Towards allelic diversity in the storage proteins of old and currently growing tetraploid and hexaploid wheats in Portugal

Using sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE), the different alleles encoded at the 6 glutenin loci and 3 ω-gliadin loci were identified from a set of 134 hexaploid and 128 tetraploid wheat accessions mainly grown in Portugal. In the hexaploid wheats (T. aestivum L.), a total of 56, 42 and 36 patterns were observed for high molecular weight-glutenin subunits (HMW-GS), low molecular weight-glutenin subunits (LMW-GS) and ω-gliadins respectively. For HMW-GS encoded at Glu-A1, Glu-B1 and Glu-D1 loci, 4, 10 and 6 alleles were observed, respectively. LMW-GS displayed similar polymorphism, as Glu-A3, Glu-B3 and Glu-D3 loci, which comprises 5, 9 and 3 alleles. Twenty-four alleles were observed for ω-gliadins found at Gli-A1, Gli-B1 and Gli-D1 loci with, 5, 16 and 3 alleles respectively. For tetraploid collection fifty different alleles were identified for the seven loci studied Glu-A1 (3), Glu-B1 (13), Glu-A3 (6), Glu-B3 (7), Glu-B2 (2), Gli-A1 (5) and Gli-B1 (14). The genetic distances within hexaploid and tetraploid wheats were presented using cluster representation. The mean value of genetic variation indices (H) for wheat storage protein loci was slightly lower in current commercially available varieties (0.592) and highest for old varieties (0.574).     

Protein Heterogeneity in European Wheat Landraces and Obsolete Cultivars: Additional Information II

The endosperm storage protein of 46 European wheat (Triticum aestivum L.) landraces and obsolete cultivars have been fractionated by SDS-PAGE to determine the composition of high molecular weight glutenin subunits (HMW-GS) composition. It has been discovered that about 46% of the wheats were heterogeneous, comprising 2–11 different glutenin profiles. Eighteen of them were observed to be homogeneous. A total of 13 HMW-GS alleles, including 3 at the Glu-A1, 8 at the Glu-B1, and 3 at the Glu-D1 loci were revealed. HMW-GS null controlled by locus Glu-A1, subunits 7 + 8 by Glu-B1, and 2 + 12 by Glu-D1 predominated. However low frequented alleles such as 17 + 18, 20, 6, and 7 were observed. Furthermore, other new alleles encoding HMW-GS at the locus Glu-B1 have been found in one of France cultivar (Saumur d’Automne). The glutenin-based quality score ranged from 4 to 10.     

Genetic diversity of storage protein genes in common wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) cultivars from China and its comparison with genetic diversity of cultivars from other countries

Contemporary trends and perspectives of Chinese winter wheat breeding programs were explored using multiple alleles of gliadin (Gli) and glutenin (Glu)-coding loci as genetic markers. To estimate genetic diversity and specific features of Chinese cultivars, the allele frequencies and genetic diversity H in Chinese wheat pool were calculated and compared to those of cultivars from 11 regions of the world. Among all these cultivars the Chinese ones exhibited the highest allelic diversity of the Gli loci while showing relatively low genetic variability for the Glu loci. Most (96%) of the cultivars examined had unique Gli allele compositions, which enabled to differentiate these cultivars with high precision. Cluster analysis of the genetic distances among the wheats from different regions showed that the Chinese cultivars were close to Italian and Russian ones, sharing with them the common Gli alleles. Clustering of modern cultivars and that of cultivars bred 10–15 years ago was essentially the same. All cultivars from all of the countries examined were classified into three groups according to their quality based on their Glu allele compositions. The Chinese cultivars showed a moderate quality score of 7.0, which conforms to the quality evaluation based on SDS sedimentation. This quality proved to be insufficiently high as compared to cultivars from other countries. However, the genetic diversity estimation suggests that Chinese cultivars have a potential for quality improvement.     

Protein heterogeneity in European wheat landraces and obsolete cultivars: Additional information

The objective of this study was to determine the composition of high molecular weight glutenin subunits of landraces and obsolete cultivars. Altogether glutenin profiles of 67 European wheats were analyzed by sodiumdodecylsulphate polyacrylamide gel electrophoresis. Nineteen of them were observed to be homogeneous, whereas 48 (71%) were heterogeneous in glutenin profiles. Heterogeneous accessions possessed from 2 to 9 different glutenin phenotypes. Seventeen high molecular weight (HMW)-glutenin subunits have been found, three belonged to Glu-1A, 11 to Glu-1B, and three to Glu-1D locus. The most frequented HMW-GS at the Glu-A1, Glu-B1, and Glu-D1 complex loci were 0, 7+9, and 2+12, respectively. However, allele low frequented in wheat such as 13+16, 20, 6, 7, 8, and 9 were observed also. Furthermore, other new alleles encoding HMW-GS at the locus Glu-1B with relative molecular weight 120 and 104 kDa have been found in one of the line of the Swedish cultivar Kotte. TheGlu-1 quality score in the examined accessions varied broadly with some lines reaching the maximum value of 10.     

Polymorphism of high molecular weight glutenin subunits in three species of Aegilops

A collection of 136 accessions of Aegilops umbellulata (39), Ae. comosa (75) and Ae. markgrafii (22) was analysed for high-molecular-weight (HMW) glutenin subunits composition. The homogeneity of the accessions was studied and 55.1% of the collection was homogeneous for HMW glutenin subunits (29 Ae. umbellulata, 33 Ae. comosa and 14 Ae. markgrafii). The HMW glutenin subunits of Ae. umbellulata are encoded by the Glu-U1 locus; in Ae. comosa results showed that this proteins are encoded at the 1M chromosome, and the locus was named Glu-M1. In Ae. markgrafii it was assumed that HMW glutenin subunits were encoded by an homoeologous locus and it was named Glu-C1. All the accessions of Ae. umbellulata and Ae. markgrafii expressed both, x-type and y-type subunits. Among the Ae. comosa accessions, only one expressed an x-type subunit alone. All the accessions of Ae. umbellulata and some of Ae. comosa had x-type glutenins of higher molecular weights than those commonly present in bread wheat. A total of 8 alleles were detected at the Glu-U1 locus, 11 at the Glu-M1 and 4 at the Glu-C1. The new HMW glutenin variation found in this work suggests their possible utilisation in breeding for wheat quality.     

Intra- and interpopulation diversity for HMW glutenin subunits in Spanish spelt wheat

The diversity of HMW glutenin subunits in spelt wheat, Triticum aestivum ssp. spelta, was studied electrophoretically in 333 accessions grouped in 50 populations originally collected from Asturias, North of Spain, in 1939. The inter- and intra-population distribution of HMW glutenin alleles at the Glu-A1, Glu-B1 and Glu-D1 loci were investigated. The results show that the genetic variation in HMW glutenin subunits is mainly present within populations, being the variation between populations only 21%. The materials analysed showed a wide polymorphism for the HMW glutenin subunits, although some allelic variants were clearly dominant. This suggests the possibility of a loss of variability before the collection that could have increased with the subsequent reduction of the cultivation area of this species in this Spanish region.     

Genetic variation of high-molecular-weight glutenin subunit composition in Asian wheat

To clarify the genetic properties of the HMW glutenin subunit composition of Asian endemic wheats, SDS–PAGE analysis was conducted using 1,139 bread wheat accessions that were originally collected in Asia. The samples were divided into six regional groups, Western Asia, Caucasia, Central Asia, Afghanistan, Southern Asia, and Eastern Asia. The genotype Glu-A1c, Glu-B1b, and Glu-D1a encoding subunits null, 7+8, and 2+12 had an overall frequency of 55.2%. Thus, we conclude that it is the typical genotype of the HMW glutenin subunits that characterize Asian endemic wheat. The frequency of the typical Asian genotype was relatively high in the central belt of Asia (Western Asia, Afghanistan, and Eastern Asia) and low in the marginal regions (Caucasia, Central Asia, and Southern Asia). In Southern Asia, the frequency of Glu-B1i, which encodes subunit 17+18, was the highest at the Glu-B1 locus. In Caucasia and Central Asia, the frequency of Glu-D1d, which encodes subunit 5+10 (which is considered to be the most useful for making bread), was high. The level of genetic variation, as estimated using the frequencies of the various alleles, was relatively low in the central belt of Asia and high in the marginal regions. Among the three Glu-1 loci, the highest number of alleles was detected at the Glu-D1 locus. This result was caused by the presence of rare Asian specific alleles at the Glu-D1 locus, in which a newly found allele, Glu-D1bs, encoding subunit 2.1+12 was included.     

Effects of Wheat Bug (Eurygaster maura) Protease on Glutenin Proteins

Proteolytic degradation of 50% 1-propanol insoluble (50PI) glutenin of six common wheat cultivars by wheat bug (Eurygaster maura) protease was investigated using reversed-phase HPLC. Wheat at the milk-ripe stage was manually infested with adult bugs. After harvest, bug-damaged kernels were blended (2:1, kernel basis) with undamaged grain of the same cultivar. Samples of ground wheat were incubated in distilled water for different times (0, 30, 60, and 120 min). The incubated whole meal samples were subsequently freeze-dried and stored until analysis. The degree of proteolytic degradation of 50PI glutenin was determined based on the quantity of total glutenin subunits (GS), high molecular weight GS (HMW-GS), and low molecular weight GS (LMW-GS). For ground wheat samples incubated for ≥30 min, 50PI glutenin was substantially degraded as evidenced by a >80% decrease on average in total GS, HMW-GS, and LMW-GS. Some cultivars showed different patterns of glutenin proteolysis as revealed by differences in the ratios of HMW-GS to LMW-GS between sound and bug-damaged samples; a significant decrease in this ratio was found for four cultivars. This evidence, combined with other observations, indicated that there were intercultivar differences in polymeric glutenin resistance to the protease of the wheat bug Eurygaster maura. While the nature of this resistance is unknown, it should be possible to select and develop wheat cultivars with improved tolerance for wheat bug damage. Propanol insoluble glutenin, which corresponds to relatively large glutenin polymers, appears to be an excellent quantitative marker for this purpose.     

Polymorphism of high M r glutenin subunits in wild emmer Triticum turgidum subsp. dicoccoides: chromatographic,electrophoretic separations and PCR analysis of their encoding genes

Triticum turgidum subsp. dicoccoides (Körn. ex Asch. et Graebn.) Thell. (AABB), the immediate progenitor of tetraploid and hexaploid wheats, is a species characterised by a wide range of protein polymorphism and by high protein content. Surveys on polymorphism and genetic control of the high molecular weight glutenin subunits (HMW-GS) present in this species, in two forms x- and y-type at the Glu-A1 and Glu-B1 loci, are still considered useful, both to improve technological properties of breeding varieties and to study the genome evolutionary process in wheats. Comparative Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoretic and Reversed Phase High Performance Liquid Chromatographic analyses (SDS-PAGE, RP-HPLC) of the HMW-GS present in several accessions of T. turgidum subsp. dicoccoides allowed the detection of new alleles of Glu-A1 and Glu-B1 loci, with x- and y-type glutenin subunits, apparently similar to those present in cultivated wheats in molecular weight, but different in surface hydrophobicity. In addition, changes in the number of x- and y-type subunits at the glutenin loci were also ascertained. The y-type subunits at the Glu-A1 locus, which are never expressed in cultivated bread and durum wheats, and single y-type expressed glutenin subunits at the Glu-B1 locus were also identified in several accessions. DNA extracted from samples, differing in number or type of HMW-GS and corresponding to x- and y-type genes at Glu-1 loci, were amplified using specific primers, two of which were constructed within the transposon-like sequence of Chinese Spring DNA and analysed by polymerase chain reaction. The results showed this insertion in some accessions of T. turgidum subsp. dicoccoides and also the presence of silent Ax, Bx and By type genes. The usefulness for breeding of these comparative analyses carried out on different HMW-GS alleles detected in Triticum turgidum subsp. dicoccoides, is discussed.     

Effects of Prolamins Encoded by Chromosomes 1B and 1D on the Rheological Properties of Dough in Near-Isogenic Lines of Bread Wheat

Fourteen bread wheat near-isogenic lines (NILs) with different alleles at 1B- and 1D-chromosome loci Glu-1, Glu-3 and Gli-1 coding for high molecular weight glutenin subunits (HMW-GS), low molecular weight-GS, and gliadins, respectively, were grown in replicated plots to investigate the individual and combined effects of glutenin and gliadin components on the rheological properties of dough as determined by the Chopin alveograph. NILs did not reveal significant differences in seed yield, protein content, kernel weight, test weight, flour yield, and starch damage. On the contrary, they had a large variation in alveograph dough tenacity P (55–93 mm), swelling G (17–26 mL) and strength W (140–252 J × 10^-4). The null alleles at the Gli-D1/Glu-D3 loci, and allele Glu-D1d (HMW-GS 5+10) were found to have a strong positive influence on dough tenacity and a remarkable negative influence on dough swelling (extensibility) when compared to alleles Gli-D1/Glu-D3b and Glu-D1a (HMW-GS 2+12), respectively. On the other hand, alleles Glu-B1c (HMW-GS 7+9) and Gli-B1/Glu-B3k gave greater G values than alleles Glu-B1u (HMW-GS 7*+8) and Gli-B1/Glu-B3b. The effects of individual Glu-1, Gli-1, or Glu-3 alleles on P and G values were largely additive. The impact of the null allele at Gli-D1/Glu-D3 on gluten strength was highly positive in NILs possessing HMW-GS 2+12, and negligible or negative in NILs containing HMW-GS 5+10, suggesting that there is scope for improving dough quality by utilizing this allele in combination with HMW-GS 2+12. Gli-D1/Glu-D3-encoded prolamins were shown to play a major role in conferring extensibility to dough, and could account for the superior breadmaking characteristics of bread wheat as compared to durum wheat.     

Genetic variability at the Glu-1 loci in old and modern wheats (triticum aestivum L.) cultivated in Slovakia

The high molecular weight glutenin subunits (HMW-GS) composition at the Glu-1 complex loci, in 23 old original wheat genotypes cultivated in Slovakia several decades ago and 32 modern Slovak and Czech wheat cultivars growed in Slovakia at present were studied by SDS-PAGE. Some of the HMW-GS – subunit pairs 3+12, 17+18, and subunit 20, present in old historical wheats were missing in modern cultivars utilized in Slovakia nowadays. There were observed 15 different HMW-GS encoded by 11 alleles or allelic pairs in old genotypes. Lower number of different HMW-GS and competent alleles were observed in a set of modern wheat cultivars – 11 different HMW glutenin subunits encoded by 8 alleles or allelic pairs. The same number of different HMW-GS patterns was revealed in both sets of wheats. From the point of view of genetic variability, it could be concluded that long-term effort of breeders and decreasing of cultivation of landraces and old cultivars are associated with the loss of several HMW-GS alleles and decreasing of genetic variability of wheats. Molecular characterization can reveal broad allelic variability of old wheat genotypes and landraces. Their maintenance in genetic resource collections can prevent losses of these interesting genes.     

Effect of Single Substitution of Glutenin or Gliadin Proteins on Flour Quality of Alpha 16, a Canada Prairie Spring Wheat Breeders' Line

The effect of genetic variation in the glutenin and gliadin protein alleles of Alpha 16, a Canada Prairie Spring (CPS) wheat line, on the dough mixing, bread, and noodle quality properties were evaluated. The presence of a gliadin component (BGGL) and the low molecular weight glutenin subunit (LMW-GS) 45 found in the selection Biggar BSR were associated with significant increases in dough strength characteristics. The results of the study showed that gliadins, LMW-GS, and high molecular weight glutenin subunits (HMW-GS) can influence bread- and noodle-making properties of wheat flour. Genotype-by-environment interactions were not significant for most of the quality parameters studied, indicating that the differences observed in quality characteristics were mainly due to the effect of genotype.     

Purification and Characterization of the Glutenin Subunits of Triticum tauschii,Progenitor of the D Genome in Hexaploid Bread Wheat

N-terminal amino acid sequences and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) molecular weights have been determined for high-performance liquid chromatography (HPLC)-purified high molecular weight (HMW) and low molecular weight (LMW) glutenin subunits (GS) of Triticum tauschii ssp. strangulata, contributor of the D genome to hexaploid bread wheat. The use of three different extraction procedures resulted in similar glutenin preparations. On the basis of N-terminal sequences, the same types of glutenin subunits that have been reported in bread and durum wheats (HMW-GS of both the x and y types and LMW-GS of the LMW-s, LMW-m, α-, and γ-types) were found in T. tauschii. However, the HMW-GS in T. tauschii were in greater proportion relative to LMW-GS when compared to reported values for a bread and durum wheat. Our results support the likelihood that differences in the proportions of the various subunits contributed by the A, B, and D genomes, rather than qualitative differences in the types of subunits, are responsible for the major differences in quality characteristics between bread wheat and durum wheat.     

Evaluation of geographic distribution of high-molecular-weight glutenin subunits (HMW-GS) in wild and cultivated Triticum species

Variation of high-molecular-weight glutenin subunit (HMW-GS) in 632 wild and cultivated Triticum accessions was investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. A total of 11 alleles of HMW-GS in diploid species, 22 in tetraploid species, and 15 in hexaploid species were detected. Diploid species on Glu-1A locus and tetraploid species Glu-1B locus showed the highest diversity, respectively. Tetraploid species had the highest level of diversity on three Glu-1 loci, followed by hexaploid and diploid, based on Shannon’s information index, Nei’s genetic diversity, and percentage of polymorphic loci. Molecular variance analysis confirmed main variance of HMW-GS within species, regions, and locations, respectively. Variance among species and regions was enhanced gradually with the increase of ploidy. Significant non-random distributions between the phylogenic trees of HMW-GS and the locations of accessions were tested by GenGIS software, indicated that geographic factors played an important role along the different orientations in the spread of Triticum species. We found one original diversified center in diploid what located around Elazig, Malatya, Gaziantep, Urfa, and Kiziltepe in Turkey, and three diversified centers in tetraploid wheat, including Turkey–Armenia–Georgia–Iran, Portugal–Spain, and Ethiopia, respectively, and two diversified adjacent areas between Turkey and Switzerland and around Turkey, Georgia, and Armenia. The original center of diploid species located in southeast Turkey, where the unexpressed 1Ay subunit was mainly distributed in T. urartu, could be one of the candidate regions of polyploidization of Triticum L. The regional distribution of HMW-GS and species also provided geographic evidences for the existence of founder effect on the spread of Triticum species. The present study suggests that integrating genetic diversity with geographic characterization in Triticum could very useful for collection, conservation, and utilization, as well as for research microevolution and domestication.     

Allelic variation and distribution of HMW glutenin subunit 1Ay in Triticum species

The allelic variation and distribution of high-molecular-weight (HMW) glutenin subunit 1Ay in 814 Triticum lines were investigated by sodium dodecyl sulfate polyacrylamide-gel electrophoresis (SDS–PAGE). 1Ay subunit existed in 13 out of analyzed 21 species. The four species T. turgidum L., T. polonicum L., T. turanicum Jakubz. and T. zhukovskyi Men. et Er. were firstly discovered with expressed 1Ay subunit. The distribution frequencies for diploid, tetraploid and hexaploid wheats were at 87.89, 20.31 and 1.79%, respectively. Among the observed eight 1Ay alleles, three with the electrophoretic mobilities similar to 1Bx6, 1By8, and between 1By8 and 1Dy10 were firstly observed. Five had the mobilities similar to 1Bx6, 1Bx7, 1By8, 1Dy10, and 1Dy12 in Glu-1B and Glu-1D loci of hexaploid wheat. It is very difficult to distinguish these 1Ay alleles in Glu-1Ay from those in hexaploid wheat. The predominant 1Ay alleles were those with the mobilities similar to 1Bx7, 1By8, 1Dy10 and 1Dy12, and faster than 1Dy12. Comparison results of 1Ay alleles in different species indicated that multiple diploid lines were involved in the evolution process of tetraploid wheat. The 1Ay allelic variations and genetic resources might be useful in the quality improvement of common wheat.     

Molecular characterization of two novel Glu-D1-encoded subunits from Chinese wheat (Triticum aestivum L.) landrace and functional properties of flours possessing the two novel subunits

The high molecular weight glutenin subunits (HMW-GS) can be used for wheat quality improvement. Two novel alleles (designated 1Dx1.5* and 1Dy12.2*, respectively) at the Glu-D1 locus were identified in the Chinese wheat landrace variety ‘Jiuquanjinbaoyin’ by comparison of subunit mobility with that previously identified in several standard hexaploid wheats. The 1Dx1.5* and 1Dy12.2* genes were isolated using the allele-specific PCR primers and the complete open reading frames (ORFs) were obtained. Allele 1Dx1.5* consists of 2487 bp encoding a mature protein of 827 amino acid residues, whereas 1Dy12.2* consists 1980 bp encoding 658 residues. Comparisons of amino acid sequences analysis showed that 1Dx1.5* had higher similarity with the HMW-GS isolated from the wheat related species (Aegilops tauchi Coss.) than from the bread wheat varieties (Triticum aestivum L.). The 1Dy12.2* amino acid sequence showed a generally similar to the 1Dy12* isolated from Chinese endemic wheats. Meanwhile, the dough properties of the lines expressing (null, 7+8, 1.5*+10), (null, 7+8, 2+12.2*) and (null, 7+8, 2+12), respectively, were measured by a Mixograph, which demonstrates that the alleles 1.5*+10 can be considered as having positive impact on dough strength when compared with the alleles 2+12. In addition, the subunits 2+12.2* also showed a greater impact on dough strength than 2+12.     

Genetic variability of high molecular weight glutenin subunits in bread wheat from continental Portugal, Madeira and Canary Islands

The genetic variability of high molecular weight glutenin subunits (HMWGS) composition at the Glu-1 loci in bread wheat (Triticum aestivum L.) was studied electrophoretically using the SDS–PAGE in 3,470 individuals representing 159 populations originated from the Canary Islands (Spain), the Archipelago of Madeira (Portugal) and the continental Portugal. A total of 25 alleles were detected, resulting in 69 different allele combinations. The geographical distribution of the high molecular weight glutenin alleles confirms historical data regarding circulation of wheat germplasm between the Iberian Peninsula and Madeira and between Madeira and the Canary Islands and vice versa.     

High Molecular Weight (HMW) Glutenin Subunit Composition of Some Nordic and Middle European Wheats

A collection of 123 winter and 106 spring wheat (Triticum aestivum L.) cultivars and breeding lines commonly grown in Nordic and Middle European countries were characterised for the composition of high-molecular-weight (HMW) glutenin subunits on the ground of data from literature and experiments of author. HMW glutenin subunit composition was determined by one-dimensional sodium dodecyl sulphate- polyacrylamide gel electrophoresis (SDS-PAGE). The present database includes data for cultivars and breeding lines from Finland (FIN – 56), Estonia (EST – 27), Sweden (SW – 27), Germany (D – 24), Lithuania (LIT – 17), United Kingdom (UK – 6), France (F – 3), Poland (POL – 5), Italy (IT – 7), Netherlands (NL – 6), Norway (NOR – 12), Russian Federation (RUS – 14 items). The occurrence of individual alleles and corresponding HMW glutenin subunits in surveyed cultivars is demonstrated. Special attention has been paid to cultivars growing in neighbouring countries with the aim to apply them in Estonian plant breeding. The database consists of 4 tables with data of HMW glutenin subunits, encoding them Glu-1 alleles, quality score and sources of data. The database could be useful for varietal identification and for plant breeders to improve wheat quality and accelerate the breeding process.     

Genetic diversity of HMW glutenin subunits in diploid,tetraploid and hexaploid <Emphasis Type="Italic">Triticum</Emphasis> species

The genetic variations of high-molecular-weight (HMW) glutenin subunits in 1051 accessions of 13 Triticum subspecies were investigated using sodium dodecyl sulfate polyacrylamide-gel electrophoresis. A total of 37 alleles were detected, resulting in 117 different allele combinations, among which 20, 68 and 29 combinations were observed in diploid, tetraploid and hexaploid wheats, respectively. Abundance and frequency of allele and combinations in tetraploid wheats were higher than these in hexaploid wheats. Allele Glu-A1c was the most frequent subunit at Glu-A1 locus in tetraploid and hexaploid wheats. Consequently, the results also suggested that the higher variations occurred at Glu-B1 locus compared to Glu-A1 and Glu-D1. Therefore, carthlicum wheat possessing the allele 1Ay could be presumed a special evolutional approach distinguished from other tetraploid species. Furthermore, this provides a convenient approach of induction of the 1Ay to common wheat through direct cross with carthlicum wheat. Alleles Glu-B1c and Glu-B1i generally absent in tetraploid wheats were also found in tetraploid wheats. Our results implied that tetraploid and hexaploid wheats were distinguished in dendrogram, whereas carthlicum and spelta wheats and however displayed the unique performance. In addition, founder effect, no-randomness of diploidization, mutation and artificial selection could cause allele distribution of HMW-GS in Triticum. All alleles of HMW-GS in Triticum could be further utilized through hybrid in the quality improvement of common wheat.     

HMW-glutenin and gliadin variations in Tibetan weedrace, Xinjiang rice wheat and Yunnan hulled wheat

Nine Tibetan weedrace, 9 Xingjiang rice wheat and 14 Yunnan hulled wheat accessions were evaluated for the variability of HMW-glutenins and gliadins. Higher variability was observed for both HMW-glutenins and gliadins in Tibetan weedrace and Xingjiang rice wheat, while lower variability was observed in Yunan hulled wheat. There were 4 HMW-glutenin and 9 gliadin patterns in 9 Tibetan weedrace accessions, 5 HMW-glutenin and 8 gliadin patterns in 9 Xingjiang rice wheat accessions, and 3 HMW-glutenin and 8 gliadin patterns in 14 Yunnan hulled wheat accessions. In Xinjiang rice wheat, one accession (i.e. Daomai 2) carried subunits 2.1 + 10.1 encoded by Glu-D1, which is very rare in common wheat.