Effect of the 1BL.1RS translocation and of the Glu-B3 variation on fifteen quality tests in a doubled haploid population of wheat (Triticum aestivum L.)

To investigate the impact of 1BL.1RS translocation on protein content, starch quality, dough rheology, RMT volumes and other quality traits, a doubled haploid population was created and sown in a two-year field experiment. Translocated genotypes accumulated more proteins in the endosperm than non-translocated genotypes. Decrease in the gelatinization of starch was associated with the 1BL.1RS translocation. As for rheological parameters, adapted to bread types not requiring high mixing energy, the 1BL.1RS translocation significantly reduced the elasticity, tenacity and strength of the dough compared to allele c of Glu-B3. Tolerance to over-mixing was also significantly lower in translocated DH lines. In contrast to previously published work, the presence of allele Glu-D3 c resulted in significantly higher tenacity, and thus strength, compared with the allele Glu-D3 b in the present DH population. The final baking test performed on the DH lines of the population, combining favourable alleles for dough rheology and high protein content, demonstrated that in some cases lower tenacity induced by the 1BL.1RS translocation or by Glu-B3 b increases the volume of the loaves.     

Separate effects on gluten strength of Gli-1 and Glu-3 prolamin genes on chromosomes 1A and 1B in durum wheat

Two recombinants between Gli-A1 and Glu-A3 prolamin genes and seven between Gli-B1 and Glu-B3 obtained from two crosses of durum wheat were classified on the basis of the prolamin alleles at the Glu-A1, Gli-A1, Glu-A3, Gli-A2, Glu-B1, Gli-B1 and Glu-B3 loci. The separate effects on gluten strength of gliadin genes at Gli-1 and low M_r glutenin subunit genes at Glu-3 were estimated by comparing the SDS-sedimentation test values of the recombinants with those of the same progeny having the same prolamin composition, except for the recombined alleles. The results showed clearly that low M_r glutenin subunit genes at Glu-A3 and Glu-B3, rather than gliadin genes at Gli-A1 and Gli-B1, were responsible for the differences in gluten strength.     

Effect of the 1BL.1RS translocation and of the Glu-B3 variation on fifteen quality tests in a doubled haploid population of wheat (Triticum aestivum L.)

To investigate the impact of 1BL.1RS translocation on protein content, starch quality, dough rheology, RMT volumes and other quality traits, a doubled haploid population was created and sown in a two-year field experiment. Translocated genotypes accumulated more proteins in the endosperm than non-translocated genotypes. Decrease in the gelatinization of starch was associated with the 1BL.1RS translocation. As for rheological parameters, adapted to bread types not requiring high mixing energy, the 1BL.1RS translocation significantly reduced the elasticity, tenacity and strength of the dough compared to allele c of Glu-B3. Tolerance to over-mixing was also significantly lower in translocated DH lines. In contrast to previously published work, the presence of allele Glu-D3 c resulted in significantly higher tenacity, and thus strength, compared with the allele Glu-D3 b in the present DH population. The final baking test performed on the DH lines of the population, combining favourable alleles for dough rheology and high protein content, demonstrated that in some cases lower tenacity induced by the 1BL.1RS translocation or by Glu-B3 b increases the volume of the loaves.     

Association analysis reveals effects of wheat glutenin alleles and rye translocations on dough-mixing properties

The glutenin loci of wheat (Triticum aestivum L.) are important determinants of bread-making quality, although the effects of alleles at those loci are incompletely understood. We applied an association analysis method to assess the effects of glutenin alleles and 1RS wheat–rye (Secale cereale L.) translocations on dough-mixing properties in 96 wheat cultivars and advanced lines grown at three Colorado locations while accounting for population structure and relatedness of individuals in the population. The results indicated that (1) in the majority of cases, controlling relatedness of individuals reduced the significance of associations between glutenin loci and Mixograph traits; (2) the Glu-D1 and Glu-B3 loci and 1RS translocations had greater impacts on dough-mixing properties compared to other glutenin loci; (3) Glu-B1w, Glu-D1d, and Glu-B3b were consistently associated with greater (more favorable) Mixograph peak time (MPT) than other alleles at the respective loci, whereas Glu-B1e, Glu-D1a, and Glu-B3c were associated with reduced MPT; (4) the 1BL.1RS translocation was associated with a decrease in Mixograph properties. Our results indicate that taking multiple-level relatedness of individuals into account can improve the results of association analysis for wheat-quality traits.     

Antigenicity of Wheat Prolamins: Detailed Epitope Analysis using a Panel of Monoclonal Antibodies

Putative continuous epitopes, recognised by five panels of monoclonal antibodies (MAb) with differing specificities for gliadins and glutenin subunits, were identified using overlapping nonapeptides. These peptides corresponded to the entire sequence of an α/β-gliadin, a γ-gliadin, an ω-prolamin (homologous to ω-gliadin), a low molecular weight glutenin subunit (L M_rGS) and several high molecular weight glutenin subunits (HM_r GS). Antibodies that bound to γ- or ω-gliadins, L M_rGS or HM_r GS bound to the peptides at similar concentrations used normally in direct ELISA, but little binding to the peptides was seen for several antibodies that bound specifically to small groups of α/β-gliadins. Epitopes for these antibodies in α/β-gliadin may be discontinuous (i.e. derived from amino acid residues that are brought together by folding of the polypeptide chain or by juxtaposition of two polypeptide chains), since binding of these antibodies to gliadins was greatly decreased following the reduction of intra-molecular disulphide bonds. While some regions in particular subunits were immunodominant, such as the cysteine–cysteine containing peptide found in the central domain of many prolamins, a diversity of reaction patterns was found. Cross-reaction of antibody with peptides from other prolamin families was often due to binding to a peptide having significant sequence homology, but in some cases no homology was obvious. Some major trends were as follows. Antibodies which bound to most or all H M_rGS recognised the central repeat region, while those that were selective for one or two subunits bound to epitopes in the unique N- and/or C-terminal domains. A high proportion of the epitopes recognised by MAb to α-, β-, ω-gliadins and L M_rGS contained cysteine; these MAb may be useful in detecting covalent binding sites within or between subunits. Although a number of MAb bound a wide range of gliadins and GS, several of these recognised single (and differing) epitopes in the target proteins. However, comparatively few MAb recognised epitopes from either the N- or C-terminal regions of the target proteins. Several explanations are possible; either these regions are buried in the immunogen and not accessible for antibody production or alternatively the repeat sequences are immunodominant.     

Characterization of a wheat mutant missing low-molecular-weight glutenin subunits encoded by the B-genome

DH20, a new wheat mutant missing low-molecular weight glutenin subunits encoded by the Glu-B3 locus, was discovered among double haploid lines obtained from a cross between the Korean wheat cultivars Keumkang and Olgeuru. Absence of the Glu-B3 LMW-GS proteins was determined by one-dimensional gel electrophoresis (SDS-PAGE) and confirmed by two-dimensional gel electrophoresis (2-DGE) and tandem mass spectrometry (MS/MS). The deletion of Glu-B3 genes was also demonstrated using allele specific DNA markers. Basic agronomic traits, protein content, dough mixing properties and bread loaf volume of DH20 and parental wheat cultivars were evaluated in field-grown wheat over a two year period. This mutant is a valuable resource for understanding the function of individual LMW-GS alleles or genes at the Glu-B3 locus using either breeding or biotechnology approaches.     

Effect of Allelic Variation of Glutenin Subunits and Gliadins on Baking Quality in the Progeny of Two Biotypes of Bread Wheat cv. Ulla

During the determination of the HMW glutenin subunit composition of Finnish varieties, the variety Ulla was observed to contain two biotypes which differed from each other at two loci:Glu-A1andGlu-A3/Gli-A1. One of them, called Ulla 1, contained subunit 2* (Glu-A1b) andGlu-A3o/Gli-A1o, and Ulla 2 contained the null allele (Glu-A1c) andGlu-A3a/Gli-A1c. In order to determine the effect of this allelic variation on quality, the two biotypes were crossed and random lines were produced from the progeny by single seed descent. In total, 95 F6 lines were analysed from four bulked Ulla progeny lines. Significant interaction between the allelic variants of HMW glutenins and LMW gluten proteins affected the SDS-sedimentation volume at the mean flour protein level of 13·1% (dmb); the effect of LMW gluten variants was larger in the lines deficient of a HMW glutenin subunit than in lines having a HMW glutenin subunit (2*). At the higher flour protein levels (mean=15·1%, dmb) the effect on SDS-sedimentation volume was additive; progeny carrying alleles b (subunit 2*) and o/o atGlu-A1andGlu-A3/Gli-A1had significantly greater sedimentation volumes than the progeny carrying alleles c (no subunit) and a/c, respectively. The SDS-sedimentation volumes indicated differences in the quantities of the polymeric glutenins, gel proteins which have been shown to reflect dough strength. In the four bulked Ulla progeny lines, the variation in HMW glutenin subunits affected the dough strength values of the Extensigraph. However, the variation in LMW glutenin subunits did not affect Extensigraph dough strength values, as was predicted by SDS-sedimentation volumes. In the Ulla progeny, adding a HMW glutenin subunit affected Extensigraph dough strength more than adding a LMW glutenin subunit, although both increased the SDS-sedimentation volumes. Moreover, the variation in LMW gluten proteins affected the dough mixing stability in the Farinograph and test baking results of the Ulla progeny.     

Comparative Studies of High MrSubunits of Rye and Wheat. II. Partial Amino Acid Sequences

A panel of anti-peptide antibodies specific for each of the different N-terminal sequence types of B- and C-low molecular mass glutenin subunits (L M_rGS) were utilised in immunoblotting studies to identify the chromosomal location of genes encoding different sequences and to characterise the allelic variation of the encoding loci. The MET-type sequences were predominantly found among the B- subunits, while the α- and γ- sequences predominated in the C- subunits. The quantitatively major SHIPGLERPS sequence was found in both the B- and C- mobility regions. Using either biotypes in the cultivar, Aroona or genetic lines containing double rye chromosome 1 substitutions and thus expressing only single LM_r GS alleles, the sequences were determined for most of the major polypeptides expressed by each LM_r GS allele. The L M_rGS from different genomes encoded different numbers of each sequence type. Furthermore, different polypeptides within a particular «block» of subunits encoded by a given allele often had differing N-terminal sequences. However, subunits of similar electrophoretic mobilities encoded by different alleles at each locus usually had identical N-terminal sequences, suggesting that they may instead differ in the number of repeats. In Chinese Spring, genes encoding the SHIPGLERPS and METSHIPGL sequence types were predominantly present on chromosomes 1B and 1D, while the related METSRVPGL sequence was only encoded on 1D. In contrast, the METSCIPGL, α- and γ-sequences were encoded on each of chromosomes 1A, 1B and 1D. Several different electrophoretic and immunoblotting approaches using null lines suggested that some of the α-type L M_rGS may also be encoded by group 6 chromosomes, particularly 6D. The anti- SHIPGLERPS antibody also recognised chromosome 1B encoded β-, γ- and ω-gliadins, while the anti-METSRVPGL antibody recognised 1D encoded α- and β-gliadins. The absence of sequences within the major gliadin families that are highly homologous to the latter two N-terminal L M_rGS sequences may suggest that some monomeric L M_rGS could exist within the electrophoretically-resolved gliadins. These antibodies will provide valuable reagents for the study of the roles of particular L M_rGS families in the structure and function of the glutenin macropolymer, the role of different LM_r GS types in determining the influence of allelic variation of L M_rGS composition on dough properties, and potentially in the development of diagnostics for these flour components.     

Effect of allelic variation at the Glu-3/Gli-1 loci on breadmaking quality parameters in hexaploid wheat (Triticum aestivum L.)

Low molecular weight glutenin subunits (LMW-GS) encoded by the Glu-3 loci are known to contribute to wheat breadmaking quality. However, the specific effect of individual Glu-3 alleles is not well understood due to their complex protein banding patterns in SDS-PAGE and tight linkage with gliadins at the Gli-1 locus. Using DNA markers and a backcross program, we developed a set of nine near isogenic lines (NILs) including different Glu-A3/Gli-A1 or Glu-B3/Gli-B1 alleles in the genetic background of the Argentine variety ProINTA Imperial. The nine NILs and the control were evaluated in three different field trials in Argentina. Significant genotype-by-environment interactions were detected for most quality parameters indicating that the effects of the Glu-3/Gli-1 alleles are modulated by environmental differences. None of the NILs showed differences in total flour protein content, but relative changes in the abundance of particular classes of proteins cannot be ruled out. On average, the Glu-A3f, Glu-B3b, Glu-B3g and Glu-B3i_Man alleles were associated with the highest values in gluten strength-related parameters, while Glu-A3e, Glu-B3a and Glu-B3i_Chu were consistently associated with weak gluten and low quality values. The value of different Glu-3/Gli-1 allele combinations to improve breadmaking quality is discussed.     

High Mr Glutenin Subunits of Indian Wheat Cultivars: Association of Subunits 5 + 10 with the 1BL/1RS Wheat-Rye Translocation

The seed proteins of 110 commercially-released Indian wheat cultivars were fractionated using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) to determine their high M_r glutenin subunit compositions. Amongst the cultivars, three alleles were indentified for the Glu-A1 locus (subunits 1, 2^* and the null phenotype), eight alleles for the Glu-B1 locus (7, 7 + 8, 7 + 9, 6 + 8, 20, 13 + 16, 17 + 18 and a new allele) and two for the Glu-D1 locus (2 + 12 and 5 + 10). Nine of the cultivars were heterogeneous and possessed two or more 'biotypes' with respect to high M_r subunits. The cultivars were also analysed for the presence of the 1BL/1RS wheat-rye translocation by SDS-PAGE of unreduced prolamins and hybridisation of DNA dot blots with a rye-telomere-specific repetitive DNA probe, pAW-161. Both methods revealed that the majority of newly-released Indian wheat cultivars carry this translocation, thus confirming the agronomic superiority of these lines. While most of the normal wheat cultivars possessed high M_r subunits 2 + 12, 14 of the 18 translocation cultivars had the allelic subunits 5 + 10, even though no selection was made for these subunits during the breeding process. This suggests that the subunits 5 + 10 may play a compensating role for the loss of dough strength associated with the 1BL/1RS translocation.     

Protein bodies ontogeny and localization of prolamin components in the developing endosperm of wheat caryopses

During caryopsis development, prolamins are initially stored in individual protein bodies, then generate a protein matrix in the ripe caryopsis. The ontogeny of the protein bodies was analyzed by fluorescence and electron microscopy from 7 to 43 days after anthesis (dAA), a period of time from the cellularization of endosperm to its desiccation. A series of antibodies specific to each prolamin type (α/β-, γ-, ω-gliadins, low-molecular weight and high-molecular weight glutenin subunits) made it possible to localize and co-localize the different prolamins in organelles of endosperm cells at different developmental stages. Protein bodies containing prolamins were observed as early as 7 dAA. At the early developmental stages, protein bodies were spherical with diameters around 1–2 μm. Later, around 15 dAA, the PBs enlarged, and aggregation and/or coalescence were prominent at 21 dAA. From 33 dAA, individual PBs were no longer visible, but a protein matrix was confined in the space between starch granules. All prolamins were found in the same protein bodies, without any segregation according to their types. Immunochemical labelling of prolamins failed to reveal in TEM analyses any particular internal organization in protein bodies. Glutenin subunits and gliadins were observed in the Golgi apparatus at the early stages of endosperm development.     

Influence of sulphur fertilisation on quantities and proportions of gluten protein types in wheat flour

Although different supplies of sulphur (S) during wheat growth are known to influence the quantitative composition of gluten proteins in flour, an effect on the amount and on the proportions of single protein types has yet not been determined. Therefore, wholemeal flours of the spring wheat ‘Star’ grown on two different soils and at four different levels of S fertilisation (0, 40, 80, 160 mg S per container) were analysed in detail using an extraction/HPLC procedure. The results demonstrated that the amount of total gluten proteins as well as of the crude protein content of flour was little influenced, whereas amounts and proportions of single protein types were strongly affected by the different S fertilisation. The changes were clearly dependent on the Cys and Met content of each protein type. The amount of S-free ω-gliadins increased drastically, and that of S-poor high-molecular-weight (HMW) glutenin subunits increased moderately in the case of S deficiency. In contrast, the amounts of S-rich γ-gliadins and low-molecular-weight (LMW) glutenin subunits decreased significantly, whereas the amount of α-gliadins was reduced only slightly. S deficiency resulted in a remarkable shift of protein proportions. The gliadin/glutenin ratio increased distinctly; ω-gliadins became major components, and γ-gliadins minor components, whereas the ratio of HMW to LMW glutenin subunits was well-balanced.     

小麦种质资源宁春4号的研究和利用

小麦品种宁春4号不仅是中国的一个优良春小麦品种,也是一个优异的种质资源.它含有来自美洲、欧洲、亚洲、澳洲优良小麦品种的遗传物质,含有Rht2等基因,具有1、17+18、5+10优质HMW-GS组合,以及Glu-A3b、Glu-B3f优质LMW-GS组合,属于非1BL/1RS易位系小麦品种.与其他宁夏春小麦品种相比,宁春4号在不同生育期功能叶片的叶绿素含量、缓降期内的平均叶绿素含量均最高;光饱和点最小;从孕穗期至开花期旗叶光合速率日平均值、最高值最大.宁春4号与部分小麦近缘属种杂交表现出较高的可杂交性,利用其做亲本与其他小麦杂交已选育出一批优良品种.由于长期坚持对宁春4号小麦品种提纯复壮,使其在生产上28年不衰退.宁春4号是一种兼性类型的小麦品种,现已筛选出冬性宁春4号,品质有较大的改善.     

Characterisation of polyclonal and monoclonal anti-peptide antibodies specific for some lowMrsubunits of wheat glutenin and their use in the detection of allelic variants atGlu-3loci

Polyclonal and monoclonal antibodies (Mabs) were produced against the major type ofN-terminal amino acid sequence of lowM_rglutenin subunits. The reactivities of these antibodies were determined using glutenin extracts of several bread wheat cultivars of known allelic composition. Analyses were performed by immunoblotting after one or two-dimensional electrophoresis. One Mab (Mab 6x1) was found to react with lowM_rglutenin subunits encoded by chromosomes 1B and 1D but not with subunits controlled by chromosome 1A. Only some of the subunits encoded at theGlu-D3locus were recognised. In contrast, this Mab reacted with all the subunits controlled by theGlu-B3locus. After single dimension SDS–PAGE, we observed significant differences between immunoblot patterns of cultivars expressing different lowM_rglutenin subunits from chromosome 1B. Mab6 x1 is a useful reagent for analysing the allelic composition at theGlu-B3locus.     

宁夏引黄灌区冬小麦谷蛋白亚基组成和1BL/1RS易位分析及品质性状研究

为全面了解宁夏引黄灌区冬小麦品质概况,为冬小麦品质改良和粮食生产提供理论依据。选用冬小麦主栽品种、亲本材料和高代品系30份。用SDS-PAGE分析了其中18份材料的HMW—GS、LMW—GS组成和1BL／1RS易位系分布状况。并对23个冬小麦品种的营养与加工品质进行了研究。结果表明,2#、7＋9、2＋12、Glu-A3a、Glu-A3c、Glu-B3h和Glu—B3j在宁夏引黄灌区冬小麦中分布较广,1BL／1RS易位系分布相当普遍。分布频率为27．8％。参试品种的籽粒硬度、面粉PPO活性、SDS沉淀值、形成时间、稳定时间和评价值的变异范围较大,变异系数分别为25．37％、33．68％、21．42％、26．58％、43．95％和29．31％。多数冬小麦品种（系）的千粒重、出粉率和湿面筋含量低于对照宁春4号。而蛋白质含量、SDS沉淀值、吸水率和稳定时间优于宁春4号。供试品种（系）中。HMW-GS品质评分、籽粒硬度、蛋白质含量、SDS沉淀值均较高,并且不含1BL／1RS易位系的有烟优361、济麦20、鲁875067和923—9等,可用于宁夏引黄灌区冬麦品质改良。     

A Null Gli-D1 Allele with a Positive Effect on Bread Wheat Quality

The French wheat cultivar Darius (Da) has very good bread-making quality, even though it possesses the high M_r glutenin subunit combination 2, 7 and 12, which is associated with poor quality, and a null allele at the Gli-D1 locus. Darius was crossed with three cultivars, Corin (Cor), Capitole (Cap) and Courtot (Cou), of poor, medium, and good quality, respectively. The three progenies (Cor × Da, Cap × Da and Da × Cou) were used to investigate the genetic basis of the good quality of Darius. Gliadin and glutenin compositions were analysed by acid polyacrylamide gel electrophoresis (A-PAGE) and SDS-PAGE, respectively, from half F2 grains, and the quality was evaluated using six technological criteria for the corresponding plants. The high M_r glutenin subunit alleles of Darius produced a negative effect on quality. The null allele of Darius, characterised by the absence of the Gli-D1 encoded ω-gliadins, was associated significantly with higher dough tenacity P , and strength W (up to 40% in the Cor × Da progeny). Darius had a higher amount of B zone low M_r glutenin subunits than the three other cultivars. The null allele of Darius reduced the dough extensibility in the two first progenies, and probably increased the ratio of aggregated glutenin to unaggregated gliadins. These results demonstrated that using only one locus breeders can improve particular quality traits.     

Effect of hydrostatic pressure and temperature on the chemical and functional properties of wheat gluten: Studies on gluten, gliadin and glutenin

The effect of hydrostatic pressure (0.1–800 MPa) in combination with various temperatures (30–80 °C) on the chemical and physical properties of wheat gluten, gliadin and glutenin was studied. Chemical changes of proteins were determined by extraction, reversed-phase high-performance liquid chromatography (HPLC), sodium dodecylsulphate (SDS) polyacrylamide gel electrophoresis (PAGE), circular dichroism (CD) spectroscopy, thiol measurement and studies on disulphide bonds. Rheological changes were measured by extension tests and dynamic stress rheometry. Treatment of gluten with low pressure (200 MPa) and temperature (30 °C) increased the proportion of the ethanol-soluble fraction (ESF) and decreased gluten strength. The enhancement of both pressure and temperature provoked a strong reduction of the ESF and the thiol content of gluten. Within gliadin types, cysteine containing α- and γ-gliadins, but not cysteine-free ω-gliadins were sensitive to pressure and were transferred to the ethanol-insoluble fraction. Disulphide peptides isolated from treated gluten confirmed that cleavage and rearrangement of disulphide bonds were involved in pressure-induced reactions. Increased pressure and temperature induced a significant strengthening of gluten, and under extreme conditions (e.g. 800 MPa, 60 °C), gluten cohesivity was lost. Isolated gliadin and glutenin reacted differently: solubility, HPLC and SDS-PAGE patterns of gliadin having a very low thiol content were not influenced by pressure and heat treatment; only conformational changes were detected by CD spectroscopy. In contrast, the properties of isolated glutenin having a relatively high thiol content were strongly affected by high pressure and temperature, similar to the effects on total gluten.     

Glutenin subunit compositions and breadmaking quality characteristics of synthetic hexaploid wheats derived from Triticum turgidum × Triticum tauschii (coss.) Schmal Crosses

The Glu-B1, Glu-D1 and Glu-B3 encoded glutenin subunit compositions of a population of synthetic hexaploid wheats (AABBDD, 2n=6x=42), which was random for flour protein (FP), SDS-sedimentation (SDSS), Alveograph strength (W), the tenacity/extensibility (P/G) ratio and bread loaf volume (LV) were examined in this study. The synthetics were produced from various crosses involving several Triticum lurgidum cultivars and Triticum lauschii (coss.) Schmal accessions. The Glu-A1 null allele as well as three Glu-B1 (subunits 7 + 8, 6 + 8 and 20), 13 Glu-D1 and two Glu-B3 (LMW-1 and LMW-2) allelic variants were present in the synthetic population. Thirty-six different glutenin subunit combinations, including the Glu-B1, Glu-D1 and Glu-B3 encoded alleles, were observed. The synthetic hexaploids showed large variations for all quality parameters evaluated. All quality characteristics except one (P/G ratio, which showed no association with allelic variations at Glu-B3) were influenced by allelic variations at the Glu-B1 and Glu-B3 loci; subunits 6 + 8 and 7 + 8 showed significantly better quality effects than subunit 20. Low M_r glutenin subunits LMW-1 and LMW-2 showed both negative and positive quality effects. The Glu-D1 locus of T. tauschii contributed various alleles not found in bread wheat. The influence of new Glu-D1 alleles on the bread-making quality characteristics of the synthetic wheats could not be established, partly because there was a limited frequency of some of the alleles in the population, and partly because some synthetics, having a common Glu-D1 allele, showed quality differences associated with allelic variation at Glu-B1 and/or Glu-B3. Differential quality effects could be observed, however, among some Glu-D1 alleles. Synthetics derived from a common durum wheat source showed better overall quality characteristics and bread loaf volume when they possessed subunits 5 + 12 or 1·5 + 10 than when they had any other Glu-D1 encoded glutenin subunit.     

Development of introgression lines with 18 alleles of glutenin subunits and evaluation of the effects of various alleles on quality related traits in wheat (Triticum aestivum L.)

In this report, we present a set of 104 ILs with 18 alleles for five glutenin loci. They were developed from crossing and backcrossing 64 varieties as donor parents to Yanzhan 1 as recurrent parent. The effects of the 18 alleles on nine dough quality parameters were evaluated in a similar background using these lines. The results showed that Glu-A1a produced the highest SDS-sedimentation volume (Ssd), midline time x=8 width (MTxW), mixing tolerance (MT) and the lowest weakening slope (WS). At the Glu-B1 locus, Glu-B1f produced the highest values for all quality parameters but WS. At the Glu-D1 locus, Glu-D1d was the best for Ssd, grain hardness (GH), midline peak width (MPW), MTxW and MT. The positive effects of Glu-B1f on GH and Glu-B3b on Ssd were mainly from the effect of GPC. Overall, 5 interactive loci and 13 interactive alleles were found to be significant. No negative interaction between high quality glutenin alleles was detected. The preferred allele combinations for breeding were recommended based on the additive and interactive effects. Our results suggest that the ILs with multiple alleles are ideal genomic stocks for evaluating the effects of alleles on some traits and for pyramiding favorable alleles in breeding wheat varieties.     

Relationships Between Chromosome 1B-encoded Glutenin Subunit Compositions and Bread-making Quality Characteristics of Some Durum Wheat (Triticum turgidum) Cultivars

The high and low M_r glutenin subunit compositions (controlled by the Glu-1 loci and the Glu-B3 locus, respectively) and the bread-making quality characteristics of 26 durum wheat (Triticum turgidum) genotypes were determined. The relationships between quality parameters and Glu-B1 and Glu-B3 controlled glutenin subunit composition were also investigated. The Glu-A1-controlled null allele was present in all the genotypes. High M_r subunits 20, 6 + 8 and 7 + 8 occurred in similar proportions in the cultivars analysed. The Glu-B3 low M_r allelic variants, LMW-1 and LMW-2, were both represented, with LMW-1 being present in lower proportion. Flour protein, SDS-sedimentation volume, dough strength (Alveograph W value), dough mixing time and bread loaf volume varied among the genotypes. Most samples had high Alveograph tenacity/extensibility (P/G) ratios, typical of tenacious gluten character. SDS-sedimentation volume, dough strength, dough mixing time and bread loaf volume were all interrelated. An association with flour protein content was observed only for mixing time, while the Alveograph tenacity/extensibility ratio was not correlated with the other parameters. Comparisons within the Glu-B1 and Glu-B3 loci indicated that the high M_r subunit 7 + 8 and the low M_r subunit LMW-2 had significantly greater beneficial effects on gluten strength and bread-making quality than the high M_r subunits 6 + 8 or 20 and the low M_r subunit LMW-1, respectively. High M_r subunit 6 + 8 had greater beneficial effects on quality than subunit 20.