Sodium Dodecyl Sulfate Sedimentation Volume Research Articles

Response to heat stress and glutenins allelic variation effects on quality traits in durum wheat

AbstractIn the context of climate change, high temperature is one of the main abiotic stresses hampering durum wheat production. Through the characterization of an international panel of 271 genotypes, this study investigates the effects of heat stress on quality traits and identifies which glutenins (Glu‐1, Glu‐2 and Glu‐3 loci) alleles are the most important to obtain high gluten strength under optimal and high temperature conditions. In parallel with the wide variability observed in the panel, the genotype and environmental effects, including their interaction, showed highly significant effect on test weight, thousand kernel weight, grain protein content (GPC), sodium dodecyl sulphate sedimentation volume (SDSS) and SDSS index. Only one genotype maintained test weight and thousand kernel weight under heat‐stress conditions whereas for GPC, SDSS and SDSS index, most genotypes increased values. All Glu loci had significant effects on grain protein content (with the exception of Glu‐B2), SDSS and SDSS Index. None of the Glu loci interacted with the environment or years under study. Among the identified alleles, Glu‐A1b, Glu‐B1an, Glu‐B1a, Glu‐B2a, Glu‐A3a.x, Glu‐A3d, Glu‐B3a and Glu‐B3ax (including the LMW‐2 pattern) were associated with high values for SDSS and SDSS Index. Genotypes identified in this study, with good performances under optimal and high temperature growing conditions, could be useful for breeding programs. The non‐interaction of the Glu loci with the environment facilitates the introgression of desired alleles regardless of high growing temperatures.

The Landscapes of Gluten Regulatory Network in Elite Wheat Cultivars Contrasting in Gluten Strength.

Yangmai-13 (YM13) is a wheat cultivar with weak gluten fractions. In contrast, Zhenmai-168 (ZM168) is an elite wheat cultivar known for its strong gluten fractions and has been widely used in a number of breeding programs. However, the genetic mechanisms underlying the gluten signatures of ZM168 remain largely unclear. To address this, we combined RNA-seq and PacBio full-length sequencing technology to unveil the potential mechanisms of ZM168 grain quality. A total of 44,709 transcripts were identified in Y13N (YM13 treated with nitrogen) and 51,942 transcripts in Z168N (ZM168 treated with nitrogen), including 28,016 and 28,626 novel isoforms in Y13N and Z168N, respectively. Five hundred and eighty-four differential alternative splicing (AS) events and 491 long noncoding RNAs (lncRNAs) were discovered. Incorporating the sodium-dodecyl-sulfate (SDS) sedimentation volume (SSV) trait, both weighted gene coexpression network analysis (WGCNA) and multiscale embedded gene coexpression network analysis (MEGENA) were employed for network construction and prediction of key drivers. Fifteen new candidates have emerged in association with SSV, including 4 transcription factors (TFs) and 11 transcripts that partake in the post-translational modification pathway. The transcriptome atlas provides new perspectives on wheat grain quality and would be beneficial for developing promising strategies for breeding programs.

Grain and flour characteristics of eastern U.S. soft winter wheat desirable for making soft‐bite white salted noodles

AbstractBackground And ObjectivesThe genetic backgrounds and growing conditions of eastern U.S. soft winter (ESW) wheat vary widely and thus produce grains of diverse quality characteristics, which encompass those required for making soft‐bite white salted noodles (WSN). However, these characteristics have yet to be identified and cataloged. The grain and flour characteristics and WSN making quality of 25 ESW wheat varieties and four commercial noodle flours (CNFs) were analyzed to identify grain and flour characteristics desirable for making WSN.FindingsKernel hardness, protein content, and gluten strength‐related parameters of ESW wheat were significantly associated with WSN cooking and textural properties, while damaged starch content was the major determinant of WSN adhesiveness. A total of 9 out of 25 ESW wheat flours exhibited protein characteristics, WSN color and textural properties that closely matched to those of CNFs.ConclusionsESW wheat varieties with kernel hardness of 16.0–45.4, damaged starch content of 1.9%–4.4%, flour protein content of 8.6%–10.2%, sodium dodecyl sulfate sedimentation volume of 30.4–41.6 ml and lactic acid solvent retention capacity of 115.6%–142.7% were identified to produce WSN of comparable quality to those of CNFs.

Effect of Sitophilus zeamais (Coleoptera: Curculionidae) Infestation on the Protein Physicochemical and Structural Properties of Wheat Grain.

Boring pests such as Sitophilus zeamais (S. zeamais) are major threats in grain storage. However, how these pests affect the proteins of stored grains remains largely unknown. Here we aimed to investigate the effect of S. zeamais infestation on wheat protein during postharvest storage. In this study, wheat grain infested by S. zeamais was sampled at egg (4 d), larval (20 d), pupal (35 d), and adult stages (45 d), respectively. The protein's physicochemical and structural properties and the edible quality of whole wheat noodle were analyzed. The results showed that S. zeamais infestation significantly decreased the quality of wheat protein by altering its constitution and structure properties. Especially, compared with the control, the content of wet and dry gluten, gluten index, sodium dodecyl sulfate sedimentation volume, sulfhydryl groups, and disulfide bonds in insect-infested wheat decreased by 19.40, 5.42, 18.40, 8.12, 29.13, and 14.30%, respectively, during the storage period of one life cycle of S. zeamais. Additionally, the proportions of wheat protein fractions (albumin [1.16-fold], globulin [0.96-fold], gliadin [1.16-fold], and glutenin [0.95-fold]) and secondary structures (α-helix [0.91-fold], β-fold [0.96-fold], β-turn [1.06-fold], and random coil [1.05-fold]) of protein changed significantly, and the gluten network structure was broken in S. zeamais-infested wheat. Furthermore, the color of whole wheat noodle became darker, cooking loss rate increased, and textural properties (hardness, adhesiveness, springiness, cohesiveness, chewiness, and resilience) decreased as well. The results in the present study provided new insights for analyzing the quality deterioration mechanism and further quality improvement of boring pests-infested wheat grain.

Pinb-D1p is an elite allele for improving end-use quality in wheat (Triticum aestivum L.).

We identified ten QTLs controlling SDS-SV trait in a RIL population derived from ND3331 and Zang1817. Pinb-D1p is an elite allele from Tibetan semi‑wild wheat for good end-use quality. Gluten strength is an important factor for wheat processing and end-product quality and is commonly characterized using the sodium dodecyl sulfate-sedimentation volume (SDS-SV) test. The objective of this study was to identify quantitative trait loci (QTLs) associated with wheat SDS-SV traits using a recombinant inbred line (RIL) population derived from common wheat line NongDa3331 (ND3331) and Tibetan semi-wild wheat accession Zang1817. We detected 10 QTLs controlling SDS-SV on chromosomes 1A, 1B, 3A, 4A, 4B, 5A, 5D, 6B and 7A, with individual QTLs explaining 2.02% to 15.53% of the phenotypic variation. They included four major QTLs, Qsdss-1A, Qsdss-1B.1, Qsdss-1B.2, and Qsdss-5D, whose effects on SDS-SV were due to the Glu-A1 locus encoding the high-molecular-weight glutenin subunit 1Ax1, the 1B/1R translocation, 1Bx7 + 1By8 at the Glu-B1 locus, and the hardness-controlling loci Pina-D1 and Pinb-D1, respectively. We developed KASP markers for the Glu-A1, Glu-B1, and Pinb-D1 loci. Importantly, we showed for the first time that the hardness allele Pinb-D1p positively affects SDS-SV, making it a good candidate for wheat quality improvement. These results broaden our understanding of the genetic characterization of SDS-SV, and the QTLs identified are potential target regions for fine-mapping and marker-assisted selection in wheat breeding programs.

통밀빵 제조에 적합한 통밀가루 품질지표 규명

Purpose: This study was to identify the major quality parameters of whole wheat flour suitable for making whole wheat bread. Methods: The commercial twelve whole wheat flour samples were analyzed for physicochemical characteristics and bread-baking performance. Results: The tested samples showed a wide range of ash contents, water, sodium carbonate solvent retention capacity (SRC), sodium dodecyl sulfate (SDS)-sedimentation volumes, particle sizes, and colors. The bread-making performance of the flours also showed significant variations in crumb colors, dough heights, bread heights, and bread volumes. The correlation and principal component analyses of the quality characteristics of whole wheat flour and whole wheat bread showed that the dough height and the bread height and volume correlated negatively with the ash content and water SRC but positively with the SDS sedimentation of the whole wheat flour. However, the firmness of the bread showed the opposite relationship. Conclusion: In conclusion, the ash content, water SRC, and SDS sedimentation volume of the whole wheat flour can be used as valuable indicators to predict the quality of the whole wheat bread.

Identification and Validation of Stable Quantitative Trait Loci for SDS-Sedimentation Volume in Common Wheat (Triticum aestivum L.).

Sodium dodecyl sulfate-sedimentation volume is an important index to evaluate the gluten strength of common wheat and is closely related to baking quality. In this study, a total of 15 quantitative trait locus (QTL) for sodium dodecyl sulfate (SDS)-sedimentation volume (SSV) were identified by using a high-density genetic map including 2,474 single-nucleotide polymorphism (SNP) markers, which was constructed with a doubled haploid (DH) population derived from the cross between Non-gda3753 (ND3753) and Liangxing99 (LX99). Importantly, four environmentally stable QTLs were detected on chromosomes 1A, 2D, and 5D, respectively. Among them, the one with the largest effect was identified on chromosome 1A (designated as QSsv.cau-1A.1) explaining up to 39.67% of the phenotypic variance. Subsequently, QSsv.cau-1A.1 was dissected into two QTLs named as QSsv.cau-1A.1.1 and QSsv.cau-1A.1.2 by saturating the genetic linkage map of the chromosome 1A. Interestedly, favorable alleles of these two loci were from different parents. Due to the favorable allele of QSsv.cau-1A.1.1 was from the high-value parents ND3753 and revealed higher genetic effect, which explained 25.07% of the phenotypic variation, mapping of this locus was conducted by using BC3F1 and BC3F2 populations. By comparing the CS reference sequence, the physical interval of QSsv.cau-1A.1.1 was delimited into 14.9 Mb, with 89 putative high-confidence annotated genes. SSVs of different recombinants between QSsv.cau-1A.1.1 and QSsv.cau-1A.1 detected from DH and BC3F2 populations showed that these two loci had an obvious additive effect, of which the combination of two favorable loci had the high SSV, whereas recombinants with unfavorable loci had the lowest. These results provide further insight into the genetic basis of SSV and QSsv.cau-1A.1.1 will be an ideal target for positional cloning and wheat breeding programs.

Morpho-physiological and qualitative variation of domesticated einkorn (Triticum monococcum L. ssp. monococcum)

A pool of 158 Triticum monococcum L. ssp. monococcum accessions, originating from different traditional cropping areas and representative of the einkorn germplasm collection maintained at Sant’Angelo Lodigiano, was characterised for 20 morpho-physiological and qualitative descriptors. The accessions were grown for 4 years in two different Po plain (Italy) locations. The traits analysed were growth habit, awn length, glume colour and hairiness, rachis brittleness, heading date, plant height, spike length, n° spikelets/spike, spikelet density, n° kernels/spikelet, kernel length, width, thickness and volume, thousand kernels weight, protein and carotenoid content, sodium dodecyl sulphate sedimentation volume and specific sedimentation volume. A broad variation for all the traits studied was detected and promising accessions for breeding purposes were identified. Several characteristics showed a clear region-specific pattern: the samples tracing their origin to warmer climates were earlier-maturing, taller, had shorter spikes, fewer spikelet/spike, bigger kernels and lower protein content than those from cooler regions. A Principal Components Analysis highlighted the existence of two clusters composed mainly of Maghreb/Iberia and of Prealpine genotypes, whose peculiar characteristics are most likely a consequence of adaptation, by natural selection or by human practices and ingenuity, to their growing environments.

Allelic Variation for Prolamins in Spanish Durum Wheat Landraces and Its Relationship with Quality Traits

Wheat landraces are currently being explored mainly as a source of allelic variation related to crop resilience and low-input adaptation. Characterization of their high- and low-molecular weight glutenin subunits can aid breeders to select as donor local materials those ensuring good end-use properties in the derived elite cultivars. By using protein electrophoretic methods, we have determined the prolamin allelic profile of 116 Spanish durum wheat landraces. Their quality properties (as defined by grain protein content, sodium dodecyl sulfate (SDS) sedimentation volume and mixograph behavior) have also been assessed. The study has identified six novel glutenin alleles plus some other rare alleles some of which have been associated with improved durum wheat quality. Most of the novel variation detected needs to be characterized in a wider sample of varieties to establish any eventual beneficial effect on functional quality. Further analysis of the quality properties associated to specific allele combinations of Glu-A3, Glu-B3, and Glu-A1 has disclosed some clues on the influence on quality of certain non-allelic interactions between these main prolamin-encoding loci. Some of the landraces, showing outstanding values for the gluten quality parameters analyzed, might be directly used by farmers interested in the cultivation of traditional varieties for specialized food markets.

Effectiveness of Genomic Selection by Response to Selection for Winter Wheat Variety Improvement.

Prediction performance for winter wheat grain yield and end-use quality traits. Prediction accuracies evaluated by cross-validations are significantly overestimated. Nonparametric algorithms outperform the parametric alternatives in cross-year predictions. Strategically designing training population improves response to selection. Response to selection varies across growing seasons and environments. Considering the practicality of applying genomic selection (GS) in the line development stage of a hard red winter (HRW) wheat (Triticum aestivum L.) variety development program (VDP), the effectiveness of GS was evaluated by prediction accuracy and by the response to selection across field seasons that demonstrated challenges for crop improvement under significant climate variability. Important breeding targets for wheat improvement in the southern Great Plains of the United States, including grain yield, kernel weight, wheat protein content, and sodium dodecyl sulfate (SDS) sedimentation volume as a rapid test for predicting bread-making quality, were used to estimate the effectiveness of GS across harvest years from 2014 (drought) to 2016 (normal). In general, nonparametric algorithms reproducing kernel Hilbert space (RKHS) and random forest (RF) produced higher accuracies in both same-year cross-validations (CVs) and cross-year predictions for the purpose of line selection. Further, the stability of GS performance was greatest for SDS sedimentation volume but least for wheat protein content. To ensure long-term genetic gain, our study on selection response suggested that across this sample of environmental variability, and though there are cases where phenotypic selection (PS) might be still preferred, training conducted under drought or in suboptimal conditions could provide an encouraging prediction outcome when selection decisions were made in normal conditions. However, it is not advisable to use training information collected from a normal season to predict trait performance under drought conditions. Finally, the superiority of response to selection was most evident if the training population (TP) can be optimized.

Influence of protein characteristics and the proportion of gluten on end-use quality in Korean wheat cultivars

The effects of protein characteristics and the proportion of gluten on end-use quality in 13 Korean wheat cultivars for three years were verified in this study. Year, cultivar, and the interaction between the year and the cultivar influenced protein characteristics, the proportion of gluten except for γ- and ω-gliadin using RP-HPLC (reversed-phase high-performance liquid chromatography), and end-use quality. Protein characteristics and the proportion of gluten in Korean wheat cultivars were between those of Australian standard white (ASW) and hard wheat (AH). Korean wheat cultivars exhibited a higher average α+β gliadin proportion than imported wheat, a γ-gliadin proportion similar to that of dark northern spring wheat, and the same ω-gliadin proportion as AH. They showed a bread-loaf volume intermediate between those of ASW and AH and a texture of cooked noodles similar to that of soft white wheat, but less springiness than imported wheat. The cookie diameter of Korean wheat cultivars was similar to that of hard red winter wheat. There was a correlation between bread-loaf volume and protein characteristics, except for the protein content in Korean wheat cultivars. Springiness and cohesiveness of cooked noodles were not correlated with protein characteristics, while hardness was correlated with the protein content and water absorption of a mixograph. Cookie diameter was negatively correlated with the sodium dodecyl sulfate (SDS) sedimentation volume and water absorption of a mixograph. The end-use quality was not correlated with any proportion of gluten composition. Principal component analysis (PCA) showed that the proportion of gluten was not related to the quality of the bread (both PCs, 81.3%), noodle (77.7%), and cookie (82.4%). PCA explained that Keumkang is suitable for superior bread, while Uri is good for cooked noodles and cookies.

Genetic Dissection of End-Use Quality Traits in Adapted Soft White Winter Wheat.

Soft white wheat is used in domestic and foreign markets for various end products requiring specific quality profiles. Phenotyping for end-use quality traits can be costly, time-consuming and destructive in nature, so it is advantageous to use molecular markers to select experimental lines with superior traits. An association mapping panel of 469 soft white winter wheat cultivars and advanced generation breeding lines was developed from regional breeding programs in the U.S. Pacific Northwest. This panel was genotyped on a wheat-specific 90 K iSelect single nucleotide polymorphism (SNP) chip. A total of 15,229 high quality SNPs were selected and combined with best linear unbiased predictions (BLUPs) from historical phenotypic data of the genotypes in the panel. Genome-wide association mapping was conducted using the Fixed and random model Circulating Probability Unification (FarmCPU). A total of 105 significant marker-trait associations were detected across 19 chromosomes. Potentially new loci for total flour yield, lactic acid solvent retention capacity, flour sodium dodecyl sulfate sedimentation and flour swelling volume were also detected. Better understanding of the genetic factors impacting end-use quality enable breeders to more effectively discard poor quality germplasm and increase frequencies of favorable end-use quality alleles in their breeding populations.

Soft wheat quality characteristics required for making baking powder biscuits

Fifteen soft wheat varieties were evaluated for their grain, milling, flour and dough mixing characteristics, as well as their solvent retention capacities (SRCs), pasting properties and suitability for making baking powder biscuits, to identify wheat quality characteristics required for making biscuits. Grain and flour protein contents and sodium dodecyl sulfate sedimentation (SDSS) volume showed positive relationships with biscuit height and shape factor (SF). Kernel hardness, damaged starch content and water SRC exhibited negative correlations with biscuit specific volume (SV), while peak viscosity and grain protein content were positively associated with biscuit SV. Stepwise multiple regression analysis indicated that biscuit height and SV can be predicted from flour protein content (R2 = 0.65) and damaged starch content (R2 = 0.69), respectively; while SDSS volume and flour yield together predict biscuit SF (R2 = 0.83). Cluster analysis based on biscuit height and SF indicated that seven soft wheat varieties with flour protein contents greater than 7.9% and SDSS volumes lower than 32.0 mL produce good-quality biscuits with high height, intermediate SF, great SV and soft crumb. The results of this study suggest that soft wheat flours with intermediate-to-high protein contents (7.9–9.7%), intermediate SDSS volumes (20.0–32.0 mL) and low damaged starch contents (1.9–3.4%) are suitable for making desirable-quality biscuits.

Qualitative Effect of Added Gluten on Dough Properties and Quality of Chinese Steamed Bread

Glutens isolated from 15 soft red winter (SRW) wheat flours were added into a SRW wheat flour to obtain protein levels of 9.6 and 11.3% for determination of the qualitative effect of added gluten on the dough properties and quality of northern‐style Chinese steamed bread (CSB). Sodium dodecyl sulfate sedimentation (SDSS) volume of the gluten source flour exhibited positive relationships with mixograph absorption, midline peak time (MPT), and midline peak value (MPV) of the gluten‐added flours and with surface smoothness, crumb structure, and total score of CSB prepared from the gluten‐added flours regardless of protein content. Positive correlations were also observed between SDSS volume of the gluten source flour and specific volume and stress relaxation score of CSB prepared from the gluten‐added flours of 11.3% protein. The increase in protein content from 9.6 to 11.3% by gluten addition raised mixograph absorption, MPT, and MPV but had no apparent effect on resistance breakdown, dough maximum force for extension, and extensibility, and it increased CSB specific volume and crumb structure score without affecting surface smoothness, stress relaxation, and total score. Mixograph parameters exhibited significant relationships with CSB total score, indicating that they could be effective predictors of the CSB‐making quality of flours.

Exploring Functionality of Hard and Soft Wheat Flour Blends for Improved End‐Use Quality Prediction

Blending wheat or flour to meet end‐use requirements is a critical part of the production process to deliver consistent quality products. The functionality of commercial Canadian hard red wheat flour (HWF) and soft red wheat flour (SWF) blends with ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 (HWF/SWF, w/w) was investigated with new and standard methods to discern which functional properties may be indicators of bread quality and processing performance. Rheological characteristics including farinograph water absorption behavior, dough development time (DT), stability, extensigraph extensibility, and gluten aggregation of wheat flours were significantly influenced by the proportion of HWF in blends of SWF and HWF (P < 0.05). The SWF content in the blends had negative linear relationships with the protein content, lactic acid solvent retention capacity, water absorption, and GlutoPeak peak torque. Polynomial relationships were observed for sodium dodecyl sulfate sedimentation volume, DT, stability, extensibility, resistance, GlutoPeak peak time, and bread loaf volume with the amount of SWF in blends. The results indicate that linear responses may be more closely tied to protein content, whereas polynomial responses may be more indicative of protein quality and baking performance. The GlutoPeak peak time was sensitive to the addition of HWF in the blends, showing a significant change in gluten aggregation kinetics between the 0 and 25% HWF samples. Principal component analysis (PCA) confirmed that GlutoPeak peak time was a significant factor in differentiating the 0% HWF. Protein secondary structures identified in the final baked bread were also PCA factors differentiating the 0% HWF sample. Although the 0% bread sample did not deviate from the observed polynomial trend for bread loaf volume, the differences in bread protein secondary structures may translate into differences in processing tolerance in commercial settings.

Effects of rain shelter or simulated rain during grain filling and maturation on subsequent wheat grain quality in the UK

SUMMARYThe effects of simulated additional rain (ear wetting, 25 mm) or of rain shelter imposed at different periods after anthesis on grain quality at maturity and the dynamics of grain filling and desiccation were investigated in UK field-grown crops of wheat (Triticum aestivumL., cvar Tybalt) in 2011 and in 2012 when June–August rainfall was 255·0 and 214·6 mm, respectively, and above the decadal mean (157·4 mm). Grain filling and desiccation were quantified well by broken-stick regressions and Gompertz curves, respectively. Rain shelter for 56 (2011) or 70 days (2012) after anthesis, and to a lesser extent during late maturation only, resulted in more rapid desiccation and hence progress to harvest maturity whereas ear wetting had negligible effects, even when applied four times. Grain-filling duration was also affected as above in 2011, but with no significant effect in 2012. In both years, there were strong positive associations between final grain dry weight and duration of filling. The treatments affected all grain quality traits in 2011: nitrogen (N) and sulphur (S) concentrations, N : S ratio, sodium dodecyl sulphate (SDS) sedimentation volume, Hagberg Falling Number (HFN), and the incidence of blackpoint. Only N concentration and blackpoint were affected significantly by treatments in 2012. Rain shelter throughout grain filling reduced N concentration, whereas rain shelter reduced the incidence of blackpoint and ear wetting increased it. In 2011, rain shelter throughout reduced S concentration, increased N : S ratio and reduced SDS. Treatment effects on HFN were not consistent within or between years. Nevertheless, a comparison between the extreme treatment means in 2012 indicated damage from late rain combined with ear wetting resulted in a reduction ofc. 0·7 s in HFN/mm August rainfall, while that between samples taken immediately after ear wetting at harvest maturity or 7 days later suggested recovery from damage to HFN upon re-dryingin planta. Hence, the incidence of blackpoint was the only grain quality trait affected consistently by the diverse treatments. The remaining aspects of grain quality were comparatively resilient to rain incident upon developing and maturing ears of cvar Tybalt. No consistent temporal patterns of sensitivity to shelter or ear wetting were detected for any aspect of grain quality.

Quality Requirements of Soft Red Winter Wheat for Making Northern‐Style Chinese Steamed Bread

Flours of 19 soft red winter (SRW) wheat varieties having protein contents of 6.6–9.9% were used to determine the suitability of SRW wheat for making northern‐style Chinese steamed bread (CSB) and the influences of flour characteristics on the quality attributes of CSB. Fourteen varieties produced CSB of acceptable to good quality with a total score greater than 70. Both protein content and dough strength‐related parameters, including sodium dodecyl sulfate sedimentation (SDSS) volume, wet and dry gluten contents, and midline peak time (MPT), were significantly associated with the quality attributes of CSB. The rapid viscosity analyzer setback value exhibited significant negative correlations with specific volume, smoothness, crumb structure, and total score of CSB. Stepwise multiple regression analysis indicated that 89% of variability in total scores of CSB could be predicted from SDSS volume, wet gluten content, and MPT. Contributions of high‐molecular‐weight glutenin subunits 7*+8 and 5+10 to flour characteristics, specific volume, stress relaxation score, and total score of CSB were greater than those of their counterpart allelic variations. Absence of the 1B/1R translocation in SRW wheat varieties was desirable for the production of CSB.

Common wheat and cereal bug interactions: kernel quality depletion and immunodetection of damage

SUMMARYSeveral species of Heteroptera are responsible for kernel damage in wheat, Triticum aestivum L. (Poaceae), which affects bread-making quality. In Europe, the most noxious bugs belong to the genera Eurygaster (Scutelleridae) and Aelia (Pentatomidae). In the present work, five bug species frequently found in wheat fields in north-western Italy, Eurygaster maura, E. austriaca, Aelia acuminata, Nezara viridula and Carpocoris purpureipennis, were tested in field trials for their capacity to induce wheat damage. The sodium dodecyl sulphate sedimentation volume test was used as the qualitative control. Among the bug species tested, E. maura was the most noxious pest, with C. purpureipennis being almost as noxious as E. maura. In contrast, E. austriaca and A. acuminata, which have been considered the wheat pests of major importance, as well as N. viridula, caused no or only moderate damage to wheat quality. The adoption of an antiserum specifically produced with E. maura salivary glands proved to be effective and specific in detecting bug damage. Therefore, this polyclonal antibody is promising for the development of a reliable test for the quick evaluation of commercial wheat flour batches.

Quality characteristics of parental lines of wheat mapping populations

The aim of this work was to evaluate the main quality traits in the parental lines of wheat segregating populations to identify the best for subsequent genetic mapping of the traits. Significant differences (p < 0.001) among wheat genotypes were observed. Many of the examined crosses appeared to be suitable for the purpose, showing differences among parental lines as high as 4.6% for protein content, 6.4% for gluten content, 69 for gluten index, 50 mL for sodium dodecyl sulphate sedimentation volume, and 33.9 g for thousand-kernel weight, whereas differences accounting for 4.8, 2.4, and 7.3 were observed for yellow index, red index and brown index, respectively. The results pointed out that for studying at the same time the quantitative and qualitative features of gluten, the wheat populations derived from Latino x MG29896 and Saragolla x 02-5B-318 could be particularly appropriate. In addition, the latter cross was suitable to deepen the knowledge of yellow index regulation.

Effect of Rht alleles on wheat grain yield and quality under high temperature and drought stress during booting and anthesis.

The present study examined the effects of gibberellin semi-sensitive reduced height (Rht) alleles on wheat grain yield and quality under high temperature and drought stress during booting and anthesis stages. Near-isogenic lines (NILs) of winter wheat (Rht (tall), Rht-B1b, Rht-D1b, Rht-B1c, Rht-8c, Rht-D1c, Rht-12) having background of Mercia and Maris Widgeon cultivars were compared under variable temperatures (day/night: 20/12, 27/19, 30/22, 33/25, 36/28, and 39/31 °C) and irrigation regimes. Pots were transferred to controlled thermal conditions (Saxcil growth chamber) during booting and anthesis stages and were maintained at field capacity (FC) or had water withheld. High temperature (>30 °C) and drought stress for seven consecutive days during booting and anthesis stages reduced the grain yield, while increased nitrogen (N) and sulphur (S) concentrations. A 50 % reduction in grain yield was fitted to have occurred at 37.4 °C for well-watered plants and at 31.4 °C for drought-stressed plants. The N and S concentrations were higher for severe dwarfs, whereas no significant differences were observed between tall and semi-dwarfs in Mercia. In the taller background (Maris Widgeon), N and S concentrations were significantly higher compared with that in Mercia. In Mercia, the severe dwarf Rht-D1c had higher Hagberg falling number (HFN) and sodium dodecyl sulphate (SDS) sedimentation volume. In both backgrounds, semi-dwarfs and severe dwarfs had higher HFN. Moreover, the SDS sedimentation volumes in Maris Widgeon were also higher than that in Mercia. Greater adaptability and improved grain quality traits suggested that severe dwarf Rht alleles are better able to enhance tolerance to high temperature and drought stress in wheat.