Authors:D. Horvat, N. Ðukić, D. Magdić, J. Mastilović, G. Šimić, A. Torbica, and D. Živančev
Glutenin polymers composed of HMW and LMW subunits are important contributors to the wheat end-use properties. Twenty-six winter wheat cultivars differing in bread processing quality were collected at the experimental fields of the Agricultural Institute Osijek, Croatia and Institute of the Field and Vegetable Crops Novi Sad, Serbia, in 2008/2009 season. The HMW glutenins composition and glutenin proteins content were determined by SDS-PAGE and RP-HPLC, respectively, with aim to determine the relationship between glutenin protein fractions and wheat quality properties. Significant differences were found between Croatian and Serbian cultivars in several quality attributes (GI, WA, DDT, DS and R/EXT) as well as in the content of total glutenins and LMW glutenins and GLI/GLU ratio. The dominant HMW subunits in analyzed cultivars were 2*, 7 + 9/7 + 8 and 5 + 10. Principal component analysis (PCA) confirmed the presence of association between HMW glutenins composition and GI, dough E, R and R/EXT, while the glutenins quantitative data showed pronounced relation with P, DDT, DS, E, R and R/EXT. GLI/GLU ratio had the opposite effect on these parameters.
Authors:N. Tsenov, D. Atanasova, I. Todorov, I. Ivanova, and I. Stoeva
Seventy-six promising bread winter wheat lines were investigated in relation to the allelic composition of grain storage proteins. The aim of the study was: i) to find out a possible relation between wheat quality and the separate low molecular loci and ii) to examine the potential of some of the existing
alleles to increase the quality. Five indices were investigated that covered almost all aspects of grain quality: sedimentation value, wet gluten content, dough stability, bread volume, quality index and valorimeter. The samples for quality analysis were from a 3-year period of investigation. Different statistical approaches were used to study the influence of
on the level of the indices. The LMW-GS were determined by SDS-PAGE (Payne et al. 1980). It was determined that locus
had the strongest influence on quality among the loci, that determine the low molecular glutenins. The
alleles influenced the end-use quality irrespective of the HMW-GS and LMW-GS composition background against which their effect was expressed. There were important variations among the separate alleles of
locus for their direct effect on end-used quality.
had strong positive effect on the end-use quality against the background of all HMW combinations.
had a similar positive effect. The
allele was connected with high quality in wheat but its effect was weaker than that of
and was not significant for some of the investigated indices.
Authors:N. Tsenov, D. Atanasova, I. Todorov, I. Ivanova, and I. Stoeva
Seventy-three common winter wheat varieties developed throughout the breeding history of the DAI were investigated for their diversity of allelic variants on storage proteins component composition in grain. The high- and low molecular weight protein structures were determined by the widely used SDS-PAGE method of Payne et al. (1980). The ratio between the individual alleles on the loci of high and low molecular weight glutenin was analyzed. The change in the HMW-score was followed according to the period when the respective varieties were developed. The configuration
, which was established in about 45% of the investigated genotypes, was most frequent in the high-molecular variants of glutenin. Concerning the low-molecular weight glutenins in 21 out of the 73 investigated varieties, the combination
was observed; it coincided with the spectrum of the widely used variety Bezostaya 1. Highest diversity was established in the allelic variants of
, in which 6 and 5 alleles, respectively, were observed. The quality of the varieties developed at DAI was relatively high (score 8.1). About a quarter of them are with high end-use quality confirmed in production. This is mainly due to the concentration of “strong” positive alleles in glutenin as a result from the intensive use of parents directly or indirectly related to Bezostaya 1, which lead to decrease of the percent of
(2 + 12). Quality should be further increased by additional diversity of combinations between “possitive” as effect on end-use grain quality alleles. Concerning HMW loci to keep of high grain end-use quality, it is necessary to maintain the status of
(2*), as well as of
(5 + 10).
Dough mixing properties are important in determining wheat processing and end-use quality. The Reomixer is a mixograph type device which provides mixing curves, described in detail by a total of 17 parameters. We analyzed the Reomixer mixing parameters of 26 breeding lines grown in 2007, in four contrasting environments (with and without Nitrogen fertilization, under water stress or irrigated). Using these data, we attempted to condense the information by identifying the most suitable parameters for use in a breeding program. We used the following criteria: high reproducibility (minimum coefficient of variation among repetitions), high genotype influence (i.e. high heritability), larger amount of information about overall variation of the other mixing parameters and complementarity of information (low correlation with other selected parameters). Mixing parameters varied widely for all criteria and no one parameter was best for all of them. Based on average performance we selected: “initial slope”, “peak time”, “peak height”, “end width” and “breakdown”, as having better ranking for the first three criteria and being less correlated between themselves than other mixing parameters. The five selected parameters cover all phases of dough development and describe all basic rheological aspects of mixing properties.
Authors:H. Khoshro, M. Bihamta, M. Hassanii, M. Omidi, and M. Aghaei
Low molecular weight glutenin subunits are important components of wheat seed storage protein, and play a significant in determining the end-use quality characteristics of wheat varieties. Allelic variation of the LMW-GS is associated with the significant differences of dough quality in bread and durum wheat, and has been widely evaluated at protein level in wheat and its relatives. In this study seven specific primers, specifically amplify genes located at the
loci, were employed to assay the length variation of LMW-GS genes in the A and D-genomes of diploid wheats. A total of 86 accessions of diploid wheats, including 10 accessions of
and 76 accessions of
, were investigated. Seven alleles were detected in accessions of
locus) by two pairs of specific primers and eighteen alleles were detected in accessions of
locus) by five pairs of specific primers. A higher level of allelic variation of LMW-GS was found in accession
with Nei’s genetic variation index (H) of 0.82 and 0.92, respectively. This allelic variation could be used as valuable source for the enrichment of genetic variations and the alteration of flour-processing properties of the cultivated wheat.
Authors:X.L. Jiang, G.F. Chen, X.J. Li, G. Li, Z.G. Ru, and J.C. Tian
This study aimed to clarify the genetic mechanisms behind wheat flour color. Flour colorrelated traits (L*, a*, and b*) and polyphenol oxidase (PPO) activity are important parameters that influence the end-use quality of wheat. Dissecting the genetic bases and exploring important chromosomal loci of these traits are extremely important for improving wheat quality. The diverse panel of 205 elite wheat varieties (lines) was genotyped using a highdensity Illumina iSelect 90K single-nucleotide polymorphisms (SNPs) assay to disclose the genetic mechanism of flour color-related traits and PPO activity. In 2 different environments and their mean values (MV), 28, 30, 24, and 12 marker-trait associations (MTAs) were identified for L*, a*, b* traits, and PPO activity, respectively. A single locus could explain from 5.52% to 20.01% of the phenotypic variation for all analyzed traits. Among them, 5 highly significant SNPs (P ≤ 0.0001), 11 stable SNPs (detected in all environments) and 25 multitrait MTAs were identified. Especially, BS00000020_51 showed pleiotropic effects on L*, a*, and b*, and was detected in all environments with the highest phenotypic contribution rates. Furthermore, this SNP was also found to be co-associated with wheat grain hardness, ash content, and pasting temperature of starch in previous studies. The identification of these significantly associated SNPs is helpful in revealing the genetic mechanisms of wheat colorrelated traits, and also provides a reference for follow-up molecular marker-assisted selection in wheat breeding.
Authors:N. Daskalova, S. Doneva, Y. Stanoeva, I. Belchev, and P. Spetsov
Four amphiploid lines (SHW) based on T. monococcum (Tm) and T. boeoticum (Tb) were crossed to T. durum varieties to generate 13 combinations. Field germination and winter survival of hybrid plants in F2 were assessed. Among all crosses, those with SHW8A-Tb and SHW9A-Tm showed highest field germination but with different degrees of spike fragility. The variation on seed number and weight per main spike was studied in F4–6 from SHW8ATb/ Progres and SHW5A-Tb/Severina crosses after individual selection for these traits. Ten lines with durum phenotype from the former and three genotypes with dicoccum plant shape from the latter cross were developed. SDS-PAGE indicated the presence of HMW-GS 1Ax2*+1Aynull subunits in four lines, among which 1Ax2* was inherited from T. boeoticum acc.110 through SHW8A-Tb. Most of the selected genotypes possessed γ-gliadin45, which was relating to good end-use quality. Powdery mildew testing showed that all progenies resulted from the SHW8A-Tb/Progres were susceptible to 12 races of the pathogen, while three lines derived from the SHW5A-Tb/Severina cross behaved differently: G32 expressed resistance to six, G33 to 2, and G34 to 5 races. The selected genotypes from crosses involving SHW with T. boeoticum exhibited good breeding performance compared to tetraploid wheat parents, and might be of breeding interest to further research.
Authors:Z. Yan, S. Dai, D. Liu, Y. Wei, and Y. Zheng
A novel HMW-GS of Dx5** with slightly faster migration rate than that of Dx5, was found in a Tibet bread wheat landrace using SDS-PAGE. Moreover, Dx5** is the subunit with the fastest migration rate in
locus. The gene for this subunit was isolated and its sequence was obtained in the present study. This gene was very similar to Dx5 both in nucleotide and deduced amino acid sequence. At the nucleotide sequence level, Dx5** different from Dx5 by the deletion of a 27 bp fragment and two nucleotide replacements at position 353(G/C) and 692(C/G), respectively. At the amino acid sequence level, Dx5** different from Dx5 by the deletion of a hexaploid (LGQGQQ) and a tripeptide (GQQ) repetitive motif and two amino acid replacements at position 118(C/S) and 231(A/G), respectively. These results suggested that the Dx5** was a derivation of Dx5 and was formed by replication slippage. Moreover, the specific cysteine (C) located at the beginning of the repetitive domain of Dx5, which proved to be critical for the end-use quality of wheat flours, was replaced by serine (S) in Dx5**.