth-related traits. Additionally, it increased the levels of ROS in plants, which reduced the antioxidant capability by 18.8% (SOD), 39.2% (POD), 32.6% (CAT), and 25.01% (GR) in wild rice. Nevertheless, the addition of silicon dioxide nanoparticles reduced oxidative damage and the overall amount of Cd uptake, which lessened the toxicity caused by Cd. Reduced formation of reactive oxygen species (ROS), including MDA and H₂O₂, and an increased defense system of antioxidants in the plants provided evidence for this. Moreover, SiO₂NPs enhanced the Cd resistance, upregulated the genes related to antioxidants and silicon, and reduced metal transporters’ expression levels.

Whole-genome doubling or polyploidy increases plants' tolerance to biotic and abiotic stress. Cadmium (Cd) damages the plant's metabolic system, leading to decreased plant development. The role of tetraploidy and iron nanoparticles (Fe NPs) in minimizing Cd toxicity in rice was investigated in this work. Diploid (E285) and tetraploid (T485) rice lines were treated with Cd (100 μM) and different doses of Fe NPs (0, 10, 25, and 50 mg L⁻¹). The Cd exposure substantially decreased agronomic traits (root and shoot length, shoot and root fresh weight), chlorophyll contents, and antioxidant enzyme activity and increased reactive oxygen species (ROS). The Cd toxicity effect was more pronounced in diploid rice than in tetraploid rice. The application of Fe NPs to Cd-contaminated rice plants reversed the detrimental consequences of Cd in tetraploid and diploid rice cultivars, verified by the substantial upturn in plant growth parameters, chlorophyll contents, decreased ROS, and increased levels of antioxidant enzymes. The Cd uptake was significantly reduced by tetraploidy and Fe NPs, which negatively controlled the expression patterns of Cd transporter genes (like OsNRAMP2 and OsHMA2). The strongest association was seen between diploid rice and cadmium levels in seedlings. Transmission electron microscopy revealed that Cd, especially in diploid rice, caused cell structure damage that Fe NPs and tetraploidy almost repaired. This study demonstrated that tetraploidy and Fe NPs could alleviate Cd toxicity by lowering Cd accumulation, ROS, and cell damage.