Allelic variation in high-molecular-weight glutenin subunit Loci of Glu-1 in Japanese common wheats

Seed storage proteins of 131 Japanese Norin wheat (Triticum aestivum) varieties were fractionated by sodium dodecyl sulfate polyacrylamide gel electrophoresis to determine allelic make-up in varieties at each of three loci that control high-molecular-weight (HMW) glutenin subunits. Three alleles were identified at the Glu-A1 locus, six at the Glu-B1 locus and five at the Glu-D1 locus. Twenty-four different, major glutenin HMW subunits were identified and each contained three to five subunits and seventeen different glutenin subunit patterns were observed for 19 subunits in the 131 Japanese Norin varieties. Fourteen alleles were identified by comparison of subunit mobility with that previously found in hexaploid wheat. Japanese Norin varieties showed a specific pattern of allelic variation in glutenin HMW subunits, different from that of Chinese and other country common wheats in allelic frequency at Glu-1 loci. This revised version was published online in July 2006 with corrections to the Cover Date.     

Glu-1和Glu-3等位变异对不溶性谷蛋白含量的影响

不溶性谷蛋白含量（IG/P）对小麦烘烤品质有重要决定作用。用我国秋播麦区的251份品种和高代品系，CIMMYT优质小麦Pavon与澳大利亚劣质小麦Avocet的DH系，优质面包小麦中优9507的两个杂交组合，即中优9507/鲁麦5号和中优9507/晋麦45 F5代，分析了IG/P与揉面仪参数的关系。结果表明，IG/P与和面时间及耐揉性呈极显著正相关，r     

Effect of variation at Glu-D1 on club wheat end-use quality

Club wheats (Triticum aestivum L.), having the allele at the C locus conferring short spike rachis internodes and giving compact appearance of spikes, which have unique and highly desirable soft white wheat end-use quality characteristics are a vital submarket class of soft white wheat in the US Pacific Northwest. Two important varieties, ‘Tyee’ and ‘Albit’, are heterogeneous for high molecular weight glutenin subunits 2 + 12 and 5 + 10 encoded by the Glu-D1 locus. Replicated near-isogenic lines (NILs) of club wheats ‘Tyee’ and ‘Albit’ were grown in four field environments and used to determine the effect of Glu-D1 coded high molecular weight glutenin subunits (HMWGS) 5 + 10 and 2 + 12 on various end-use quality traits. The greatest effect of variation at this locus was observed for mixing time to peak, where there was significant variation (P < 0.01) between each 5 + 10 and 2 + 12 NIL group in each environment. Mixing time values for the 2 + 12 NILs for both ‘Albit’ and ‘Tyee’ ranged from 0.60 to 1.23 min lower than the 5 + 10 NILs. Mean values for traits mixing time to peak, cake volume, and viscosity were more favourable for the 2 + 12 NIL groups for all genotypes in all environments. No effects of these HMWGS were detected for test weight, kernel hardness, whole wheat protein, flour yield, ash, flour protein or cookie diameter. Selection for HMWGS 2 + 12 in club wheat breeding programmes should have positive effects on end-use quality.     

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.     

High-Molecular-Weight Glutenin Subunits of the Most Commonly Grown Wheat Cultivars in the U.S. in 1984*

All wheat varieties (106) grown in the U.S. on more than 100,000 acres (38,610 ha) as of the latest (1984) crop variety survey were characterized by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The high-molecular-weight glutenin subunit (HMW-GS) band patterns for each variety were assigned the corresponding Payne numbers and theoretical quality scores based on those assignments. The subunit assignments were compared for the different wheat varieties and the five main wheat classes grown in the U.S. Hard red spring (HRS) and winter (HRW) wheats used mainly for breadmaking showed a remarkably high percentage of bands associated with good breadmaking quality. The allele 5+10, which has the strongest association with good quality, was present in 91 % of the hard red spring wheats and 62 % of the hard red winter wheats. Also, 91 % of all HRS and 53 % of HRW wheat varieties had quality scores of 9 or 10 (10 is the highest possible score). Evidently, by selecting for quality through close cooperation with quality testing laboratories, U.S. breeders have unknowingly selected for high quality glutenin subunits in their released varieties. HRS and HRW wheat varieties are normally grown in different environments in time and/or space, accounting to a large extent for differences in protein content (～2 %) and other quality traits in the two crops. The uniformly high theoretical quality scores of the HRS wheats compared to more variable scores for HRW wheats may help to explain the popular perception that spring wheats have intrinsically higher quality than winter wheats. Admixing grain from variable (some poorer, most good) HRW wheat varieties (due to genetics or environment) has probably also led to the perception of overall lower quality for HRW than HRS wheats. In the soft red winter (SRW) and soft white (SW) wheat classes where the end-use is typically cookies and cakes, 40 and 90 %, respectively, have the allele 2+12 that correlates with poor bread baking quality. The absence of alleles for good bread baking quality may be predictive of good quality for soft wheat products.     

The HMW glutenin suhunit composition of bread-wheat varieties bred in Pakistan

A total of 50 bread-wheat varieties bred in Pakistan were characterized for the composition of the high-molecular-weight glutenin subunit (HMW-GS). The glutenin subunits, as revealed by sodium dodecyl-sulfate-polyacrylamide-gel electrophoresis (SDS-PAGE) were numbered according to Payne's numbering system and, varieties were accordingly assigned theoretical quality scores. All varieties were found to possess either subunit 1 or 2* coded by the A genome. Subunits 17+18 and 7 + 9 of the B genome and 5+10 of the D genome were predominantly found in this set of varieties. The frequency of the appearance of Glu-l alleles in the varieties was different from that seen in other countries, especially in terms of the absence of the ‘null’ form of the A genome and the presence of novel subunits at the Glu-Bl and Glu-Dl loci. The compositions of HMW-GS were generally of good quality, with more than 50% of the varieties achieving quality scores of 9–10 with a high (8.6) average score. The results in this study indicate that wheat varieties bred in Pakistan have a narrow genetic base in terms of HMW glutenin subunits. It appears that the breeders have been selecting wheat genotypes of glutenin subunits associated with good quality without knowing the actual composition of these subunits. The database established on the basis of these results is useful for wheat-improvement programmes aimed at varietal identification and breeding for good quality parameters.     

Rye Chromatin Variation in Yugoslavian Wheats

C-banding, which stains the heterochromatic regions of chromosomes, was utilized in order to ascertain whether or not several varieties from a Yugoslavian wheat-breeding program contained a 1RS/1BL substitution or a 1RS/1BL translocation. Only one variety contained the 1R (1B) substitution, while in the remaining sixteen varieties, the 1RS/1BL translocation was present. The C-banding results were confirmed utilizing an SDS-PAGE analysis, and the results indicated that both techniques should be used together. In all of the Yugoslavian wheats containing observable rye chromatin, the C-band corresponding to the nucleolus organizing region (NOR) was clearly reduced over that found in the wheat parents used in Yugoslavia or the other wheats from around the world containing either the substitution or the trans location. Some unknown selection pressure applied in the Yugoslavian wheat program in Novi Sad over the years has evidently caused a deletion of most of the rye NOR region.     

Variation of B subunits of glutenin in durum,wild and less-widely cultivated tetraploid wheats*

Three major types of B subunits of glutenin patterns were detected among 240 durum wheat lines collected from eleven countries by the one-step one-dimensional SDS-PAGE procedure. Most commercial durum lines had the LMW-2 type while extensive variation of other banding patterns was found for lines particularly from North African and Mediterranean region. A total of 281 wild and less-cultivated tetraploid wheat lines (var. dicoczoides, Triticum dicoccum and T. polonicum) were also studied for the variation of low molecular weight glutenin subunits and extensive variation was found. The complexity of banding patterns observed among the T. turgidum species indicate a rich source of glutenin variation with a potential value to be used for quality improvement of cultivated wheat when their functional properties have been tested.     

Genetic Variation for Anther Callus Inducibility in Crosses of Highly Culturable Winter Wheats

Heritability studies suggest that variation among genotypes for callus inducibility should respond to selection. The objective of this study was to determine if crosses among parents with high callus initiation frequencies would produce segregation from which genotypes with improved callus inducibility could be selected. The winter wheat (Triticum aestivum L.) cultivars‘Centurk 78’, ‘Norstar’ and ‘Norwin’ were chosen as parents, based on their high callus initiation frequencies and diverse parentage. F₂ populations from crosses between each of these parents were evaluated for callus initiation frequencies and callus vigor as determined by growth rate and healthy appearance. Heterosis was detected for callus initiation in the‘Norwin’בNorstar’ cross and for callus vigor in all crosses. Broad sense heritability estimates of 0.25 and 0.37 for callus initiation in the ‘Centurk 78’בNorstar’ and ‘Norwin’בNorstar’ crosses, respectively, suggest this trait can be improved by selection. Heritability estimates for callus vigor were less promising, ranging from 0.11 to 0.24.     

Glu-1和Glu-3等位变异对小麦加工品质的影响

Glu-1位点等位基因编码的高分子量麦谷蛋白亚基（HMW-GS）和Glu-3位点等位基因编码的低分子量麦谷蛋白亚基（LMW-GS）是决定小麦加工品质的重要因素。用优质面包小麦中优9507的两个杂交组合，即中优9507/鲁麦5号和中优9507/晋麦45 F5代，澳大利亚优质面包小麦Sunstate的两个杂交组合，即Sunstate/济南16和Sunstate/鲁麦21 F2     

Genetic Variability for Haploid Production in Crosses Between Tetraploid and Hexaploid Wheats with Maize

Crosses were made between 14 wheat genotypes (11 tetraploid, 3 hexaploid) and a single Fl hybrid of maize that was used as the male parent. The experimental design consisted of randomized blocks with three replications. Plants were grown under controlled greenhouse conditions (day length 16 h and temperature 25 °C/15 °C, day/night). To enhance embryo survival, 2, 4-D treatment (10 mg/1) was applied to spikes 24 h after pollination with maize. Embryos were recovered from all tetraploid and hexaploid wheats at a rate of 2.09 to 26.76 per 100 pollinated florets. Haploid and doubled haploid plants were obtained from all hexaploid genotypes (T. aestivum) and from 5 of 11 tetraploid genotypes (T. turgidum var.). The most important point of these experiments was the ability to produce haploid plants from tetraploid wheat for two reasons: firstly, anther culture cannot be applied in tetraploid wheat (T. turgidum var.) due to the inefficiency of embryo formation and the high proportion of albino plants. Secondly, to date, crosses between tetraploid wheat and maize have resulted in embryo formation, but not in haploid plants.     

Allelic variation at high-molecular-weight glutenin subunit Loci, Glu-A1, Glu-B1 and Glu-D1, in Japanese and Chinese hexaploid wheats

Variation in the electrophoretic banding patterns of high-molecular-weight (HMW) glutenin subunits of 274hexaploid wheat (Triticum aestivum) varieties from China was examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and 27 different major HMW glutenin subunits were identified. Each variety contained three to five subunits and 29different glutenin subunit patterns were observed in274 Chinese hexaploid wheats. Seventeen alleles were identified based on the comparison of subunits mobility with that previously identified in a set of standard hexaploid wheats. The Chinese hexaploid wheats exhibited allelic variation in HMW glutenin subunit composition and the variation differed from that of Japanese and hexaploid wheats of other countries. This revised version was published online in July 2006 with corrections to the Cover Date.     

Identification of Rye Chromosome 1R Translocations and Substitutions in Hexaploid Wheats Using Storage Proteins as Genetic Markers

Grain protein compositions of 106 advanced generation backcross lines from crosses involving ‘Amigo’ (1AL.1RS), ‘Aurora’, ‘Kavkaz’, ‘Skorospelka-35’ and ‘Sunbird’ (all 1BL.1RS) and ‘Gabo’ 1DL.1RS parents and 152 cultivars with unknown pedigree were analysed by one-dimensional SDS-PAGE. Eighty seven backcross lines and 16 cultivars carried one or other of these translocations, 2 cultivars had a 1R (1B) substitution, whereas 5 backcross lines were found to be heterogeneous for the 1BL.1RS translocation. The translocation lines were easily identified by the presence of secalins (Sec-1) controlled by rye chromosome arm IRS and a simultaneous loss of the gliadin (Gli-1) and/or triticin (Tri-1) protein bands controlled by the replaced wheat chromosome arm (1AS, 1BS or 1DS). Certain gliadins, showing no allelic variation among the genotypes analysed, were identified as markers for chromosome arms 1AS (M_r= 34 kd) and IBS (M_r= 42,33 kd). The whole chromosome substitutions 1R (1B) were recognized by scoring for the presence of Sec-1 and HMW secalin bands, Sec-3 (controlled by rye chromosome arm 1RL) and the absence of Gli-B1 and HMW glutenin subunits, Glu-B1 (controlled by wheat chromosome arm 1BL). The results have shown that protein electrophoresis provides a rapid and reliable technique for screening genotypes for these translocations and substitutions in a breeding programme.     

Characterization of high-molecular-weight glutenin subunit genes from Elytrigia elongata

Three high‐molecular‐weight glutenin subunit (HMW‐GS) genes from Elytrigia elongata (Host) Nevski were characterized by determining the coding sequences of two x‐type subunit genes Ee2.1 and Ee1.9, and one y‐type subunit gene Ee1.8 with 2082, 1938 and 1788 bp, respectively. The numbers of amino acids in the central repeat domains of Ee2.1, Ee1.9 and Ee1.8 were considerably fewer than the other known HMW‐GSs with substitutions, insertions and/or deletions involving a single or more amino acid residues. Moreover, an extra cysteine (Cys) was found in the repeated domain of x‐type subunit Ee2.1. The difference in the number and position of Cys residues might be associated with the good dough quality. The extra Cys in the good‐quality subunit Dx5 was at the beginning of the repetitive domain, while the extra Cys in Ee2.1 was at the central repetitive domain. Evolutionary relationships between the HMW‐GSs from E. elongata and the known HMW‐GSs were estimated. It transpired that Ee1.9, Ee2.1 and Bx7 were clustered into one subgroup with high bootstrap values, while Ee1.8 was closely related to Ay.     

Changes in wheat seed storage protein fingerprint due to soil mineral content

Wheat seed storage protein fingerprint is used to determine the gluten protein pattern in studies aimed at improving flour quality. Wild wheat with high seed protein content is used extensively in wheat breeding programs. Although the wild wheat growth and protein content may be influenced by environmental conditions, the gluten-protein pattern is generally considered as indicative of a genotype, without the superimposition of environmental influences. The effects of soil type, habitat, and deficiencies of N, P, K and S on seed storage protein composition were examined in nine accessions of wild wheat (Triticum turgidum var. dicoccoides) and three varieties (two T. aestivum and one T. durum). Soil from ten natural habitats of the wild wheat that had not previously received any fertilizers or manures was sampled and used to grow wheat in a greenhouse. Seed storage protein composition was characterized by SDS-PAGE. Although deficiencies in soil nutrient caused variations in the seed storage proteins, the genotype was the main factor determining the seed storage protein composition. Seed storage protein composition of genotypes varied when grown under different mineral nutrient conditions. Only one genotype was stable showing almost identical protein patterns under all growing conditions studied without any qualitative change in fingerprint pattern. In the other genotypes, as well as the cultivars, the seed storage protein was affected at least to some extent by the soil. The ‘soil effect’ is summarized in terms of three main quantitative changes in the seeds: 1 – the relative amounts of the high-molecular-weight proteins; 2 – the relative amounts of proteins in the range of 45 and 65 kD; 3 – the percentage distribution of the HMW glutenin and other groups of seed storage proteins. The soild induced also qualitative differences in the composition of seed storage proteins, mostly in those of 45–65 kD. These differences were observed whenever a deficiency of S, N, P, K or Mg was identified. Therefore, in breeding programs that use seed storage protein fingerprints of wild wheat germplasms should be exercise caution when the germplasms selected from wild habitats. This revised version was published online in July 2006 with corrections to the Cover Date.     

麦谷蛋白亚基Clu-1和Glu-3位点基因等位变异对小麦品质特性的影响

甲单向一步SDS-PAGE方法分析表明亲本品种Suneca和Cook在麦谷蛋白亚基的5个位点(Glu-B1,Glu-D1,Glu-A3,Glu-B3和Glu-D3)均含不同等位基因。本研究重点对Suneca×Cook的F_4代群体中在麦谷蛋白亚基位点均为纯合基因的60个系的出粉率(FY),面粉蛋白质含量(FP)及和面时间(PTM)进行了分析,以研究麦谷蛋白各亚基位点等位基因变异及位点间互作对小麦品质特性的影响。结果表明,不同基因型间出粉率无显著差异,Glu-D1位点等位基因d和a对FP的效应存在显著差异,Glu-Dld基因(编码5 10亚基)的正效应显著高于Glu-Dla基因(编码2 12亚基);Glu-D1、Glu-A3和Glu-B3位点上基因的等位变异对PTM有显著和极显著影响,含Glu-Dld、Glu-A3b和Glu-B3b基因的系分别比含Glu-Dla,Glu-A3d和Glu-B3h基因的系有较长的和面时间;Glu-B1位点上等位变异i和u以及Glu-D3位点等位基因b和e分别对PTM无明显影响。在这种遗传背景下,麦谷蛋白亚基位点对PTM的效应大小依次排列为Glu-D1>Glu-B3>Glu-A3>GIu-B1=Glu-D3。Glu-1位点和Glu-3位点间对和面特性的影响存在累加效应和互作效应。     

Anther culture response of F1 durum × bread wheat hybrids after colchicine application

The effect of colchicine on the androgenic response of durum × bread wheat F₁ hybrids was studied. For this, three Greek durum wheat cultivars, exhibiting good yield and pasta quality, were crossed to two bread wheat cultivars with good response to anther culture. Spikes of the resulting hybrids, containing microspores in the mid to late uninucleate stage, were selected and cultured on two different media (W₁₄ and solid potato‐2) with and without colchicine. A negative effect on anther culture response was observed when colchicine was added to the W₁₄ induction medium. A similar effect was observed in two of the hybrids when they were cultured on to potato‐2 induction medium. In both induction media, green plant production was influenced negatively by colchicine treatment. The same was observed in albino plant production. The results of the present study support the view that anther culture response is strongly genotype dependent. Finally, potato‐2 induction medium was the most suitable one for the material studied.     

Changes in the genetic structure of wheat germplasm accessions during seed rejuvenation

Changes in the genetic structure of wheat accessions caused by interspecific competition during periodic seed rejuvenation at a gene-bank were studied. Electrophoretic patterns (Acid-PAGE) of gliadin storage proteins were used to discriminate bread from durum wheat and to identify bread-wheat genotypes. Bread wheat shows high selective advantage over durum wheat and its frequency increased up to 100% after seven rejuvenation cycles. The number of bread-wheat genotypes identified in each entry varied from five to 13, but only a few prevailed and these were different in each accession. In most cases, bread wheat was already present in the field sample collected, but at low frequency. In one case, ‘seed flow’ was thought to have occurred at a very low rate among neighbouring plots. The implication of these findings for genetic resources conservation are: 1. Mixtures of wheat species within the same germplasm accession must be avoided; 2. Only in some cases are low planting densities effective in reducing competition; and 3. The genetic structure of accessions in the gene banks must be monitored.     

Comparative Analysis of High-Molecular-Weight Glutenin Subunit Composition in Various Triticum Species

Variation in high-molecular-weight glutenin subunit composition amongst Triticum durum cvs. of different origins was investigated by SDS-PAGE and compared with that reported for T. dicoccum and T. aestivum. Tetraploid wheat collections (408 cvs.) were found to carry nearly twice as many Glu-A1 and Glu-B1 alleles as a hexaploid wheat sample of comparable size. In each of the taxa considered, allelic variation at the Glu-B1 locus was markedly greater than that observed for Glu-A1. However, because all the Glu-B1 subunits so far discovered exhibit a restricted and distinctive mobility range during. SDS-PAGE, it is suggested that they are derived from a single source, possibly from Aegilops searsii. Most durum cvs. carried a ‘null’Glu-A1 allele and therefore fewer subunits than dicoccums and common wheats. It is argued that differences in the frequency of occurrence of ‘null’Glu-1 alleles between taxa probably resulted from random samplings made by early agriculturalists and breeders, rather than from an inherent tendency of polyploid wheats to suppress the activity of “redundant” genes.     

Resistance to leaf rust in cultivars of bread wheat and durum wheat grown in Spain

A set of bread wheat and durum wheat cultivars adapted to Spanish conditions was tested for resistance against leaf rust caused by different pathotypes of Puccinia triticina in field trials and in growth chamber studies. Lower levels of resistance were found in durum wheat than in bread wheat. The most frequent Lr genes found in bread wheat were Lr1, Lr10, Lr13, Lr20, Lr26 and Lr28. In durum wheat, additional resistance genes that differed from the known Lr genes were identified. The level of partial resistance to leaf rust was in general low, although significant levels were identified in some bread wheat and durum wheat cultivars.