Novel Ha Locus,Pina‐D1c/Pinb‐D1h,Affects Soft White Spring Wheat Milling and Baking

Wheat (Triticum aestivum L.) grain hardness is controlled by the Hardness locus on chromosome 5D which consists of the linked genes Puroindoline a and b (Pina and Pinb, respectively). The Ha locus haplotype, Pina‐D1a/Pinb‐D1a, is found in all soft hexaploid wheats. While Pin diversity is low among soft wheats, several novel Ha haplotypes were reported among synthetic hexaploid wheats created using the D genome donor, Aegilops tauschii. One haplotype, Pina‐D1c/Pinb‐D1h, confers a soft phenotype with increased grain hardness over Pina‐D1a/Pinb‐D1a wheats. Here, the Pina‐D1c/Pinb‐D1h haplotype was backcrossed into the soft white spring wheat cultivars ‘Vanna’ and ‘Alpowa’. Then the effect of the two haplotypes on soft wheat milling and baking quality was compared. The effects of the Pina‐D1c/Pinb‐D1h Ha locus haplotype were similar in both the Vanna and Alpowa backgrounds. The Pina‐D1c/Pinb‐D1h lines had significantly more large and fewer small flour particles in both backgrounds and 1.51% higher flour yield in the Alpowa background. The Pina‐D1c/Pinb‐D1h haplotype group was not associated with any consistent differences in solvent retention capacities or sugar snap cookie quality parameters. The results indicate that the Pina‐D1c/Pinb‐D1h haplotype could be used to modify soft wheat milling properties without substantial effects on baking quality.     

Occurrence of Puroindoline Alleles in Chinese Winter Wheats

Grain hardness is one of the most important characters that determine the end‐use quality of bread wheat (Triticum aestivum L.). Mutations in genes encoding either puroindoline a (Pina) or b (Pinb) have been associated with hard grain texture, i.e., Pina null at Pina‐D1 or seven mutations at Pinb‐D1. In this study, the diversity of puroindoline alleles in 251 Chinese winter wheat cultivars and advanced lines from four major autumn‐planted wheat regions were investigated. Among the examined cultivars, 79 were classified as soft, while 53 were mixed in hardness, and 119 were uniformly hard. Of these hard winter wheats, three of the seven reported mutation types were observed, with Pina‐D1a/Pinb‐D1b being the dominant type for hard texture; 91 genotypes carried this allele. Sixteen genotypes had the Pina‐D1b allele, and two genotypes had the Pinb‐D1d allele. A new mutation, designated as Pinb‐D1p, was detected in 10 hard genotypes, with a single nucleotide (A) deletion corresponding to position 42 in the amino acid sequence of puroindoline b, involving a lysine (K) to asparagine (N) change, and leading to a shift in the open reading frame (ORF). This deletion disrupts the last part of the tryptophanrich domain, changing it from KWWK to NGGR, which is considered essential for the lipid‐binding activity of this protein, and results in a stop codon corresponding to position Pro‐60 in the amino acid sequence. The characterization of different hardness alleles provides useful information in understanding the mechanism underlying the formation of endosperm hardness while providing breeders the means of manipulating this important trait.     

Effects on Soft Wheat (Triticum aestivum L.) Quality of Increased Puroindoline Dosage

Wheat (Triticum aestivum L.) grain hardness affects many end‐product quality traits and is controlled primarily by the Hardness (Ha) locus that contains the Puroindoline a and b genes (Pina and Pinb, respectively). All soft hexaploid wheats carry the same Pin alleles, and hard wheats carry a mutation in Pina or Pinb. Here we test the heritability and milling and flour quality effects of increased Pin dosage in soft wheat. Previous experiments have suggested that grain softness can be enhanced by increasing Ha locus dosage through chromosome substitutions. Segregation data from a cross of cultivar Chinese Spring substitution lines with six doses of the Ha locus to the locally adapted soft wheat cultivar Vanna indicate that the substituted B genome Ha locus was not transmitted and that the A genome Ha locus was transmitted normally. Genotypes with the added Pins on the A genome produced seeds that were 7.4 hardness units softer. These softer double Ha genotypes were lower in flour yields, but produced flour with lower ash content, reduced starch damage, and smaller mean particle size. Soft wheats with increased Ha dosage may be useful in improving soft wheat quality through its effects on particle size and starch damage.     

Puroindoline Genotype of the U.S. National Institute of Standards & Technology Reference Material 8441, Wheat Hardness

Grain hardness (kernel texture) is of central importance in the quality and utilization of wheat (Triticum aestivum L.) grain. Two major classes, soft and hard, are delineated in commerce and in the Official U.S. Standards for Grain. However, measures of grain hardness are empirical and require reference materials for instrument standardization. For AACC Approved Methods employing near‐infrared reflectance (NIR) and the Single Kernel Characterization System (39‐70A and 55‐31, respectively), such reference materials were prepared by the U.S. Dept. of Agriculture Federal Grain Inspection Service. The material was comprised of genetically pure commercial grain lots of five soft and five hard wheat cultivars and was made available through the National Institute of Standards and Technology (SRM 8441, Wheat Hardness). However, since their establishment, the molecular‐genetic basis of wheat grain hardness has been shown to result from puroindoline a and b. Consequently, we sought to define the puroindoline genotype of these 10 wheat cultivars and more fully characterize their kernel texture through Particle Size Index (PSI, Method 55‐30) and Quadrumat flour milling. NIR, SKCS, and Quadrumat break flour yield grouped the hard and soft cultivars into discrete texture classes; PSI did not separate completely the two classes. Although all four of these methods of texture measurement were highly intercorrelated, each was variably influenced by some minor, secondary factors. Among the hard wheats, the two hard red spring wheat cultivars that possess the Pina‐D1b (a‐null) hardness allele were harder than the hard red winter wheat cultivars that possess the Pinb‐D1b allele based on NIR, PSI, and break flour yield. Among the soft wheat samples, SKCS grouped the Eastern soft red winter cultivars separate from the Western soft white. A more complete understanding of texture‐related properties of these and future wheat samples is vital to the use and calibration of kernel texture‐measuring instruments.     

Creation and Characterization of a Double Null Puroindoline Genotype in Spring Wheat

Wheat (Triticum aestivum L.) grain hardness is controlled by the Ha locus, which is composed of two closely linked genes, Puroindoline a (Pina ) and Puroindoline b (Pinb ). Hard grain results from mutations in either of the Pin genes. Previous results have shown that the Pina‐D1b (Pina null) allele has harder grain than other naturally occurring Pin alleles. Our goal was to create, identify, and characterize a double null Pin genotype by identifying a Pinb null mutation in a variety carrying the Pina‐D1l null allele. Seeds of Fortuna, which has a premature stop codon in Pina , were treated with ethyl methanesulfonate. Two premature stop codon mutations were identified in Pinb using direct sequencing. The double null Pin haplotype was characterized after backcrossing to the parent variety Fortuna to create Pina null populations segregating for the presence of Pinb . The double null group was 6 units harder than the single null with no difference in other kernel characteristics. The milling characteristics differed between the two classes; the double null class had less break flour with a greater fraction of large and a smaller fraction of small flour particles compared with the single null class. Neither water absorption nor loaf volume was impacted by the change in grain hardness; however, Na₂CO₃ tests indicated greater starch damage in the double nulls. The double null Pin genotype may find a niche in hard wheat products for which flours with larger particle size are desired.     

Relationship Between Wheat (Triticum aestivum L.) Grain Hardness and Wet‐Milling Quality

Grain hardness variation has large effects on many different end‐use properties of wheat (Triticum aestivum). The Hardness (Ha) locus consisting of the Puroindoline a and b genes (Pina and Pinb) controls the majority of grain hardness variation. Starch production is a growing end‐use of wheat. The objective of this study was to estimate the differences in starch yield due to natural and transgenically conditioned grain hardness differences. To accomplish this goal, a small‐scale wet‐milling protocol was used to characterize the wet‐milling properties of two independent groups of isogenic materials varying in grain hardness and in Pin expression level. The first group of lines consisted of hard/soft near‐isogenic lines created in cultivars Falcon or Gamenya in which lines carried either the Pina‐D1a (functional) or the Pina‐D1b (null) alleles of Pina. The second group of lines consisted of Pina, Pinb, or Pina and Pinb overexpressing lines created in Hi‐Line, a hard red spring wheat. Soft near‐isogenic lines had higher starch extractability than the hard Pina null counterparts. This difference in starch extractability was more pronounced between Hi‐Line and its transgenic isolines, with highest levels of extractable starch observed in the transgenic isoline with intermediate grain texture. The results demonstrate that the Ha locus and puroindoline expression are both linked to wet‐milling starch yield and that selection for increased Ha function increases starch yield through the enhanced separation of starch granules and the protein matrix during wet milling.     

Effect of Variation in Amylose Content and Puroindoline Composition on Bread Quality in a Hard Spring Wheat Population

Milling and breadbaking quality of hard‐textured wheat may be influenced by alternative alleles at the Wx loci controlling percent amylose in the endosperm, and the puroindoline (pin) loci controlling grain hardness. For this experiment, we developed recombinant inbred lines (RIL) from a cross between Choteau spring wheat cultivar and experimental line MTHW9904. Choteau has the PinB‐D1b mutation conferring grain hardness and the Wx‐B1a allele at the Wx‐B1 locus conferring wild‐type amylose content. MTHW9904 has the PinA‐D1b allele conferring grain hardness and the Wx‐B1b allele conferring lower amylose content, causing a partial waxy phenotype. RIL with the PinB‐D1b mutation (n = 49) had significantly softer kernels, higher break flour yield, and higher loaf volume than lines with the PinA‐D1b mutation (n = 38). Lines with partial waxy phenotype due to Wx‐B1b (n = 43) had significantly lower kernel weight, lower amylose content, and higher flour swelling power than lines with wild‐type starch due to Wx‐B1a (n = 51). These results provide additional evidence for the positive effect of PinB‐D1b on bread quality in hard wheats, while genotype at Wx‐B1 was generally neutral for bread quality in this population. Interactions between the Pin and Wx loci were minimal.     

Influence of Puroindolines A and B Individually and in Combination on Wheat Milling and Bread Traits

Endosperm texture in wheat (Triticum aestivum L.) is determined by the Pina and Pinb genes located within the Hardness (Ha) locus on chromosome 5D. We have previously shown that Pina and Pinb can act alone to produce intermediate-textured grain or act together to produce soft grain. The objective here was to isolate the role of PINA and PINB individually and in combination on milling and bread traits by analyzing F₃ recombinant lines created by crosses between PINA and PINB null cultivars with Pina-D1a and Pinb-D1a overexpressing transgenic lines. Homozygous lines that contained either the Pina-D1b/Pinb-D1a (Pina null) or Pina-D1a/Pinb-D1e (Pinb null) Ha locus with or lacking transgenically added Pina or Pinb were analyzed for milling and bread traits. Addition of Pina-D1a to Pina-D1b/Pinb-D1a and addition of Pinb-D1a to Pina-D1a/Pinb-D1e Ha locus genotypes gave soft grain with lower flour yield, flour ash, and a higher proportion of small flour particles. Addition of Pinb-D1a produced greater negative effects on loaf volume than addition of Pina-D1a. Grain hardness, flour protein, flour ash, and mixograph water absorption were positively correlated, which is indicative of the complex phenotype conditioned by PINs. The results demonstrate that PIN overexpression leads to a reduction in grain hardness and reduced flour yield, flour ash, and flour particle size. PIN expression also results in reduced loaf volume and flour water absorption.     

Comparison of Quality‐Related Alleles Among Australian and North American Wheat Classes Exported to Japan

Grain hardness, amylose content, and glutenin subunit composition are critical determinants for end‐use properties of wheat. To improve the end‐use properties of domestic wheats, we studied these traits between the Australian and North American wheat classes exported to Japan in 2009 and 2011 by analyzing the corresponding alleles. Most hard classes had Pina‐D1b or Pinb‐D1b. A partial waxy allele (Wx‐B1b) was found in all Australian Standard White (ASW) seeds in 2009 and two‐thirds of ASW seeds in 2011. All or most American hard wheat seeds had Glu‐D1d. Most U.S. Western White (WW) seeds had a null allele (Glu‐A1c) or alleles that lacked one of the two Glu‐B1 subunits. Most hard red winter (HRW) seeds had Glu‐B3b or Glu‐B3g. Quality characteristics of these classes seemed to be consistent with these results. In addition, we also found new Glu‐1 and Glu‐3 alleles in HRW and WW. These results suggested that although there are variations in its allelic composition from year to year, each class has unique quality‐related alleles corresponding to its end use. We proposed two matrices for classification of starch properties on the basis of Pin and Wx allelic combinations and for classification of gluten strength on the basis of glutenin allelic combinations.     

A Study of Puroindoline b Gene Involvement in the Milling Behavior of Hard‐Type Common Wheats

Differences in milling behavior among hard‐type common wheat (Triticum aestivum) cultivars are well known to millers. Among them, the French cultivar Soissons, which contains the Pinb‐D1d allelic form of the puroindoline b gene, is particularly distinguished for its high milling value. Near‐isogenic lines (NILs) differing by the allelic forms of the puroindoline b gene, Pinb‐D1d or Pinb‐D1b (one of the most frequent alleles found in the European wheat population), were constructed. Grain characteristics obtained after wheat cultivation in distinct environmental conditions were compared between NILs and the cultivar Soissons, as was their fractionation behavior. Results showed that NILs containing the Pinb‐D1d allele displayed lower values of grain hardness and vitreousness than did the corresponding lines containing the Pinb‐D1b allelic form under the same cultivation conditions. Both genetic background and environmental conditions appeared to affect grain texture. Measured single‐kernel characterization system hardness index values of the samples under study were found to be correlated with the vitreousness values. Studies of the milling behavior helped to point out that grain vitreousness is an important factor acting on endosperm breakage ability, whatever the genetic background of the wheat. Our results also demonstrated that, at similar levels of vitreousness, the endosperm of Soissons could more easily be reduced than that of other wheat lines.     

Effects of Allelic Variations in Wx‐1, Glu‐D1, Glu‐B3, and Pinb‐D1 Loci on Flour Characteristics and White Salted Noodle‐Making Quality of Wheat Flour

Doubled haploid wheat lines developed from a cross between a hard white winter wheat variety of normal starch endosperm and a waxy wheat variety were used to determine the effects of allelic variation in Wx‐1, Glu‐D1, Glu‐B3, and Pinb‐D1 loci on physiochemical properties of flour, noodle dough properties, and textural quality of cooked noodles. Milling yield, damaged starch content, protein content, and SDS sedimentation volume of flour were influenced the most by allelic composition of Pinb‐D1 loci, less by Wx‐1 loci, and least by Glu‐B3. Wheat lines carrying Pinb‐D1b or Glu‐B3h alleles exhibited higher milling yield and damaged starch content of flour than those with Pinb‐D1a and Glu‐B3d alleles. Wheat lines carrying the Pinb‐D1b allele were higher in protein content and SDS sedimentation volume than those carrying Pinb‐D1a. Mixograph water absorption was largely influenced by allelic composition of Wx‐1 loci, whereas mixograph mixing time and mixing tolerance were predominantly determined by allelic composition of Glu‐D1 loci. Amylose content and pasting properties of starch were mainly determined by allelic composition of Wx‐1 loci with little influence by allelic compositions of Glu‐D1, Glu‐B3, and Pinb‐D1 loci. Allelic composition of Wx‐1 loci contributed 53.4% of the variation in optimum water absorption of noodle dough and 26.7% of the variation in thickness of the noodle dough sheet. The variation of 7.8% in optimum water absorption of noodle dough was contributed by the allelic composition of Pinb‐D1 loci. Allelic composition of Wx‐1 loci was responsible for 73.2, 74.4, and 59.6% in the variation of hardness, springiness, and cohesiveness of cooked noodles, respectively. Cohesiveness of cooked noodles was also influenced by the allelic compositions of Glu‐B3 and Pinb‐D1 loci to a smaller extent.     

Wheat Grain Hardness Among Chromosome 5D Homozygous Recombinant Substitution Lines Using Different Methods of Measurement

The level of grain hardness of wheat (Triticum aestivum) cultivars profoundly affects milling properties and end-use. We examined grain hardness among a genetically defined set of 83 chromosome 5D homozygous recombinant substitution lines derived from soft wheat cv. Chinese Spring and hard wheat cv. Cheyenne and compared four common methods of measuring wheat grain hardness. Measures of grain hardness included a modified particle size index, Brabender Quadrumat flour milling, near-infrared reflectance (NIR) spectroscopy, and the single-kernel characterization system (SKCS). Duncan's multiple range test was used to group recombinant lines according to parental classes. Quadrumat milling fractions, percent bran and middlings, were well correlated to NIR and SKCS grain hardness, whereas break flour, a traditional measure of grain hardness, was poorly correlated to other hardness measures. NIR and SKCS grain hardness measures provided the greatest and similar mean separations. Both methods identified recombinant lines as being significantly outside either parental class and significantly different from and in between the two parental classes. Between two divergent environments, correlations (r) for Quadrumat bran and middlings percents and NIR and SKCS hardness ranged from 0.83 to 0.94. Analysis of variance indicated that lines differed substantially for hardness, and hardness was highly influenced by environment, albeit consistently, as indicated by low line-location model interaction terms. The results confirmed the presence of major allelic differences assignable to chromosome 5D and suggested the action of minor gene(s). Break flour, in particular, showed strong indications of transgressive segregation independent of the Hardness (Ha) locus. The Perten 4100 SKCS provided the best (most discriminating) measure of the material properties of the wheat endosperm manifested by the action of the Ha locus.     

Characterization of Genes Encoding Wheat Grain Hardness from Chinese Cultivar GaoCheng 8901

The puroindoline‐b (Pinb‐D1) gene from Chinese hard wheat cultivar GaoCheng 8901 (Triticum aestivum L.) was obtained using two pairs of primers designed based on the known Pinb‐D1 gene sequence and polymerase chain reaction (PCR) amplification. The PCR amplification was made using the genomic DNA of the wheat as a template and the specific fragment ≈450 bp in size was screened. The results indicated that the Pinb‐D1 gene in GaoCheng 8901 shared 99.78% and 99.32% homology in nucleotide acid sequence and amino acid sequence, respectively, compared with the Pinb‐D1 gene from hard wheat cultivars Wanser and Cheyenne. A new mutation in this Pinb‐D1 gene, different from the six known mutations in the Pinb‐D1 gene, was characterized with a change of a lysine to glutamic acid at position 45 in its protein sequence. This mutation, designated as Pinb‐D1l in this study, might contribute to the formation of grain hardness in GaoCheng 8901. The characterization of Pinb‐D1 gene would be helpful in manipulating grain hardness of wheat through genetic engineering.     

Hardness Measurement of Bulk Wheat by Single‐Kernel Visible and Near‐Infrared Reflectance Spectroscopy

Reflectance spectra (400 to 1700 nm) of single wheat kernels collected using the Single Kernel Characterization System (SKCS) 4170 were analyzed for wheat grain hardness using partial least squares (PLS) regression. The wavelengths (650 to 700, 1100, 1200, 1380, 1450, and 1670 nm) that contributed most to the ability of the model to predict hardness were related to protein, starch, and color differences. Slightly better prediction results were observed when the 550–1690 nm region was used compared with 950–1690 nm region across all sample sizes. For the 30‐kernel mass‐averaged model, the hardness prediction for 550–1690 nm spectra resulted in a coefficient of determination (R²) = 0.91, standard error of cross validation (SECV) = 7.70, and relative predictive determinant (RPD) = 3.3, while the 950–1690 nm had R² = 0.88, SECV = 8.67, and RPD = 2.9. Average hardness of hard and soft wheat validation samples based on mass‐averaged spectra of 30 kernels was predicted and compared with the SKCS 4100 reference method (R² = 0.88). Compared with the reference SKCS hardness classification, the 30‐kernel (550–1690 nm) prediction model correctly differentiated (97%) between hard and soft wheat. Monte Carlo simulation technique coupled with the SKCS 4100 hardness classification logic was used for classifying mixed wheat samples. Compared with the reference, the prediction model correctly classified mixed samples with 72–100% accuracy. Results confirmed the potential of using visible and near‐infrared reflectance spectroscopy of whole single kernels of wheat as a rapid and nondestructive measurement of bulk wheat grain hardness.     

Development of SNP assays for genotyping the puroindoline b gene for grain hardness in wheat using pyrosequencing

Grain hardness is one of the most important quality characteristics of cultivated bread wheat (Triticum aestivum L.) and has been reported to result from either a failure to express puroindoline a (Pina) or single-nucleotide mutations in puroindoline b (Pinb). Up to now, seven alleles from Pinb-D1a to Pinb-D1g were identified in bread wheat. Compared to the DNA coding region of Pinb-D1a (allele for softness), six single-nucleotide polymorphisms (SNPs) were detected in six alleles for Pinb-D1. In this study, we used pyrosequencing technology to develop two SNP assays for identification of the seven Pinb alleles and characterized SNP variations in the Pinb of 493 European wheat varieties. Of the three hardness alleles Pinb-D1b, Pinb-D1c, and Pinb-D1d detected in this study, Pinb-D1b was the most predominant hardness allele in European hard wheats. The hardness genotypes of partial German wheat varieties available confirmed the reliability and validation of the SNP assays developed for the Pinb locus. Therefore, pyrosequencing technology offers an efficient, precise, and reliable concept for high-throughout genotyping to assist selection of grain hardness genes in wheat quality breeding programs.     

Application of the Single‐Kernel Characterization System to Durum Wheat Testing and Quality Prediction

The Single Kernel Characterization System (SKCS 4100) measures single kernel weight, width, moisture content, and hardness in wheat grain with greater speed than existing methods and can be calibrated to predict flour starch damage and milling yield. The SKCS 4100 is potentially useful for testing applications in a durum improvement program. The mean SKCS 4100 kernel weight and moisture values from the analysis of 300 individual kernels gave good correlations with 1,000 kernel weight (r² = 0.956) and oven moisture (r² = 0.987), respectively. Although significant correlations were obtained between semolina mill yield and SKCS 4100 weight, diameter, and peak force, they were all very low and would be of little use for prediction purposes. Similarly, although there were significant correlations between some SKCS 4100 parameters and test weight and farinograph parameters, they too were small. The SKCS 4100 has been calibrated using either the single kernel hardness index or crush force profile to objectively measure the percentage vitreous grains in a sample with reasonable accuracy, and it correlates well with visual determination. The speed and accuracy of the test would be of interest to grain traders. An imprecise but potentially useful calibration was obtained for the prediction of semolina mill yield using the SKCS 4100 measurements on durum wheat. The SKCS 4100 is useful for some traits such as hardness, grain size and moisture for early‐generation (F3) selection in a durum improvement program.     

Compressive Strength of Wheat Endosperm: Comparison of Endosperm Bricks to the Single Kernel Characterization System

The three major classes of endosperm texture (grain hardness) of soft and hard common, and durum wheat represent and define one of the leading determinants of the milling and end‐use quality of wheat. Although these three genetic classes are directly related to the Hardness locus and puroindoline gene function, much less is known about the kernel‐to‐kernel variation within pure varietal grain lots. Measurement of this variation is of considerable interest. The objective of this research was to compare kernel texture as determined by compression failure testing using endosperm bricks with results of whole‐kernel hardness obtained with the Single Kernel Characterization System 4100 hardness index (SKCS HI). In general terms, the variation obtained with the SKCS HI was of similar magnitude to that obtained using failure strain and failure energy of endosperm brick compression. Objective comparisons included frequency distribution plots, normalized frequency distribution plots, ANOVA model R², and coefficients of variation. Results indicated that compression testing and SKCS HI similarly captured the main features of texture classes but also reflected notable differences in texture properties among and within soft, hard, and durum classes. Neither brick compression testing nor the SKCS HI may be reasonably expected to correctly classify all individual kernels as to genetic texture class. However, modest improvements in correct classification rate or, more importantly, better classification related to end‐use quality may still be achievable.     

Specific Glu‐D1ƒ Allele Frequency of Japanese Common Wheat Compared with Distribution of Glu‐1 Alleles in Chinese Wheat

The quality of wheat (Triticum aestivum L.) grain favored in breadmaking is strongly affected by components of seed storage protein, particularly high molecular weight glutenin subunits (HMW‐GS). The HMW‐GS 2.2 controlled by the Glu‐D1ƒ allele is frequently found in Japanese cultivars and landraces. In the investigation into the factors affecting the distribution of the allele, the available data on HMW‐GS of common wheats from Japan were analyzed and compared with the data for intensity of winter habit and wheat flour hardness. We show that the main factors affecting the Glu‐D1ƒ allele frequency in Japanese wheat were the intensity of natural selection for winter habit and artificial selection for flour hardness. According to a study of the worldwide distribution of Glu‐1 alleles, the Glu‐D1ƒ allele is rare. However, Glu‐D1ƒ allele was the most common Japanese wheat seed storage protein allele. It is well known that Chinese wheat contributed to Japanese landraces, and Japanese landraces contributed to modern cultivars from Japan. However, common Japanese and Chinese wheats differ in the frequencies of Glu‐D1ƒ allele. These results may be explained either by the founder effect or by a selective bottleneck in Japanese common wheat genetic resources.     

Evaluation of the Single Kernel Characterization System (SKCS) for Measurement of Sorghum Grain Attributes

The single kernel characterization system (SKCS) has been widely used in the wheat industry, and SKCS parameters have been linked to end‐use quality in wheat. The SKCS has promise as a tool for evaluating sorghum grain quality. However, the SKCS was designed to analyze wheat, which has a different kernel structure from sorghum. To gain a better understanding of the meaning of SKCS predictions for grain sorghum, individual sorghum grains were measured for length, width, thickness (diameter), and weight by laboratory methods and by the SKCS. SKCS predictions for kernel weight and thickness were highly correlated to laboratory measurements. However, SKCS predictions for kernel thickness were underestimated by ≈20%. The SKCS moisture prediction for sorghum was evaluated by tempering seven samples with varying hardness values to four moisture levels. The moisture contents predicted by SKCS were compared with a standard oven method and, while correlated, SKCS moisture predictions were less than moisture measured by air oven, especially at low moisture content. Finally, SKCS hardness values were compared with hardness measured by abrasive decortication. A moderate (r = 0.67, P < 0.001) correlation was observed between the hardness measurements. The SKCS predictions of kernel weight and diameter were highly correlated with laboratory measurement. Moisture prediction, however, was substantially lower by the SKCS than as measured by an air oven method. The SKCS should be suitable for measuring sorghum grain attributes. Further research is needed to determine how SKCS hardness predictions are correlated to milling properties of sorghum grain.