Long-grain Rice Varieties Research Articles

Design and experiment of impeller seed guide device for rice internal suction hole direct seeding device

Multi-grain hole-forming sowing and uniform hole spacing are important agronomic requirements for precise hole-direct seeding of rice.This paper designs a kind of impeller type seed guiding device. The main structural parameters of the impeller seed guide device were analyzed by constructing the kinematics model of the rice seed in the impeller seed guide process. The experiment analysis were carried out with the long-grain rice variety Chuangliangyou 4418 as the seeding object. The optimal structural parameter combination of seeding-guiding device was determined as inner impeller radius 56 mm, blade offset angle 11° and seeding angle 36°. On this basis, the seeding performance test of different seed guiding devices of internal suction seed-metering device was carried out by using rice seeds with different external dimensions. The test results show that the impeller has better cavitation and hole spacing uniformity than the seed guide tube. The average hole diameter is not higher than 21.7 mm, the qualified rate of hole diameter is not lower than 96.1%, and the coefficient of variation of hole spacing is not higher than 10.1%. Compared with the seed guide tube, which is increased by 32%, 16% and 34% respectively, and the average hole distance is about 200 mm in theory.

Impact of the drying air conditions on the milling quality of a long-grain rice variety at different moisture content ranges using a lab-scale dryer

During the harvest season, rice needs to be dried immediately to prevent deterioration. Therefore, the rice industry must have the capacity to dry fast while minimizing the milling quality loss. The aim of this study was to assess the impact of drying processing variables on milling quality and drying duration, at different stages of drying. To this purpose, a thin-layer lab-scale dryer was used at different drying air temperatures, relative humidities (RH), and grain moisture content (MC) ranges. At MC up to 15%, it was possible to dry at a temperature of 47ºC and 27% RH maintaining a low milling quality loss. At lower MC, the drying air temperature should decrease to 35ºC and 50% RH to maintain the milling quality loss low. This condition increases the drying duration (compared with drying at 47ºC). Therefore, a two-stage drying program was proposed, using more severe drying conditions during the first stage (MC up to 15%) and softening the conditions during the final stage (MC from 15 to 13%). This drying program allows decreasing the drying duration, maintaining a low milling quality loss. The implementation of step-wise drying programs is expected to increase the efficiency of the commercial process.

Effect of the drying air conditions on the drying rate and milling quality of a long-grain rice variety

This work aims to study the effect of different drying air conditions on the drying rate and milling quality of a Uruguayan long-grain rice variety. It was observed that increasing the drying air temperature or lowering the drying air relative humidity decreased the milling quality. At temperatures above glass transition, this effect was greater. However, it was possible to dry the rice at a drying rate of up to 3 percentage points of moisture per hour (on a dry basis) maintaining a high milling quality. This was achieved when a 1-hour tempering was performed after drying. At higher drying rates, the milling quality decreased sharply even when tempering was performed. These results aim to contribute to the understanding of the drying process, allowing its optimization by increasing the drying rate without losing milling quality.

Determination of the Drying Kinetics Modeling and Activation Energy of Medium-Grain and Long-Grain Rough Rice under Isothermal Conditions

The available literature revealed a gap in reporting the rough rice drying kinetics parameters under isothermal conditions, particularly for Arkansas medium- and long-grain varieties. Therefore, medium-grain (RO170112 and Titan) and the long-grain (Diamond and Wells) rough rice varieties were dried under isothermal conditions. The drying process occurred under 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, and 100°C in a system emulating the thermogravimetric analyzer. Drying kinetics models were studied for four well-known models: Page, Newton, Logarithmic, and Henderson & Pabis. The drying kinetics constants were determined for the four studied models. The initial moisture content of rough rice was 28.2% db. Profound moisture reduction was observed during the first three hours of drying, followed by less moisture content reduction. The results showed that at the drying temperature of 100°C and after 6 hours of the drying process, the lowest moisture content reached 13.9% (db) for Titan rough rice. The drying rate of rough rice ranged between 7.41 and 2.01%/h during the first hour of drying under the studied temperature range of 40°C to 100°C. The drying rate was higher with the higher temperature levels during the first three hours. Among all the studied models, the Page, Newton, and Logarithmic models best fit 25%, 25%, and 50% of the twenty-eight studied cases. The challenge that arose from these results led to evolving a mathematical solution by joining the three models in one equation. The combined model showed the best fit for all the studied cases, with R2 ranging between 0.9999 and 0.9954 for the medium- and long-grain rice varieties. Increasing the drying temperature increased the effective moisture diffusivity values. The highest effective moisture diffusivity of 18.104 × 10-9 m2/s was obtained at the drying temperature of 100°C for medium-grain rice, Titan. The activation energy values ranged between 17.77 and 24.48 kJ/mol for the four rough rice varieties.

Optimization of selected plant growth regulators on callus induction of Oryza sativa L. var MR 219

MR 219, an indica rice from a cross between MR 137 and MR 151 is a long-grain rice variety of high-yielding, good quality of shape and taste, short maturation as well as resistance to blast and bacterial leaf blight. However, it is regarded as a recalcitrant variety due to its low ratio of callogenesis and regeneration in in vitro culturing. This would be a hindrance to crop improvements such as genetic transformation and other crop improvement methods. The objective of this study was to optimize the concentrations and combinations of plant growth regulators (PGRs) which were 2,4-Dichlorophenoxyacetic acid (2,4-D), Kinetin (KIN) and Naphthalene acetic acid (NAA) on its callus induction that ranging from 0.5 to 15.0 mg/L. The callus was induced from the mature seeds of MR 219 on the Murashige and Skoog (MS) media supplemented with 4.4 g/L of MS powder with vitamins, 30.0 g/L of sucrose and 3.5 g/L of gelrite with the addition of 2,4-D, KIN and NAA in different concentrations and combinations. All media supplemented with 2,4- D had successfully induced the callus and 2.0 mg/L of 2,4-D was the best concentration for the callus induction with a 100% success rate. The addition of 15.0 mg/L of NAA, provided less time taken for callus induction with better callus morphology which resulted in fewer browning problems.

Variability of grain and milled rice quality traits of long-grain rice variety

The article presents results of studying 14 families of longgrain rice variety Sharm, divided into two groups. A detailed assessment of technological indicators of grain and milled rice quality in primary seed production nurseries (P-1 and P-2) is given. Variability and correlation of traits is calculated. The experiment was carried out in the period 2016-2018 under the conditions of a field experiment as a control nursery, on the rice irrigation system of FSBSI “FSC of Rice” (Federal State Budgetary Scientific Institution “Federal Scientific Rice Centre”), Krasnodar. In a group of families with typical plants, significant excess of some technological indicators of grain and milled rice quality was revealed in comparison with the original variety Sharm, entered in the state register in 2013: for example, the weight of 1000 grains of the combined families after rejection was 27.6 g; fracturing is significantly lower - 10.2%; also, in terms of the total milling yield, head rice content, significant excess of the combined families was noted - 67; 92.1 and 59.6%. The variability of the considered technological traits is weak and varies within the range of up to 10%, with the exception of fracturing (CV up to 93%), since it is highly susceptible to weather fluctuations. In both groups of families, a close positive correlation was found between the head rice content in the milled rice and its content in the grain (r = 0.981 and 0.989) and a negative average relationship between fracturing and the total milling yield (r = -0.568 and -0.646, respectively). When rejecting families of the variety Sharm in P-1 and P-2, it is recommended to use, in addition to morphological characteristics, the indicator of the mass of 1000 grains and the grain index (l / b).

Assessment of Rhyzopertha dominica (F.) progeny and feeding damage on rice dried with infrared radiation

Infrared radiation (IR) is a method of drying grains that eliminates insect and microbial pests. It is unknown if IR could cause grains to be more susceptible to insects. Thus, the effects of IR on Rhyzopertha dominica development and feeding damage using long-grain rice varieties, Clearfield XL745 (hybrid) and CL152 (pureline), were examined. Rough rice was dried with three IR intensities: 2.15, 2.83, and 10.84 kW/m2. The number of progeny developed, feeding damage, and frass weight after IR-drying were compared with air-drying methods for rough rice and rice milled to brown rice after drying. Since R. dominica develop internally, X-ray technology was used to examine internal progeny and feeding damage. Progeny development and kernel damage appeared to be more affected by fraction (brown rice) than the cultivar of rice or intensity of IR used, with more progeny produced on brown rice than rough rice. An IR intensity of 10.84 kW/m2 increased the number of overall progeny, the amount of adults, and frass produced on CL152 brown rice. An intensity of 10.84 kW/m2 also increased the amount of larvae observed for both varieties and fractions. The intensity of 10.84 kW/m2, under the conditions of this study, is not recommended for drying rice.

Physicochemical properties of long rice grain varieties in relation to gluten free bread quality

The aim of this study was conducted to determine the breadmaking potential of six long-grain rice varieties (INIAP 14, INIAP 15, INIAP 16, INIAP 17, F09 and F50) and to identify any flour characteristic governing their breadmaking behavior. Pasting parameters, thermal parameters assessed by differential scanning calorimetry and bread quality parameters (specific volume, color, and crumb texture profile analysis) were assessed. Results confirmed the suitability of long-grain rice varieties for breadmaking. Nevertheless, significant differences were observed in flour properties among varieties. A significant correlation was observed between specific volume of the gluten-free bread (GFB) with swelling power (r = 0.71, P < 0.01), breakdown viscosity (r = −0.97, P < 0.01) and conclusion temperature (Tc) of gelatinization (r = 0.81, P < 0.05). Moreover, a strong correlation was found between cohesiveness and properties of rice flour such as peak temperature (Tp) (r = −0.96, P < 0.001), DH (r = 0.71 P < 0.05) and swelling volume (r = 0.82, P < 0.05). The quality characteristics of the gluten-free breads made of long-grain rice flour were comparable to those reported in commercial GFB. INIAP 14 and F09 were the most promising varieties for bakery applications. Results suggested that the most important parameters of rice flour when defining breadmaking performance of GFB would be WBC, SP, SV, Tp, Tc and enthalpy.

A study of Hassawi rice (Oryza sativa L.) in terms of its carbohydrate hydrolysis (in vitro) and glycaemic and insulinaemic indices (in vivo)

A high prevalence of Type 2 diabetes exists in Saudi Arabia. Epidemiological evidence suggests that low glycaemic index (GI) diets reduce diabetes risk. Yet, little is known about the GI of traditional Saudi Arabian staples such as Hassawi rice (HR). HR was evaluated in terms of its GI and insulinaemic index (II). Comparisons were made in vitro assessing glucose released enzymatically. A long-grain rice variety available in both United Kingdom and Saudi Arabia was studied as a comparison. For GI and II measurements, HR, Uncle Ben's rice (UBR) and a standard glucose solution were consumed by healthy subjects (n=13) on seven randomised occasions. Capillary bloods were collected at specific times over 2 h after food intake. Food and Agriculture Organization/World Health Organization protocols were used to determine GI and II. For the in vitro studies, cooked rice was incubated with hydrolytic enzymes under standardised conditions. Samples were taken at t=20 and t=120 min and rapidly available glucose (RAG) and slowly available glucose (SAG) were computed. Values of RAG and SAG were lower for HR compared with their respective values for UBR (P<0.001 and P=0.011, respectively). However, no significant difference was observed for GI (P>0.05) despite a lower insulin response noted for HR (P=0.007). HR had a similar GI to UBR, although a lower insulin response was evident. RAG and SAG values were different for the two rice varieties despite similar GI values. These differences may be important in terms of their metabolic impact and outcome on diabetes.

Comparison of Physicochemical Properties and Starch Structure of Red Rice and Cultivated Rice

Sixteen red rice accessions from the southern United States were studied for their physical, milling, pasting, and thermal properties, chemical composition, and starch fine structure relative to cultivated medium- and long-grain rice varieties. All red rice samples were medium-grain, but their physicochemical properties were different from those of Bengal, a cultivated medium-grain rice. Their apparent amylose and crude protein contents were generally higher, and their amylopectin structure consisted of a higher percentage of the shorter branch chains (DP6-24) and a lower percentage of the longer branch chains (DP25-65). Red rice starch pasting and thermal properties were similar to those of Wells, a long-grain rice cultivar. The red rice samples can be classified into two major clusters according to their kernel properties by hierarchical cluster analysis: one cluster with more resemblance to Wells and another cluster with more resemblance to Bengal. Starch structure and kernel physicochemical properties may offer an alternative way of classifying red rice in addition to phenotypic and genetic indices.

Nutraceutical Concentrations within the Bran of Various Rice Kernel Thickness Fractions

Several important nutraceutical compounds, such as tocotrienols, tocopherols, and oryzanols, can be extracted from rice bran, a by-product of milling. This study was conducted to not only provide information regarding nutraceutical concentrations within the rice kernel based on bran collected from successive milling, but also to determine levels of nutraceutical concentrations across several different thickness fractions. Nutraceutical compounds were measured in the bran from two long-grain rice varieties, Cypress and Drew. Rough rice was separated into three thickness fractions (<1·84, 1·84–1·98, and >1·98 mm) and each fraction milled for three successive 10 s milling durations. Bran was collected from each milling duration of each thickness fraction to allow quantification of the nutraceutical content. Results showed that bran collected from rice milled for longer durations (30 s) had lower levels of tocotrienols and tocopherols compared to bran from shorter milling durations (10 s). The highest concentration of oryzanols was in the rice bran from the first 10 s milling duration. Overall, compared to bran from thinner kernels (<1·84 mm), the bran from thicker kernel fractions contained a higher content of nutraceuticals.

EFFECTS OF VARIETY AND HARVEST MOISTURE CONTENT ON EQUILIBRIUM MOISTURE CONTENTS OF RICE

Equilibrium moisture contents (EMC) of two long-grain rice varieties (Kaybonnet and Cypress) and one medium-grain variety (Bengal) were measured at temperatures of 4, 21, and 38°C with relative humidities (RHs) ranging from 11 to 96%. In addition to temperature and RH, variety was a significant factor affecting rice EMC. Harvest moisture content (HMC) and harvest location did not significantly affect the EMC of rough rice. Rice harvested at a lower moisture content (MC) had lower EMC values than rice harvested at a higher MC when equilibrated to high RHs; however, these differences were primarily attributed to hysteresis effects. An EMC model including temperature, RH, and variety was developed. At most RHs, the EMCs of Bengal, Kaybonnet, and Cypress rough rice were approximately 0.2 to 0.8 percentage points higher than that calculated from the Chung EMC equation. New coefficients of the Chung equation for rough and milled rice are provided.

Utilisation of anther culture in rice (Oryza sativa L.) breeding in Italy

Increasing market demand has led to efforts to select for non-sticky, long-grain rice varieties suited to the Italian environment. The variability of recombinant populations derived from crosses between Italian and USA genotypes was exploited. Together with the conventional breeding methods, in vitro anther culture was used to obtain homozygous lines from crosses more quickly. Moreover, hybrid lines were obtained from crosses otherwise impossible to exploit owing to sterility in the F, generation (namely those resulting from crosses involving semi-dwarf USA varieties). Plant regeneration was obtained from 6 F, hybrids whose parents were chosen for their grain quality or their suitability to the Italian environment. About 5500 plantlets were regenerated. Of these, 1000 were albino, and about 50% of the green ones died after transplanting into soil; 65% of the surviving plants were sterile, so about 1000 progeny were obtained (30-445 for each cross). Progeny with desirable characteristics were evaluated for agronomic traits. On the basis of these results, limits and possibilities of anther-culture breeding in rice are discussed.

Relationship of the Height Rice is Cut to Harvesting Test Parameters

Data were collected from four long-grain rice varieties to develop a relationship between the height at which rice is when combined and the amount of material other than grain (MOG) above the cut. A quadratic equation described the relationship between the MOG ratio (MOG above the cut divided by the total MOG) and the height ratio (height of cut divided by the plant height) with an R2 value of 99.6% and a mean square error of 0.0004.

Effects of Combine Operating Parameters on Harvest Loss and Quality in Rice

Combine tests were conducted in commercial rice fields near Keiser, Arkansas. Data was collected and analyzed for two long-grain rice varieties, Newbonnet and Lemont, over a period of two harvest seasons. The test system used allowed for the collection of the clean grain auger discharge, shoe discharge, and rotor discharge separately and simultaneously. Independent variables tested were field speed (feedrate), material-other-than-grain to grain (MOG/G) ratio, moisture content, rotor speed, and concave clearance. Feedrate was the most important factor affecting combine harvest loss. Material-other-than-grain to grain ratio was the second most important factor affecting loss rates. Moisture content, by itself, was significant only in the Newbonnet variety but affected loss rate in the Lemont variety by influencing feedrate and MOG/G ratio. Rotor speed also influenced loss rates but affected each of the varieties differently. Concave setting was significant in both varieties but to a lesser degree in Newbonnet. Head rice yields from combine-harvested samples and hand-harvested samples followed similar trends. Less than two percentage points of reduction in head rice yield were found in the combine-harvested samples when compared to hand-harvested samples.

Modeling Long-grain Rice Milling Quality and Yield During the Harvest Season

Three mathematical models were developed to predict percent milled rice (PMR), percent head rice (PHR), and field yield (FY) of long-grain varieties as a function of rice moisture content (m.c.) at harvest. The concept of potential yield was used in the model development. The actual yield was equal to the potential yield minus the yield reduction caused by specific weather conditions. The PMR and PHR models were validated using experimental data collected for three long-grain rice varieties from 1987 to l990. The potential FY model was validated using the data reported by Morse et al. (1967) and Bal and Ojha (1975). Predicted PMRs compared well with the experimental data with the average prediction errors of less than 1.9 percentage points. The average differences between the predicted and measured PHRs were less than 2.4 percentage points when rice was harvested between 13 and 24% m.c. Large prediction errors (more than 5 percentage points) were obtained in limited cases where rice was harvested at m.c.s greater than 24% or less than 13%. The predicted FYs compared reasonably well with the experimental data by Morse et al. (1967) and Bal and Ojha (1975) with the average errors of 3.5 and 6.8%, respectively.

Breeding of California long-grain and pearl rice varieties with high yields and good grain quality.

A very early-maturing, intermediate plant height, long-grain rice variety, "Callfornla Bell" (NFD-69), and a very early-maturing, short-stature, pearl rice variety, "Calpearl" (NFD-62 C), were developed by hybridization. Yield trials were carried out with California long-grain, medium-grain and short-grain check varieties. Averaging three years' seeding dates in the Firebaugh breeding nursery, one year's small plot adaptation test in four different rice-growing areas, and one year in a large commercial-scale field of a major rice-growing area, Calpearl came out in the first class with significantly higher yields (>10%) than all check varieties. Averaging early, mid-season and late plantings, Calperal yielded more than 11 tons dried paddy per hectare. California Belle ranked in the second class, but there was no significant yield difference as compared with M-101, a very early-maturing short-stature check variety. Three early-maturing check varieties were included in the third class after Duncan's test. Calpearl had especially high produc-tivity after delayed planting, which makes it attractive as a second crop following winter crops of barley or wheat. Calpearl has a larger grain size than the California short-grain varieties and is the first pearl-type rice with attractive translucent kernels without white belly or chalkiness. California Belle has slender grain, translucence, also without white belly or chalkiness. Chemical analysis on milled rice starch showed that both Californla Belle and Calpearl were typical and met U. S. long-grain and short-grain standards, respectively. Cboked California Bell rice is extremely white with favorable texture and taste. The success of long-graln breeding introduces a new phase in the California rice industry. Indica genes incorporated in Japonica rice have made the highly-productive Calpearl possible.