Genetic diversity of European spelt wheat (Triticum aestivum ssp. spelta L. em. Thell.) revealed by glutenin subunit variations at the Glu-1 and Glu-3 loci

Summary High and low molecular weight glutenin subunit (HMW-GS and LMW-GS) compositions of 270 European spelts, 15 Iranian spelts and 25 bread wheat cultivars were analyzed by one- and two-dimensional gel electrophoresis. The results revealed a total of 22 HMW-GS alleles (4 at Glu-A1, 11 at Glu-B1 and 7 at Glu-D1) and 32 allele combinations among the three Glu-1 loci. Two major genotypes of HMW-GS: 1, 13+16, 2+12 and 1, 6.1+22.1, 2+12 were found to occur in Central European spelt wheat cultivars and landraces at higher frequencies of 35 and 28%, respectively. The Glu-B1 locus displayed the greatest variation and genetic diversity index (H) was 0.69 whereas Glu-A1 and Glu-D1 showed H index values of 0.26 and 0.19, respectively. The dendrogram constructed by HMW and LMW glutenin subunit bands revealed that European spelts form a separated cluster from common wheat suggesting that spelt and common wheat form distinct groups. In addition, all 15 Iranian spelt land variety accessions differed from European spelts and possessed similar HMW-GS alleles to common wheat. Because of a wider polymorphism Central European spelt wheats are an important genetic reserviour for improving common wheat quality. Both authors contributed equally to this work     

Biochemical and molecular characterisation of Glu-1 loci in Argentinean wheat cultivars

The high molecular weight glutenin subunit (HMW-GS) composition of acollection of 107 Argentinean bread wheat cultivars was analysed bysodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE).Allelic variation at the Glu-1 loci was identified and its frequencycalculated. Eleven alleles were detected, three encoded at the Glu-A1locus, six at the Glu-B1 locus and two at the Glu-D1 locus. Alow frequency of the null allele at the Glu-A1 locus and a highfrequency of subunits 5+10 at the Glu-D1 locus were observed.Reversed phase-high performance liquid chromatography (RP-HPLC)analysis was used to further characterise HMW-GS. Two different types ofBx subunit 8 (named subunits 8 and 8) were detected, the latterhaving shorter elution time. Subunit 8 was not identifiable bySDS-PAGE. According to quantification by RP-HPLC analysis, two groupsof subunit 7 were observed. One group, with a relatively high proportionof subunit 7 (approximately 39% of the total amount of HMW-GS)appeared in cultivars with allele 7+8 at the Glu-B1 locus; asecond group of subunit 7 (around 24% of the total amount ofHMW-GS), was found in alleles 7+8, 7+8 and 7+9. Restrictionfragment length polymorphisms (RFLP) analyses of HMW-GS genes werealso carried out after digestion of genomic DNA with HindIII andTaqI restriction enzymes. The relationship between DNA fragment sizeand glutenin subunits, as estimated by electrophoretic mobility inSDS-PAGE, was also examined. The restriction enzyme TaqIdemonstrated to be a useful tool to detect homozygous plants in selectionprograms against the Glu-A1 null allele.     

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.     

Sources of resistance to tomato spotted wilt virus (TSWV) in cultivated and wild species of Capsicum

Summary The high molecular weight (HMW) subunits of glutenin extracted from flour of 36 Yogoslav wheat cultivars were separated by SDS-PAGE to identify their alleles, and the frequency of each allele was calculated. Eleven alleles from the three Glu-loci were recognized, three at the Glu-A1 locus, six at the Glu-B1 locus and two at the Glu-D1 locus. The most frequent allele was a (55.5%) from Glu-D1, which controls synthesis of subunits 2+12. The Glu-1 quality score varied from 4 (KG-III/27, KG-75, Morava and KG-101/7) to 10 (Lepenica). The mean Glu-1 quality score of cultivars and lines from Kragujevac was 6.8, for cultivars from Zagreb 7.2, and for cultivars from Novi Sad was 7.9. Most of the genotypes with a quality score of 8 or above, had high sedimentation values (Zeleny test). There were no significant differences in allelic composition at the Glu-1 loci among wheat genotypes from Kragujevac, Novi Sad and Zagreb.     

Allelic variation and composition of HMW-GS in advanced lines derived from d-genome synthetic hexaploid / bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

The objective of this study was to identify allelic variations at Glu-1 loci of wheat (Triticum aestivum L.) advanced lines derived from hybridization of bread wheat and synthetic hexaploid wheats (2n = 6x = 42; AABBDD). Locally adapted wheat genotypes were crossed with synthetic hexaploid wheats. From the 134 different cross combinations made, 202 F₈ advanced lines were selected and their HMW-GS composition was studied using SDS-PAGE. In total, 24 allelic variants and 68 HMW-GS combinations were observed at Glu-A1, Glu-B1, and Glu-D1 loci. In bread wheat, the Glu-D1 locus is usually characterized by subunits 1Dx2+1Dy12 and 1Dx5+1Dy10 with the latter having a stronger effect on bread-making quality. The subunit 1Dx5+1Dy10 was predominantly observed in these advanced lines. The inferior subunit 1Dx2+1Dy12, predominant in adapted wheat germplasm showed a comparative low frequency in the derived advanced breeding lines. Its successful replacement is due to the other better allelic variants at the Glu-D1 locus inherited in these synthetic hexaploid wheats from Aegilops tauschii (2n = 2x = 14; DD).     

Allelic variation at the storage protein loci of 55 US-grown white wheats

Fifty soft white and hard white wheat cultivars (Triticum aestivum L.), and five club wheat cultivars (T. compactum L.) were partially characterized in terms of their storage protein compositions, i.e. gliadins, and high molecular weight and low molecular weight glutenin subunits (HMW-GS and LMW-GS, respectively). At the Glu-1 loci, HMW-GS composition 1,7 + 9,2+ 12 was found to be predominant, being expressed in 11 cultivars out of 55. The most common alleles at the loci coding for gliadins and LMW-GS were found to be Gli-A1/Glu-A3a (43.6%), Gli-B1/Glu-B3b (36.4%), Gli-D1a/Glu-D3a (38.1%) and Gli-Dli/Glu-D3a (21.8%). Two-dimensional fractionation (acid-poly-acrylamide gel electrophoresis (A-PAGE) × sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE)) of reduced and alkylated glutenins revealed that the number and the relative mobility of LMW-GS polypeptides were different from those reported for the corresponding Glu-3 alleles of hard-bread wheat cultivars. This result could account for the different technological properties of soft white wheats compared with hard-bread wheat cultivars, owing to the major impact of LMW-GS on dough quality.     

Glu-1位点等位变异及表达量对麦谷蛋白聚合体粒度分布的影响

选用我国春播麦区23份(试验I)和北部冬麦区21份(试验II)品种(系),研究了Glu-1位点等位变异及其亚基表达量对谷蛋白聚合体粒度分布的影响。结果表明,Glu-1位点等位变异及其亚基表达量显著影响谷蛋白聚合体的粒度分布,且影响程度受蛋白质含量,尤其是高分子量谷蛋白总量水平的影响。在高分子量谷蛋白总量较低时(试验I),Glu-B1和Glu-D1位点对不溶性谷蛋白大聚体含量(UPP)及其占聚合体蛋白总量的百分比(%UPP)的加性效应都达1%显著水平;Glu-B1和Glu-D1位点单个亚基对两者的贡献分别为7^OE+8^* >7+9 >17+18 >7+8和5+10 >2+12,具有5+10亚基组合的%UPP显著高于具有2+12的亚基组合。高分子量谷蛋白的亚基表达量与UPP含量呈高度正相关,相关系数为0.79~0.93(P < 0.01)。而在高分子量谷蛋白总量较高时(试验II),仅Glu-D1位点对%UPP的加性效应达5%显著水平,5+10亚基对%UPP的贡献显著高于2+12和4+12;亚基组合间的聚合体粒度分布无显著差异。高分子量谷蛋白的亚基表达量与UPP含量的相关系数为0.42~0.86(P < 0.05或0.01)。结合高分子量谷蛋白表达量和优质亚基进行选择,能有效提高不溶性谷蛋白大聚体的含量和相对比例,有利于面筋强度和加工品质的进一步提高。     

The high and low molecular weight glutenin subunits and ω-gliadin composition of bread and durum wheats commonly grown in Portugal

A collection of 63 bread wheats (Triticum aestivum L.) and 21 durum wheats (Triticum durum Desf.) commonly grown in Portugal since 1982 were characterized for the composition of wheat storage proteins (WSP), high molecular weight glutenin subunits (HMW-GS), low molecular weight glutenin subunits (LMW-GS) and ω-gliadins. The composition of HMW-GS, LMW-GS and &-gliadins, encoded at loci Glu-1, Glu-3 and Gli-1, respectively, was revealed by sodium dodecyl sulphate polyacrylamide gel electrophoresis. WSP allelic compositions of bread and durum wheat patterns were given. In the bread wheats, a total of 24, 24 and 18 patterns were observed for HMW-GS, LMW-GS and ω-gliadins, respectively. Forty-two different alleles were identified for the nine loci studied, Glu-A1 (3), Glu-B1 (7), Glu-D1 (4), Glu-A3 (5), Glu-B1 (7), Glu-D3 (2), Gli-A1 (2), Gli-B1 (8) and Gli-D1 (4). In the case of durum wheats, 19 alleles were identified: one allele at Glu-A1, two at Glu-B3, Glu-B2 and Gli-A1, three at Glu-B1, four at Glu-A3 and five at Gli-B1. For HMW-GS, LMW-GS and ω-gliadins, three, six and six different patterns were revealed, respectively. This study represents the first attempt to discriminate the bread and durum wheat varieties commonly grown in Portugal by the allelic variation of storage proteins. The database is useful for varietal identification and for plant breeders who seek to devise effective programmes aimed at improving wheat quality.     

Allelic variation of the HMW glutenin subunits in Aegilops tauschii accessions detected by sodium dodecyl sulphate (SDS-PAGE), acid polyacrylamide gel (A-PAGE) and capillary electrophoresis

Variability of high molecular weight glutenin subunits (HMW-GS) was studied in198 accessions of Ae. Tauschii (2n=2x=14, DD) by sodium dodecyl sulphate(SDS-PAGE) and acid polyacrylamide gel electrophoresis (A-PAGE) and capillary electrophoresis (CE). A high allelic variation of HMW-GS, including some novel x- and y-type subunits and variable subunit combinations were observed. One accession(TD159) showed a x-type null form. The results by A-PAGE analysis revealed that the subunits Dx5 ^t and Dy10 ^t encoded by Glu-D ^t 1 locus in Ae. tauschii were different in relative mobilities in comparison with the subunits Dx5 and Dy10 found in bread wheats, whereas they had the same mobilities, respectively, when separated by SDS-PAGE. The higher resolution of Ae. tauschii HMW-GS separated by CE method showed two clear peaks in accordance with x- and y-type subunits, respectively,except the accession TD151 which possessed only subunit Dy12.1^*t. The electro elution time of the x-type and y-type subunits were about 13–14 and 7–8minutes, respectively. Characterization of wheat HMW-GS was facilitated by using CE which provides high resolution and increases the speed of analysis in conjunction with the traditional gel electrophoretic methods. A total of 42HMW-GS alleles were identified, among which were several alleles not presently detected in bread wheats. Hence Ae. tauschii is potentially a valuable genetic resource for quality improvement of bread wheat. This revised version was published online in August 2006 with corrections to the Cover Date.     

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.     

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。     

小麦重组自交系群体HMW-GS的检测与分析

利用重组自交系群体--RILL-8群体的131个系为材料,检测和分析了其高分子量麦谷蛋白亚基及亚基组合.结果表明,RIL-8群体Glu-A1、Glu-B1、Glu-D1位点编码的亚基分别为1、N,7 9、7 8和5 10、2 12,主要存在7种亚基组合类型.不同亚基及亚基组合类型在相同位点上仅存在1对等位基因差异,可以用其进行相同位点不同亚基及亚基组合对品质性状效应值的估算.     

Glu-D1位点亚基缺失弱筋小麦新种质的创制及其品质分析

辐射诱变是一种重要的变异手段,为了丰富小麦的品质性状变异资源,通过采用60Co-?射线辐射普通小麦品种‘冀3235’幼胚愈伤组织的方法,获得辐射诱变处理的再生植株。对再生株后代种子进行麦谷蛋白亚基的SDS-PAGE分析,结果从中发现了不含Glu-D1位点编码的高分子量麦谷蛋白亚基的材料。经进一步的系谱选择,选育成了稳定遗传的7份材料。与对照‘冀3235’相比,这些株系的农艺性状无明显差异,醇溶蛋白A-PAGE电泳谱带也完全相同,仅在麦谷蛋白SDS-PAGE电泳图谱的Glu-D1位点上有差异（变异系缺少Glu-D1位点控制的亚基,对照‘冀3235’为2+12）。品质分析结果表明,Glu-D1位点缺失系的面粉品质发生了很大变化,其湿面筋没有检出,沉降值显著下降。这些变异系是培育弱筋小麦品种和评价Glu-D1位点功能的珍贵材料。     

Characterization of HMW-GS and evaluation of their diversity in morphologically elite synthetic hexaploid wheats

High molecular weight glutenin subunit composition and variation in 95 Elite-1 synthetic hexaploid (SH) wheats (Triticum turgidum/Aegilops tauschii; 2n = 6× = 42; AABBDD) were determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis method (SDS-PAGE). Twenty two different alleles at Glu-1 loci in SHs were observed. Forty four different patterns of HMW-GS in synthetics were found. This higher HMW glutenin composition was due to higher proportion of D-genome encoded subunits in these SHs. 8% urea/SDS-PAGE better discriminated subunit 2* than 12% gels. However 12% urea/SDS-PAGE allowed differentiated mobility of Glu-D^t1 subunits. Genetic variability at Glu-D^t1 locus was greater than Glu-A1 and Glu-B1 loci. The relative high frequency of superior alleles, Glu-B1b and Glu-D^t1d indicated the superior bread making quality attributes embedded in these synthetic hexaploid wheats. Of the 95 Elite-1 SHs 27.1% possessed superior alleles at Glu-A1 and 51% had superior alleles at Glu-B1 locus. At Glu-D^t1 frequency of inferior allele 1Dx2 + 1Dy12 was very low (5.26%) and nine different rare alleles along with the higher frequency (22.1%) of D-genome encoded subunit, 1Dx5 + 1Dy10, were observed. These superior alleles shall form the priority selective sieve for their usage in wheat improvement efforts.     

小麦高分子量谷蛋白亚基间的互补效应对面包加工品质的影响

利用偃展1号的10个HMW-GS近等基因系,研究了不同HMW-GS基因对面包烘烤品质的效应。两年的品质测试结果基本一致,说明所用近等基因系是评价亚基组成对加工品质影响的较理想材料。不同HMW-GS组成对面包评分影响较大,变异系数达到21.5%。相关分析表明,面包体积与形成时间(r = 0.90, P < 0.01)、沉淀值(r = 0.89, P < 0.01)、稳定时间(r = 0.67, P < 0.05)和面粉蛋白质含量(r = 0.52, P < 0.05)均达显著正相关;面包评分与面包体积(r = 0.98, P < 0.01)、沉淀值(r = 0.93, P < 0.01)、形成时间(r = 0.89, P < 0.01)也呈显著正相关。Glu-A1位点1Ax1基因的表达可以提高多数品系的面包评分;当Glu-A1位点是Null、Glu-D1位点是5’+12时,Glu-B1位点等位变异的面包加工品质效应为7+8 > 14+15 > 6+8 > 7,而当Glu-A1位点是1号亚基、Glu-D1位点是5’+12时,Glu-B1位点的等位变异的面包品质效应为6+8 > 14+15 > 7;当Glu-A1位点是Null时,14+15与5+10组合优于与5’+12组合,7+8与5’+12组合优于与5+10组合;1Dx5基因的沉默显著降低面包烘烤品质,HMW-GS对面包品质的作用似乎在X-亚基和Y-亚基之间存在一定的配合效应,任何一种基因的缺失或沉默都会造成品质的明显下降。     

Diversity of seven glutenin and secalin loci within triticale cultivars grown in Europe

Analysis by SDS-PAGE of the majority of hexapoid triticales (× Triticosecale) (134 cultivars) grown in Europe allowed to identify 40 alleles at seven loci: Glu-A1, Glu-B1, Glu-R1, Gli-R2, Glu-B2, Glu-A3 and Glu-B3. Glu-B1 and Glu-B3 loci were the most polymorphic with 9 alleles at each locus. 95 allelic combinations were observed including 71 specific for one cultivar each. On the basis of allelic frequencies at the seven loci, genetic distances between hexapoid triticales grouped according to their origins revealed two clusters: winter triticales mostly originating from European germplasm and spring triticales essentially of CIMMYT origin. Comparison of allele frequencies between hexaploid triticale cultivars and a world collection of bread (Triticum aestivum) and durum (Triticum durum) wheat was investigated at Glu-A1 and Glu-B1: only a significant association was found for Glu-A1 alleles (γ²=2.26, p=0.36) between triticale and bread wheat. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic analysis of resistance to Karnal bunt (Tilletia indica,Mitra) in bread wheat

Summary Karnal bunt caused by Tilletia indica in wheat seriously affects the quality of the grains. It is important to generate information on the genetics of resistance to this pathogen so as to aid resistance breeding. For this purpose, four Karnal bunt-resistant lines from China, Brazil and CIMMYT (International Maize and Wheat Improvement Center) and a susceptible Indian cultivar, WL711, were used. The parents, F1 and F3 progenies of five parental diallel crosses revealed that independently segregating loci with three partial dominant resistance alleles were involved in the resistance of Karnal bunt. Lines RC7201/2^*BR2 and Roek//Maya/NAC carried one locus for resistance while Shanghai#7 and Aldan/IAS58 have two and three loci, respectively. One common locus was present in all four resistant parents, which imparted a high level of resistance.     

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.     

The effect ofGlu-B1 high molecular weight glutenin subunits on biscuit-making quality of wheat

Summary The aim of this study was to assess the effect of specificGlu-B1 HMW-GS on biscuit-making quality. Three soft spring wheat cultivars with the sameGlu-A1 andGlu-D1 HMW-GS, but differentGlu-B1 HMW-GS were used in crosses. F₂₄ derived lines were developed from these crosses.Glu-B1 HMW-GS 6+8 and 17+18; and 7+9 and 17+18 were compared. Lines with HMW-GS 6+8 versus those with HMW-GS 17+18 had a higher flour protein- and alveograph P/L ratio, shorter mixograph mixing time, more vitreous kernels, and a lower alveograph distensibility and strength (all values significant at p=0.05). Lines with HMW-GS 7+9 compared to those with 17+18 showed significant differences for flour extraction and biscuit diameter. The presence of HMW-GS 17+18 was significantly correlated with several biscuit-making quality characteristics in the Dirkwin/Zaragosa F₂₄ lines but not in the Waverley/Zaragosa F₂₄ lines, therefore the effect of HMW-GS 17+18 was modified by the genetic background in which they were expressed.     

Allelic variation and genetic diversity of high molecular weight glutenin subunit in Chinese endemic wheats (Triticum aestivum L.)

The high molecular weight glutenin subunit (HMW-GS) compositions of 66 Chinese endemic wheats were determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Ten alleles at the Glu-1 loci were detected in 50 Tibetan weedrace wheat accessions which in combination resulted in seven different HMW-GS patterns. Four HMW-GS patterns were observed among 10 Yunnan hulled wheat accessions, and two patterns in six Xingjiang rice wheat accessions. Two novel alleles (Bx7** + By8, Bx7 + By8**) and two rare alleles (Dx2 + 1Dy12*, Dx2 + null) were found in Tibetan weedrace accessions, with one of the latter (Dx2 + Dy12*) also being found in Yunnan hulled wheat. The mean indices of genetic variation at the Glu-1 loci in Yunnan hulled wheat, Tibetan weedrace wheat and Xingjiang rice wheat were 0.2232, 0.1655 and 0.0926, respectively, showing that Yunnan hulled wheat and Tibetan weedrace wheat had higher genetic variation than Xingjiang rice wheat.