Mixograph Parameters Research Articles

Quality and Agronomic Trait Analyses of Pyramids Composed of Wheat Genes NGli-D2, Sec-1s and 1Dx5+1Dy10.

Due to rising living standards, it is important to improve wheat's quality traits by adjusting its storage protein genes. The introduction or locus deletion of high molecular weight subunits could provide new options for improving wheat quality and food safety. In this study, digenic and trigenic wheat lines were identified, in which the 1Dx5+1Dy10 subunit, and NGli-D2 and Sec-1s genes were successfully polymerized to determine the role of gene pyramiding in wheat quality. In addition, the effects of ω-rye alkaloids during 1BL/1RS translocation on quality were eliminated by introducing and utilizing 1Dx5+1Dy10 subunits through gene pyramiding. Additionally, the content of alcohol-soluble proteins was reduced, the Glu/Gli ratio was increased and high-quality wheat lines were obtained. The sedimentation values and mixograph parameters of the gene pyramids under different genetic backgrounds were significantly increased. Among all the pyramids, the trigenic lines in Zhengmai 7698, which was the genetic background, had the highest sedimentation value. The mixograph parameters of the midline peak time (MPT), midline peak value (MPV), midline peak width (MPW), curve tail value (CTV), curve tail width (CTW), midline value at 8 min (MTxV), midline width at 8 min (MTxW) and midline integral at 8 min (MTxI) of the gene pyramids were markedly enhanced, especially in the trigenic lines. Therefore, the pyramiding processes of the 1Dx5+1Dy10, Sec-1S and NGli-D2 genes improved dough elasticity. The overall protein composition of the modified gene pyramids was better than that of the wild type. The Glu/Gli ratios of the type I digenic line and trigenic lines containing the NGli-D2 locus were higher than that of the type II digenic line without the NGli-D2 locus. The trigenic lines with Hengguan 35 as the genetic background had the highest Glu/Gli ratio among the specimens. The unextractable polymeric protein (UPP%) and Glu/Gli ratios of the type II digenic line and trigenic lines were significantly higher than those of the wild type. The UPP% of the type II digenic line was higher than that of the trigenic lines, while the Glu/Gli ratio was slightly lower than that of the trigenic lines. In addition, the celiac disease (CD) epitopes' level of the gene pyramids significantly decreased. The strategy and information reported in this study could be very useful for improving wheat processing quality and reducing wheat CD epitopes.

Discrimination of Glutopeak Test and Mixograph Parameters for Evaluation of Wheat Flour Supplemented with Hazelnut Skin, Cross-Linked Starch, and Oxidized Starch.

Hazelnut skin is a by-product produced from hazelnut processing. It can be used as a nutritional supplement due to its high nutrient values. The purpose of this study was to evaluate the dough properties of refined flour (RF) with the addition of hazelnut skin (HS), cross-linked starch (CS), and oxidized starch (OS). Principal component analysis showed a positive correlation between maximum torque, torque after maximum, and aggregation energy. Usage of 10% HS significantly (p < 0.05) decreased the mixograph MID line peak value indicating a weaker dough. Random forest (RFT) was conducted to classify the samples and to determine the importance levels of the analysis parameters. According to the results, AE and mixograph MID line peak values were the most discriminant parameters to distinguish the samples into groups. High-level HS alone caused undesirable effects on the dough quality, yet the addition of modified starches could be used to compensate for the undesirable effects. When used together, the interaction between hazelnut skin and modified starches should be considered. Glutopeak provides a means for assessing the impacts of additives such as hazelnut skin or modified starches on flour functionality.

Influence of high-molecular-weight glutenin subunit deletions at the Glu-A1 and Glu-D1 loci on protein body development, protein components and dough properties of wheat (Triticum aestivum L.)

High-molecular-weight glutenin subunits (HMW-GSs) play a critical role in determining the viscoelastic properties of wheat. As the organelle where proteins are stored, the development of protein bodies (PBs) reflects the status of protein synthesis and also affects grain quality to a great extent. In this study, with special materials of four near-isogenic lines in a Yangmai 18 background we created, the effects of Glu-A1 and Glu-D1 loci deletions on the development and morphological properties of the protein body, protein components and dough properties were investigated. The results showed that the deletion of the HMW-GS subunit delayed the development process of the PBs, and slowed the increases of volume and area of PBs from 10 days after anthesis (DAA) onwards. In contrast, the areas of PBs at 25 DAA, the middle or late stage of endosperm development, showed no distinguishable differences among the four lines. Compared to the wild type and single null type in Glu-A1, the ratios of HMW-GSs to low-molecular-weight glutenin subunits (LMW-GSs), glutenin macropolymer (GMP) content, mixograph parameters as well as extension parameters decreased in the single null type in Glu-D1 and double null type in Glu-A1 and Glu-D1, while the ratios of gliadins (Gli)/glutenins (Glu) in those types increased. The absence of Glu-D1 subunits decreased both dough strength and extensibility significantly compared to the Glu-A1 deletion type. These results provide a detailed description of the effect of HMW-GS deletion on PBs, protein traits and dough properties, and contribute to the utilization of Glu-D1 deletion germplasm in weak gluten wheat improvement for use in cookies, cakes and southern steamed bread in China and liquor processing.

USING MIXOGRAPH PARAMETERS AND SOME QUALITY PROPERTIES IN SELECTION OF DURUM WHEAT GENOTYPES

This research was carried out in order to determine some chemical, physical and rheological (mixograph) traits of 4 standard durum wheat varieties and 11 durum wheat lines in 2015-2016 under irrigated conditions in Gözlü and Central location of Konya according to randomized block design with three replications. Means of quality parameters varied for thousand kernel weight (30.26-38.45 g), protein ratio (12.94-14.77%), SDS sedimentation (13.75-29.75 ml), color (b value) (20.45-23.35), mixograph development time (1.55-3.79 min), peak height (46.47-81.38%), softening (slope) (6.46-28.85 min/%), peak width (2.19-15.13%), peak area (54-165 Nm) and total area (energy) (236-407 Nm). Significant differences were found between wheat varieties in terms of examined features. Durum wheat lines having weak, strong and very strong gluten were identified in this research. Keywords: Wheat breeding, landraces, genetic structure, semolina, dough traits, gluten index, mixograph parameters.

The Influence of Water and Nitrogen Availability on the Expression of End-Use Quality Parameters of Spring Wheat

Wheat (Triticum aestivum L.) grain quality is determined by multiple physical and chemical attributes. However, previous studies mainly focused on protein quantity and composition, which may not be adequate for understanding grain quality, especially end-use quality. Field experiments were conducted at two locations for two years to better understand how and to what extent water and nitrogen (N) availability affect flour end-use quality. Four drought stress levels (i.e., mild, moderate, severe, and well-watered) and four N rates (i.e., zero, low, medium, and high) were applied to two spring wheat cultivars (i.e., Dayn and Egan). Evaluated end-use quality traits, including milling quality, mixograph parameters, flour protein and gluten contents, solvent retention capacity (SRC), and baking quality. Most end-use quality parameters were not significantly different between the well-watered treatment and mild drought stress in both cultivars. Nitrogen availability above the low rate (168 kg N ha−1) failed to further improve most end-use quality traits in either cultivar. Among all the end-use quality traits, lactic acid SRC may be a reliable indicator of flour end-use quality. These results indicate that mild drought stress (i.e., a 25% reduction in irrigation throughout the growing season) may not negatively affect end-use quality and excessive N fertilization offers minimal improvement in end-use quality. Such information could facilitate the development of irrigation and fertilization guidelines targeting at grain quality.

Characteristics of normal and waxy corn: physicochemical, protein secondary structure, dough rheology and chapatti making properties.

The physicochemical, protein secondary structure, dough rheological and chapatti making properties of normal and waxy corn types were evaluated. Waxy corn grains showed the highest L* and b* value, while red-pigmented corn grains had the highest a* value. Higher accumulation of K, Mg, Na and Ca minerals in corn was recorded, while Cu, Mn, Fe and Zn were present in trace. Meal prepared from waxy corn had higher L*, a* and b* values as well as ash, protein and fat content. A significant decrease in various mixograph parameters was observed with increase in water level during dough development. A decrease in dynamic rheological parameters (G', G'' and tan δ) of dough from all corn types was recorded with increase in water level. Dough developed from waxy corn meal had lower G' and G'' as compared to that from normal corn types. FTIR spectra of dough from different corn types at different water levels showed various peaks in amide-I region with most prominent peak at about 1650cm-1 followed by 1640-1645 and 1610-1620cm-1 regions. The peak intensities increased with increase in water level which was an indicative of the increase in intermolecular and antiparallel (IM+AP) β-sheet as well as α-helix and β-sheet structures. Dough developed from waxy corn showed change in peak intensities at high moisture level only. The chapatti made from normal (yellow) corn showed higher consumers' acceptability score, while that from waxy corn was poor.

Genotype, environment, seeding rate, and top-dressed nitrogen effects on end-use quality of modern Nebraska winter wheat.

Fine-tuning production inputs such as seeding rate, nitrogen (N), and genotype may improve end-use quality of hard red winter wheat (Triticum aestivium L.) when growing conditions are unpredictable. Studies were conducted at the Agronomy Research Farm (ARF; Lincoln, NE, USA) and the High Plains Agricultural Laboratory (HPAL; Sidney, NE, USA) in 2014 and 2015 in Nebraska, USA, to determine the effects of genotype (6), environment (4), seeding rate (3), and flag leaf top-dressed N (0 and 34 kg N ha-1 ) on the end-use quality of winter wheat. End-use quality traits were influenced by environment, genotype, seeding rate, top-dressed N, and their interactions. Mixograph parameters had a strong correlation with grain volume weight and flour yield. Doubling the recommended seeding rate and N at the flag leaf stage increased grain protein content by 8.1% in 2014 and 1.5% in 2015 at ARF and 4.2% in 2014 and 8.4% in 2015 at HPAL. The key finding of this research is that increasing seeding rates up to double the current recommendations with N at the flag leaf stage improved most of the end-use quality traits. This will have a significant effect on the premium for protein a farmer could receive when marketing wheat. © 2017 Society of Chemical Industry.

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.

Effect of Saline Organic Acid Solutions Applied During Wheat Tempering on Flour Functionality

Previously, we showed that tempering with saline organic acid solutions can reduce the aerobic plate count of wheat by as much as 4.3 log CFU/g. The purpose of this study was to evaluate the impact of these tempering solutions on the functional properties of resulting whole grain (WGF) and straight‐grade (SGF) flours. Wheat was tempered to 15.5% moisture by tempering with sterile distilled water (control) or solutions containing NaCl (26% [w/v]) together with organic acid (acetic or lactic 2.5 and 5.0% [v/v]). After milling, fractions were collected and recombined as needed to obtain WGF or SGF. The acid content in WGF was higher than in SGF, indicating limited penetration of the organic acids into the endosperm of the grain. In WGF, the saline organic acid treatments caused a decrease in paste viscosity and bread crumb cell sizes in breads. In SGF, the saline organic acid treatments caused significant changes in paste viscosity and some Mixograph parameters; however, principal components analysis indicated that the treatments did not substantially affect SGF functionality. Thus, WGF was altered by the saline organic acid solutions, whereas SGF functionality was minimally affected by tempering treatments, perhaps because of acids only partially penetrating into the endosperm.

Cloning and functional analysis of a novel x-type high-molecular-weight glutenin subunit with altered cysteine residues from Aegilops umbellulata

In common wheat (Triticum aestivum L.) and its relative species, considerable progress has been made in understanding the structure and function of the high-molecular-weight glutenin subunit (HMW-GS). As a species closely related to wheat, Aegilops umbellulata is an important resource for wheat genetic improvement. In this paper, we report a novel HMW-GS 1Ux3.5 in Aegilops umbellulata Y361. The complete open reading frame (ORF) coding for 1Ux3.5 was cloned and sequenced. Analysis of the deduced amino acid sequence revealed that the primary structure of 1Ux3.5 was similar to those of previously published HMW-GSs. The 1Ux3.5 possessed an extra cysteine residue in the repetitive domain, indicating that the subunit may be related to excellent dough quality. Subsequently, the single proteins of 1Ux3.5 and 1Dx5 (used as positive control) were purified at a scale sufficient for incorporation into flour for a dough quality test. Both the SDS sedimentation volume and mixograph parameters demonstrated that 1Ux3.5 showed a greater contribution to the dough quality than 1Dx5. Therefore, the 1Ux3.5 subunit from Aegilops umbellulata may have potential value in improving the processing properties of hexaploid wheat varieties.

PATTERN ANALYSIS OF TURKISH BREAD WHEAT LANDRACES AND CULTIVARS FOR GRAIN AND FLOUR QUALITY

This research was carried out to characterize both 200 pure lines selected from Turkish bread wheat landraces and 25 Turkish bread wheat cultivars based on 3 grain quality traits [thousand kernel weight (TKW), protein content (PC), Zeleny sedimentation test (ZSDS)] and 5 mixograph parameters. Univariate and Multivariate (clustering and ordination) techniques were used to investigate the diversity present among the pure lines and cultivars. Both cluster and ordination analyses suggested that there were ten groups of studied genotypes. Applying genotype-by-trait (GT) biplot analysis to the multiple quality trait data revealed that GT-biplot graphically displayed the interrelationships among traits and facilitated visual comparison of pure lines and selection. The results also showed that, based on the quality traits, the pure lines in different groups were belonged to different provinces of Turkey. They were also proved to be highly diverse for 8 quality trait values (both mixograph and grain quality) to breeders and end-users. Especially most of the pure lines had higher PC, midline peak value of mixogram (MPV), midline time x = 8 min integral of mixogram (MTxI) and ZSDS values than some of the cultivars. Also, our results were very contributive in selection of precious pure lines for further breeding programs.

Quality Characteristics of Wholemeal Flour and Bread from Durum Wheat (Triticum turgidum L subsp. durum Desf.) after Field Treatment with Plant Water Extracts.

The use of selected plant water extracts to control pests and weeds is gaining growing attention in organic and sustainable agriculture, but the effects that such extracts may exert on the quality aspects of durum wheat are still unexplored. In 2014, 5 plant water extracts (Artemisia arborescens, Euphorbia characias, Rhus coriaria, Thymus vulgaris, Lantana camara) were prepared and distributed on durum wheat cv Valbelice to evaluate their potential herbicidal effects. After crop harvesting, the major physicochemical and technological parameters of wholemeal flours obtained from each treatment were measured and compared with those from chemical weeding and untreated controls. A baking test was also performed to evaluate the breadmaking quality. In wholemeal flours obtained after the treatment with plant extracts protein and dry gluten content were higher than in control and chemical weeding. Wholemeal flours obtained after chemical weeding reached the highest Mixograph parameters, and that from durum wheat treated with R. coriaria extract demonstrated a very high α-amylase activity. We concluded that the treatments with plant water extracts may influence many quality traits of durum wheat. This occurrence must be taken into account in overall decisions concerning the use of plant extracts in pest and weed management practice.

Genome-Wide QTL Mapping for Wheat Processing Quality Parameters in a Gaocheng 8901/Zhoumai 16 Recombinant Inbred Line Population.

Dough rheological and starch pasting properties play an important role in determining processing quality in bread wheat (Triticum aestivum L.). In the present study, a recombinant inbred line (RIL) population derived from a Gaocheng 8901/Zhoumai 16 cross grown in three environments was used to identify quantitative trait loci (QTLs) for dough rheological and starch pasting properties evaluated by Mixograph, Rapid Visco-Analyzer (RVA), and Mixolab parameters using the wheat 90 and 660 K single nucleotide polymorphism (SNP) chip assays. A high-density linkage map constructed with 46,961 polymorphic SNP markers from the wheat 90 and 660 K SNP assays spanned a total length of 4121 cM, with an average chromosome length of 196.2 cM and marker density of 0.09 cM/marker; 6596 new SNP markers were anchored to the bread wheat linkage map, with 1046 and 5550 markers from the 90 and 660 K SNP assays, respectively. Composite interval mapping identified 119 additive QTLs on 20 chromosomes except 4D; among them, 15 accounted for more than 10% of the phenotypic variation across two or three environments. Twelve QTLs for Mixograph parameters, 17 for RVA parameters and 55 for Mixolab parameters were new. Eleven QTL clusters were identified. The closely linked SNP markers can be used in marker-assisted wheat breeding in combination with the Kompetitive Allele Specific PCR (KASP) technique for improvement of processing quality in bread wheat.

Heritability and expression of selected mixograph parameters in progeny of parents varying for mixing time

The mixograph performs certain rheological measurements during dough mixing and is a good predictor of wheat end-use quality. The aim of this study was to determine the expression and the heritability of mixing characteristics measured with Mixsmart® software and some quality characteristics in hard red spring wheat parents and their F1 progeny. Six parents varying in midline peak time and envelope peak time were crossed in a half diallel design. Parents and progeny were planted in three different environments. General combining ability (GCA) was a significant source of variation for the measured characteristics, and parents differed widely in terms of GCA effects. Midline-development time, -peak integral and -peak time showed high narrow sense heritability. Envelope peak-integral and -tail width displayed high narrow sense heritability for some, but not all locations. High GCA:SCA (specific combining ability) ratios indicated the prevalence of additive gene effects for midline-development time, -peak integral and -peak time, indicating that these characteristics are largely genetically determined, and that selection for them should lead to genetic gain.

Towards the understanding of end-use quality in intermediate wheatgrass (Thinopyrum intermedium): High-molecular-weight glutenin subunits, protein polymerization, and mixing characteristics

Intermediate wheatgrass (Thinopyrum intermedium; IWG), is a perennial crop that is well-known for providing good environmental services. As a perennial relative of wheat, IWG has good potential for development into a perennial grain crop. But the diversity and potential of the end-use quality of IWG grain are still unknown. Here, to understand the end-use quality of IWG, we investigated the variability among seed from 60 IWG genotypes in high-molecular-weight glutenin subunits (HMW-GS), protein polymerization, and mixing characteristics. IWG genotypes have high grain protein content, ranging from 16.4 to 23.6%. Of the total proteins, the percentage of polymeric proteins show a large range across IWG genotypes, varying from 9.2 to 25.1%. Many genotypes have limited amounts of polymeric proteins, but several genotypes have large amounts of polymeric proteins and promising mixing properties, comparable to common wheat, Triticum aestivum. The amount of protein polymers in the SDS buffer unextractable fraction are significantly correlated (r ≥ 0.76) with mixograph parameters. Furthermore, we observed that HMW-GS variants showed differential contribution to protein polymerization and mixograph parameters. But the composition of HMW-GS in IWG was contributed by both parents, which might bring challenges for the evaluation of grain quality of open-pollinated IWG genotypes.

Allelic diversity of HMW and LMW glutenins in Indian wheats and their relationship with sedimentation volume and mixograph parameters

Two hundred and forty diverse set of wheat cultivars released in India during the last several decades were evaluated for HMW and LMW glutenin alleles, for assessing their diversity and effect on sedimentation volume and mixograph parameters. Both SDS-PAGE and PCR based markers were employed in identifying alleles encoded at Glu-1 and Glu-3 loci. Extensive allelic variation was observed at both the Glu-1 and Glu-3 loci. There was prevalence of Glu-A1b, Glu-B1i, Glu-D1a, Glu-A3c, Glu-B3b, Glu-B3g and Glu-D3b. The alleles Glu-A1b, Glu-B1i, Glu-D1d, Glu-A3b, Glu-B3g/h and Glu-D3b exhibited high SDS-sedimentation volume. Glu-B1i and Glu-D1d showed highly significant positive effect (p < 0.001) on sedimentation volume and also had additive effects. However, surprisingly overall there was decline in the frequency of Glu-B1i allele during last two decades in Indian wheat breeding and not a single 1B/1R translocation cultivar possessed this allele. Glu-A1b showed significant positive effect on mixograph peak time, peak slope and peak width. Glu-B3g exhibited significantly higher mixograph peak time and width at 8 and Glu-B3h showed higher dough stability. Glu-B3j (1B/1R translocation) exhibited highest peak slope indicating the negative effect on dough strength. This information can be useful in designing breeding program for the improvement of Indian bread wheat quality.

Influence of allelic prolamin variation and localities on durum wheat quality

Thirty-seven varieties of a Mediterranean durum wheat collection grown in Tunisia and Spain were analysed for their allelic composition in prolamins, as well as their protein concentration, sodium dodecyl sulphate sedimentation (SDSS) test and mixograph parameters. Genotype was a greater source of variation in all measurements than locality. Uncommon high and low molecular glutenin subunits (HMW-GS and LMW-GS) were found (V and 2•• subunits at Glu-A1, 13 + 16 at Glu-B1, 5* subunit and ax allele at Glu-A3). The rare combinations 2 + 4+14 + 18 and 8 + 9+13 + 16+18 subunits at the Glu-B3 locus were found. Glu-A3ax had a positive influence on SDSS and mixograph parameters. Of all the prolamins, those that have the B-LMW-GS composition aaa (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu-A1c and Glu-B1d gave the best semolina quality. By contrast, semolina quality is poor when this same composition is associated with the Glu-A1c and Glu-B1e and even poorer when associated with the Glu-A1c and Glu-B1f. In addition, the cultivars with B-LMW-GS allelic composition aab (for Glu-A3, Glu-B3 and Glu-B2 loci, respectively), when associated with the Glu-A1c and Glu-B1d, gave high quality, whereas when associated with the Glu-A1c and Glu-B1e or with Glu-A1o and Glu-B1f, the quality was very poor.

Comparing Small‐Scale Testing Methods for Predicting Wheat Gluten Strength Across Environments

Gluten strength is the main factor determining the rheological and processing properties of wheat. Rapid, small‐scale tests that can indirectly predict gluten strength are extremely important for wheat‐breeding selection, particularly when using pedigree methodology. The efficiency and reliability of three small‐scale tests (SDS sedimentation volume [SDSS], swelling index of glutenin [SIG], and lactic acid retention capacity [LARC]) across three environments (E1, no stress; E2, drought stress; and E3, heat stress) were evaluated by using 15 common wheat and nine durum wheat cultivars. In the case of common wheat, SIG highlighted its advantage for predicting gluten strength, even under stress environments, compared with LARC and SDSS, whereas SDSS showed the best relationship with bread loaf volume. For durum wheat, SIG showed the best predicting value in E1 and E3; however, under drought stress, SDSS, SIG, and LARC all lost their good ability for predicting gluten strength in durum wheat, which needs further investigation. Also, the comparison between two mixograph parameters (mixograph peak time and mixograph peak integral) for predicting gluten strength and the suitability of testing SIG and LARC with whole meal (or semolina) instead of refined flour were also investigated.

Characteristics of modern triticale quality: glutenin and secalin subunit composition and mixograph properties.

Triticale is a hardy, high yielding cereal crop with a reputation for poor gluten strength. The secalogluten formation capacity was investigated in 17 modern triticale cultivars by defining their HMW glutenin and 75K γ-secalin alleles and then assessing SDS-sedimentation height and mixograph parameters in a subset of cultivars. The allelic diversity was poor with only 13 alleles identified at four loci; nevertheless, sufficient variability existed to allow secalogluten improvement through crossbreeding and selection. SDS-sedimentation height of triticale (35.5 mm) and mixing time (2.7 min) was equivalent to soft wheat but significantly less than hard wheat. However, flour protein content was 16% less in triticale compared to wheat, despite similar grain protein contents, suggesting triticale stores a lower proportion of grain protein in the endosperm. The confounding factor of protein content must be considered as part of an equitable analysis of gluten quality in cultivar breeding, in the interpretation of previous triticale research, and when comparing triticale to wheat. Improved glutenin properties will expand the utility of triticale in human food products and, thus, increase potential profitability.

QTL Mapping for Dough Mixing Characteristics in a Recombinant Inbred Population Derived from a Waxy × Strong Gluten Wheat (Triticum aestivum L.)

Protein and starch are the most important traits in determining processing quality in wheat. In order to understand the genetic basis of the influence of Waxy protein (Wx) and high molecular weight gluten subunit (HMW-GS) on processing quality, 256 recombinant inbred lines (RILs) derived from the cross of waxy wheat Nuomai 1 and Gaocheng 8901 were used as mapping population. DArT (diversity arrays technology), SSR (simple sequence repeat), HMW-GS, and Wx markers were used to construct the molecular genetic linkage map. QTLs for mixing peak time (MPT), mixing peak value (MPV), mixing peak width (MPW), and mixing peak integral (MPI) of Mixograph parameters were evaluated in three different environments. The genetic map comprised 498 markers, including 479 DArT, 14 SSR, 2 HMW-GS, and 3 Wx protein markers, covering 4 229.7 cM with an average distance of 9.77 cM. These markers were identified on 21 chromosomes. Eighteen additive QTLs were detected in three different environments, which were distributed on chromosomes 1A, 1B, 1D, 4A, 6A, and 7D. QMPT-1D.1 and QMPT-1D.2 were close to the Glu-D1 marker accounting for 35.2, 22.22 and 36.57% of the phenotypic variance in three environments, respectively. QMPV-1D and QMPV-4A were detected in all environments, and QMPV-4A was the nearest to Wx-B1. One minor QTL, QMPI-1A, was detected under three environments with the genetic distances of 0.9 cM from the nearest marker Glu-A1, explaining from 5.31 to 6.67% of the phenotypic variance. Three pairs of epistatic QTLs were identified on chromosomes 2D and 4A. Therefore, this genetic map is very important and useful for quality trait related QTL mapping in wheat. In addition, the finding of several major QTLs, based on the genetic analyses, further suggested the importance of Glu-1 loci on dough mixing characteristics.