1BL/1RS translocation in durum wheat and its effect on end use quality traits

The gluten proteins document the genotypic identity of a wheat variety, in addition to providing valuable clues about its ancestry and technological properties. In this study, an Indian durum wheat genotype B662 was identified to carry 1BL/1RS translocation and characterized further for its effect on end use quality traits. Comparison of the end use quality traits of B662 with five other durum cultivars without 1BL/1RS, showed decreased gluten content, lower swelling index of glutenins and low MSDS-SV indicating that, B662 with 1BL/1RS is not good for pasta making. In F_2:3 seeds from a durum wheat cross between the 1BL/1RS cultivar B662 and HI8498 without the translocation, the secalin Sec-1 loci segregated in theoretically expected 3:1 proportion and were inherited as a block of the rye chromosome arm. The analysis of F_2:3 harvests for the two most important durum wheat quality tests showed that the presence of 1BL/1RS translocation did not alter the grain protein content values, but was associated with significant reduction of micro SDS-sedimentation volume indicating inferior quality, thus limiting the commercial exploitation of durum wheat genotypes with 1BL/1RS translocation. The cautious use of rye translocation in Indian durum wheat breeding is suggested.     

Characteristics of common wheat cultivars of West Siberia carrying the wheat-rye 1RS.1BL translocation

Using genomic in situ hybidization, among the common wheat cultivars produced in West Siberia (Siberian Research Institute of Agriculture, Omsk) with the involvement of the winter wheat cultivar Kavkaz carrying the wheat-rye 1RS.1BL translocation we identified three cultivars with this translocation: Omskaya 29, Omskaya 37, and Omskaya 38. The protein and crude gluten contents in the grain of these cultivars are equal to or exceed the levels observed in cultivars without the wheat-rye translocation. The common wheat cultivars carrying the wheat-rye translocation were evaluated in terms of resistance of plants reaching wax ripeness to leaf rust and powdery mildew in the natural field conditions. The cultivars Omskaya 37 and Omskaya 38 displayed a high field resistance to leaf rust and were resistant to a variable extent to powdery mildew. The cultivar Omskaya 29 was susceptible to leaf rust and powdery mildew pathogens. Importance of the selection direction and the role of the genetic background in developing common wheat cultivars carrying the wheat-rye translocation is discussed.     

Cytogenetic characteristics of wheat lines with modified 1RS.1BL rye-wheat translocation

The higher frequency (almost 90%) of inheritance through pollen of heterozygous hybrids has been shown for the modified 1RS.1BL translocation compared with the 1BL telocentric, and, as a result, the segregations at the Gli-B1 and Glu-B1 loci strongly deviated from the expected values. The distance between the Glu-B1 locus and the centromere was 15.7–24.4 cM. Products of the 1RS_m.1BL translocation “misdivision” were observed at a frequency of 0.05%. Both the Pavon MA1 lines and the winter wheat line with the 1RS_m.1BL _al translocation have shown a significant decrease in the level of homologous chromosome pairing, causing aneuploidy. These lines did not contain any reciprocal translocations with respect to the Kuyal’nik cultivar. A “hybrid desynapsis” has been observed in F₁ hybrids (Kuyal’nik × Pavon MA1) in contrast to analogous hybrids from a winter line by the 1RS_m.1BL _al type. No single case of the 21_Closed ^II formation has been observed among the studied 693 pollen mother cells (PMCs), which would have indicated the presence of pairing between the short arms of the 1RS_m.1BL translocations and the intact chromosome 1B.     

Effect of the 1BL.1RS wheat-rye translocation on the androgenic response in spring bread wheat

The study was conducted to investigate the effect of the 1BL.1RS wheat-rye-translocation on the androgenic response in spring bread wheat. Therefore, four bread wheat cultivars carrying the translocation, four Greek and three Canadian bread wheat cultivars without the translocation were used. An equal number of anthers from each cultivar, containing microspores in the mid (MU) to late uninucleate (LU) microspore developmental stage, were cultured after cold pre-treatment for seven days at 4°C. W14, 190-2 and the basic MS were used as induction, regeneration, and rooting media respectively. The best androgenic response was recorded in two cultivars carrying the translocation. Only two cultivars lacking the translocation responded to anther culture. It is concluded that the positive effect of the 1BL.1RS translocation on anther culture response of bread wheat cultivars cannot be attributed entirely to its presence because the genetic background of the cultivars carrying the translocation could be also important.     

Identification of 1AL/1RS translocation in winter common wheat varieties of Ukrainian selection

Analysis of alcohol-soluble protein (gliadin) patterns of a group of winter common wheat varieties from different breeding centers of Ukraine resulted in identification of six varieties with the rye 1AL/1RS translocation. The line 7086 AR also carries this translocation. The identified 1AL/1RS translocation is similar to that of the variety Amigo in the secalin pattern. The appearance of this translocation in varieties developed in different breeding centers of the forest-steppe of Ukraine indicates its involvement in coadaptive gene associations.     

The molecular genetic characterization of the 'Bobwhite' bread wheat family using AFLPs and the effect of the T1BL.1RS translocation

Bobwhite is a generic name that refers to all sister lines derived from the cross CM 33203 with the pedigree Aurora//Kalyan/Bluebird/3/Woodpecker made by the CIMMYT bread wheat program in the early 1970s. Individual sister lines can be distinguished by their unique selection history. One of the parents, Aurora, contains the T1BL.1RS translocation from rye, and approximately 85% of the sister lines have inherited the translocation. The sister lines demonstrate great variability for agronomic traits such as maturity, height, grain color, reaction to leaf rust, stem rust, yellow rust, septoria leaf blotch and powdery mildew. Certain groups of sister lines derived from particular F(1) plants can be distinguished by their phenotype. One hundred and one Bobwhite sister lines were fingerprinted using four AFLP enzyme/primer combinations. Following multivariate analysis, two main and very distinct clusters were found, which reflected the presence or absence of the T1BL.1RS translocation. Within these clusters, lines clustered together, for the most part, with other sister lines sharing a common selection history. Removal of the AFLP markers that were correlated with the presence or absence of the translocation caused lines to cluster based on pedigree alone. Therefore, the presence of translocations in wheat could bias genetic diversity studies using unmapped markers such as AFLPs that are located on the translocated segment(s), with the result that the resulting clusters will not reflect the true degree of relatedness.     

Recombination frequency in the locus Gli-D1 of common wheat T. aestivum L

The recombination frequency at the gliadin locus Gli-D1 of common wheat was determined by the maximum likelihood method. Recombination was observed between the gene encoding the fastest omega-component of the allele Gli-D1j, and the genes encoding the other omega-gliadins of this allele. The frequency of recombination was 0.65 +/- 0.18% for the cross between the near-isogenic lines of winter common wheat with respect to gliadin loci Gli-D1-4 and Gli-B1-3 and 0.78 +/- 0.45% for the cross between the varieties Yunnat and B-16.     

Reconstruction in wheat of complete chromosomes 1B and 1R from the 1RS.1BL translocation of 'Kavkaz' origin.

Translocation 1RS.1BL originally from the 'Aurora' and 'Kavkaz' wheats has spread to bread wheats all over the world. It offers several resistance genes and appears to significantly increase yields. For future study of the arm location of the yield-increasing factors, complete chromosomes 1B and 1R were reconstructed from the 1RS.1BL translocation. This was accomplished by centric misdivision and fusion in double monosomies 20 II + 1RS.1BL I + 1BS.1RL I. The frequency of misdivision and misdivision-fusion of the two unpaired chromosomes was 23.1%, which was much higher than expected but comparable with that observed in other stocks grown under similar conditions. Transmission of the reconstructed chromosomes to progeny was normal. In addition to all possible misdivision and misdivision-fusion products, two chromosomes of ambiguous origin were recovered: chromosome 1B with a proximal insert of about 40% of 1RS and chromosome 1R with a proximal insert of about 30% of 1BS. The study demonstrates that centric translocations can misdivide and fuse again to produce stable chromosomes with new arm combinations.     

Effect of the 1BL.1RS translocation on the wheat endosperm, as revealed by proteomic analysis

The introduction of the 1RS chromosome of rye into wheat made wheat more resistant to several pathogens. Today, this resistance has been overcome but the 1BL.1RS translocation remains interesting because of the improved yield and despite the lower rheological properties it produces. Nothing has been reported yet on the impact of rye chromatin introgression on the grain proteome of wheat. The comparison of the 2-DE profiles of 16 doubled haploid lines, with or without the 1BL.1RS translocation, revealed quantitative and qualitative proteic variations in prolamins and other endosperm proteins. Eight spots were found specifically in lines having the 1BL.1RS translocation; 16 other spots disappeared from the same lines. Twelve spots, present in both genotypes, met the criteria for up- or down-regulated spots. In translocated genotypes, a highly overexpressed spot, identified as a gamma-gliadin with nine cysteine residues, suggests that the lack of LMW-GS induced by 1BL.1RS is counterbalanced by an overexpression of a relatively similar prolamin. Moreover, a spot that was absent from 1BL.1RS genotypes was identified as a dimeric alpha-amylase inhibitor. It was considered to be a valuable candidate to explain the sticky dough associated with translocated cultivars.     

Distribution of 1AL.1RS and 1BL.1RS wheat-rye translocations in Triticum aestivum using specific PCR

Chromosome arm 1RS of rye (Secale cereale) is a valuable resource for wheat (Triticum aestivum) improvement. 1AL.1RS and 1BL.1RS translocations play an important role in wheat breeding, since wheat carrying these chromosomal translocations has higher tolerance to biotic and abiotic stress. In this study, the presence of 1RS and the distribution of 1AL.1RS and 1BL.1RS wheat-rye translocations were examined in 66 Iranian cultivars and 70 regional foreign accessions of bread wheat, using three rye-specific primers (“RYER3/F3”, “O-SEC5′-A/O-SEC3′-R”, “PAWS5/S6”). Based on “RyeR3/F3”, the presence of 1RS was verified in 15 (23%) Iranian cultivars and in two (3%) foreign accessions. Further, “O-SEC5′-A/O-SEC3′-R” and “PAWS5/S6” were used to distinguish 1AL.1RS and 1BL.1RS translocations. According to results from these primers, 1BL.1RS was identified in 14 (21%) Iranian cultivars and two (3%) foreign accessions. The results confirm that “Sholeh” is the only cultivar (1.5%), among all cultivars and accessions, that carries 1AL.1RS. This study provides a useful tool in marker-assisted selection of materials containing 1RS, and in the creation of new Iranian common wheat cultivars with a larger genetic diversity in wheat breeding programs.     

Seedling lethality in wheat: a novel phenotype associated with a 2RS/2BL translocation chromosome

Summary When grown at normal temperatures, wheat plants disomic for a 2RS/2BL translocation chromosome substituting for chromosome 2B show seedling lethality. Morphological and physiological studies could not determine the cause of death. However, the seedling lethality can be partly to completely inactivated at higher temperatures and in stressed environments. The lethality can also be completely suppressed if the translocated chromosome is introduced into different wheat cultivars. These wheats must contain genes which suppress the lethal phenotype caused by disomy of 2RS/2BL.Whilst the temperature effect indicates that the seedling lethality is related to the grass clump dwarf phenotype of wheat, our results show that the genes involved in seedling lethality, its suppression and inactivation, are not related to the D genes which cause grass clump dwarfing in wheat.     

Production of a new wheat line possessing the 1BL.1RS wheat-rye translocation derived from Korean rye cultivar Paldanghomil

The 1BL.1RS translocations between wheat (Triticum aestivum L.) and rye (Secale cereale L.) are widely used in bread wheat breeding programs, but all modern wheat cultivars with the 1BL.1RS have shown genetic vulnerability due to one rye source – a German cultivar, Petkus. We have developed, a new 1BL.1RS wheat-rye translocation line from the backcross of the F₁ hybrid of wheat cv. Olmil and rye cv. Paldanghomil, both cultivars from Korea. The GISH technique was applied to identify the presence of rye chromatin in 467 BC₁F₆ lines selected from 77 BC₁F₅ lines. Only one line, Yw62–11, showed wheat-rye translocated chromosomes, with a somatic chromosome number of 2n=42. C-banding patterns revealed that the translocated chromosome was 1BL.1RS, showing prominent bands in the terminal and sub-terminal regions of the short arm as well as in the centromeric region and terminal region of the long arm. This new 1BL.1RS translocation line formed 21 bivalents like common wheat at meiotic metaphase I, thereby showing complete homology. Received: 28 February 2001 / Accepted: 17 April 2001     

Transfer of the 1BL/1RS wheat-rye-translocation from hexaploid bread wheat to tetraploid durum wheat

Summary The present study describes a cytological stable alien chromosome translocation in tetraploid durum wheat. By crossing the hexaploid 1BL/1RS wheat-rye translocation line Veery to the tetraploid durum wheat cultivar Cando it was possible to select a 28 chromosomic strain homozygous for the 1BL/1RS translocation. The disease resistance potential of the short arm of rye chromosome 1R, which has been widely introduced in many hexaploid bread wheat cultivars could be now also used for the improvement of durum wheat.     

Diallelic analysis of quantitative traits in hexaploid wheat (Triticum aestivum L.)

Abstract

A complete diallel study of crosses between eight wheat varieties was carried out to determine the relative magnitude of components of genetic variation and heritability for important grain yield, quality and drought‐related traits. The data appeared adequate for the additive‐dominance model. The additive effects predominated for most traits, and consequently the narrow‐sense heritability was high to moderately high for flag leaf area, weight and venation, stomatal frequency and size, epidermal cell size, biomass, protein content, number of tillers, spike length, spike density, 1000‐grain weight and grain yield. These results appear promising for selecting better plants in the segregating populations with some degree of improvement for yield, quality and physiological efficiency.     

Development of a wheat genotype combining the recessive crossability alleles kr1kr1kr2kr2 and the 1BL.1RS translocation, for the rapid enrichment of 1RS with new allelic variation

The main objective of the present work was to develop a wheat genotype containing both the recessive crossability alleles (kr1kr1kr2kr2), allowing high crossability between 6x wheat and diploid rye, and the 1BL.1RS wheat/rye translocation chromosome. This wheat genotype could be used as a recipient partner in wheat–rye crosses for the efficient introduction of new allelic variation into 1RS in translocation wheats. After crossing the wheat cultivars ‘Mv Magdaléna’ and ‘Mv Béres’, which carry the 1BL.1RS translocation involving the 1RS chromosome arm from ‘Petkus’, with the line ‘Mv9 kr1’, 117 F₂ plants were analysed for crossability, ten of which had higher than 50% seed set with rye and thus presumably carried the kr1kr1kr2kr2 alleles. Four of the ten plants contained the 1BL.1RS translocation in the disomic condition as detected by genomic in situ hybridization (GISH). The wheat × rye F₁ hybrids produced between these lines and the rye cultivar ‘Kriszta’ were analysed in meiosis using GISH. 1BL.1RS/1R chromosome pairing was detected in 62.4% of the pollen mother cells. The use of fluorescent in situ hybridization (FISH) with the repetitive DNA probes pSc119.2, Afa family and pTa71 allowed the 1R and 1BL.1RS chromosomes to be identified. The presence of the 1RS arm from ‘Kriszta’ besides that of ‘Petkus’ was demonstrated in the F₁ hybrids using the rye SSR markers RMS13 and SCM9. In four of the 22 BC₁ progenies analysed, only ‘Kriszta’-specific bands were observed with these markers, though the presence of the 1BL.1RS translocation was detected using GISH. It can be concluded that recombination occurred between the ‘Petkus’ and ‘Kriszta’ 1RS chromosome arms in the translocated chromosome in these plants.     

Rapid detection of 1B, 1BL/1RS heterozygotes in the development of homozygous 1BL/1RS translocation stocks of Triticum turgidum (2n = 4x = 28).

A biochemical marker was utilized to facilitate detection of chromosome 1B, 1BL/1RS translocation heterozygote plants in segregating backcross progenies during the development of 1BL/1RS homozygous lines in several Triticum turgidum L. cultivars (2n = 4x = 28; AABB). Isoelectric focussing of glucose phosphate isomerase (GPI) on either pH 3.5-9.5 or 5.5-8.5 polyacrylamide gels facilitated the detection of 1B, 1BL/1RS translocation heterozygotes from the homozygous 1B or 1BL/1RS derivatives during each backcross of the heterozygote to the respective recurrent parent. The biochemical diagnostic procedure complements the more time consuming and cumbersome chromosome banding technique. This GPI diagnostic in durum 1BL/1RS development is also swifter than a similar stocks development in T. aestivum where both GPI and acid PAGE are essential.     

偏型1BL／1RS小麦雄性不育系诱导单性孤雌生殖机理的研究初报

采用石蜡切片法就胚胎学对偏型1BL／1RS小麦雄性不育系诱导单性孤雌生殖的机理进行了研究。结果表明：(1)从受精过程中的一些异常现象,如未受精极核贴近反足细胞、珠被附近有助细胞团等。初步显示助细胞是偏型1BL／1RS小麦雄性不育系单性孤雌生殖的胚细胞来源;(2)延迟授粉前大部分胚囊表现正常,延迟授粉不能诱发偏型1BL／1RS小麦雄性不育系的卵细胞单性生殖。     

Haploid production in durum wheat by the interaction of Aegilops kotschyi cytoplasm and 1BL/1RS chromosomal interchange

The present study describes the development of an alloplasmic haploid-inducer in durum wheat cv Cando. This cultivar possesses the homozygous wheat-rye translocation 1BL/1RS from the 6x-wheat cv Veery. The nucleus of 4x-Cando-Veery 1BL/1RS was introduced into Aegilops kotschyi cytoplasm by initially using (kotschyi)-Salmon as the maternal parent. In the cross of this alloplasmic durum line with Cando-Veery 1BL/1RS, which was used as the recurrent pollen parent, haploids (n=14) were produced. The frequency of haploids increased from 5.7% in the F₁ generation to 14% in the BC₁ generation. The presence of rye chromosome arm 1RS and the concomitant loss of 1BS in (kotschyi)-Cando-Veery 1BL/1RS are necessary for haploid induction. Proposals are made which may enable the use of haploids produced by nucleo-cytoplasmic interactions in future wheat breeding programs.