Harvest Moisture Content Research Articles

Impact of Kernel Thickness on Germination and Vigor of Seed Rice

Highlights The impact of kernel thickness grading on seed germination and vigor was explored in medium and low moisture content seeds using two hybrid rice cultivars (RTv7303 & RT7301). Rough rice samples were size fractionated into two thickness fractions (thick >2.03 mm and thin 1.91>>2.03 mm) and dried to 12.5% moisture content (MC) at temperatures of 40°C and 60°C and 25% relative humidity (RH). It was discovered that harvested rice seeds at a medium MC (19% to 21%) and a temperature of 60°C increased seed germination and vigor. Thick kernels outperformed thin kernels in terms of seed germination but were not statistically different when compared to unsorted kernels. ABSTRACT. Rough rice lots harvested on the field contain varying kernel thicknesses within the panicles. These variations influence the drying characteristics of seeds and, thus, the seed germination and vigor. In this study, two hybrid long-grain rice cultivars (RTv 7303 & RT 7301) with harvest moisture contents (HMC) ranging from 19% to 21% and 15% to 17% wet basis (w.b.) for medium and low MC seeds were used, respectively. These rough rice samples were size fractionated into two thickness fractions (thick >2.03 mm and thin 1.91>>2.03 mm), with non-fractionated samples labeled as unsorted or control samples. Kernels from each sub-lot were dried to 12.5% MC at 40°C and 60°C air temperatures and 25% constant relative humidity (RH). Immediately after drying, samples were selected for seed germination and vigor assessments. RTv 7303 had higher seed germination compared to RT 7301, indicating that the two cultivars were genetically different from each other. Thick kernels had significantly higher seed germination (SG) than thin kernels, but there was no significant difference compared to unsorted kernels. Additionally, the percentage points difference between the thick versus unsorted and thin kernels varies from ˜1-pp to 8-pp for low MC seeds and from 2.5-pp to 6-pp for medium MC seeds. The seed vigor index (SVI) difference between the two cultivars is around 3.0 m.% and 1.5 m.% for medium and low MC, respectively. Harvested rice seeds with a medium MC (19% to 21%) and dried at a temperature of 60°C resulted in greater seed germination and vigor. Ultimately, these findings highlight the role of thickness grading in seed assessments. Thus, it was concluded that if the thin kernels could be screened out from the harvested rice lots, seed germination and vigor would increase significantly. Keywords: Rice drying, Rice seed, Seed germination, Seed vigor, Thickness grading.

Жизнеспособность семян и адаптивность раннеспелых гибридов кукурузы в условиях Южного Урала

Abstract. The purpose is to study and identify the best high-yielding with rapid loss of grain moisture during ripening, ecologically plastic and stable corn hybrids adapted to the conditions of the Southern Urals. Methods. The studies were carried out in 2017–2020 in the North Caucasian and Ural regions of the Russian Federation at the earliest and optimal sowing dates, taking into account the temperature regime of the soil. Eight new early-ripening maize hybrids of the FSBSI ARRSI of corn breeding in 2016 were studied. Laboratory seed germination was determined at a temperature of +20 °C according to the method of V. S. Sotchenko and others and by cold germination in filter paper rolls after each year of storage. Field germination was determined by counting the number of seedlings after sowing. Plasticity and stability were calculated according to the method of S. F. Eberhart, W. F. Russel. Results. After four years storage of corn hybrids Nur and Mashuk 170 MV, the laboratory germination of seeds remained at the level of 98–99 % with cold germination. In the conditions of the Ural region, the hybrids Baikal and Mashuk 171 became ecologically plastic and productive, referring to high intensity forms. The hybrids with the lowest grainharvesting moisture for all the years of studying Bilyar 160 (27.0 %) and Ural’skiy 150 (27.5 %) were identified as adapted for growing for grain in the Ural region. Scientific novelty. For the first time, a variety test of new early-ripening maize hybrids bred by FSBSI ARRSI of corn was carried out in two ecological and geographical points. The results of the study of ecological plasticity, adaptability to natural and climatic conditions, yield, harvest moisture content of grain, preservation of the viability of seeds of hybrids during storage will make it possible to identify the most adaptive early-ripening hybrids according to a set of characteristics for the conditions of the Ural region.

The influence of nitrogen and variety on rice grain moisture content dry-down

Rice field management around maturity and harvest are some of the most difficult decisions growers face. Field drainage and harvest timing affect quality, yield, and post-harvest drying costs. These decisions are informed by grain moisture content (MC). Over three years, three sites and three varieties, we studied the field dry-down rate and time to optimal harvest MC. We showed that field-specific parameters significantly affected these characteristics, including rice variety, Nitrogen applied (NA), mid-season N uptake (NU) and dry matter (DM). Increased N and DM is associated with increased MC and thus delays time to harvest. We developed models based on linear regression and nonlinear machine learning (ML) algorithms, including parameters describing these field-specific conditions. Cross validation across the three years provided a realistic expectation of model prediction errors. A linear model with the addition of nonlinear predictors achieved competitive performance compared with more complex and less interpretable ML models. When MC was modeled as a function of days since heading, similar or better accuracy was achieved to using accumulated weather parameters. Moisture content was predicted with mean absolute error of 2.1 %. The predicted time from heading to harvest MC was improved by the inclusion of field-specific parameters (N and variety) from mean absolute error of 6.8 days to 5.7 days. The final linear regression model explained 80 % of the moisture variability in the dataset, and provided estimates of dry-down rates, moisture as a function of time, and time to reach harvest moisture. This study shows the importance of including field-specific parameters when estimating of rice harvest timing, and provides methods to model these effects.

Aging characteristics of rice dried using microwave at 915 MHz frequency

AbstractBackground and ObjectivesRice aging is an intrinsic phenomenon that leads to physicochemical changes in rice kernels. The goal of this study is to determine the physicochemical properties of rice dried using a 915 MHz microwave and then aged. Two rice cultivars, a medium grain cultivar Titan and long grain hybrid cultivar XL753, with a harvest moisture content of 20% ± 1% (wet basis) were used for the study. The rice samples were treated with two different drying methods, natural air drying as control and microwave heating at 915 MHz frequency followed by tempering and natural air cooling at 25°C and 56% relative humidity (RH). Microwave‐dried samples were treated at specific energies ranging from 360 to 630 kJ/kg of initial wet grain mass (kJ/kg‐grain). Head rice samples were stored for 6 months at 4°C and 25°C representing nonaged and aged samples, respectively. Physicochemical properties of the samples were determined.FindingsAged microwave‐dried rice had significantly higher setback viscosity, cooked rice hardness and gumminess, and significantly lower peak viscosity and solid loss than nonaged rice. The changes in the viscosity profiles of aged microwave‐dried rice were generally similar to the trends recorded for aged control rice. Furthermore, aging significantly increased the water uptake and kernel elongation ratio of microwave‐dried rice cultivar XL753 but had no significant impact on rice cultivar Titan. Statistical models indicate that the solid loss of microwave‐dried rice decreases by 0.083% while the final viscosity, kernel elongation ratio, and hardness increase by 30 cP, 0.014, and 41 g respectively, with every degree Celsius increase in aging temperature (between 4°C and 25°C), when all other variables are kept constant. Also, aged microwave‐dried rice that were treated at 360 and 525 kJ/kg‐grain were practically equivalent in terms of hardness and solid loss.ConclusionsNatural aging of microwave‐dried rice (dried at 915 MHz frequency) led to changes in some physicochemical properties which were generally similar to the aging patterns of the control rice. Microwave specific energy of 525 kJ/kg‐grain is recommended for rice drying because it produces rice with desirable drying and aging properties.Significance and NoveltyThis study provides processing recommendations that can be used to select microwave parameters for rice drying, which will achieve desirable rice properties.

Influence of harvest moisture content and milling duration on microwave‐dried rice physicochemical properties

AbstractBackground and ObjectivesHarvest moisture content (HMC) and milling duration are important factors that influence milled rice quality. The goal of this study is to determine the effect of HMC and milling duration on the physicochemical properties of long grain and medium grain microwave‐dried rice. A long‐grain hybrid rice cultivar (XL753) and a medium‐grain rice cultivar (Titan) with initial HMCs of 16%, 18%, and 20% (wet basis) were sourced from rice farms in Arkansas, USA. The rice samples were dried with the 915 MHz industrial microwave at a specific energy of 525 kJ/[kg‐grain]. The control samples were dried with natural air in an equilibrium moisture content chamber set at 25°C and 56% relative humidity. Following drying, the samples were milled at milling durations of 30, 45, and 60 s, and physicochemical properties were determined.FindingsHMC had significant (p < .05) impacts on head rice yield, crude protein content, and final viscosity of microwave‐dried rice for both cultivars. There were strong positive correlations (Titan: 0.86, XL753: 0.88) between HMC and head rice yield and negative correlations (Titan: −0.85, XL753: −0.62) between HMC and final viscosity of microwave‐dried rice. Milling duration significantly influenced the surface lipid content and whiteness index of microwave‐dried rice for both cultivars. Furthermore, milling duration had significant impacts on the starch damage content and trough viscosity of microwave‐dried rice cultivar XL753 but no significant impact on cultivar Titan. Statistical models predicted HMC of 20% and milling duration of 45 and 42 s for processing microwave‐dried rice cultivars Titan and XL753 respectively, to obtain rice with superior characteristics.ConclusionsHMC and milling duration significantly influenced some physicochemical properties of microwave‐dried rice. We recommend that further studies should be conducted on the cooking, sensory, and storage properties of microwave‐dried rice, to provide information on end‐use and consumer acceptability.Significance and NoveltyThis study provides science‐based information that is vital for optimizing the harvesting and processing conditions of rice dried using the 915 MHz industrial microwave.

Assessment of Grain Harvest Moisture Content Using Machine Learning on Smartphone Images for Optimal Harvest Timing.

Grain moisture content (GMC) is a key indicator of the appropriate harvest period of rice. Conventional testing is time-consuming and laborious, thus not to be implemented over vast areas and to enable the estimation of future changes for revealing optimal harvesting. Images of single panicles were shot with smartphones and corrected using a spectral–geometric correction board. In total, 86 panicle samples were obtained each time and then dried at 80 °C for 7 days to acquire the wet-basis GMC. In total, 517 valid samples were obtained, in which 80% was randomly used for training and 20% was used for testing to construct the image-based GMC assessment model. In total, 17 GMC surveys from a total of 201 samples were also performed from an area of 1 m2 representing on-site GMC, which enabled a multi-day GMC prediction. Eight color indices were selected using principal component analysis for building four machine learning models, including random forest, multilayer perceptron, support vector regression (SVR), and multivariate linear regression. The SVR model with a MAE of 1.23% was the most suitable for GMC of less than 40%. This study provides a real-time and cost-effective non-destructive GMC measurement using smartphones that enables on-farm prediction of harvest dates and facilitates the harvesting scheduling of agricultural machinery.

The estimation of the new self-pollinated waxy maize lines and hybrids (Zea mays l. Ceratina)

Though waxy maize is a valuable raw material for the starch industry, its subspecies are still poorly studied. The purpose of the current work was to study the new self-pollinated hybrids and lines of waxy maize according to a complex of economically valuable traits and to identify promising ones for further breeding. The study was carried out at the FSBSI “Agricultural Research Center “Donskoy” in 2019–2020. The objects of research were 40 self-pollinated waxy maize lines and 30 hybrids developed in the Center. They were studied according to a set of economically valuable traits. There have been identified the self-pollinated lines (24/82, 26/18, 26/51, 24/15) with a high kernel productivity of 0.91–2.23 t/ha, low and medium harvest moisture content of kernel (14.0–14.7%), high resistance to lodging (0–4.6% of lodged plants), weak infestation with smut on a natural background (0–5.0% of damaged plants). There have been identified the lines (24/15, 26/18), characterized by a high starch content in matured kernel (69.2% and 69.8%). There have been developed the new waxy maize hybrids (91×93, 103×105), which significantly exceeded the standard hybrid ‘Zernogradsky 282 MB’ both in kernel productivity (on 0.41–0.80 t/ha) and in the yield of amylopectin starch (on 0, 20–0.54 t/ha). The new hybrids were characterized with low harvest moisture content of kernels (13.3–13.9%), resistance to lodging and smut on a natural background. There have been identified the new maize hybrids (91 × 94, 91×93, 91×95) with a high starch content (68.5–68.9%), an average oil content (4.4–4.6%) and protein percentage (12.1–12.2%) in matured kernel.

Effects of Field Processing of Sorghum Grain on Popping Traits

Interest in the use of popped sorghum in food products has resulted in a niche market for sorghum hybrids with high popping quality but little work has been done to assess the relative effects of field processing methods of grain on popping quality. This study evaluated the relative effects of harvest moisture and threshing methods on the popping quality of sorghum grain. A grain sorghum hybrid with good popping quality was produced during two different years in Texas wherein it was harvested at two moisture levels (low and high) and grain was removed from panicles using five different threshing methods (hand, rubber belt, metal brushes and two metal concave bar systems). Years, harvest moisture content and threshing method influenced all three popping quality measurements (popping efficacy, expansion ratio and flake size), but threshing method had an order of magnitude larger effect than either moisture level or year. While many of the interactions were significant, they did not influence the general trends observed. As such, the threshing methods with less direct impact force on the grain (hand and rubber belt) had higher popping quality than those samples threshed with greater impact force on the grain (metal-based systems). The popping quality differences between threshing system are likely due to a reduction in kernel integrity caused by the impacts to the kernel that occurred while threshing the grain. The results herein indicate that field processing of the grain, notably threshing method has significant impacts on the popping quality and should be taken into consideration when grain sorghum is harvested for popping purposes.

Ecological approach in the adapted breeding system of mid-late maize hybrids (FAO 300-399) in the Lower Volga region

The article examines the results of the ecological testing of maize hybrids (FAO 300-399), created in different selective centers of Russia. The volume of nursery ecological testing of hybrids varied in the range of 15-30 titles. Plot area 14.8 m2. The plant density for harvesting in the Saratov region is 45 thousand plants / ha. Repetition three times. The cultivation technique is zonal. The hydrothermal coefficient during the growing season varied from 0.32 to 1.1. The amplitude of variation of the parameters of maize hybrids in the years of research was: plant height - 149.1 ... 268.1 cm; the height of the cob is 37.8 ... 106.0 cm; grain yield - 1.13 ... 8.69 t / ha; harvest moisture content of grain - 9.21 ... 46.85%; the protein content in the grain is 7.16 ... 13.83%. Insignificant coefficients of skewness (As) and kurtosis in most years of research characterize the samples of hybrids as corresponding to the normal distribution. As a result of the research, it has been established that, in terms of grain yield of corn hybrids, hybrids created at the FGBNU «NСZ im. P.P. Lukyanenko», which also feature increased grain moisture during harvesting. Lower costs for drying grain will be required for the cultivation of hybrids Ak – OOO «Agroplasma», OOO «Pioneer Hi-Brad Rus», FGBNU «NСZ im. P.P. Lukyanenko»

СКОРОСТЬ ПОТЕРИ ВЛАГИ ЗЕРНОМ КУКУРУЗЫ В ПЕРИОД СОЗРЕВАНИЯ В ЗАВИСИМОСТИ ОТ ГЕНОТИ-ПА И УСЛОВИЙ СРЕДЫ

High grain moisture during harvesting is a factor that restrains the expansion of corn (Zea mays L.) crops in the Ural region. A decrease in the harvesting moisture content of seeds is achieved by corn breeding for early maturity (early flowering of the ear) and for accelerated moisture loss from grain in the pre-harvesting period. In our study, it was found for the first time that in the conditions of southern Russia under weather conditions that weakly limit moisture losses, the harvesting moisture of corn grain is determined by the rate of pre-harvesting moisture losses while in the Ural region where the weather conditions are periodically unfavorable the moisture losses are mainly due to the early maturity of the studied hybrids. This work aims to identify corn hybrids with an increased rate of moisture loss during grain ripening and to assess this trait under unfavorable hydrothermal conditions. The studies were carried out in 2016-2018 in two contrasting geographical sites, in the foothill zone of the North Caucasus (experimental field of the All-Russian Research Institute of Corn, the settlement Pyatigorskiy, Predgornii District of the Stavropol Territory) and in the northern forest-steppe of the Southern Urals (South Ural GAU, village Miasskoye, Krasnoarmeyskiy District, the Chelyabinsk Province). Six ultra-early corn hybrids (Zea mays L.) Nur, Ross 130 MV, Obsky 140 SV, Kubansky 141 SV, Mashuk 150 MV, Uralskiy 150 and early ripening Bilyar 160 hybrid were involved in the study. The field experiment was arranged in triplicate using a randomized field plot layout (28 m2 plots with a full set of hybrids per plot). The recorded phenological phases were germination, ear flowering and physiological ripeness of grain detected by the corn kernel “black layer” as an indicator of physiological maturity. The corn grain moisture was measured gravimetrically from July 25 to September 11 in the North Caucasus and from August 15 to October 10 in the South Urals. Samples weighting not less than 70 g were dried at 150 °С to a constant weight (a SNOL 58/350 exicator, Elektrotechnika, AB, Republic of Lithuania; a CAS MW-II electronic Weighing Scale, CAS Corporation, Republic of Korea). For analysis, 10 ears of 1.2 to 1.8 kg were collected and completely threshed in three reps. Grain sampling was carried out with a 3-7-day intervals providing 8 to 16 control points. Statistical hypotheses were tested by methods of variance, correlation and regression analysis. It was found that in the northern site, the calendar dates of flowering of the ear occurred in the beginning or end of the third decade of July, that is, 22-36 days later than in the south site. In the conditions of the North Caucasus, flowering occurred in the third decade of June—early July, the grain physiological ripeness was reached from 1 to 7 August, that is, grain maturation and filling in ultra-early maturing hybrids occurred under favorable hydrothermal conditions. Consequently, environmental conditions did not limit the rate of moisture loss in grain, which provided reliable estimates of the differences between hybrids according to the trait. The research revealed significant differences in the rate of moisture loss both between the study sites and the hybrids. In the North Caucasian region, the rate of moisture loss in grain after reaching physiological ripeness varied for hybrids from 0.63 to 0.78 % per day with slight variation over the years. Under higher relative humidity and low air temperature the likelihood of which in the pre-harvest period is high for the Ural region, the rate of moisture loss decreased to 0.21-0.35 % per day, and under favorable hydrothermal conditions it reached only 0.52-0.72 % per day. It has been established that the harvest moisture content of corn grain is associated with two main characteristics of hybrids, i.e., the early maturity and the ability to quickly lose moisture at the final stages of ontogenesis. The contribution of each factor is due to the conditions of grain ripening. I.e., for the south of Russia, grain moisture is largely due to the ability of a hybrid to accelerate moisture losses. On the contrary, in the conditions of the Southern Urals, the early flowering of the ear is of primary importance. Differences between hybrids in the rate of moisture loss under these conditions appear irregularly and are often leveled by the influence of the environment. Therefore, for the northern zone of corn sowing, the corn breeding for its ability to rapidly lose moisture from grain makes sense only in combination with breeding for a short growing season which should be considered as a priority trait when creating adapted hybrids.

GENOTYPE AND ENVIRONMENT INFLUENCE ON THE RATE OF GRAIN MOISTURE LOSS IN CORN DURING RIPENING PERIOD

High grain moisture during harvesting is a factor that restrains the expansion of corn (Zea mays L.) crops in the Ural region. A decrease in the harvesting moisture content of seeds is achieved by corn breeding for early maturity (early flowering of the ear) and for accelerated moisture loss from grain in the pre-harvesting period. In our study, it was found for the first time that in the conditions of southern Russia under weather conditions that weakly limit moisture losses, the harvesting moisture of corn grain is determined by the rate of pre-harvesting moisture losses while in the Ural region where the weather conditions are periodically unfavorable the moisture losses are mainly due to the early maturity of the studied hybrids. This work aims to identify corn hybrids with an increased rate of moisture loss during grain ripening and to assess this trait under unfavorable hydrothermal conditions. The studies were carried out in 2016-2018 in two contrasting geographical sites, in the foothill zone of the North Caucasus (experimental field of the All-Russian Research Institute of Corn, the settlement Pyatigorskiy, Predgornii District of the Stavropol Territory) and in the northern forest-steppe of the Southern Urals (South Ural GAU, village Miasskoye, Krasnoarmeyskiy District, the Chelyabinsk Province). Six ultra-early corn hybrids (Zea mays L.) Nur, Ross 130 MV, Obsky 140 SV, Kubansky 141 SV, Mashuk 150 MV, Uralskiy 150 and early ripening Bilyar 160 hybrid were involved in the study. The field experiment was arranged in triplicate using a randomized field plot layout (28 m2 plots with a full set of hybrids per plot). The recorded phenological phases were germination, ear flowering and physiological ripeness of grain detected by the corn kernel “black layer” as an indicator of physiological maturity. The corn grain moisture was measured gravimetrically from July 25 to September 11 in the North Caucasus and from August 15 to October 10 in the South Urals. Samples weighting not less than 70 g were dried at 150 °С to a constant weight (a SNOL 58/350 exicator, Elektrotechnika, AB, Republic of Lithuania; a CAS MW-II electronic Weighing Scale, CAS Corporation, Republic of Korea). For analysis, 10 ears of 1.2 to 1.8 kg were collected and completely threshed in three reps. Grain sampling was carried out with a 3-7-day intervals providing 8 to 16 control points. Statistical hypotheses were tested by methods of variance, correlation and regression analysis. It was found that in the northern site, the calendar dates of flowering of the ear occurred in the beginning or end of the third decade of July, that is, 22-36 days later than in the south site. In the conditions of the North Caucasus, flowering occurred in the third decade of June—early July, the grain physiological ripeness was reached from 1 to 7 August, that is, grain maturation and filling in ultra-early maturing hybrids occurred under favorable hydrothermal conditions. Consequently, environmental conditions did not limit the rate of moisture loss in grain, which provided reliable estimates of the differences between hybrids according to the trait. The research revealed significant differences in the rate of moisture loss both between the study sites and the hybrids. In the North Caucasian region, the rate of moisture loss in grain after reaching physiological ripeness varied for hybrids from 0.63 to 0.78 % per day with slight variation over the years. Under higher relative humidity and low air temperature the likelihood of which in the pre-harvest period is high for the Ural region, the rate of moisture loss decreased to 0.21-0.35 % per day, and under favorable hydrothermal conditions it reached only 0.52-0.72 % per day. It has been established that the harvest moisture content of corn grain is associated with two main characteristics of hybrids, i.e., the early maturity and the ability to quickly lose moisture at the final stages of ontogenesis. The contribution of each factor is due to the conditions of grain ripening. I.e., for the south of Russia, grain moisture is largely due to the ability of a hybrid to accelerate moisture losses. On the contrary, in the conditions of the Southern Urals, the early flowering of the ear is of primary importance. Differences between hybrids in the rate of moisture loss under these conditions appear irregularly and are often leveled by the influence of the environment. Therefore, for the northern zone of corn sowing, the corn breeding for its ability to rapidly lose moisture from grain makes sense only in combination with breeding for a short growing season which should be considered as a priority trait when creating adapted hybrids.

Impact of specific energy input of a 915 MHz microwave dryer on quality, functional, and physicochemical properties of different rice cultivars

AbstractBackground and objectivesThe 915 MHz industrial microwave has a great penetration depth relative to the 2.45 GHz microwave and holds the potential to achieve one‐pass drying of deeper rice beds within a short drying duration. The objective of this research is to determine the effect of microwave specific energy on the quality, functional, and physicochemical properties of different rice cultivars. Two rice cultivars were used: a medium grain cultivar (Titan) and a long grain hybrid cultivar (XL753) from two different locations (Burdette and Carlisle). Rice samples at harvest moisture content of 20% wet basis were dried using the 915 MHz industrial microwave at specific energies ranging from 360 to 720 kJ per kg of initial wet grain mass (kJ.[kg‐grain]‐1). Rice physicochemical and functional properties were analyzed.FindingsResults indicate that specific energy had a significant effect (p‐value < 0.0001) on moisture removal and head rice yield. On average, increasing specific energy (drying duration 3–4 min, power 4–6 kW) resulted in increased moisture points removed from 2.5% to 7.3% and 3.7% to 7.5% for long grain hybrids and medium grain cultivars, respectively, while head rice yield decreased. Setback and final viscosities increased while peak viscosity decreased with increasing specific energies. Kernel surface lipid and protein content slightly decreased with increasing specific energies, although specific energy did not have a significant effect on these responses. Resistant starch content decreased with increasing specific energy for hybrid rice. Water and oil absorption capacities varied at different specific energies. The most desirable specific energy for moisture removal that maintains rice quality characteristics (relative to control samples) was 525 kJ.[kg‐grain]‐1.ConclusionsThe 915 MHz industrial microwave has the potential to achieve one‐pass drying of rice. A study of the best specific energy for drying different cultivars of rice using this technology is essential to meet the diverse industrial needs for rice drying.Significance and noveltyThis study provides science‐based information on the properties of different rice cultivars dried using the 915 MHz microwave and selection of desirable microwave parameters for rice drying. The technology has a great potential to transform the rice drying industry by decreasing rice drying duration, improving milling yield, and energy efficiency.

Development of Prediction Model for Harvest Moisture Content of Rough Rice Using Meteorological Data and Color Characteristics

HighlightsMoisture content, meteorological data, and leaf color characteristics of rice were investigated by harvest time.The moisture content decreased, and leaf color value increased as days after heading passed.Harvest moisture content prediction models were developed using meteorological data and leaf color.It is necessary to use both leaf color and meteorological data to determine the harvest time.Abstract.In this study, ambient temperature, accumulated temperature, and rice leaf color values were measured before harvest time to develop models for predicting the harvest moisture content (HMC) of short-grain rice. Field tests were conducted on Chuchung and Whang-gum-nu-ri, which are short-grain rice cultivars, at different experimental plots, for four years. As days after heading (DAH) passed, the moisture content (MC) decreased, and leaf color (L*, a*, and b* values) tended to increase. An experimental model that can predict HMC was developed based on the experimental results of 3 years, and the experimental results of the remaining 1 year were used for verification. The coefficient of determination of the HMC prediction model that used ambient and accumulated temperatures was 0.719, and that of the prediction model that used leaf color was as low as 0.418. However, the coefficient of determination of the integrated model that used all the factors, i.e. ambient and accumulated temperatures and leaf color, was as high as 0.915. Therefore, to determine the harvest time using the HMC of rough rice, leaf color, and meteorological data should be used together. Leaf color tended to increase markedly as the DAH increased, but the leaf color values were not similar for the same MC each year. This is because leaf color is influenced not only by MC but also by various cultivation factors such as soil conditions and growth rate during the rice cultivation process. Keywords: Accumulated temperature, Harvest, Harvest moisture content, Leaf color, Rice, Short variety.

Impacts of Specific Power of Microwave at 915 MHz Frequency on Drying and Milling Characteristics of Parboiled Rough Rice

HighlightsThis research investigated the feasibility of using a microwave (MW) set at 915 MHz frequency to dry high moisture content (MC) parboiled rough rice at 44.3% MC dry basis (d.b.).The research evaluated the impacts of specific power delivered during the drying of parboiled rough rice using a MW on post-drying milling characteristics.The volumetric heating phenomenon provided by MW offered a method to quickly remove 23.1% points of moisture from parboiled rough rice in one-pass to a MC of 21.2% d.b., with minimal impacts on the kernel quality.The findings suggest that increased MW specific powers have a positive effect on rice MC reduction but negatively affects the rice milling characteristics, especially the head rice yield.The study recommended that MW specific powers exceeding 2.92 kW.[kg-DM]-1 should not be exceeded during drying of parboiled rough rice to preserve the rice milling yields.ABSTRACT. The objectives of this research were to study the impacts of specific power of MW generated at 915 MHz frequency to dry high MC parboiled rough rice on moisture removal and milling characteristics of the parboiled rough rice. Long-grain rough rice of the cultivar (cv.) Mermentau at harvest MC of 31.6% dry basis (d.b.) was parboiled by soaking at 73°C for 3 h and then steamed at 67 kPa for 10 minutes. Following the parboiling process the sample was subjected to the MW drying. The drying was accomplished at MW specific powers that ranged from 1.10 to 8.77 kW. [kg-DM] -1 and 0.37 to 2.92 kW. [kg-DM] -1 (power per unit dry matter mass of the grain). These treatment levels of MW specific power were varied by heating parboiled rough rice for 2 and 6 minutes (min) at MW powers that ranged from 1 to 24 kW. The process of parboiling increased the rough rice MC to 44.3% dry basis (d.b.). During the MW drying, as the specific power increased, the general tendency was for rough rice final moisture content (FMC), milled rice yield (MRY) and head rice yield (HRY) to decrease while the drying rate increased. Parboiled rough rice samples treated with a specific power of 8.77 kW.[kg-DM] -1 while maintaining specific energy input at 0.29 kWh.[kg-DM] -1 had least-square means FMC, drying rate, MRY and HRY of 19.7% d.b. (S.D ± 1.1%), 12.3% d.b. [min-1] (S.D ± 0.8%) (2 min drying duration), 68.18% (S.D ± 1.70%) and 67.51% (S.D ± 0.73%) respectively. However, treatment at a lower specific power of 2.92 kW.[kg-DM] -1 while maintaining the same specific energy input of 0.29 kWh.[kg-DM]-1) resulted in least-square means FMC, drying rate, MRY and HRY of 21.2% d.b. (S.D ± 0.5%), 3.9% d.b. [min-1] (S.D ± 0.1%) (2 min drying duration), 73.22% (S.D ± 0.84%) and 73.21% (S.D ± 0.21%) respectively. The increased drying rates for treatments with higher specific power was associated with higher treatment powers and shorter treatment durations. Higher specific powers negatively impacted the observed MRY and HRY. The findings suggest that increased MW specific powers have a positive effect on rice MC reduction but above a certain threshold of specific power (2.92 kW.[kg-DM]-1) may negatively affect the milling characteristics of the parboiled rice. When used to dry high MC parboiled rough rice, rice processors should know that there exists an optimum drying rate that if exceeded the milled rice quality is negatively affected thus generating an economic loss to the parboiled rice industry. The volumetric heating phenomenon provided by microwave (MW) offers a means to quickly dry high MC parboiled rough rice. This can translate to considerable economic savings for the rice processor who often experiences low drying rates because of limited drying capacity, especially at peak rice harvest times. When drying rates are optimized, rice processors can expect minimal impacts on the kernel quality which can also be translated to considerable economic savings for the rice processor. Keywords: 915 MHz microwave, Microwave drying, Milling Quality, Parboiled rice, Specific power.

The results and prospects of maize breeding in the Agricultural Research Center “Donskoy”

The current paper has presented the results of breeding work on maize in the Agricultural Research Center “Donskoy”. The three-line and double interlinear middle early and middle ripening maize hybrids of various economic use ‘Zernogradsky 242 MV’, ‘Zernogradsky 282 MV’, ‘Zernogradsky 288 MV’, ‘Zernogradsky 299 MV’, ‘Zernogradsky 354 MV’, ‘Zernogradsky MV’, ‘Stepnyak MV’ were developed and included into the State List of Breeding Achievements from 2006 to 2020. The Competitive Variety Testing has identified a new high-heterosis simple hybrid ‘Zernogradsky 352 MB’ and the new early ripening hybrids ‘Krucha M × KB 215’, ‘Krucha M × SP 56/57’ with low harvesting grain moisture. The main method used to develop maize hybrids was an interline hybridization using heterosis in the first generation (F1 ). There have been determined the priority directions of further breeding, namely early ripeness, grain humidity-transfer intensity during ripening, drought resistance, high starch content in grain. There has been developed new initial material for each direction of breeding. There have been selected the introduced testers (‘Alpha M’, ‘Almaz M’, ‘Aurora S’, ‘Milena M’, ‘Istok S’) to develop early-ripening hybrids. There have been identified the early and middle-early ripening self-pollinated lines ‘C 207’, ‘RD 12’, ‘TVA 308’, ‘PLS 61’, ‘KB 215’, etc., with a high grain humidity-transfer intensity during ripening (0.95–1.30% per day), low harvest moisture content of grain (10.8–13.8%). There have been developed the new self-pollinated waxy maize lines (24/29/5, 25/64/10, 26/8, 26/4, 26/80, 24/28) with 68.1–69.8% of amylopectin starch in grain. There have been identified the new self-pollinated maize lines resistant to water stress (DS 498/217-3, DS 257/85-5, DS 498/203, KB 262, etc.) promising for breeding drought-resistant maize hybrids.

ECOLOGICAL STABILITY MAIZE HYBRIDS RELATIVELY GRAIN YIELD IMPORTANT CONDITION INCREASE IN GROSS PRODUCTION

The relevance of the conducted scientific analysis of long-term data of the competitive test of the State Institution Institute of Grain Crops of the NAAS, regarding the grain yield of maize hybrids, is due to the problems of climate change that has been observed. Due to an increase in air temperature and a long without a frosty period, corn is not only guaranteed to ripen in the Steppe, with timely sowing and harvesting, but also has a harvest moisture content of grain close to the base. Corresponding climate changes motivated the rapid expansion of the territory of corn cultivation in Ukraine, an increase in acreage, gross production, and grain yield of this crop. However, the dangers caused by stress factors of the flight period are increasing, which focuses on the problem of creating hybrids that are resistant to the extreme conditions of the northern Steppe. Due to the determination of the parameters of the tolerant types, models of hybrids were formed and recommended for use in production in the conditions of various ecological territories of Ukraine. The article discusses the results of the progress of the yield of corn hybrids due to breeding improvement, reflected in changes in the actual indicators of grain harvest and harvest moisture of grain caused by climate change and their impact on the elements of crop cultivation technologies. It was determined that under stressful conditions, the grain yield of maize hybrids decreased by an average of 2.9 t / ha, and the harvest moisture content of the grain increased by 1.6%. It was also noted that over the past 25 years, the yield of corn grain in the test, on average for a five-year period, increased from 5.69 (1995-1999) to 7.14 t / ha (2016-2020) with a decrease in the harvest moisture content of grain from 22.4 to 16.1%. In the discussion of the research results, the regularities of the formation of the trait "drought resistance" of hybrids are revealed, the genetic and agrotechnological components of the formation of the trait, their influence on the characteristics of crop cultivation are distinguished. As a result, the value of a hybrid with an average but stable grain yield, which is determined by economic feasibility, is proved, in comparison with high-intensity forms, which are characterized by significant fluctuations. In order to obtain high and stable yields of corn grain in each farm, it is necessary to plan the varietal structure of crops with an assortment of hybrids that have a diverse type of reaction to the variability of environmental conditions.

Characteristics of the new self-pollinated waxy maize lines

The subspecies of waxy maize (Zea mays L. Ceratina) has not been adequately studied, despite the fact that its kernels are considered a valuable raw material in the food and technical industries. The purpose of the current work was to study new self-pollinated waxy maize lines and identify promising maize hybrids with an increased content of amylopectin starch in kernels. The study was carried out in the FSBSI “Agricultural Research Center “Donskoy” in 2017-2019. The initial material was presented by 40 new self-pollinated maize lines (I6) belonging to the waxy subspecies. They were studied according to the set of traits. The highly variable traits were kernels' productivity, plant lodging, blister smut infection, one cob weight (V = 27.4-191.6%); the moderate variable traits were a height of cob attachment, number of cobs per plant, 1000-kernel weight, number of kernels in a row and per cob (V = 10.3-19.0%); the slightly variable traits were harvesting moisture content in kernels, length of the period “sprouts - cobs' flowering”, plant height (V = 2.2-9.6). There have been identified the new lines ‘24/86', ‘25/92(2)', ‘26/8', ‘25/94' with a high content of amylopectin starch in kernels (68.6-69.4%), kernels' productivity (0.96-1.76 t/ha), low harvest moisture content of kernels (13.7-15.1%), high resistance to lodging (0-3.3% of lodged plants), weak infection of blister smut on a natural background (0.4-6, 5% of infected plants), with an average cob attachment height (42-53 cm). The new self-pollinated line ‘27/8' had an average starch content in kernels (68.0%), but was identified by high kernels' productivity (2.70 t/ha) and high values of other economically valuable traits. The results of the structural analysis have shown that the waxy maize lines formed the yields due to the combination of high values of various elements of the grain yield structure. For example, the most productive line ‘26/8' differed in the maximum weight of one cob (93.9 g) and 1000 kernel weight (251 g).

Efecto de la variedad y de la humedad de cosecha en la temperatura de transición vítrea de variedades uruguayas de arroz

The glass transition temperature (Tg) of a material is the range of temperatures where the transition between a glassy and a rubbery state occurs, producing changes that are reflected in its physicochemical properties. The objective of this research is to determine the glass transition curves (Tg vs. grain moisture content) of three Uruguayan rice varieties and assess whether there are significant differences among them. The influence of the harvest moisture content (HMC) is also evaluated. To do this, each rice sample is dried for different periods of time to obtain grain moisture contents (GMC) in a range between 10% and 22% (on a wet basis). The Tg is then measured by differential scanning calorimetry (DSC). The results are compared by applying ANOVA and the Tukey test. It was observed that the Tg increases as GMC decreases for the three varieties studied. The glass transition curves show that there are significant differences among the three varieties in the range of GMC going from 12% to 16%. The HMC did not affect the Tg in the range studied. The results obtained can be applied to optimize the rice drying process, minimizing the formation of fissures.

Genetic markers associated with seed longevity and vitamin E in diverse Aus rice varieties

AbstractVitamin E is known to scavenge lipid peroxy radicals and has a purported role in preventing seed deterioration during storage. In our previous studies using 20 rice varieties from different variety groups, the specific ratio of vitamin E homologues rather than total vitamin E content was associated with seed longevity. To validate this result, we extended the experiment to a rice panel composed of 185 Aus (semi-wild rice) varieties. Seed longevity values were determined through storage experiments at 45°C and 10.9% seed moisture content (MC). Eight types of vitamin E homologues (α-, β-, γ- and δ-tocopherol/tocotrienol) were quantified by ultra-performance liquid chromatography. The theoretical initial viability in NED, Ki, was positively correlated with γ- and δ-tocopherols and negatively correlated with α-tocotrienol. The time for viability to fall to 50% during storage at elevated temperature and relative humidity, p50, was positively correlated with δ-tocopherol. The harvest MC was negatively correlated with all seed longevity traits. Taking this factor into account in a genome-wide association (GWA) analysis, we were able to correct false positives. A consistent major peak on chromosome 4 associated with −σ−1 was detected with a mixed linear analysis. Based on rice genome annotation and gene network ontology databases, we suggest that RNA modification, oxidation–reduction, protein–protein interactions and abscisic acid signal transduction play roles in seed longevity extension of Aus rice. Although major GWA regions were not overlapped across traits, three genetic markers, on chromosomes 1, 3 and 4, were associated with both δ-tocopherol and Ki and two markers on chromosome 1 and 8 were associated with both δ-tocopherol and p50.

Variation in seed longevity among diverse Indica rice varieties.

Background and AimsUnderstanding variation in seed longevity, especially within closely related germplasm, will lead to better understanding of the molecular basis of this trait, which is particularly important for seed genebanks, but is also relevant to anyone handling seeds. We therefore set out to determine the relative seed longevity of diverse Indica rice accessions through storage experiments. Since antioxidants are purported to play a role in seed storability, the antioxidant activity and phenolic content of caryopses were determined.MethodsSeeds of 299 Indica rice accessions harvested at 31, 38 and 45 d after heading (DAH) between March and May 2015 and differing in harvest moisture content (MC) were subsequently stored at 10.9 % MC and 45 °C. Samples were taken at regular intervals and sown for germination. Germination data were subjected to probit analysis and the resulting parameters that describe the loss of viability during storage were used for genome-wide association (GWA) analysis.Key ResultsThe seed longevity parameters, Ki [initial viability in normal equivalent deviates (NED)], −σ−1 (σ is the time for viability to fall by 1 NED in experimental storage) and p50 [time for viability to fall to 50 % (0 NED)], varied considerably across the 299 Indica accessions. Seed longevity tended to increase as harvest MC decreased and to decrease as harvest MC increased. Eight major loci associated with seed longevity parameters were identified through GWA analysis. The favourable haplotypes on chromosomes 1, 3, 4, 9 and 11 enhanced p50 by ratios of 0.22–1.86.ConclusionsThis is the first study to describe the extent of variation in σ within a species’ variety group. A priori candidate genes selected based on rice genome annotation and gene network ontology databases suggested that the mechanisms conferring high seed longevity might be related to DNA repair and transcription, sugar metabolism, reactive oxygen species scavenging and embryonic/root development.