Effects of Thickness Fraction Process on Physicochemical Properties, Cooking Qualities, and Sensory Characteristics of Long-Grain Rice Samples

A process of removing thinner kernels of rough rice, i.e., thickness fraction process, has been suggested as a method for increasing milling yields in the rice industry. This study aimed at determining whether physicochemical properties, cooking qualities, and sensory characteristics of rice samples could be changed by the addition of a thickness fraction into the rice process stream. Each of four long-grain rice cultivar lots was assigned into two groups: unfractionated and thickness-fractionated. For the thickness-fractionated group, thin rice kernels (<1.9 mm) of rough rice were discarded from unfractionated rice samples. Unfractionated and thickness-fractionated rice samples were compared with respect to physicochemical properties, cooking qualities, and sensory characteristics. The results showed that the removal of such thin kernels decreased the breakage and chalkiness rates and increased head rice yields. Fractionated rice samples exhibited lower amylose contents and crude protein contents but higher gelatinization temperatures than unfractionated rice samples. While the optimum cooking duration and width–expansion ratios of thickness-fractionated rice samples were higher than those of unfractionated ones, there was a negligible impact of the thickness fraction process on sensory characteristics of long-grain rice samples. In conclusion, the thickness fraction process affects physicochemical properties and cooking qualities more than the sensory characteristics of rice samples.

Evaluation Genetic Variation and Diversity of Grain Yield and Quality Traits in Rice (Oryza sativa L.) Genotypes for Low Input NPK Fertilizers

Determination of genetic variance in a large number of rice genotypes is an effective strategy for increasing yield. The goal of this research was to determine the genetic variability, phenotypic (PCV) and genotypic (GCV) coefficients of variation, broad-sense heritability, expected genetic advance and multivariate analysis for eight rice grain quality and yield traits, in twenty Egyptian and exotic genotypes under low NPK fertilizer input levels at RRTC, Sakha, Kafr El-Sheikh, Egypt and evaluated across two successive seasons. Results revealed highly significant mean squares for all traits. High estimates of both PCV and GCV were detected for grain elongation followed by gelatinization temperature and head rice. High estimates of heritability were noted for grain length, grain shape, hulling, milling, head rice, amylose content, grain elongation and grain yield. Results revealed that highly significant differences among different genotypes were observed for studied characteristics under different NPK levels. Cluster results revealed that genotypes from the same origin or taxonomy type were clustered together. Diversity analysis showed four clusters. Cluster I and III had maximum genotypes (70%) and Cluster IV showed the highest mean values for studied traits. The results revealed that PC1 and PC2 accounted for 65.6% of the diversity between genotypes investigated. These findings show that some genotypes have a lot of diversity, indicating an opportunity to breed for low-input genotypes without sacrificing grain production and quality. GZ10590-1-3-3-2 and IET1444, both of which have high grain yield, can be employed as hybrid parents and could help with further genetic research for reduced NPK input.

Genetic Dissection of Yield Determinants in Advance Breeding Lines (ABLs) of Rice (Oryza sativa L.) under Irrigated Condition of Chhattisgarh, India

The present study was undertaken to study the extent of genetic variability, character association and path analysis in 53 irrigated late duration breeding lines for 12 quantitative and 10 quality parameters. Analysis of variance revealed the presence of significant variation among the breeding lines for all the characters except for total tillers per plant, effective tillers per plant, spikelet fertility percentage and grain yield per plant. The highest magnitude of PCV and GCV were displayed by grain yield per plant followed by harvest index, filled spikelet per panicle and 1000 seed weight. The greater extent of heritability in broad sense were recorded for days to maturity, days to 50% flowering, 1000 seed weight, plant height, total spikelet per panicle, kernel length, kernel L:B ratio, grain length, head rice recovery percentage, amylose content, hulling and milling percentage. However, high heritability coupled with high genetic advance as percent of mean were displayed by plant height, number of spikelet per panicle, filled spikelet per panicle,1000 seed weight, kernel length, kernel L:B ratio, grain length, head rice recovery percentage and amylose content. Grain yield per plant exhibited positive significant correlation with harvest index, effective tillers per plant, 1000 seed weight, spikelet fertility %, days to maturity and days to 50% flowering. Path analysis revealed direct effect on grain yield were exerted by days to 50% flowering followed by harvest index, 1000 seed weight, total tillers per plant, number of spikelet per plant, effective tillers per plant and plant height indicating their importance in rice breeding programs.

Optimization method of microwave drying process parameters for rice

In this work, the optimal process to improve the efficiency of microwave drying of rice is studied. The optimal conditions for reducing the crack rate and improving the head rice rate are analyzed according to the principle of the orthogonal experiment. The optimization method of the rice microwave drying process parameters is proposed to simultaneously consider the two indicators, namely, crack and head rice rates, based on the grey system theory. The grey correlation degree analysis is carried out on the process conditions of the microwave drying rice. The result shows that the main factor affecting the integrity rate of the rice grain is the vacuum degree, and the main factor affecting the crack rate is the loading density. The grey correlation degree curve of head rice and crack rate fluctuates greatly, and the correlation between the two indexes is high. According to the grey correlation degree, the optimal parameters are microwave power of 500 W, vacuum degree of 0.02 MPa, and loading density of 1289.89 kg/m3. The head rice and crack rate are both optimized when drying under the parameters. The results provide a guiding method for the study of the correlation degree between drying indexes and provide a method basis for the further selection of the best drying process.

Rice Response to Sub-Lethal Concentrations of Paraquat, Glyphosate, Saflufenacil, and Sodium Chlorate at Multiple Late-Season Application Timing as Influenced by Exposure

In Mississippi, rice reproduction and ripening often overlaps with soybean maturation creating potential for herbicide exposure from desiccants applied to soybeans onto rice. Six independent studies were conducted concurrently at the Delta Research and Extension Center in Stoneville, MS from 2016 to 2018 to determine the response of rice to sub-lethal concentrations of soybean desiccants during rice reproductive and ripening growth stages. Studies included the desiccants paraquat, glyphosate, saflufenacil, sodium chlorate, paraquat+saflufenacil, and paraquat+sodium chlorate applied at a rate equal to 1/10 of Mississippi recommendations. Treatments were applied at five different rice growth stages beginning at 50% heading (defined as 0 d after heading (DAH)), with subsequent applications at one week intervals (0, 7, 14, 21, and 28 DAH) up to harvest. Injury was observed 7 days after application (DAA) with five of six desiccants at all application timings. No injury was observed with glyphosate application across all rating intervals. Rough rice grain yield following all glyphosate applications was reduced by >6%. In the studies evaluating paraquat injury ranged from 5 to 18% at all evaluations, regardless of application timing. Rough rice grain yield was reduced >12% 0 to 21 DAH, following paraquat application. Similar trends were observed with paraquat+saflufenacil and paraquat+sodium chlorate, with rice exhibiting yield decreases >6% following an application 0 to 14 and 0 to 21 DAH, respectively. In studies evaluating saflufenacil and sodium chlorate rough rice grain yield was >95% of the untreated across all application timings Yield component trends closely resembled reductions observed in rough rice grain yield. Reductions in head rice yield were >5% following applications of paraquat or paraquat+saflufenacil 0 to 14 and 0 to 21 DAH respectively. Late-season exposure to sub-lethal concentrations of desiccant from 50% heading (0 DAH) to 28 DAH has an impact on rough rice grain yield, yield components, and head rice yield.

BRRI Dhan100: A Zinc Enriched Rice Variety Suitable for Irrigated Ecosystem in Bangladesh

Recently released zinc enriched, high yielding, medium slender grain containing rice variety BRRI dhan100, appropriate for irrigated ecosystem of Bangladesh is an improvement over existing zinc enriched rice varieties for Bangladesh. The variety has satisfactorily passed the Proposed Variety Trial (PVT) conducted in the farmers’ field in Boro 2019-20 season. As a result National Seed Board (NSB) approved this variety for commercial cultivation in the Boro season (dry season) in 2021. It has modern plant type with 101 cm plant height and matures by 148 days. The proposed variety showed 1.20 t/ha higher yield than check variety BRRI dhan84. Identifying characters of this variety are green leaf, intermediate plant height, erect flag leaf, medium slender grain, intermediate leaf senescence grain. It can produce 7.7 - 8.8 t/ha grain yield. Thousand grain weight of the variety is 16.7 gm and head rice yield is 64%. The rice has zinc content 25.7 mg/kg, 26.8% amylose content with 7.8% protein content. The zinc enriched BRRI dhan100 is a superb variety for cultivating in the Boro season (dry) and farmers can be economically benefited and the country will be nutritionally benefited by the cultivation of BRRI dhan100.

EFFECT OF TWO STAGE DRYING EMPLOYING FLUIDIZED BED DRYING, TEMPERING FOLLOWED BY FIXED BED DRYING ON HEAD RICE YIELD OF BRRI DHAN28 RICE VARIETY IN BANGLADESH

Drying of high moisture paddy to achieve quality milled rice is an important issue in a paddy producing country like Bangladesh. This study has been conducted to investigate the impact of two stage drying technique namely, fluidized bed drying, tempering and followed by fixed bed drying method on quality of BRRI Dhan28 rice variety in terms of head rice yield (HRY). Moist paddy was dried in fluidized bed dryer (FBD) as first stage drying to reduce moisture from 25-27% to 18-19% using three drying temperatures of 120, 130, and 150°C at three bed thicknesses of 8, 10, and 12 cm. The first stage dried samples were immediately tempered for 30 minutes and dried in second stage drying by fixed bed dryer using 40±10C temperature maintaining bed thickness as 30 cm for the further reduction of moisture content to 13-14% (wb). Sun drying method was followed as complete drying of control sample. Control sample was used to compare the milling quality of rice dried in two stage drying technique. In addition, head rice yield was also compared to existing industrial paddy drying complexes. The results revealed that HRY of rice samples obtained from different drying methods was comparable. All the sets of drying parameters in two stage drying yielded better quality HRY than the control and even existing industrial drying method. The highest HRY (53.43%) of milled rice was obtained in the two-stage drying. On the other hand, the samples dried in the sun drying and industrial drying using Louisiana State University (LSU) dryer yielded 49.77% and 48.25% HRY, respectively. Therefore, the two-stage drying technique can be used for drying of high moisture paddy to obtain quality dried rice.