Survey and new insights in the application of PCR‐based molecular markers for identification of HMW‐GS at the Glu‐B1 locus in durum and bread wheat

Wheat, among all cereal grains, possesses unique characteristics conferred by gluten; in particular, high molecular weight glutenin subunits (HMW‐GS) are of considerable interest as they strictly relate to bread‐making quality and contribute to strengthening and stabilizing dough. Thus, the identification of allelic composition, in particular at the Glu‐B1 locus, is very important to wheat quality improvement. Several PCR‐based molecular markers to tag‐specific HMW glutenin genes encoding Bx and By subunits have been developed in recent years. This study provides a survey of the molecular markers developed for the HMW‐GS at the Glu‐B1 locus. In addition, a selection of molecular markers was tested on 31 durum and bread wheat cultivars containing the By8, By16, By9, Bx17, Bx6, Bx14 and Bx17 Glu‐B1 alleles, and a new assignation was defined for the ZSBy9_aF1/R3 molecular marker that was specific for the By20 allele. We believe the results constitute a practical guide for results that might be achieved by these molecular markers on populations and cultivars with high variability at the Glu‐B1 locus.     

Introgression of useful genes from Thinopyrum intermedium to wheat for improvement of bread‐making quality

To study the influence of genes from Thinopyrum intermedium on traits affecting the bread‐making quality of wheat, two derivatives from a putative disomic addition line in cultivar ‘Vilmorin 27’ were used in cytological, biochemical and molecular characterization. Cytological analysis suggested that one of the derivatives (Line‐1) had a terminal deletion involving the long arm of chromosome 1D (2n = 42, Del‐1DL”), and the other (Line‐2) was a conventional addition line, but also carried the same deletion on chromosome 1D (2n = 44, Thi”+Del‐1DL”). Amplification and sequencing of high‐molecular‐weight glutenin subunit (HMW‐GS) genes coded by the Th. intermedium chromosome in Line‐2 indicated the presence of one x‐type with an extra cysteine and four (rather than one) unique y‐type genes. Rheological studies of Line‐1 showed significantly lower dough strength compared to ‘Vilmorin 27’, confirming the recognized role of Glu‐1D coded HMW‐GSs. Line‐2 showed significantly higher dough strength compared to the background cultivar, indicating a significant potential of Th. intermedium for improvement of bread‐making quality in wheat.     

Mixolab参数与粉质、拉伸参数及面包烘烤品质的关系

根据仪器测定的面粉品质特性预测面包烘烤品质是进行小麦品质改良的重要方法。法国肖邦公司(Chopin Technologies, France)最新推出的Mixolab分析仪可以同时测定面粉加水后恒温揉混及面团升温后蛋白质弱化和淀粉糊化特性,明确其与现有相似仪器如粉质仪和拉伸仪等的关系对小麦品质测试具有重要意义。利用 Mixolab分析仪、粉质仪、拉伸仪测定了41份高代育种品系的有关参数和面包烘烤品质,并分析了Mixolab与粉质仪和拉伸仪相关参数的关系及预测面包品质的可靠性。结果表明,可以用Mixolab的形成时间、稳定时间、面团受热后蛋白质弱化值(C2值)和到达淀粉糊化反弹值的时间(C4时间)来预测粉质仪和拉伸仪的品质参数,可解释其变异的74%~90%;可以直接用C2值预测面包体积、外观、结构和总分,决定系数分别为52%、73%、70%和68%;预测面包质地和弹性的参数不仅包含Mixolab稳定时间和C2值,还有表示淀粉糊化特性的C3时间、C4和C5值及C5温度。用Mixolab分析仪既可以了解蛋白质特性和面包烘烤品质的关系,又明确了淀粉品质对面包品质的显著影响,在品质测试中有其独特之处。Mixolab、粉质仪和拉伸仪各参数对预测小麦面包体积、内部质地结构等烘烤品质性状的贡献不同。     

2··, a new high molecular weight glutenin subunit coded by Glu-A1: its predicted structure and its impact on bread-making quality

The suitability of wheat varieties for bread‐making depends on their glutenin subunits. The amino acid composition of these gluten building‐blocks have a strong influence on the rheology of the dough and, thus, on the suitability of the variety for bread‐making. This study reports a new x‐type high molecular weight glutenin subunit coded by the locus Glu‐A1 and named 2··. To investigate the impact of this allele on 10 quality parameters, a doubled haploid (DH) population of Triticum aestivum, segregating for Glu‐A1, was created. The statistical analysis demonstrates that, at Glu‐A1, the subunit 2·· is as favourable for quality as the subunit 2*. This is in accordance with results showing that the 2·· open reading frame still has the same number of cysteines as 2*. The small differences in the length of the central domain had no detectable effect on the elasticity, tenacity and baking quality, of the dough.     

北方冬麦区新育成优质品种的面包和馒头品质性状

本研究旨在了解近年北方冬麦区育成优质小麦品种的品质状况, 为优质小麦新品种选育和推广提供重要信息。2013—2014和2014—2015年度将52份国内及6份国外代表性优质品种种植于河北高邑和山东济宁, 测定粉质仪和拉伸仪参数及面包和馒头品质性状, 并分析蛋白质组分含量对面团流变学特性及面包和馒头成品品质的影响。结果表明, 大部分参试品种的粉质仪稳定时间在7 min以上, 品种间面筋强度、面包和馒头成品品质均存在显著差异。CA0493、师栾02-1、12品404、新麦26和Karl 5个品种面包品质好, 其中师栾02-1和Karl的馒头品质也较好, 可以作为兼用型品种在品质育种中应用。拉伸仪品质特性是反映强筋品种面包品质的重要指标, 建议在进行面包品质改良时, 重视拉伸特性。不溶性谷蛋白聚合体含量与面筋强度和面包品质呈显著正相关, 可作为品质育种的选种指标。     

Effect of Shading from Jointing to Maturity on High Molecular Weight Glutenin Subunit Accumulation and Glutenin Macropolymer Concentration in Grain of Winter Wheat

Accumulations of high molecular weight glutenin subunits (HMW‐GS) and glutenin macropolymer (GMP) in wheat grains are important indicators of grain quality. Two wheat cultivars, Yangmai 158 (shading tolerant) and Yangmai 11 (shading intolerant) which contains the same subunit pairs of 7 + 8 and 2 + 12, were used to evaluate the impacts of shading on HMW‐GS accumulation and GMP concentration in the grain. Three shading levels were implemented from jointing to maturity, i.e. S1, S2 and S3, in which the plants received 8 %, 15 % and 23 % less radiation of the control (S0), respectively. The initial formation of HMW‐GS was pre‐dated by shading. The rapid HMW‐GS accumulation duration was shortened, and the accumulation rate during late grain filling period was lowered in the two relatively severe shaded treatments (S2 & S3). Thus, the total HMW‐GS accumulation in single grain at maturity was lower in S2 and S3 than in the control (S0). However, concentrations of HMW‐GS and GMP at maturity increased because of the reduced single grain weight in S2 and S3, as compared to S0. In contrast, the low density shading (S1) prolonged the rapid accumulation duration of HMW‐GS, hence increased the accumulation and concentration of HMW‐GS in the grains. Consequently, S1 reduced falling number and SDS‐sedimentation volume, while shortened dough development time (DDT) and dough stability time (DST). In contrast, S2 and S3 increased falling number, wet‐gluten concentration and SDS‐sedimentation volume, and lengthened the DDT and DST. In addition, the fluctuations in accumulations of HMW‐GS and GMP and most quality traits because of shading in Yangmai 158 were less than Yangmai 11. The interrelations between HMW‐GS accumulation, GMP concentration and quality of grain and dough were further discussed.     

Detection of HMW glutenin subunit variations among 205 cultivated emmer accessions (Triticum turgidum ssp. dicoccum)

The high molecular weight glutenin subunits (HMW‐GS) encoded by Glu‐1 loci among 205 accessions of cultivated emmer wheat (Triticum turgidum ssp. dicoccum Schrank) collected from different regions of Europe and China were separated and characterized by SDS‐PAGE in combination with two‐dimensional gel electrophoresis (A‐PAGE × SDS‐PAGE) and acidic capillary electrophoresis. High genetic polymorphisms in HMW‐GS compositions were found. A total of 40 alleles (6 for Glu‐A1 and 34 for Glu‐B1) and 62 subunit combinations (genotypes) were detected, some of which were not previously described. At Glu‐A1 locus, two novel alleles, designated Glu‐A1x coding for the subunit 1A × 1.1 and Glu‐A1y coding for the subunit 1A × 2.1′ were found while seven new subunits (1B × 17*, 1B × 6′, 1B × 13′, 1B × 20*, 1By9*, 1By14.1 and 1By8.1) and 20 novel alleles at Glu‐B1 locus were detected. In particular, some additional protein components were detected, which probably were 1Ay subunits encoded by Glu‐A1 locus. The introduction of both Ax and Ay subunits from tetraploid wheats into hexaploid wheats may increase the genetic variability of gluten genes and consequently improve flour technological properties.     

Introduction of high molecular weight glutenin subunits 5 + 10 for the improvement of the bread-making quality of hexaploid triticale

In an earlier study, chromosome 1D of the hexaploid breadwheat cultivar ‘Chinese Spring’ was introduced into hexaploid triticale to improve its bread‐making quality. That specific chromosome, 1D, carried the a allele at the Glu‐D1 locus coding for high molecular weight (HMW) glutenin subunits 2 + 12, and since subunits 2 + 12 are associated with poor bread‐making quality in wheat, in the present study hexaploid 1D substitution triticale was crossed with octoploid triticale with the d allele at the Glu‐D1 locus encoding HMW glutenin subunits 5 + 10. Following backcrosses to different triticale varieties, 1D substitution lines were established that had Glu‐D1 allele a or d in an otherwise genetically similar background, and the influence of these two different alleles on bread‐making quality of hexaploid triticale was compared. The agronomic performance of 76 selected lines was evaluated in a field trial. The Zeleny sedimentation value was determined as a parameter for bread‐making quality, and related to the presence of chromosome 1D, the different glutenin alleles and the nature of the substitution. The presence of chromosome 1D had a significant and positive effect on the Zeleny sedimentation value, but the difference between the two glutenin alleles 2 + 12 and 5 + 10 was not as obvious as in wheat. Owing to its high cytological stability and minimal effect on agronomic performance, substitution 1D(1A) appears to be the most desirable one to use in triticale breeding.     

Pan bread and dry white Chinese noodle quality in Chinese winter wheats

Improvements in pan bread quality and Chinese dry white noodle (DWCN) quality are the major breeding objectives in the north China winter wheat region. Eighty-one wheat cultivars and advanced lines were sown in two locations in the 2000–2001 season to evaluate the quality of winter wheat germplasm and investigate the association between pan bread quality and DWCN quality. Significant variability was observed for grain, pan bread, and DWCN quality attributes. Six cultivars and lines showed very good pan bread quality, 23 showed excellent DWCN quality in both locations, and the cultivars Yumai 34 and Sunstate showed superior quality for both food products. Protein content and grain hardness were significantly associated with pan bread quality, while the gluten quality-related parameters SDS-sedimentation value, Farinograph stability, and Extensograph maximum resistance, were significantly associated with pan bread quality score, and accounted for 59.3–72.3% of its variation. Yellow colour (b, CIE Lab) showed a strong negative association with pan bread and DWCN quality largely due to the strong and negative association between yellow colour and gluten strength parameters in this germplasm pool. Flour ash content and polyphenol oxidase (PPO) had a negative moderate effect on noodle colour, while protein content and grain hardness were negatively associated with noodle colour, appearance, and smoothness. The association between SDS-sedimentation volume, Farinograph stability, and Extensograph maximum resistance and DWCN score fitted a quadratic regression model, accounting for 31.0%, 39.0%, and 47.0% of the DWCN score, respectively. The starch pasting parameters, peak viscosity and paste breakdown, contributed positively to DWCN quality, with r = 0.57 and 0.55, respectively. Quality requirements for pan bread and DWCN differ in colour, gluten strength, and pasting viscosity. It is suggested that PPO, yellow pigment, SDS sedimentation volume, and peak viscosity are parameters that could be used to screen for DWCN quality in the early generations of a wheat-breeding program.     

Allelic variation at the <Emphasis Type="Italic">Glu-1</Emphasis> and <Emphasis Type="Italic">Glu-3</Emphasis> loci,presence of the 1B.1R translocation,and their effects on mixographic properties in Chinese bread wheats

Allelic variations at the Glu-1 and Glu-3 loci play an important role in determining dough properties and bread-making quality. Two hundred and fifty-one cultivars and advanced lines from four major Chinese wheat-producing zones in the autumn-sown wheat regions were used to investigate the high-molecular-weight glutenin subunits (HMW GS) and low-molecular-weight glutenin subunit (LMW GS) composition controlled by the Glu-1 and Glu-3 loci, respectively, as well as the presence of the 1B.1R translocation, and to determine the association of storage protein composition with protein content, SDS sedimentation value, and dough-mixing properties measured by mixograph. Three, nine, and four allelic variations were present at Glu-A1, Glu-B1, and Glu-D1, respectively. Subunits 1, N, 7+8, 7+9, and 2+12 are the dominant HMW GS, with frequencies of 51.3, 39.4, 38.2, 45.0, and 59.8%, respectively. Five and eight allelic variations were present at the Glu-A3 and Glu-B3 loci (data of Glu-D3 were not available), Glu-A3a, Glu-A3d, Glu-B3j (presence of the 1B.1R translocation), and Glu-B3d are the dominant LMW GS, with frequencies of 37.1, 31.7, 44.6, and 20.3%, respectively. The frequencies of allelic variation at Glu-1 and Glu-3 differ greatly in different regions. The effects of HMW GS and LMW GS on SDS sedimentation value, mixing time, and mixing tolerance were significant at P = 0.01, with Glu-D1 and Glu-B3 showing the largest contributions to mixing time and mixing tolerance. Averaged data from two locations showed that the quality effects of glutenin loci could be ranked as Glu-B3 > Glu-B1 > Glu-A1 > Glu-D1 > Glu-A3 for SDS sedimentation value, Glu-D1 > Glu-B3 > Glu-A1 = Glu-B1 = Glu-A3 for mixing time, and Glu-D1 > Glu-B3 = Glu-B1 > Glu-A3 > Glu-A1 for mixing tolerance, respectively. The significant and negative effect of the 1B.1R translocation on dough properties was confirmed. It was concluded that the high frequency of undesirable HMW GS and LMW GS and the presence of the 1B.1R translocation are responsible for the weak gluten property of Chinese germplasm; hence, reducing the frequency of the 1B.1R translocation and integration of desirable subunits at Glu-1 and Glu-3 such as 1, 7+8, 14+15, 5+10, Glu-A3d, and Glu-B3d, could lead to the improvement of gluten quality in Chinese wheats.     

Positive effect of the high-molecular-weight glutenin allele, Glu-D1d, on the bread-making quality of common wheat

The seed storage proteins of wheat flour are the determinants of bread‐making quality. Many cultivars having good bread‐making quality carry the Glu‐D1d allele responsible for the development of glutenin, a major seed storage protein. The Glu‐D1d allele was introduced into four leading Japanese wheat cultivars by recurrent backcrossing and the quality of these near‐isogenic lines (NILs) was evaluated by the sodium dodecyl sulphate sedimentation value of their flour. The values for the NILs were significantly higher than for the corresponding recipient cultivars. However, the values did not reach the level of the cultivar that had been used as the donor of the Glu‐D1d allele.     

Relationship between common wheat (Triticum aestivum L.) gluten proteins and dough rheological properties

This paper reports the correlation between the rheological properties of bread wheat dough and the types and quantities of endosperm proteins in 28 common wheat cultivars. Different methods were used to analyse the allelic composition of these cultivars and the relative quantities of the different proteins contributing to the gluten structure. Neither dough strength (W) nor tenacity/extensibility (P/L) correlated with allelic composition. Different wheats with the same allelic composition (i.e., with respect to glutenins) showed different rheological properties. The glutenins were the most influential components of W and P/L, especially the high molecular weight (HMW) glutenin subunits and in particular the type x form. These proteins seem to increase W and are the main constituents of the gluten network. The gliadins and low molecular weight (LMW) glutenin subunits appear to act as a “solvent”, and thus modify the rheological properties of the dough by either interfering with the polymerisation of the HMW glutenin subunits, or by altering the relative amounts of the different types of glutenin available. Thus, the protein subunits coded for by the alleles Glu-B1x7 and Glu-D1x5 stabilised the gluten network, whereas those coded for by Glu-B1x17 and Glu-D1x2 had the opposite effect. Dough properties therefore appear to depend on the glutenin/gliadins balance, and on the ratio of the type x and type y HMW proteins. The influence of external factors seems to depend on the allelic composition of each cultivar.     

The high and low molecular weight glutenin subunit polymorphism of Algerian durum wheat landraces and old cultivars

The high molecular weight (HMW) and B‐zone low molecular weight (B‐LMW) glutenin subunit composition of 45 Algerian durum wheat (Triticum turgidum L. var. durum) landraces and old cultivars were examined by sodium‐dodecyl‐sulphate polyacrylamide gel electrophoresis (SDS‐PAGE). Nine accessions were heterogeneous and presented two or three genotypes. All together, 33 glutenin patterns were detected, including 12 for HMW and 15 for B‐LMW glutenin subunits. Twenty‐four different alleles were identified for the five glutenin loci studied, Glu‐A1 (3), Glu‐B1 (6), Glu‐A3 (8), Glu‐B3 (5) and Glu‐B2 (2). Five new alleles were found, three at Glu‐A3 and two at Glu‐B3. At the Glu‐1 loci, the Glu‐A1c‐Glu‐B1e allelic composition was predominant (31%). For the B‐LMW glutenins, the most common allelic composition was Glu‐A3a‐Glu‐B3a‐Glu‐B2a (36%). The collection analysed shows a high percentage of glutenin alleles and allele combinations related to high gluten strength, together with some others that have not been tested so far. This information could be useful to select local varieties with improved quality and also as a source of genes to develop new lines when breeding for quality.     

Development of two multiplex PCR assays targeting improvement of bread-making and noodle qualities in common wheat

Wheat quality properties are genetically determined by the compositions of high and low molecular weight glutenin subunits, grain hardness, polyphenol oxidase (PPO) activity and starch viscosity. Two multiplex PCR assays were developed and validated using 70 cultivars and advanced lines from Chinese autumn‐sown wheat regions. Multiplex PCR I includes molecular markers for genes/loci ω‐secalin, Glu‐B1‐2a (By8), Glu‐D1‐1d (Dx5), Glu‐A3d, Glu‐B3 (for non‐1B·1R type) and Pinb‐D1b targeting improved gluten parameters and pan bread quality. Multiplex PCR II comprises markers for genes/loci Ppo‐A1, Ppo‐D1 and Wx‐B1b targeting improved noodle quality. The results were consistent with those achieved by SDS‐PAGE and RP‐HPLC, indicating that the two multiplex assays were highly effective, with good repeatability and low costs enabling their use in wheat breeding programmes. In total, nine alleles (subunits) at locus Glu‐B1, four at Glu‐D1 and five at Glu‐A3 locus were identified, and the alleles (subunits) Glu‐B1b (7 + 8), Glu‐B1c (7 + 9), Glu‐D1a (2 + 12), Glu‐D1d (5 + 10), Glu‐A3a, Glu‐A3c and Glu‐A3d were most frequently present in the cultivars and lines tested. The 1B·1R translocation was present in 28 (40.0%) lines, whereas the Wx‐B1 null allele for better noodle quality was present in only seven (10.0%) cultivars and advanced lines, and 37 (52.9%) lines had Pinb‐D1b associated with hard grains. The allele Ppo‐A1b on chromosome 2AL associated with lower PPO activity was present in 38 (54.3%) genotypes, whereas the less effective allele Ppo‐D1a on chromosome 2DL, also associated with low PPO activity was present in 45 (64.3%) of genotypes. These two multiplex PCR assays should be effective in marker assisted selection targeting improved pan bread‐making and noodle qualities.     

Identification of low-molecular weight glutenin subunits of wheat associated with bread-making quality

Although it is known that the compositions of low‐molecular weight glutenin subunits (LMW‐GSs) are important factors for bread‐making quality of wheat, it is still not clear which LMW‐GSs confer improved bread‐making quality and how those LMW‐GSs interact with high‐molecular weight (HMW) GSs. Using a hard red winter wheat line with good bread‐making quality and a Japanese wheat cultivar with poor quality as well as their progeny we identified LMW‐GSs associated with the bread‐making quality. One such LMW‐GS, KS2, which had a molecular weight of 42 kDa and was allelic to HS1, was associated with bread‐making quality. Furthermore, by using four recombinant inbred lines with different HMW‐GS and LMW‐GS combinations, KS2 and HMW‐GS 5+10 showed interaction effects on the bread‐making quality. Two‐dimensional polyacrylamide gel electrophoresis (Page) analysis showed that KS2 consists of two protein components and that HS1 is composed of three components. The N‐terminal amino acid sequences of the five components were identical to the most frequently analysed sequence of LMW glutenin components.     

Directions in breeding for winter wheat yield and quality in South Africa from 1930 to 1990

Summary Changes in the genetic yield and quality potential of South African winter wheat cultivars since 1930 were investigated by means of canonical variate analysis. Yield potential improved by 87%, while test weight and protein percentage changed marginally. Flour colour improved mostly since 1965, but advancement of flour yield declined after 1984. Dough strength increased since 1930, yet current levels of dough strength should not be exceeded. When compared to farinograph assessment of dough strength, mixograph dough development time appears to be a less sensitive indicator of variation in dough strength. Selection on the basis of mixograph dough development time only, could influence a breeder's perception of the dough quality profile of his breeding programme. Protein efficiency was maintained despite improvement in yield potential. Baking quality improved by 20%. The genetic winter wheat potential advanced significantly since 1930 in meeting the increased nutritional demands of the South African population.Abbreviations BSI Baking strength index - CBP Chorleywood Breadmaking Process - CVA Canonical variate analysis - CV₁ First canonical variate - CV₂ Second canonical variate - FCL Flour colour - FDT Farinograph dough development time - FLY Flour yield - FPC Flour protein content - FST Farinograph stability - FWS Farinograph water absorption - GPR Grain protein content - GPY Grain protein yield - LFV Loaf volume - MDT Mixograph dough development time - SDS SDS sedimentation volume - STY Starch yield - TSW Test weight - WBS Water absorption - YLD Yield     

Introduction to bread wheat (Triticum aestivum L.) and assessment for bread-making quality of alleles from T. boeoticum Boiss. ssp. thaoudar at Glu-A1 encoding two high-molecular-weight subunits of glutenin

Two alleles, Glu-A1r encoding high-molecular-weight (HMW) glutenin subunits 39+40 and Glu-A1s encoding HMW glutenin subunits 41+42, were introgressed to bread wheat (Triticum aestivum L.) cv. Sicco from two accessions of T. boeoticum Boiss. ssp. thaoudar (A genome species, 2n=2x=14). Alleles at Glu-A1 in current commercial bread wheats encode zero or one subunit, and alleles at the homoeoloci Glu-B1 and Glu-D1 encode a maximum of two subunits; hence the maximum number of subunits found in commercial wheats is five, whereas the lines incorporating Glu-A1r and Glu-A1s carry six. Using near-isogenic lines, the current results demonstrated that the introduction of Glu-A1r resulted in diminished dough stickiness and improved stability during mixing compared with Glu-A1a encoding subunit 1, and a small improvement in gluten strength as shown by the SDS- sedimentation test. The introduction of Glu-A1a also resulted in a small improvement in gluten strength predicted by the SDS-sedimentation test. Thus the alleles are of potential value in breeding programmes designed to improve bread-making quality.     

Diversity of five glutenin loci within durum wheat (Triticum turgidum L. ssp. durum (Desf.) Husn.) germplasm grown in Algeria

The HMW and B‐LMW glutenin subunits composition of 120 durum wheat germplasm grown in Algeria was examined using SDS‐PAGE. All together, 39 glutenin patterns were detected, including eight for HMW and 21 for B‐LMW glutenin subunits. Twenty‐six different alleles were identified for the five glutenin loci studied, that is, Glu‐A1 (3), Glu‐B1 (7), Glu‐A3 (5), Glu‐B3 (9) and Glu‐B2 (2). Two new alleles were found at Glu‐B3 locus: Glu‐B3new₁ encodes for five subunits (7 + 8 + 14 + 16 + 18) and Glu‐B3new₂ codes for five subunits (4 + 6* + 12 + 15 + 15*), of which subunit 15* with mobility between bands 15–16 was not described previously. At the Glu‐1 loci, the Glu‐A1c/Glu‐B1e allelic composition was predominant. For the B‐LMW glutenins, the most common allelic composition was Glu‐A3a/Glu‐B3a/Glu‐B2a. The collection analysed shows glutenin alleles and allele combinations related to high gluten strength. This information could be useful to select varieties with improved quality and also as a source of genes to develop new lines when breeding for quality.     

小麦Glu-1位点变异和1B/1R易位对谷蛋白亚基表达量和面包加工品质的影响

选用北方冬麦区近年来育成的优质强筋品种及山东省主栽品种共42份, 采用反相高效液相色谱法(RP-HPLC)和凝胶色谱法(SE-HPLC)对小麦贮藏蛋白组分进行量化, 分析了不同高分子量谷蛋白亚基(HMW-GS)组成对其表达量、面团流变学特性和面包加工品质的影响。结果表明, Glu-D1位点对谷蛋白亚基含量和加工品质的加性效应最大, 达5%显著水平, 贡献率为28.5%~71.3%。在Glu-A1和Glu-D1位点, 单个亚基对谷蛋白亚基含量和加工品质的贡献分别为1>2*>N和5+10>2+12>4+12, 而在Glu-B1位点, 则表现为差异不显著。不同亚基组合的HMW–GS表达量差异达5%显著水平, 相同亚基组合的品种间贮藏蛋白组分表达量的变异较大, 亚基表达量的差异可能是导致品种间品质差异的重要原因。1B/1R易位显著降低LMW-GS、谷蛋白总量和%UPP, 导致加工品质变劣。选择具有优质亚基组合, 且谷蛋白亚基表达量高的类型, 是有效改良面筋强度, 进一步提高优质新品种选育的有效途径。     

Relationship Between High Molecular Weight Glutenin Subunit Composition and Gluten Quality in Ethiopian-grown Bread and Durum Wheat Cultivars and Lines

The high molecular weight glutenin subunit (HMW-GS) composition of 42 Ethiopian-grown bread wheat and 31 durum wheat cultivars and lines were examined using SDS-PAGE. Low variability in HMW-GS composition was present in both classes of wheat. A total of 10 variants with 14 different HMW patterns and seven variants with six different patterns were identified in bread and durum wheat, respectively, reflecting the limited ability of HMW-GS for cultivar identification. The most predominant alleles were 2*, 7 + 9 and 5 + 10 in bread wheat and nul and 7 + 8 in durum wheat. The Glu-1 quality scores for bread wheat ranged from 6 to 10, with an average value of 8.7. The variation in HMW-GS significantly correlated with and accounted for 44 % of the total variation in gluten quality, measured by the sodium dodecyl sulphate sedimentation test. In durum wheat, HMW-GS variation at Glu-B1 explained about 25 % of the variation in gluten quality. The high frequency of the 7 + 8 alleles among the landraces and the significant contribution of Glu-B1 alleles to the total variation in gluten quality indicate the potential benefit of Ethiopian tetraploid landraces in the development of lines suitable for both bread and pasta production.