Thin Kernel 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.

Reduction of deoxynivalenol, T-2 and HT-2 toxins and associated Fusarium species during commercial and laboratory de-hulling of milling oats

Oats (Avena sativa L.) are well known for their nutritional properties but are susceptible to the growth of different Fusarium fungi resulting in mycotoxin contamination of harvested oats. In this study, oat samples from harvest years 2011 to 2017 were preselected for their suitability as milling oats for food purposes with DON contents below 1750 µg/kg. The reduction of DON, T-2 and HT-2 toxins during the commercial de-hulling process was analysed. While the average reduction for the sum of T-2 and HT-2 toxins in large oat kernels was 85%, the reduction for thin kernels was 66%. The reduction for DON was about 60% and did not differ for the two kernel fractions. In laboratory de-hulling experiments, milling oat samples and de-hulled oat kernels with known DON, T-2 and HT-2 toxin content were correlated with the associated DNA amount of Fusarium graminearum, Fusarium culmorum and Fusarium langsethiae. The reduction of the Fusarium DNA amount after de-hulling was comparable to the reduction of the associated mycotoxins. Notably, the correlation between F. langsethiae DNA amounts and the sum of T-2 and HT-2 toxin contents was R 2 = 0.69 in milling oats and it rose to R 2 = 0.85 in de-hulled oat kernels. In laboratory tests, at least one third of the initial levels of DON and the sum of T-2 and HT-2 toxins could be removed by polishing off the first parts of the outer layers; two thirds remained in the polished oat kernels. These observations indicate that de-hulling alone may not be completely sufficient to remove mycotoxin contamination in oats. These findings are of high importance in the discussion of determining legal maximum levels for DON or the sum of T-2 and HT-2 toxins in intermediate and final products.

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.

Effect of Nitrogen and Seeding Rate on β-Glucan, Protein, and Grain Yield of Naked Food Barley in No-Till Cropping Systems in the Palouse Region of the Pacific Northwest

Barley (Hordeum vulgare L.) has a storied history as a food crop, and it has long been a dietary staple of peoples in temperate climates. Contemporary research studies have focused mostly on hulled barley for malt and animal feed. As such, nitrogen (N) and seeding rate agronomic data for naked food barley are lacking. In this study, we evaluated the effects of N on ß-glucan and protein content, and N and seeding rate on phenotypic characteristics of naked food barley, including grain yield, emergence, plant height, days to heading, days to maturity, test weight, percent plump kernels, and percent thin kernels. Experiments were conducted at two no-till farms, located in Almota, WA, and Genesee, ID, in the Palouse region of the Pacific Northwest from 2016 to 2018. The experiment comprised two varieties (“Havener” and “Julie”), employed N rates of 0, 62, 95, 129, and 162 kg N ha−1, and seeding rates of 250, 310, and 375 seeds/m−2. Increased N fertilization rate was shown to significantly increase all response variables, except β-glucan content of the variety Julie, days to heading, test weight, and percent plump and thin kernels. Increased N fertilization resulted in higher mean grain yield of Havener and Julie in both Almota and Genesee up to 95 kg N ha−1. Havener had higher yields (3,908 kg N ha−1) than Julie (3,099 kg N ha−1) across locations and years. Julie had higher β-glucan (8.2%) and protein (12.6%) content compared to Havener (β-glucan = 6.6%; protein = 9.1%). Our results indicate that β-glucan content is associated with genotype, environmental, and agronomic factors in dryland cropping systems of the Palouse.

Effect of grinding and extraction conditions on the determination of antioxidant activity and phenolic acids in barley

In the present study, the objective was to evaluate the effects of barley kernel size, grind level, and extract solvent on the antioxidant activities associated with total phenolic content and phenolic acid compositions. Three barley varieties (Kindred, Azure, and Tradition), were used and the results showed that with the exception of superoxide anion radical scavenging activity, thin kernel size fraction (2.0 mm) showed much higher antioxidant activities and total phenolic content than those in the 2.4 mm and 2.8 mm fractions when averaged across barley cultivar, grind level, and extract solvent. A similar trend was found for individual phenolic acid compositions among kernel sizes. Simple correlation analysis revealed that total phenolic content showed strong correlation with DPPH· scavenging activity, ABTS + scavenging activity, and reducing power. Generally, fine grind and 80% acetone extract showed averaged highest values in antioxidant activities, total phenolic content, and individual phenolic acid compositions. Stepwise linear regression showed that extract solvent was the most important factor for DPPH· scavenging activity, ABTS + scavenging activity, reducing power, and iron chelating activity. The sum of syringic acid and caffeic acid exhibited a dominant role in explaining the major variation in antioxidant activities except for superoxide anion radical scavenging activity.

Impact of Genotype, Environment, and Malting Conditions on the Antioxidant Activity and Phenolic Content in US Malting Barley

The phenolic content and antioxidant potential of malting barley are important in brewing. The objective of our study was to investigate the effects of barley genotype, growing environment, and malting conditions on the total phenolic content and antioxidant activities of malting barley grown in North America. Eight barley cultivars grown at three locations over three years were used. For the malting study, a single barley cultivar, separated into different kernel size fractions, was germinated for various periods of time and then processed by kilning or freeze-drying. Total phenolic content (TPC) and some of the antioxidant activities, including DPPH, ABTS, and superoxide anion radical scavenging activities, reducing power, and iron (II) chelating activity, were significantly impacted by the barley genotype, growth environment, and their interactions. The TPC and most antioxidant activities were also influenced by malting conditions and were generally higher in the malted barleys of the thin kernel size fraction, four-day germination, and in samples processed by kilning, when compared to the plumper kernel size fractions, one and two days of germination, and freeze-dried samples, respectively. There were interactions between malting parameters, and stepwise regression analysis was used to suggest the contribution of each parameter to the TPC and antioxidant activities.

Predicting Zea mays Flowering Time, Yield, and Kernel Dimensions by Analyzing Aerial Images.

Image analysis methods for measuring crop phenotypes may replace traditional measurements if they more efficiently and reliably capture similar or superior information. This study used a recreational-grade unmanned aerial vehicle carrying a spectrally-modified consumer-grade camera to collect images in which each pixel value is a vegetation index based on the normalized difference between the blue and near infrared wavelength bands (BNDVI). The subjects of the study were Zea mays hybrids with good yield potential grown in 4-row plots. Flights were conducted at least once per week during three successive growing seasons in south-central Wisconsin. Average BNDVI for each plot (genotype) rose steadily through June, peaked in July, and then declined as plants matured. BNDVI histograms changed shape over the season as the canopy concealed soil, became more uniformly green, then senesced. Principal Components Analysis (PCA) captured the change in histogram shape. PC1 represented canopy closure. PC2 represented the mean of the BNDVI distribution. PC3 represented the spread of the distribution. Correlation analysis showed that flowering time correlated with PC2 and PC3 best (r ≈ 0.5) a few days before the event (day in which 50% of the plants exhibited tassels). Three ears were picked from each plot to quantify kernel dimensions by image analysis before each plot was mechanically harvested to determine grain weight per plot. Correlations between this measurement of yield and PC2 were low in June but exceeded 0.4 within 10 days after flowering. Kernel length correlated similarly with PC2. The correlation between PC2 and kernel thickness displayed a similar but inverted time course. These results indicate that greater mid-season BNDVI values correlate positively with yield comprised of tall, thin kernels. Partial least squares regression performed on the BNDVI time courses predicted flowering time (r = 0.54–0.79) and yield (r = 0.4–0.69). This three-year experiment demonstrated that readily available hardware and software can create a phenotyping platform capable of predicting maize flowering time, yield, and kernel dimensions to a useful degree.

Multiscale Modeling of Electromagnetic Telemetry in Layered Transverse Isotropic Formation

Electromagnetic telemetry (EMT) systems are utilized for measurement while drilling to transmit data from borehole to the ground surface during drilling or vice versa. To help predict the successful deployment of the EMT system within complex formation and environmental noise, a reliable numerical algorithm is developed and applied to model the EMT system for directional drilling in layered transverse isotropic (TI) formation. In the telemetry system, the long and thin drill string having three-dimensional trajectory acts as an underground antenna that can be modeled as a thin wire excited by a delta gap voltage/current source near the drill bit. Using the thin wire assumption, the developed algorithm calculates the thin wire kernel in homogeneous uniaxial media with high accuracy to reduce the dimension and complexity of the problem. The mixed-potential form of layered media Green's function and electric field integral equation are used to model the electromagnetic interaction of the drill string and layered TI media. The effect of drilling fluid outside the pipe is modeled using the volumetric equivalence principle. The accuracy and efficiency of the new algorithm are demonstrated by several numerical examples.

Impacts of Kernel Thickness and Associated Physical Properties on Milling Yields of Long-Grain Rice

Abstract. Rice milling yields are impacted by kernel physical properties, which may vary by kernel thickness. Four rice lots, comprising Wells and XL753 long-grain cultivars of both superior and inferior milling yields, were thickness graded into three fractions: thin ( 2.05 mm). Milled rice yield (MRY), head rice yield (HRY), rough-rice bulk density (I b ), and both brown-rice chalky area (chalkiness) and fissured-kernel percentage (FKP), were determined for each lot and fraction. The MRYs of thick kernels exceeded those of thin kernels for all lots, and those of medium kernels for inferior lots. The HRYs of thick kernels were less than those of medium kernels, significantly so for inferior lots. For all lots, medium kernels had greater HRYs than thin kernels. Thick kernels had greater HRYs than thin kernels for three of the four lots evaluated. Overall, I b increased, and chalkiness decreased, with increasing kernel thickness. The FKP varied by cultivar, increasing with increased thickness for only the Wells lots. Using uni-variate linear modeling, I b effectively predicted MRY (R 2 =0.91, P 2 =0.14, P 2 =0.25, P 2 =0.24, P 2 =0.46, P b , chalkiness, and FKP, improved the prediction of MRY (R 2 =0.93, P 2 =0.83, P

Impacts of Thickness Grading on Milling Yields of Long-Grain Rice

Abstract. As kernel dimensional-variability can adversely affect milling yield and quality of rice, limited thickness-grading to remove thin kernels was evaluated. Along with unfractioned (UNF) rice, rough rice was mechanically sieved, resulting in two thickness fractions, Thick (> 2 mm) and Thin (

Influence of Different Interpolation Techniques on the Determination of the Critical Conditions for the Onset of Dynamic Recrystallisation

Accurate modeling of dynamic recrystallization (DRX) is highly important for forming processes like hot rolling and forging. To correctly predict the overall level of dynamic recrystallization reached, it is vital to determine and model the critical conditions that mark the start of DRX. For the determination of the critical conditions, a criterion has been proposed by Poliak and Jonas. It states that the onset of DRX can be detected from an inflection point in the work hardening rate as a function of flow stress. The work hardening rate is the derivative of the flow stress with respect to strain. Flow curves are in general measured at a certain sampling rate, yielding tabular stress-strain data, which are per se not continuously differentiable. In addition, inevitable jitter occurs in measured flow curves. Hence, flow curves need to be interpolated and smoothed before the work hardening rate and further derivatives necessary for evaluating the criterion by Poliak and Jonas can be computed. In this paper, the polynomial interpolation originally proposed by Poliak and Jonas is compared to a new approach based on radial basis functions using a thin plate spline kernel, which combines surface interpolation of various flow curves and smoothing in a single step. It is shown for different steel grades that the interpolation method used has a crucial influence on the resulting critical conditions for DRX, and that a simultaneous evaluation by surface interpolation might yield consistent critical conditions over a range of testing temperatures.

A method for identifying oat varieties with improved resistance to oat crown rust from a series of field trials

Oat crown rust is a fungal disease caused by pathogen Puccinia coronata f. sp. avenae. Crown rust reduces oat yield and causes thin kernels with low weight. In Polish trials on spring oat one of the compulsory observed characteristics is resistance to oat crown rust. In the present work, the generalized linear mixed model with several variance components is applied to model the resistance to oat crown rust in series of oat trials. The answer to the question which oat varieties tested in two consecutive years 2009 and 2010 in Polish post registration trial system are the best in terms of resistance to crown rust was searched for.

Genetic Architecture Underlying Kernel Quality in Food‐Grade Maize

ABSTRACTKernel quality of food‐grade maize (Zea mays L.) impacts the quality of the final product and is related to dry matter loss during the alkaline cooking process. Kernel size, density, and endosperm hardness are the main kernel characteristics that determine kernel quality. Insight into the genetics governing food‐grade kernel quality parameters and the influence of environment on them was gained through a series of genetic experiments. We initially characterized kernel quality in a breeding cross involving two white food‐grade maize inbred lines, SD79 and SD80. Two hundred forty F2:3–derived lines, the two parental inbred lines, and the F1 were grown in replicated trials at one location. Test weight, 50‐kernel weight, and percentage of thin kernels were measured and then compared with data collected from the Stenvert hardness test assay. Using these kernel quality parameters five high‐quality (H) and five low‐quality (L) lines were identified. The five H lines and five L lines were subsequently used in a H × H, L × L, and H × L mating scheme to examine the genetic effects governing the main kernel quality parameters (test weight, kernel size, and kernel weight). The 45 hybrids from the combination of the two partial diallels and the NC Design II mating scheme were grown in replicated trials at three locations. In general, the inheritance of test weight, kernel weight, and kernel size is influenced primarily by additive genetic effects.

Summit oat

Mitchell Fetch, J. W., Brown, P. D., Ames, N., Chong, J., Fetch, Jr., T. G., Haber, S. M., Menzies, J. G., Tekauz, A., Townley-Smith, T. F. and Stadnyk, K. D. 2011. Summit oat. Can. J. Plant Sci. 91: 787–791. Summit is a white-hulled spring oat (Avena sativa L.) cultivar postulated to carry the crown rust resistance combination Pc38, Pc39, Pc48, and Pc68, which was effective against the prevalent pathotypes of crown rust on the Canadian prairies at the time of its release. It has very good resistance to loose and covered smut, moderately good resistance to most of the prairie stem rust races (likely due to the presence of Pg2 and Pg13) and is resistant to moderately resistant to barley yellow dwarf virus (BYDV). Summit has good kernel weight, percent plump kernels, and percent thin kernels. Summit exhibits high yielding capacity in the oat growing areas of western Canada. Summit was registered (Reg. No. 6529) in Canada 2008 November 29.

Stainless oat

Mitchell Fetch, J. W., Brown, P. D., Ames, N., Chong, J., Fetch, Jr., T. G., Haber, S. M., Menzies, J. G., Townley-Smith, T. F. and Stadnyk, K. D. 2011. Stainless oat. Can. J. Plant Sci. 91: 357–361. Stainless is a grey-hulled spring oat (Avena sativa L.) cultivar postulated to carry the crown rust resistance gene, Pc91, which was effective against the prevalent pathotypes of crown rust races on the Canadian prairies at the time of its release. Stainless could possibly also carry one or more of the crown rust resistance genes, Pc38, Pc39, and Pc68. It had very good resistance to loose and covered smut, good resistance to the prairie stem rust races (likely due to the presence of Pg2, Pg13, and Pga) and moderate tolerance to barley yellow dwarf virus (BYDV). Stainless had high kernel weight, intermediate percent plump kernels, intermediate percent thin kernels, and high levels of total dietary fibre. Stainless exhibited high yielding capacity in the eastern portion of the Black soil zone of western Canada where resistance to rust diseases is important. Stainless was supported for registration by the Prairie Grain Development Committee in February 2007. Stainless was registered (Reg. No. 6422) on 2008 Apr. 07.

Jordan oat

Jordan is a high-yielding, white-hulled spring oat (Avena sativa L.) cultivar postulated to carry the crown rust resistance combination Pc38, Pc39, and Pc68, which was effective against the prevalent pathotypes of crown rust races on the Canadian prairies at the time of its release. It has very good resistance to loose and covered smut, moderately good resistance to most of the prairie stem rust races (likely due to the presence of Pg2 and Pg13) and moderate tolerance to barley yellow dwarf virus (BYDV). Jordan has high kernel weight, high percent plump kernels, and low percent thin kernels. Jordan exhibits high yielding capacity in the oat growing areas of western Canada. Jordan was supported for registration at the Prairie Grain Development Committee Meeting in February 2005. Key words: Oat, Avena sativa L., cultivar description, yield, milling oat

Furlong Oat

Furlong is a high-yielding, tan-hulled oat (Avena sativa L.) cultivar postulated to carry the crown rust resistance combination Pc38, Pc39 and Pc68, which is effective against most of the current crown rust races on the Canadian prairies. It has very good resistance to loose and covered smut, good resistance to stem rust (likely due to Pg2 and Pg13) and moderate tolerance to barley yellow dwarf virus (BYDV). Furlong has very high kernel weight, high percent plump kernels and low percent thin kernels. According to its grain characteristics, including hull-to-groat ratio, protein content and milling yield, Furlong should be acceptable for milling purposes. Furlong is adapted for the oat-growing areas of western Canada and in particular the Black Soil Zone of Manitoba and Saskatchewan, where oat crown rust is prevalent. Key words: Oat, Avena sativa L., cultivar description, milling oat

Effects of relative time of emergence and density of wild oat (Avena fatua L.) on oat quality

Selective control of wild oat with herbicides is not possible in oat (Avena sativa L.) crops and, consequently, the high quality that is imperative to market success is continually jeopardized. Field experiments were conducted to determine the effects of relative time of emergence and density of wild oat on oat kernel size and weight. Thousand-kernel weight and percentage plump kernels were generally reduced, and percentage thin kernels were generally increased with increasing wild oat densities and earlier wild oat emergence. However, reductions were generally small and occurred only at the highest wild oat densities, which are not commonly observed in commercial fields. These findings suggest that oat growers should not control wild oat based on perceived reductions in oat physical grain quality. Key words: Competition, emergence, physical grain quality, test weight, 1000-kernel weight

High frequency scattering by a conducting ring

Asymptotic formulae are derived for the Fourier coefficients of the thin wire kernel in the integral equation for the electric current on an electrically large, thin circular loop. The total current induced on the ring by a plane electromagnetic wave is approximated by a modified physical optics term proportional to the incident field, plus resonant terms of lossy circulating waves. Numerical evaluation of the dominant poles and residues of the ring transfer function provides the amplitudes and complex propagation constants of these natural modes.

Influence of Kernel Maturity, Milling Degree, and Milling Quality on Rice Bran Phytochemical Concentrations

ABSTRACTRice bran is a rich source of phytochemicals including tocopherols (T), tocotrienols (T3), and γ‐oryzanol that have purported positive effects on human health. The screening of germplasm to determine the genetic diversity influencing contents of these compounds requires knowledge of how sample preparation influences concentrations of the phytochemicals in rice bran. Obtaining this knowledge was the objective of this study. Cultivars with different milling qualities were all milled to different degrees. The differences in bran removal among cultivars decreased as the milling time increased. Samples that were milled for 30 and 40 sec (milled to the degree of 0.23–0.44% surface lipid content [SLC]) showed no significant differences in T and T3 concentrations in the bran within cultivars. Bran starch concentration affected the rankings of cultivars based on phytochemical contents. Expression of the γ‐oryanol concentration in bran after subtracting starch reduced the concentration differences resulting from differences in degree of milling (DOM). Bran from the mature thin kernels had phytochemical contents similar to that of the mature thick kernels milled for 30 sec. The immature thin kernels had significantly lower contents of most of the bran phytochemicals than did the mature kernel fractions.