Influence of HMW and LMW glutenin subunits on gluten strength in hexaploid tritordeum

In hexaploid tritordeum, the storage proteins of advanced progenies from two crosses between three hexaploid tritordeum lines were analysed. The effects of allelic variation at the Glu-B1, Glu-H^ch1 and Glu-A3/Glu-B3 loci on gluten strength, as measured by the sodium dodecyl sulphate sedimentation test, were determined using seeds from both crosses. Neither of the two alleles found at the Glu-B1 locus in the crosses analysed had significant effects on gluten strength, but allelic variation at the Glu-H^ch1 and Glu-A3/Glu-B3 loci showed significant differences in effects on gluten strength.     

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.     

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.     

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.     

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.     

SDS-PAGE of the high-molecular-weight subunits of wheat glutenin and the characterization of 1R (1B) substitution and 1BL/1RS translocation lines

Summary The high-molecular-weight subunits of glutenin from wheat 1R(1B) substitution and 1BL/1RS translocation lines were fractionated by SDS-PAGE. Two new subunits denoted R₁ and R₂ were characterized in 1R(1B) substitution, but not in 1BL/1RS translocation lines. R₁ and R₂ were proved to be rye proteins by 2d electrophoresis (NEPHGE x SDS-PAGE).In contrast to literature citations it was demonstrated that the cultivar Winnetou is a 1R(1B) substitution line and the cultivars Clement and Mildress both are 1BL/1RS translocation lines.     

Nitrogen and phosphorus uptake and utilization efficiency in D(R) substitution lines of hexaploid triticale

Two sets of disomic substitution lines, derived from the cultivars ‘Presto’ and ‘Rhino’ of triticale, with rye chromosome pairs replaced by their wheat D‐genome homoeologues, were tested in hydroponic culture for nitrogen and phosphorus uptake and utilization efficiency. The effect of a substitution on the amount of absorbed nutrients was predominantly negative and proportional to the effect on plant dry matter. Significant decreases were found for the substitutions 5D(5R), 6D(6R) of both cultivars, 2D(2R), 4D(4R) of ‘Presto’ and 3D(3R) of ‘Rhino’. On the other hand, the nitrogen utilization efficiency was significantly increased in all substitution lines, with the exception of the 1D(1R) ones. The differences in phosphorus utilization were generally positive, but less pronounced, and significant only in the lines 2D(2R) and 6D(6R). The data suggest that presence of both rye and D‐genome chromosomes is conducive for the best effect of the applied N and P fertilizers.     

Additive and epistatic effects of allelic variation at the high molecular weight glutenin subunit loci in determining the bread-making quality of breeding lines of wheat

Summary The relation has been studied between the high molecular weight glutenin (HMWg) subunit alleles and the bread-making quality of 226 lines of winter wheat (T. aestivum L.), grown in The Netherlands. The lines represented a wide range of genetic backgrounds, and had not been selected for quality, in contrast to the established varieties used by other authors.The variation in HMWg subunit genotypes accounted for about 20% of the total variation in loaf volume among the lines. Most important was the allelic variation at the Glu-D1 locus. The Glu-D1 allele encoding the subunits 5+10 was superior to its allelic counterpart, encoding 2+12. The difference in average of loaf volume between groups of lines containing 5+10 or 2+12 was negatively related with protein content of the flours. When protein content was below 9.2%, no effect of allelic variation at the Glu-D1 locus was present. Epistatic effects between the Glu-I loci also contributed to the variation in loaf volume of the lines: i.e. the effect of allelic variation at Glu-A1 and Glu-B1 depended on the allele present at the Glu-D1. The contribution of the epistatic effects was about half the contribution of the additive effects, and should therefore be included in predictive models for bread-making quality.     

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.     

Cumulative and interaction effects of prolamin allelic variation and of 1BL/1RS translocation on flour quality in bread wheat

The allelic variation of prolamin loci was studied in three F₂ progenies from three crosses between the 1BL/1RS cultivar Triana and Yécora Rojo, Pavón and Florence Aurora, cultivars without the translocation. According to the 1:2:1 theoretical proportions observed in the allelic variants of the Glu-B3/Gli-B1 loci of the parent without the translocation, the inheritance as a block of the rye chromosome arm was confirmed. A group of F₃-F₄ recombinant lines, developed from these crosses was evaluated using the SDS-sedimentation test and the mixograph and alveograph tests. The presence of the 1BL/1RS translocation was not associated with significantly lower grain protein content values or with the optimum mixing time in the mixograph of the genotypes. The effect of the 1BL/1RS translocation on most of the quality parameters was highly dependent on the genetic pool. Significant increases in gluten strength and better mixing properties associated with the presence of some alleles of the Glu-A1, Glu-A3/ Gli-A1 and Gli-D2 loci were detected. The additivity and the interaction of prolamin gene effects with the rye translocation in the 1BL/1RS lines and its possible use in plant breeding are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Kernel hardness and baking quality of wheat — A genetic analysis using chromosome substitution lines

Summary An attempt was made to identify the chromosomal location of genetic control of a few components of wheat quality, using chromosome substitution lines of Cappelle Desprez, Cheyenne, Hope, and Timstein into the recipient variety Chinese Spring.Major factors for kernel hardness and increased baking absorption were found on chromosomes 5D of Cheyenne and Hope, and on 3B, 5D and 7D of Timstein. In Timstein, the presence of one of these chromosomes sufficed to make the wheat kernels hard.Factors for favourable dough properties were identified on a few other chromosomes, different in various varieties. These were 1A of Cappelle Desprez and Cheyenne, 3B of Hope, and 2D of Timstein. All but one of these chromosomes showed an increase in loaf volume to a level in-between those of the recipient variety Chinese Spring and the donor varieties. No relationship was found between kernel hardness and dough-making and baking properties.It was assumed that wheat quality is due to a combination of kernel hardness and favourable dough-making properties. As the genes for these factors are located on different chromosomes, it should not be too difficult to introduce both factors in existing varieties with poor baking properties. In a wheat breeding programme, the quality of new lines can be assessed in a rather simple way by determining kernel hardness and dough stability.     

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.     

Detection of QTLs to reduce cadmium content in rice grains using LAC23/Koshihikari chromosome segment substitution lines

To advance the identification of quantitative trait loci (QTLs) to reduce Cd content in rice (Oryza sativa L.) grains and breed low-Cd cultivars, we developed a novel population consisting of 46 chromosome segment substitution lines (CSSLs) in which donor segments of LAC23, a cultivar reported to have a low grain Cd content, were substituted into the Koshihikari genetic background. The parental cultivars and 32 CSSLs (the minimum set required for whole-genome coverage) were grown in two fields with different natural levels of soil Cd. QTL mapping by single-marker analysis using ANOVA indicated that eight chromosomal regions were associated with grain Cd content and detected a major QTL (qlGCd3) with a high F-test value in both fields (F = 9.19 and 5.60) on the long arm of chromosome 3. The LAC23 allele at qlGCd3 was associated with reduced grain Cd levels and appeared to reduce Cd transport from the shoots to the grains. Fine substitution mapping delimited qlGCd3 to a 3.5-Mbp region. Our results suggest that the low-Cd trait of LAC23 is controlled by multiple QTLs, and qlGCd3 is a promising candidate QTL to reduce the Cd level of rice grain.     

Effects of homoeologous group 1 and 6 chromosomes of the Cappelle-Desprez (Bezostaya 1) substitution lines on aspects of bread-making quality of wheat

Summary The group 1 and 6 inter-varietal chromosome substitution lines of Cappelle-Desprez (Bezostaya 1) were intercrossed along with the donor and recipient varieties, Cappelle-Desprez and Bezostaya 1, to give 36 genetically different families. The analysis of the means of these families showed that variation in SDS-sedimentation volume fitted a predominantly additive model. There were no significant within or between chromosome interactions among the group 1 and 6 chromosomes. Nor was there any evidence for interactions between these chromosomes and those of the background. Significant dominance/within chromosome interactions amongst the background chromosomes were however detected. Some of the positive effects on SDS-sedimentation were associated with increased grain hardness. Chromosome effects on % grain protein were not correlated with SDS-sedimentation.     

多环境下陆地棉染色体片段代换系及F_1皮棉产量与纤维品质的表型分析

以1套陆地棉染色体片段代换系为亲本材料,采用株系间随机成对杂交组配F1,在5个环境下鉴定片段代换系亲本及F1的皮棉产量与纤维品质性状表现。结果表明,与轮回亲本(中棉所36)相比,F1在铃重与皮棉产量性状上具有一定的对照优势,亲本与F1的纤维长度与比强度均表现出明显的对照优势,且环境间表现一致。F1铃重、衣分与皮棉产量在各个环境下的中亲优势均值全部为正,且相对较大。除个别环境外,纤维长度、马克隆值与比强度的中亲优势均值也全部为正,但数值相对较小。片段代换系及F1的遗传变异丰富,部分亲本与F1在多个环境下的综合表现优异,其皮棉产量与纤维品质得到同步提高,群体材料的遗传改良与杂种优势利用具有广阔前景。