Identification of Wheat Lines Possessing the 1AL.1RS or 1BL.1RS Wheat-Rye Translocation by Near-Infrared Reflectance Spectroscopy

Wheat-rye chromosomal translocations, particularly those involving the short arm of rye chromosome 1R, have been used during the past 25 years to instill resistance to plant pathogens and insects and improve the hardiness, adaptation, and yield of wheat. Unfortunately, the presence of the 1AL.1RS or 1BL.1RS rye translocations in wheat has been shown to impart inferior dough handling and baking characteristics. Although numerous analytical techniques (e.g., HPLC, monoclonal antibody tests, high-performance capillary electrophoresis) have been developed for detecting these translocations, the complexity of the analytical procedures restricts their use to research and analytical laboratories. The purpose of this study was to examine the potential of diffuse reflectance near-infrared spectroscopy, a well-accepted technique in the grain industry, for detecting 1RS-containing genotypes. This research used three independent groups of wheat samples, ranging in genetic diversity from sister lines derived from 1RS breeding populations to commercial cultivars. Based on the diffuse reflectance spectra (1,100–2,500 nm) of flour, partial least squares (PLS) models, through cross-validation, exhibited misclassification rates as low as 0%, particularly for commercial cultivars. Misclassification rates for corresponding, but separate, test sets were as low as 1%. When the same modeling procedure was applied to samples of more closely related genetic backgrounds, cross-validation misclassification rates rose to 15–20%. Most problematic were samples that were heterogeneous for 1RS such as the cultivar Rawhide. Incorporating heterogeneous samples into a calibration equation improved the classification accuracy of these samples but diminished the prediction accuracy of nonheterogeneous samples.     

Effects of Prolamins Encoded by Chromosomes 1B and 1D on the Rheological Properties of Dough in Near-Isogenic Lines of Bread Wheat

Fourteen bread wheat near-isogenic lines (NILs) with different alleles at 1B- and 1D-chromosome loci Glu-1, Glu-3 and Gli-1 coding for high molecular weight glutenin subunits (HMW-GS), low molecular weight-GS, and gliadins, respectively, were grown in replicated plots to investigate the individual and combined effects of glutenin and gliadin components on the rheological properties of dough as determined by the Chopin alveograph. NILs did not reveal significant differences in seed yield, protein content, kernel weight, test weight, flour yield, and starch damage. On the contrary, they had a large variation in alveograph dough tenacity P (55–93 mm), swelling G (17–26 mL) and strength W (140–252 J × 10^-4). The null alleles at the Gli-D1/Glu-D3 loci, and allele Glu-D1d (HMW-GS 5+10) were found to have a strong positive influence on dough tenacity and a remarkable negative influence on dough swelling (extensibility) when compared to alleles Gli-D1/Glu-D3b and Glu-D1a (HMW-GS 2+12), respectively. On the other hand, alleles Glu-B1c (HMW-GS 7+9) and Gli-B1/Glu-B3k gave greater G values than alleles Glu-B1u (HMW-GS 7*+8) and Gli-B1/Glu-B3b. The effects of individual Glu-1, Gli-1, or Glu-3 alleles on P and G values were largely additive. The impact of the null allele at Gli-D1/Glu-D3 on gluten strength was highly positive in NILs possessing HMW-GS 2+12, and negligible or negative in NILs containing HMW-GS 5+10, suggesting that there is scope for improving dough quality by utilizing this allele in combination with HMW-GS 2+12. Gli-D1/Glu-D3-encoded prolamins were shown to play a major role in conferring extensibility to dough, and could account for the superior breadmaking characteristics of bread wheat as compared to durum wheat.     

Effect of Added Fat on the Rheological Properties of Wheat Flour Doughs

The effect of added fat content on the rheological properties of wheat flour doughs was determined for three different added fat contents (2.5, 5.0, and 7.5%) at 25°C using dynamic mechanical analysis (DMA) and stress relaxation (SR) tests. Frequency sweeps indicated that added fat had a plasticizing effect on G′ and G″ in the rubbery region. SR results were parameterized using a Maxwell model and a Williams-Watts (WW) model. The WW model indicated that each dough could be characterized by just two major relaxation modes, while four elements were needed for the Maxwell model. The average relaxation time for the shorter process was <1 sec and was not affected by added fat. However, the average relaxation time for the longer WW process actually increased from 107 to 261 sec with added fat up to 5%, and then decreased again. Taken together, these results suggest that added fat actually delayed the onset of viscous flow, while simultaneously attenuating the short-time elastic properties of the gluten fraction of the dough. Furthermore, rheological testing over a wide time (frequency) scale was needed to observe the effect of added fat on both the short-time elastic and longer-time viscous behavior of these doughs.     

Effect of Oxidation on the Dynamic Rheological Properties of Wheat Flour-Water Doughs

Oxidation increased the strength of the dough. Addition of ascorbic acid or azodicabonamide (ADA) to dough increased both elastic modulus (G′) and viscous modulus (G″), while addition of cysteine decreased both values. Hydrogen peroxide, from either calcium peroxide or glucose oxidase, increased G′ and G″ and decreased tan δ (G″/G′) values. In addition to strengthening the dough, hydrogen peroxide dried the dough, but ADA did not. The absorption of doughs containing 20 GU of glucose oxidase (source of hydrogen peroxide) could be increased by ≈5% without altering the rheological properties. Presumably, the mobility of water in the gel formed by oxidative gelation decreased, thereby causing a drying of the dough.     

Rheological Properties of Soft Wheat Flour Doughs: Effect of Salt and Triglycerides

The small deformation rheological properties of wheat flour doughs in relation to their structure and hydration were studied by dynamic mechanical thermal analysis, differential scanning calorimetry, and electron spin resonance. The effect of salt and triglycerides was also examined and compared with results we obtained previously on starch dispersions. Moisture content was adjusted to 48 or 60% (w/w, wb). Samples contained 0–16% NaCl (g/100 g of flour‐water) and 0–18% triolein or lard (g/100 g of flour‐water). The obtained results suggested that starch has an active role in determining the evolution of dough rheological characteristics during heating. The main factors controlling rheological behavior during thermal treatment are the volume fraction and deformability of starch granules. Gluten changes the viscoelasticity of the continuous phase and competes with starch for water. The addition of sodium chloride to flour dispersions shifted the structural disorganization and rigidity increased during heating to higher temperatures. At >7% NaCl, the reverse effect was observed. The mechanism controlling the effect of salt on dough rheological behavior was explained in terms of effect on water properties and on starch structure and hydration. Triglycerides had a lubricant effect (i.e., lowering G′ modulus) on the wheat flour dough system. These effects are of great importance for production and quality of bakery products.     

Comparative Effects of 1BL/1RS Translocation in Relation to Protein Composition and Milling and Baking Quality of Soft Red Winter Wheat

Forty grain samples, derived from six soft red winter wheat lines with 1BL/1RS and four genotypes without the translocation, grown in four diverse environments, were used to assess test weight, flour yield, protein content of grain and flour, rheological properties, and end-use characteristics in cakes and cookies. Wheat lines with 1BL/1RS had similar or higher mean test weights than lines without the translocation. Mean flour yields were similar for the two groups. Test weight was not predictive of flour yield. Mean values for grain moisture, grain protein, and rheological properties, as measured by farinograph for mixing time stability and mixing tolerance index, were similar for wheat lines with and without 1BL/1RS. In several cases, flour from lines with 1BL/1RS produced dough with greater mixing tolerance and cakes with higher volume and softer texture than did check lines without the translocation. However, the translocation in these soft red winter wheat lines resulted in higher farinograph water absorption by the flour and decreased cookie spread. The results of this study were novel in that end-use, specifically baking quality of soft wheat lines with 1BL/1RS, varied dramatically depending on whether cookies or cakes were evaluated. Therefore, use of single-product baking tests may lead to false conclusions regarding end-use quality of 1BL/1RS soft wheat. Direct comparison between a pair of sister lines with and without 1BL/1RS indicated that the translocation had adverse effects on quality as exemplified by lower flour yield, greater farinograph water absorption, and reduced cookie diameter. However, the 1BL/1RS line had greater mixing tolerance and similar cake volume and texture scores in comparison to its sister line. In summary, 1BL/1RS lines were identified in which quality characteristics exceeded those of control cultivars and commercial flours. Genetic background and environmental factors probably affected milling and baking quality to a greater extent than the translocation. Many of the negative quality attributes previously associated with 1BL/1RS are probably due to genetic background effects and, therefore, could be greatly diminished with improvement of the genetic background in which the translocation resides.     

Apparent Dough Stickiness of Selected 1BL/1RS Translocated Soft Wheat Flours

A new method, called the Schwarzlaff‐Shephard Dough Stripping Method, was used to determine apparent dough stickiness in seven 1BL/1RS translocated soft, red, winter wheat (SRWW) lines and five SRWW lines without the translocation. Pairwise comparisons of all 1BL/1RS versus all non‐1BL/1RS lines indicated that doughs made from the 1BL/1RS lines were significantly stickier, on average, than doughs made from the non‐1BL/1RS lines. However, there was no significant difference in the apparent dough stickiness of one set of sister lines that shared a similar pedigree, 1BL/1RS line VA 93‐54‐18 versus its non‐1BL/1RS sister line VA 94‐54‐21. Another 1BL/1RS line, VA 92‐52‐22, ranked last in apparent dough stickiness and was significantly less sticky than two non‐1BL/1RS lines. VA 92‐52‐22 has a distinctly different pedigree from the other 1BL/1RS lines that we evaluated. These findings suggest that there are strong genotypic effects on dough stickiness, making it possible to develop non‐sticky cultivars of 1BL/1RS SRWW.     

Effect of Germination and Water Content on the Microstructure and Rheological Properties of Two Rye Doughs

Two rye cultivars, Marder and Motto, with falling numbers 314 and 309, respectively, were germinated in vitro. Relative to the native grains, germination induced minor local changes in the microstructure of cell walls and proteins in the kernels. Kernels of germinated and native grains were milled, and doughs were prepared from the flours, with water content and incubation time varied according to experimental design. The viscoelastic properties of the doughs were measured just after mixing and after various incubation times. The area of blue fluorescence, a measure of intact cell walls, was quantified by computer-assisted image analysis in thin sections of rye dough after mixing and incubation, and the starch structure was studied under the microscope after iodine staining. The water content of the doughs was explained well by the rheological behavior. Doughs made from flours of germinated grains were always softer than doughs made from flours of native grains, and Marder doughs were always more rigid than Motto doughs. The higher the water content, and the longer the incubation time, the greater the rheological changes during incubation. Microstructural studies showed that germination and incubation caused changes in the cell wall structures of dough that might explain the softening of the doughs.     

Relationship Between Rheological Properties and Microstructural Characteristics of Nondeveloped,Partially Developed,and Developed Doughs

Farinography and mixography are two commonly used procedures for evaluating dough properties. These procedures, however, cannot separate hydration and energy input during dough development, both of which are critically important for understanding fundamental rheological properties of dough. A rheometer and laser scanning confocal microscopy (LSCM) were used to study the relationship between rheological properties and microstructural characteristics of developed (by farinograph with both shear and extensional deformations), of partially developed (by rheometer with either shear or extensional deformation), and of nondeveloped (no deformation) dough samples of wheat flours. Rheological data revealed that developed dough had the highest G* (most elastic or strong), followed by doughs partially developed with extensional deformation, and then shear deformation, and finally by nondeveloped dough. The LSCM z‐sectioning (scanning of different layers of the sample) and the analysis of amount of protein matrix showed that developed dough had the most protein matrix and nondeveloped dough had the least protein matrix. It also showed that the higher the G*, the greater the protein network. Moreover, the type of deformation appeared to contribute to the development of protein matrix and further increase the dough strength. In this study, a combination of shear and extensional deformations by farinograph produced the most protein matrix and the strongest dough, followed by extensional deformation, shear deformation, and then no deformation.     

Effects of Transglutaminase Enzyme on Fundamental Rheological Properties of Sound and Bug‐Damaged Wheat Flour Doughs

Transglutaminase (TG) catalyzes the formation of nondisulfide covalent crosslinks between peptide‐bound glutaminyl residues and ∊‐amino groups of lysine residues in proteins. Crosslinks among wheat gluten proteins by TG are of particular interest because of their high glutamine content. Depolymerization of wheat gluten proteins by proteolytic enzymes associated with bug damage causes rapid deterioration of dough properties and bread quality. The aim of the present study was to investigate the possibility of using TG to regain gluten strength adversely affected by wheat bug proteases. A heavily bug‐damaged (Eurygaster spp.) wheat flour was blended with sound cv. Augusta or cv. Sharpshooter flours. Dynamic rheological measurements, involving a frequency sweep at a fixed shear stress, were performed after 0, 30, and 60 min of incubation on doughs made from sound or blended flour samples. The complex moduli (G* values) of Augusta and Sharpshooter doughs blended with 10% bug‐damaged flour decreased significantly after 30 min of incubation. These dough samples were extremely soft and sticky and impossible to handle for testing purposes after 60 min of incubation. To test the possibility of using TG to counteract the hydrolyzing effect of bug proteases on gluten proteins, TG was added to the flour blends. The G* values of TG‐treated sound Augusta or Sharpshooter doughs increased significantly after 60 min of incubation. The G* values of the Augusta or Sharpshooter doughs blended with bug‐damaged flour increased significantly rather than decreased after 30 and 60 min of incubation when TG was included in the dough formulation. This indicates that the TG enzyme substantially rebuilds structure of dough hydrolyzed by wheat bug protease enzymes.     

Effects of Microencapsulated High‐Fat Powders on the Empirical and Fundamental Rheological Properties of Wheat Flour Doughs

Microencapsulated high‐fat powders are a healthy and convenient alternative to fats normally used in cereal‐based products. In powder form they are easier to use than block fat. Microencapsulation involves dispersion of the fat using homogenization. The globules are then fixed by spray‐drying. Empirical and fundamental rheological tests were conducted on doughs containing commercial vegetable fat and four microencapsulated high‐fat powders. The doughs were compared with a standard dough containing no fat. The powders contained 70% vegetable fat or milk fat. The encapsulating agent used was either sodium caseinate or whey protein concentrate (5–10%). Sucrose or lactose were also present in the powders (20–25%). The powders were manufactured at low‐ or high‐pressure homogenization. Farinograph and extensigraph tests were performed on all doughs. Dynamic oscillation tests were conducted in the linear visco‐elastic region of the dough. Addition of fat and microencapsulated high‐fat powders produced using low‐pressure homogenization reduced the complex modulus of the doughs. The results showed an increase in phase angle with incorporation of commercial fat and the microencapsulated high‐fat powders. Scanning electron microscopy was conducted to examine the effects of the additives on dough structure. This study demonstrated that microencapsulated high‐fat powders, especially powders produced using low‐pressure homogenization, had some beneficial effects on dough rheology when compared with doughs produced with commercial fat.     

Effects of a Novel Barley,Himalaya 292, on Rheological and Breadmaking Properties of Wheat and Barley Doughs

A barley mutant with high‐amylose starch, Himalaya 292, combines the potential cholesterol reducing effects of barley with the gastrointestinal benefits of high‐amylose resistant starches. Himalaya 292 has alterations in the content and composition of a range of grain constituents, thus conditions for successful addition to foods need to be defined. In this study, the rheological and breadmaking properties of doughs prepared by combining wheat flours (with various gluten protein compositions) with various barley genotypes (Himalaya 292 and the control cultivars Himalaya and Torrens) have been determined. The effects of barley addition on the rheological properties of the admixtures differed. While addition of Himalaya 292 increased the strength and reduced the extensibility of admixture doughs, addition of the Himalaya and Torrens barley flours to the wheat flours reduced both strength and extensibility. The addition of Himalaya and Torrens barley flour reduced water absorption levels. However, addition of Himalaya 292 whole grain flour increased the water absorption of the admixtures significantly (P < 0.01). The baking data showed that selection of an appropriate wheat flour with a combination of strength and extensibility allows higher levels of incorporation of barley, facilitating an increased delivery per serving of constituents with positive health attributes in β‐glucan and resistant starch.     

Testing of rye-specific markers located on 1RS chromosome and distribution of 1AL.RS and 1BL.RS translocations in Turkish wheat (Triticumaestivum L., T.durum Desf.) varieties and landraces

Rye (Secale cereale L.) is a valuable source for alien chromosome translocations in wheat breeding, due to its capability to grow and sustain under harsh environmental conditions. Wheat germplasm with 1AL.1RS and 1BL.1RS wheat-rye chromosome translocations have been used worldwide by breeders. Determining 1AL.1RS and 1BL.1RS translocations in wheat is therefore of important practical value for wheat improvement. In this study, nine rye-specific markers detecting the rye chromosome 1RS in wheat background were evaluated. The markers PAWS5/S6, SCM9 and O-SEC5′-A/O-SEC3′-R amplified specific bands associated with 1AL.1RS and 1BL.1RS translocations. These three markers therefore provide a quick and reliable tool to identify and to discriminate these two wheat-rye translocations in wheat background. Six out of nine rye specific markers were subsequently used to determine the frequency of these translocations in commonly grown bread and durum wheat cultivars from Turkey. One hundred seven wheat cultivars and landraces were molecularly screened. Among them, only 4% (‘Seri-82’, ‘Yıldız-98’, ‘Tahirova’, and ‘Osmaniyem’) harbor the 1BL.1RS translocation whereas the 1AL.1RS translocation was not found. The information provided here will contribute to the creation of new Turkish wheat populations with a larger genetic diversity necessary for future requirements.     

水稻近等基因导入系芽期抗旱性鉴定及抗旱指标筛选

为筛选水稻抗旱性鉴定指标并科学鉴定水稻抗旱性,本研究以蒸馏水为对照,采用质量体积比为5％、10％、15％、20％的PEG-6000溶液处理6份川香29B近等基因导入系进行芽期抗旱鉴定,研究模拟干旱对水稻育种材料芽期种子萌发的影响,并探讨芽期抗旱性鉴定指标及筛选抗旱材料.结果表明,轻度水分胁迫对种子发芽抑制作用较小,部分...     

喀斯特山区不同母质(岩)发育的土壤主要理化性质差异性分析

在贵阳市乌当区采集了白云岩、石灰岩、钙质紫色砂页岩等9种母质(岩)上发育的土壤样品763个,分别进行了土壤主要理化性质的测定和差异性分析。结果表明不同母质(岩)发育的土壤理化性质具有很大的差异:红色粘土、老风化壳和页岩上发育的土壤pH值均为酸性至强酸性,有机质和CEC含量中等,土壤质地较粘重;石灰岩、白云岩和钙质紫色砂页岩上发育的土壤pH值为中性至微碱性,有机质和CEC含量较高,质地较为适中;砂页岩和河流冲积物上发育的土壤pH值为酸性至中性,其余理化性质为中等水平;砂岩发育的土壤pH值为强酸性,其余理化性质均较差。     

Protein and Quality Characterization of Triticale Translocation Lines in Breadmaking

Introduction of high molecular weight glutenin subunits (HMW‐GS) from the Glu‐D1d locus of wheat into triticale restores the genetic constitution of high molecular weight glutenin loci to that of wheat and subsequently improves the breadmaking quality of triticale. One means of achieving such restoration of the genetic constitution is through the use of translocation lines. The aim of this study was to evaluate and compare the performance of translocations 1A.1D and 1R.1D with HMW‐GS 5+10 and 2+12 in terms of physical dough tests and baking quality using four different sets of triticale lines, GDS7, Trim, Rhino, and Rigel. In general, significantly lower milling quality (flour yield), very low mixing times with lower loaf volume were typical of all the triticales studied except 1A.1D 5+10 lines, when compared to hard wheat flour (Pegaso). Among the lines studied, significantly higher loaf volume, mixograph dough development time (MDDT), and maximum resistance to extension (R_max) were observed with 1A.1D 5+10 lines indicating that translocation of the Glu‐D1d allele with HMW‐GS 5+10 was beneficial in terms of improving the quality attributes. Although pure triticale flour from these lines did not possess the functional characteristics for good quality bread, the translocation 1A.1D that contains HMW glutenin subunits 5+10 showed significant improvement in quality characteristics, and could reasonably be expected to yield commercially satisfactory bread loaves when combined with bread wheat flour. Significantly higher UPP, R_max, and MDDT values along with a lower gliadin‐to‐glutenin ratio in 1A.1D 5+10 of GDS7 and Rigel sets indicate that the molecular weight distribution was shifted to higher molecular weights, resulting in greater dough strength associated with 5+10 subunits.     

四川雨城区主要土壤母质上的耕地土壤性质变异研究

通过在四川省雨城区采集侏罗系沙溪庙组(J2s)、侏罗系遂宁组(J3s)、侏罗系蓬莱镇组(J3p)、白垩系夹关组(K2j)等地层9种母质上发育的耕地土壤样品共55个,并进行土壤性质测定及对比分析,结果表明:白垩系夹关组紫色砂岩上发育的耕地土壤较其他紫色母岩上发育的耕地砂粒含量高,pH低,养分含量低;第三系名山群及白垩系灌口组上发育的耕地土壤具有较其他母质高的土壤全钾;青衣江灰色河流冲积物发育的耕地土壤较其他母质发育的耕地土壤全磷和速效磷含量高,第四系冰水沉积物上发育的耕地土壤pH最低,粘粒含量高,土壤有机质及全氮、速效氮较其他母质发育的耕地土壤高。     

Agronomic and Quality Performance of Progeny Lines Derived from Spring Wheat by Durum Wheat Crosses

Hard red spring wheat (Triticum aestivum L. subsp. aestivum) and durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn) have both been selected for dryland yield potential and high grain protein, although end uses of flour are different. For this study, 14 tetraploid and 10 hexaploid lines were derived from crosses between tetraploid durum wheat and hexaploid hard red spring wheat. Our objective was to determine the impact of genetic exchange between the two classes on agronomic and quality attributes of derived progeny lines. Yield potential of both the tetraploid and hexaploid progeny was lower than the parental types. Polyphenol oxidase levels were higher by almost twofold in the hexaploid group. The tetraploid progeny group had better noodle color than did the hexaploid group. Bread quality of hexaploid group was superior, with loaf volume 362 cm³ higher than that of tetraploid progeny group. In general, the presence of durum wheat genes in the derived hexaploid lines had little impact on most quality traits. The presence or absence of the D genome tended to be the major influence on end use quality traits. Our results suggest that genetic exchange between the two groups has a small effect on end use quality, but low yield potential in the progeny suggests obtaining desirable genetic combinations for plant improvement may be challenging.     

Rheological Properties of Starch Gels from Wheat Mutants with Reduced Amylose Content

Wheat lines with reduced amylose content were recently produced by single and double mutation from a low‐amylose line, Kanto 107. They are appropriate for clarifying the influence of amylose content on starch gel properties because of their similar genetic background. When measured using the concanavalin A method (ConA), the total amylose content of isolated starches from Kanto 107 and three mutants (K107Afpp4, Tanikei A6599‐4, K107Wx2) was 24.8, 18.5, 7.1, and 1.7%, respectively. Results of differential scanning calorimetry (DSC) showed that the difference in amylose content strongly affected gelatinization conclusion temperature and enthalpy. We prepared 30 and 40% starch gels and measured their dynamic shear viscoelasticity using a rheometer with parallel plate geometry. Compressive and creep‐recovery tests were conducted under uniaxial compression. The storage shear modulus correlated highly with the amylose content of starch in 30 and 40% starch gels. The creep‐recovery test showed a clear distinction in creep curves among starch samples. When the compressive force required for 50, 80, and 95% strains was compared, starch gels with lower amylose content showed lower compressive force at 50% strain. Waxy starch gel (K107Wx2) showed higher compressive force at strain >80% than other samples due to its sticky property.