Rice Quality Improvement Research Articles

RNA-seq analysis and lipid profiling reveal the competitive regulation of starch and triacylglycerol synthesis during grain-filling stage in tetraploid rice.

Autotetraploid rice is a useful germplasm for polyploid rice breeding in improving nutritional values. Nevertheless, underlying mechanism of starch and lipid accumulation in tetraploid rice caryopsis remains largely unknown. Here, regulatory mode of starch and triacylglycerol (TAG) synthesis during grain-filling stage in diploid and tetraploid indica rice varieties 9311 was investigated. As a result, tetraploid rice exhibited the reduced starch (-13.22 %) and apparent amylose (-24.76 %) contents, increased the in vitro starch digestion percentage. Meanwhile, lipid detection and thin layer chromatography revealed an increase in fatty acids (+15.26 %) and TAG (+28.82 %) contents characterized by a significant increase in the mole ratio of C18:1 and the decrease of C16:0 and C18:2. Moreover, RNA-seq and functional analyses identified that OsAGPL1, encoding a rate-limiting enzyme involved in starch synthesis, was consistently down-regulated. Additionally, two TAG synthesis-associated genes OsSAD1 and OsFATB2 were up-regulated and down-regulated, respectively, which contributed to higher mole ratio of C18:1 and lower ratio of C16:0 in tetraploid rice caryopses. This study proposes a regulatory model of increased lipid and reduced starch synthesis during grain-filling stage and provides three candidate genes for genetic engineering in nutritional quality improvement of autotetraploid rice.

A novel transcription factor OsMYB73 affects grain size and chalkiness by regulating endosperm storage substances' accumulation-mediated auxin biosynthesis signalling pathway in rice.

Enhanced grain yield and quality traits are everlasting breeding goals. It is therefore of great significance to uncover more genetic resources associated with these two important agronomic traits. Plant MYB family transcription factors play important regulatory roles in diverse biological processes. However, studies on genetic functions of MYB in rice yield and quality are rarely to be reported. Here, we investigated a nucleus-localized transcription factor OsMYB73 which is preferentially expressed in the early developing pericarp and endosperm. We generated targeted mutagenesis of OsMYB73 in rice, and the mutants had longer grains with obvious white-belly chalky endosperm appearance phenotype. The mutants displayed various changes in starch physicochemical characteristics and lipid components. Transcriptome sequencing analysis showed that OsMYB73 was chiefly involved in cell wall development and starch metabolism. OsMYB73 mutation affects the expression of genes related to grain size, starch and lipid biosynthesis and auxin biosynthesis. Moreover, inactivation of OsMYB73 triggers broad changes in secondary metabolites. We speculate that rice OsMYB73 and OsNF-YB1 play synergistic pivotal role in simultaneously as transcription activators to regulate grain filling and storage compounds accumulation to affect endosperm development and grain chalkiness through binding OsISA2, OsLTPL36 and OsYUC11. The study provides important germplasm resources and theoretical basis for genetic improvement of rice yield and quality. In addition, we enriches the potential biological functions of rice MYB family transcription factors.

A molecular module improves rice grain quality and yield at high temperatures.

Excessive temperatures during grain filling can compromise endosperm starch biosynthesis and decrease grain quality and yield in rice. However, the molecular mechanisms underlying these remain unclear. Here, we show that heat shock protein OsHsp40-1 interacts with and elevates the ATPase activity of OsHsp70-2 in rice. OsHsp40-1 also interacts with the key starch biosynthetic enzymes OsGBSSI and OsPPDKB and thereby enhances their stability and activity, which is essential for maintaining rice quality and grain yield under moderate high-temperature (HT) conditions. Overexpression of OsHsp70-2 and OsHsp40-1 in rice significantly improved grain quality and yield at HT. Furthermore, a haplotype analysis identified favorable alleles of OsHsp70-2 and OsHsp40-1, which could be used for improving thermotolerance in rice. Collectively, our findings reveal a novel mechanism by which the OsHsp70-2-OsHsp40-1 module ameliorates the effects of HT on starch biosynthesis, providing a new strategy for genetic improvement of rice quality and yield under HT conditions.

Impact of Chinese milk vetch incorporation with reduced chemical fertilizers on the soil properties, rice growth and cadmium uptake in Cd-contaminated paddy fields

Green manure returning can improve soil fertility and crop production, and immobilize heavy metals in the soil. However, limited information is available on the effects of green manure replacing chemical fertilizers on soil properties and crop growth. In this study, we investigated the effects of Chinese milk vetch incorporation with reduced chemical fertilizers on soil properties, rice agronomic traits and cadmium (Cd) accumulation by field experiments, and four treatments were conducted: chemical fertilizer alone (CF), milk vetch alone (MV), milk vetch plus 80% chemical fertilizers (MVCF80), and milk vetch plus 50% chemical fertilizers (MVCF50). The results showed that all milk vetch treatments decreased soil pH and Eh, and increased the SOM, DOC contents and the activities of catalase and urease. The soil DTPA-Cd contents decreased by 20.41%, 18.20%, and 21.22%, and the Cd accumulation in rice root, stem, leaf, and grain decreased by 21.13%-37.62%, 20.74%-39.61%, and 21.91%-43.56% under MV, MVCF80, and MVCF50 treatments, respectively. Additionally, the MVCF80 treatment showed a better rice agronomic traits and grain yield than others. These data revealed the great potential of milk vetch incorporation with chemical fertilizer reduction in decreasing Cd accumulation in rice plants and improving rice quality and yield of Cd-contaminated paddy fields.

Molecular Basis of Lipid Metabolism in Oryza sativa L.

Lipids are the basic biological molecules in plants, serving as glycerolipids for cell membranes and triacylglycerols as an energy source. Fatty acids are the major components of plant lipids. Both lipids and fatty acids significantly influence rice quality. Recent studies, through genetic analysis, have made significant progress in uncovering the functional mechanisms and regulatory pathways of lipid metabolism including the biological synthesis and degradation of fatty acids, glycerolipids, and triacylglycerols in rice. Meanwhile, quantitative trait loci (QTLs) identified by analyzing the natural variations of the composition and contents of lipids and fatty acids have been integrated and represented on 12 chromosomes. Lipids play multifaceted roles in the growth and development and stress response of rice. Through metabolic engineering and gene-editing technologies, significant advancements have been made in improving the lipid content in rice grains. These studies highlight the understanding the of molecular basis of lipid metabolism and lay a substantial basis for the genetic improvement of rice quality.

Creating of novel Wx allelic variations significantly altering Wx expression and rice eating and cooking quality

Granule-bound starch synthase I (GBSSI) encoding gene Waxy (Wx), which largely regulates the amylose content of rice grains, is a master module determining rice eating and cooking quality (ECQ). Fine-tuning amylose level of grains is an ideal strategy to improve rice quality. Through fine editing of Wxa promoter and 5′UTR by CRISPR/Cas9 system, we created 14 types of novel Wx allelic variations, of which MT7 and MT13 were able to alter Wx expression and amylose content of grains. MT7 showed fragment deletion and base insertions in CAAT-boxes, hardly detectable expression levels of GBSSI mRNA and protein, and generated 5.87% amylose in grains. MT13 had fragment deletions in the A-box and the TATA-box, low expression levels of GBSSI mRNA and protein, and generated 9.61% amylose in grains. Besides of the amylose content, MT7 and MT13 significantly reduced protein content and increased lipid content of grains compared with Wxa. A comparison of MT7, MT13 and other allelic lines demonstrated the importance of base insertion around the second CAAT-box and 31bp-deletion following the second TATA-box in modulating Wx expression. Thus, our study generated two novel Wx allelic variations which significantly alter Wx expression and amylose content of rice grains, providing not only new germplasms for soft rice breeding, but also insights into candidate cis elements of Wx.

Improving rice quality through biochar application in China: A meta–analysis

PurposeThis research investigates the effects of biochar application on rice quality through a comprehensive meta-analysis, aiming to elucidate the ambiguous impacts of biochar on rice quality indicators and providing a comprehensive quantitative evaluation to inform sustainable agricultural practices and the practical application of biochar in rice cultivation. Design/methodology/approachUtilizing a systematic meta-analysis, this study extracts 934 pairs of observations from 28 different studies. It integrates data to assess the overarching impact of biochar on rice quality, with a specific focus on ten essential quality indicators: brown rice rate, milled rice rate, head rice rate, chalky rice rate, degree of chalkiness, length-width ratio, amylose content, protein content, gel consistency, and eating quality score. This approach enables a detailed evaluation of how biochar application influences these critical aspects of rice quality. FindingsThe meta-analysis reveals that biochar application notably enhances the processing, appearance, and eating quality score of rice, evidenced by improvements in the brown rice rate by 0.5%, milled rice rate by 1.7%, head rice rate by 6.2%, length-width ratio by 1.4%, and eating quality score by 2.6%. It also substantially reduces the chalky rice rate by 11.1% and the degree of chalkiness by 12.9%. However, the impacts on nutritional indicators, such as amylose content, gel consistency, and protein content, were found to be statistically insignificant. The most favorable effects were observed in heavy loam soil, alkaline soil(pH ≥ 7.5), soil organic content (SOM)＜10 g kg−1, biochar with a pH range of 7–8, high-temperature biochar (≥ 400 °C), and biochar derived from husk and shell. Practical implicationsThis study highlights biochar's potential to improve rice quality, particularly in terms of processing and appearance, without negatively affecting its nutritional profiles. These findings support the utilization of biochar in rice production to improve quality and provide valuable insights for the development of sustainable agricultural practices and effective biochar application guidelines. Originality/valueThis study represents a pioneering effort in agricultural science by systematically quantifying the impact of biochar on key rice quality indicators. It sheds light on the positive effects of biochar in enhancing various aspects of rice quality, underscoring its vital role in promoting sustainable agricultural practices. Through this meta-analysis, the study establishes a foundation for effective biochar usage guidelines in rice cultivation, offering substantial insights and paving new avenues for research into biochar's application in agriculture.

Milk vetch returning combined with lime materials alleviates soil cadmium contamination and improves rice quality in soil-rice system

Milk vetch (Astragalus sinicus L.) returning and lime materials is employed as an effective strategy for remediating cadmium (Cd)-contaminated paddy fields. However, the combined effects of them on alleviating Cd pollution and the underlying mechanisms remain poorly explored. Therefore, this study investigated the impact of these combined treatments on soil properties, iron oxides, iron plaque, mineral elements, and amino acids through a field experiment. The following treatments were employed: lime (LM), limestone (LS), milk vetch (MV), MV + LM (MVLM), and MV + LS (MVLS), and a control (CK) group with no materials. Results demonstrated that treatments significantly decreased soil available Cd by 19.40–32.55 %, 10.20–39.58 %, and 25.36–40.66 % at tillering, filling, and maturing stages compared to CK, respectively. Moreover, exchangeable Cd was transformed into more stable fractions. Compared with individual treatments, MVLM and MVLS treatments further decreased available Cd and exchangeable Cd. Overall, Cd in brown rice was reduced by 18.97–77.39 % compared with CK. And the Cd in iron plaque decreased by 14.12–31.14 %, 24.65–61.60 %, 2.6–38.28 % across three stages. Furthermore, soil pH, dissolved organic carbon, and cation exchange capacity increased, along with 0.22–62.09 % and 0.57–10.66 % increases in free and amorphous iron oxide contents at all stages, respectively. Compared with lime alone, the integration of MV returning facilitated increased formation of Fed, Feo and enhanced the antagonistic effect among grain Ca with Cd; Additionally, it increased AAs in brown rice, improving rice quality and potentially reducing Cd transport. Mantel tests and Partial least squares path modeling revealed a significant positive correlation between Cd in IP and rice Cd uptake and a significant negative correlation between available Cd, Fed and Feo. These findings provide valuable insights into the mechanisms involved in mitigating soil Cd bioavailability using integrated approaches with MV returning and lime materials.

Biochar Application in Combination with No Tillage Enhanced Yield and Grain Quality of Ratoon Rice

Biochar is beneficial as a clean, stable, and efficient soil amendment to improve rice quality and yield. However, there are few reports on the effects of no-tillage in combination with biochar application on rice growth, yield, and quality in regenerative rice systems. This study evaluated rice yield, grain quality, multiple antioxidant enzyme activities, and malondialdehyde content under four treatments: rotary tillage alone, rotary tillage + biochar application, no-tillage alone, and no-tillage + biochar. The results showed that the rice yield under no-tillage alone was 15% lower than that under rotary tillage alone, but that biochar application significantly increased rice yield by 10% and 20% under rotary tillage and no-tillage conditions, respectively, which might be attributed to the fact that biochar application increased panicle number, spikelet number per panicle, grain filling rate, and antioxidant enzyme activities. Additionally, biochar application also increased fine rice rate and protein content, meanwhile reducing chalkiness degree and chalky grain rate in both the main-season rice and ratoon-season rice. These results suggest that biochar application could enhance the yield and grain quality of ratoon rice, thus compensating for the no-tillage-induced yield loss. This study reveals the role of biochar in main-season rice and ratoon rice cultivation, providing a valuable reference for improved fertilizer utilization and cleaner agricultural production.

Improving Rice Quality by Regulating the Heading Dates of Rice Varieties without Yield Penalties.

The heading date, a critical trait influencing the rice yield and quality, has always been a hot topic in breeding research. Appropriately delaying the flowering time of excellent northern rice varieties is of great significance for improving yields and enhancing regional adaptability during the process for introducing varieties from north to south. In this study, genes influencing the heading date were identified through genome-wide association studies (GWAS). Using KenDao 12 (K12), an excellent cultivar from northern China, as the material, the specific flowering activator, OsMADS50, was edited using the genome-editing method to regulate the heading date to adapt to the southern planting environment. The results indicated that the osmads50 mutant line of K12 flowered about a week later, with a slight increase in the yield and good adaptability in the southern region in China. Additionally, the expressions of key flowering regulatory genes, such as Hd1, Ghd7, Ehd1, Hd3a, and RFT1, were reduced in the mutant plants, corroborating the delayed flowering phenotype. Yield trait analysis revealed that the primary factor for improved yield was an increase in the number of effective tillers, although there is potential for further enhancements in the seed-setting rate and grain plumpness. Furthermore, there were significant increases in the length-to-width ratio of the rice grains, fat content, and seed transparency, all contributing to an overall improvement in the rice quality. In summary, this study successfully obtained a rice variety with a delayed growth period through OsMADS50 gene editing, effectively implementing the strategy for adapting northern rice varieties to southern climates. This achievement significantly supports efforts to enhance the rice yield and quality as well as to optimize production management practices.

Genome-wide association mapping of quantitative trait loci for chalkiness-related traits in rice (Oryza sativa L.).

Grain chalkiness directly affects the commercial value of rice. Genes related to chalkiness reported thus far have been discovered in mutants, but it has not been identified whether these genes can be used to improve rice quality by breeding. Therefore, discovering more quantitative trait loci (QTLs) or genes related to chalkiness in the rice germplasm is necessary. This study entails a genome-wide association study on the degree of endosperm chalkiness (DEC) and percentage of grains with chalkiness (PGWC) by combining 1.2 million single-nucleotide polymorphisms (SNPs) with the phenotypic data of 173 rice accessions. Thirteen QTLs for DEC and nine for PGWC were identified, of which four were detected simultaneously for both DEC and PGWC; further, qDEC11/qPGWC11 was identified as the major QTL. By combining linkage disequilibrium analysis and SNP information, LOC_Os11g10170 was identified as the candidate gene for DEC. There were significant differences among the haplotypes of LOC_Os11g10170, and the Hap 1 of LOC_Os11g10170 was observed to reduce the DEC by 6.19%. The qRT-PCR results showed that the gene expression levels in accessions with high DEC values were significantly higher than those in accessions with low DEC values during days 21-42after flowering, with a maximum at 28days. These results provide molecular markers and germplasm resources for genetic improvement of the chalkiness-related traits in rice.

Tradisi Maddoja Bine Dalam Peningkatan Kualitas Padi Terhadap Jual Beli Gabah Perpektif Fiqih Muamalah (Studi Kasus di Takkalasi Kabupaten Barru)

The Maddoja Bine tradition is a longstanding customary practice among the people of Takkalasi, Barru Regency. This tradition, observed by the community, aims to enhance both the production and quality of rice in the context of buying and selling paddy from the perspective of Fiqh Muamalah. Employing a qualitative, descriptive approach, this study conducts an in-depth exploration encompassing all aspects of the field research method, specifically field research. Data collection involves comprehensive interviews, observations, and documentation. The research findings conclude that the Maddoja Bine practice, conducted by the people of Takkalasi once a year during the arrival of the rainy season, is a deeply rooted tradition passed down through generations or from one's ancestors. Some members of the community believe that the Maddoja Bine tradition can increase crop yields and improve rice quality compared to when the tradition is not observed. From the perspective of Fiqh Muamalah, the practice of the Maddoja Bine tradition resulting in high-quality yields enables farmers to reap profits that can recover their investments, as the quality harvests can increase the price of paddy. To avoid transactions prohibited by religious teachings, both parties must adhere to the pillars, conditions, and ethics of trade.

The communities of arbuscular mycorrhizal fungi established by different winter green manures in paddy fields promote post-cropping rice production1

Winter planting green manures in southern China effectively improve soil properties and rice production through microbial community construction. However, the effects of soil communities of arbuscular mycorrhizal fungi (AMF) from different winter planting green manures on the soil properties and post-cropping rice production remain unclear. In this study, the soil AMF communities of three common winter planting patterns in Southern China, winter fallow, winter ryegrass (Lolium multiflorum L.), and winter Chinese milk vetch (Astragalus sinicus L.), were explored and their effects on post-cropping rice production were investigated. Compared with winter fallow, the winter ryegrass and winter Chinese milk vetch patterns could alleviate soil acidification, significantly increase soil AMF spore density, and improve the soil AMF community structure. Based on sterilized soil, rice production indicators such as thousand-seed weight, theoretical yield, and the grain amylose and total sugar contents of rice inoculated with AMF spores from winter Chinese milk vetch soil were 6.68-53.57% higher than those without AMF inoculation. Rice panicle weight, seed setting rate, and theoretical yield were 15.38-22.71% higher in the treatment with AMF spores from winter ryegrass soil than in the treatments with no AMF inoculation. In addition, the protein, amylose, and total sugar contents of rice grains were 14.92, 104.82, and 802.23 mg kg-1, respectively, which were 31.31, 14.25 and 34.47% higher than those without AMF inoculation. The AMF community dominated by Glomus and Acaulospora in winter Chinese milk vetch had a more positive effect on the improvement of rice yield, while the AMF community dominated by Glomus in winter ryegrass soil was more conducive to rice quality improvement. These findings have revealed the critical role of AMF communities from green manure in rice production, which lays the theoretical basis for a promising strategy to promote the sustainable development of southern winter agriculture.

The effect of corn starch and transglutaminase on quality improvement of soybean-based analog rice

The development of soybean-based analog rice is a potential alternative to rice because of its high protein content. However, the soybean-based analog rice has poor physical properties during cooking, so improvements are required. This research aimed to investigate the effects of corn starch and transglutaminase (TGase) additions on the physicochemical properties of soybean-based analog rice. Variation of soybean flour to corn starch ratio (100:0, 80:20, 60:40, and 40:60) and TGase concentrations (0 %, 0.5 %, and 1 %) were applied. The result showed that the soybean-corn starch interaction produced a strong network, decreasing the cooking loss. The addition of corn starch also improved the lightness and whiteness of analog rice. The formulation of 60 % soybean and 40 % corn starch produced analog rice with a balanced macronutrient composition, providing moderate levels of protein, fat, and carbohydrates, a relatively higher ash content, and the most compact and smoothest microstructure. Furthermore, the addition of TGase increased the texture profile of analog rice, reduced water absorption and volume expansion, and significantly prevented cooking losses. Hence, the combination of soybean flour and corn starch, along with the addition of TGase, improved the physicochemical properties, including the high protein content, color, texture, and cooking quality of analog rice.

Genetic Effects of Grain Quality Enhancement in Indica Hybrid Rice: Insights for Molecular Design Breeding

Improving rice quality remains a crucial breeding objective, second only to enhancing yield, yet progress in quality improvement lags behind yield. The high temperature and ripening conditions in Southern China often result in poor rice quality, impacting hybrid rice production and utilization. Therefore, to address this challenge, analyzing the molecular basis of high-quality traits is essential for molecular design breeding of high-quality hybrid rice varieties. In this study, we investigated the molecular basis of grain shape, amylose content, gel consistency, gelatinization temperature, and aroma, which influence rice quality. We discovered that quality related alleles gs3, GW7TFA, gw8, chalk5, Wxb, ALKTT, and fgr can enhance rice quality when applied in breeding programs. Polymerization of gs3, GW7TFA, gw8, and chalk5 genes improves rice appearance quality. The gs3 and GW7TFA allele polymerization increasing the grain’s length-width ratio, adding the aggregation of gw8 allele can further reducing grain width. The chalk5 gene regulates low chalkiness, but low correlation to chalkiness was exhibited with grain widths below 2.0 mm, with minimal differences between Chalk5 and chalk5 alleles. Enhancing rice cooking and eating quality is achieved through Wxb and ALKTT gene polymerization, while introducing the fgr(E7) gene significantly improved rice aroma. Using molecular marker-assisted technology, we aggregated these genes to develop a batch of indica hybrid rice parents with improved rice quality are obtained. Cross-combining these enhanced parents can generate new, high-quality hybrid rice varieties suitable for cultivation in Southern China. Therefore, our findings contribute to a molecular breeding model for grain quality improvement in high-quality indica hybrid rice. This study, along with others, highlights the potential of molecular design breeding for enhancing complex traits, particularly rice grain quality.

Metabolic regulation mechanism of melatonin for reducing cadmium accumulation and improving quality in rice

Melatonin acts as a potential regulator of cadmium (Cd) tolerance in rice. However, its practical value in rice production remains unclear. To validate the hypothesis that melatonin affects Cd accumulation and rice quality, a series of experiments were conducted. The results showed that exogenous melatonin application was associated with reduced Cd accumulation (23–43%) in brown rice. Fourier transform infrared spectroscopy (FTIR) analysis showed that exogenous melatonin affected the rice protein secondary structure and starch short-range structure. Metabolomics based on LC–MS/MS revealed that exogenous melatonin altered the brown rice metabolic profile, decreased fatty acid metabolite content, but increased amino acid metabolite, citric acid, melatonin biosynthetic metabolite, and plant hormone contents. These findings indicate that exogenous melatonin can effectively reduced Cd accumulation and improve rice quality through metabolic network regulation, serving as an effective treatment for rice cultivated in Cd-contaminated soil.

OPTIMASI OPTIMASI PROSES PEMBERSIHAN BERAS: STRATEGI TERAPAN UNTUK PENINGKATAN KUALITAS HASIL PERTANIAN

This community service activity (PKM) aims to introduce and train the community to process their rice harvests using appropriate technology, in the form of a grain peeling machine. The main target of this PKM activity is the people of the Jaya Mandiri Farmers Group in Batu Layang Village RT.04/RW.15, North Pontianak District, who still have limited means for their agricultural activities. The methods applied in this PKM activity are science and technology diffusion, socialization, and active community participation. So that with this PKM activity, the community has gained knowledge and skills in processing their post-harvest rice products, and it is hoped that this can help overcome their productivity problems due to limited agricultural facilities. Cleaning rice not only aims to remove empty grains, dirt and other foreign objects, but also increases the selling value per unit weight, increases the efficiency of drying and processing post-harvest products and extends shelf life. The working principle of the automatic rice cleaning tool is that when the rice is in the main reservoir, it then goes down through a small gap so that when it comes down it is cleaned with a fan so that the dirt stuck to the rice is blown away and the clean rice enters the reservoir section. The construction of this rice cleaning machine is divided into a hoper as a place to input rice, a crankshaft system, while the drive system consists of an electric motor, pulley, belt, pegs, bearings. With this device, the process of cleaning rice can be carried out simply and easily, and the process time, namely cleaning time, is shorter. With a shorter processing time, the production rate per unit time becomes greater. Improving the quality of agricultural products is very important in supporting food security and farmer welfare. One of the key aspects in ensuring the quality of agricultural products is the post-harvest processing process, especially the rice cleaning process. In this context, this research aims to optimize the rice refining process through the implementation of effective applied strategies. This study was conducted through a comprehensive series of laboratory experiments and field tests. Refining methods involving a combination of traditional and innovative technologies were evaluated to find the most efficient strategy for improving rice quality. The research results show that the use of a combination of certain technologies can increase the efficiency of rice cleaning, as well as reduce yield losses and increase the selling value of the product. This research makes a significant contribution to the development of agricultural practices that are sustainable and oriented towards quality results. These findings have direct implications for farmers in increasing the competitiveness of their products in local and global markets, as well as in supporting government efforts to achieve national food security goals.

QTL Analysis for Rice Quality-Related Traits and Fine Mapping of qWCR3.

The quality of rice, evaluated using multiple quality-related traits, is the main determinant of its market competitiveness. In this study, two japonica rice varieties with significant differences in quality-related traits were used as parents to construct two populations, BC3F2 and BC3F2:3, with Kongyu131 (KY131) as the recurrent parent. A genetic linkage map was constructed using the BC3F2 population based on 151 pairs of SSR/InDel polymorphic markers selected between the parents. Grain-shape-related traits (grain length GL, grain width GW, and length-to-width ratio LWR), chalkiness-related traits (white-core rate WCR, white-belly rate WBR, white-back rate BR, and chalkiness rate CR), and amylose content (AC) were investigated in the two populations in 2017 and 2018. Except for BR and CR, the traits showed similar characteristics with a normal distribution in both populations. Genetic linkage analysis was conducted for these quality-related traits, and a total of 37 QTLs were detected in the two populations. Further validation was performed on the newly identified QTLs with larger effects, and three grain shape QTLs and four chalkiness QTLs were successfully validated in different environments. One repeatedly validated QTL, qWCR3, was selected for fine mapping and was successfully narrowed down to a 100 kb region in which only two genes, LOC_0s03g45210 and LOC_0s03g45320, exhibited sequence variations between the parents. Furthermore, the variation of LOC_Os03g45210 leads to a frameshift mutation and premature protein termination. The results of this study provide a theoretical basis for positional cloning of the qWCR3 gene, thus offering new genetic resources for rice quality improvement.

Germination, Physiochemical, and Morphology Changes of TR10 Rice Seeds Irradiated to Filtered and Unfiltered Neutron

In 2020, Sabah’s rice production was 117, 846 metric tonnes with a planted area of 40, 446 ha is relatively low compared to other states such as Selangor, which has 36,004 ha less planted area but can produce up to 159,535 metric tonnes more than Sabah. Low rice production in Sabah has contributed to the shortage of supply. Thus, new varieties could be needed that sufficiently produce yields that comparable to the efforts and cost of rice planting. One of the methods is producing new varieties that probably produce high yields using physical mutagen. From the literature available, gamma and neutrons were found to be the most common agents to increase rice production per unit planting area but used they were used separately. Theoretically, using fast neutron irradiation was found to produce a superior mutant. Thus, this paper aims to study the effect of rice seeds irradiated to both gamma and neutron simultaneous, and compare with neutron alone on the germination rates and physiochemical of rice seeds after the irradiations at different dosages. TR10 rice seeds were irradiated simultaneously to gamma and neutrons in the nuclear reactor core using Pneumatic Transfer System–PTS facility, while irradiation to neutrons alone was performed in a neutron chamber using Beam ports–BP facility at Nuclear Malaysia. The germination study shows a linear decrease as the irradiation doses increase in BP and fail to germinate in PTS. Yet, seeds irradiated in PTS showed no hazardous compounds and a remarkable increase in mineral content in seeds, particularly potassium and magnesium at 14 Gy. Similarly, to the shape of the starch granules in both facilities, the starch structure changes after being exposed to 14 Gy in PTS and 35 Gy in BP. As a result, seeds exposed to neutron alone induced considerably more inclusive effects and may raise growth performance and improve rice quality with optimal neutron dosage range from 7 to 14 Gy.

Improving arsenic and cadmium contaminated paddy soil health and rice quality with plant-animal-based modified biochar: A mechanistic study

Arsenic and cadmium (As/Cd) are toxic elements which negatively impact the health and productivity of rice plants by subjecting them to stress. To address these issues, we developed three biochar amendment materials derived from plant-based corn-stover with iron-magnesium modification (FM@CB), char sourced from animal-based eggshells with iron-magnesium modification (FM@EB), and a blend (1:1, w/w) of both (FM@CEB). Batch adsorption experiment revealed that FM@CB exhibited a Langmuir sorption capacity of 77 mg g−1 for As(III) and 107 mg g−1 for Cd(II). In contrast, FM@EB showed values of 63 mg g−1 for As(III) and 115 mg g−1 for Cd(II), both observed in mixed systems. The exothermic dual adsorption mechanisms could include ion exchange, cation-anion bridging, complexation with surface functional groups, and precipitation processes. Pot trials were conducted, and the findings unveiled a substantial enhancement in rice grain yield with a 2% application of FM@CB, FM@EB, and FM@CEB. Specifically, there was a notable increase of 21.9%, 34.9%, and 37.6%, respectively. Simultaneously, the application led to a reduction in grain As levels by 34.4%, 53.2%, and 42.6%, and grain Cd levels by 48.7%, 71.2%, and 59.9%, respectively, in comparison to the no-amendment control condition. Our study observed a transformation in the soil's microbial community, as beneficial bacterial genera such as Anaeromyxobacter, Citrifermentans, and Desulfovibrio emerged to assist in the detoxification of these metal contaminants. Concurrently, the application of these materials led to a reduction in harmful bacterial genera like Pseudomonas, Flavobacterium, and Massilia. In addition, these amendments decreased the bioavailable As/Cd fractions in the soil and promoted the root-iron-plaque, which effectively sequesters these contaminants, rendering rice quality improvement. Ultimately, the use of these amendments, particularly FM@CEB, holds the promise of protecting rice from harmful metal(loid)s contaminants, increasing yields, and revitalizing the soil. The presence of these unique bacterial genera, especially those capable of detoxifying As/Cd, plays a crucial role in ensuring a healthier and more secure environment for all living organisms.