Use of synthetic hexaploid wheat to increase diversity for CIMMYT bread wheat improvement

2008 ◽  
Vol 59 (5) ◽  
pp. 413 ◽  
Author(s):  
S. Dreisigacker ◽  
M. Kishii ◽  
J. Lage ◽  
M. Warburton
Keyword(s):  
Bread Wheat ◽  
Hexaploid Wheat ◽  
Phenotypic Expression ◽  
Germplasm Collection ◽  
Synthetic Hexaploid Wheat ◽  
Selection Marker ◽  
Wheat Cultivars ◽  
D Genome ◽  
Wheat Improvement ◽  
Synthetic Hexaploid

To date, the International Maize and Wheat Improvement Center (CIMMYT) has produced more than 1000 synthetic hexaploid wheats (SHWs), using diverse accessions of the D genome donor species (Aegilops tauschii). Many of these SHWs produced from many different Ae. tauschii have shown resistance or tolerance to various biotic and abiotic stresses, indicating the potential importance of the Ae. tauschii gene pool for breeding purposes. SHWs were backcrossed to CIMMYT improved germplasm to produce synthetic backcross-derived lines (SBLs), which are agronomically similar to the improved parents, but retain the introgressed traits of interest under selection and thereby new diversity. Molecular studies show that SHWs and SBLs are genetically diverse at the DNA level when compared with traditional bread wheat cultivars and preferential transmission of some alleles from the SHW parent has been seen in all genomes, indicating positive selection. Marker analyses of wheat cultivars released over time indicate that SBLs are ideal materials to simultaneously increase yield and diversity for other traits. Following successful diversification of the wheat D genome, CIMMYT has shifted to target improvement of hexaploid wheat via the A and B genomes, focusing on specific traits. Screening the CIMMYT germplasm collection of T. turgidum subsp. dicoccum for Russian wheat aphid resistance and drought tolerance revealed varying levels of phenotypic expression. Promising accessions will be used for the production of new SHWs for future introgressions into elite bread wheat backgrounds.

Population‐dependent reproducible deviation from natural bread wheat genome in synthetic hexaploid wheat

2019 ◽  
Vol 100 (4) ◽  
pp. 801-812 ◽  
Author(s):  
Abdulqader Jighly ◽  
Reem Joukhadar ◽  
Deepmala Sehgal ◽  
Sukhwinder Singh ◽  
Francis C. Ogbonnaya ◽  
...  
Keyword(s):  
Bread Wheat ◽  
Hexaploid Wheat ◽  
Wheat Genome ◽  
Synthetic Hexaploid Wheat ◽  
Synthetic Hexaploid ◽  
Bread Wheat Genome

Registration of Five Synthetic Hexaploid Wheat and Seven Bread Wheat Lines Resistant to Wheat Spot Blotch

Crop Science ◽  
2001 ◽  
Vol 41 (5) ◽  
pp. 1653-1654 ◽  
Author(s):  
A. Mujeeb‐Kazi ◽  
S. Cano ◽  
V. Rosas ◽  
A. Cortes ◽  
R. Delgado
Keyword(s):  
Bread Wheat ◽  
Hexaploid Wheat ◽  
Spot Blotch ◽  
Synthetic Hexaploid Wheat ◽  
Synthetic Hexaploid ◽  
Wheat Lines

scholarly journals Empirical verification of heterogeneous DNA fragments generated from wheat genome-specific SSR primers

2008 ◽  
Vol 88 (6) ◽  
pp. 1065-1071 ◽  
Author(s):  
Qijiao Chen ◽  
Lianquan Zhang ◽  
Zhongwei Yuan ◽  
Zehong Yan ◽  
Youliang Zheng ◽  
...  
Keyword(s):  
Common Wheat ◽  
Hexaploid Wheat ◽  
Chinese Spring ◽  
Triticum Turgidum ◽  
Sequence Data ◽  
Aegilops Tauschii ◽  
Single Locus ◽  
Synthetic Hexaploid Wheat ◽  
D Genome ◽  
Synthetic Hexaploid

Due to the high polymorphisms between synthetic hexaploid wheat (SHW) and common wheat, SHW has been widely used in genetic studies. The transferability of simple sequence repeats (SSR) among common wheat and its donor species, Triticum turgidum and Aegilops tauschii, and their SHW suggested the possibility that some SSRs, specific for a single locus in common wheat, might appear in two or more loci in SHWs. This is an important genetic issue when using synthetic hexaploid wheat population and SSR for mapping. However, it is largely ignored and never empirically well verified. The present study addressed this issue by using the well-studied SSR marker Xgwm261 as an example. The Xgwm261 produced a 192 bp fragment specific to chromosome 2D in common wheat Chinese Spring, but generated a 176 bp fragment in the D genome of Ae. tauschii AS60. Chromosomal location and DNA sequence data revealed that the176 bp fragment also donated by 2B chromosome of durum wheat Langdon. These results indicated that although a single 176 bp fragment was appeared in synthetic hexaploid wheat Syn-SAU-5 between Langdon and AS60, the fragment contained two different loci, one from chromosome 2D of AS60 and the other from 2B of Langdon which were confirmed by the segregating analysis of SSR Xgwm261 in 185 plants from a F2 population between Syn-SAU-5 and Chinese Spring. If Xgwm261 in Syn-SAU-5 was considered as a single locus in genetic analysis, distorted segregation or incorrect conclusions would be yielded. A proposed strategy to avoid this problem is to include SHW’s parental T. turgidum and Ae. tauschii in SSR analysis as control for polymorphism detection. Key words: Synthetic hexaploid wheat, microsatellite, segregation distortion, Xgwm261, transferability

A breeding strategy targeting the secondary gene pool of bread wheat: introgression from a synthetic hexaploid wheat

2019 ◽  
Vol 132 (8) ◽  
pp. 2285-2294 ◽  
Author(s):  
Ming Hao ◽  
Lianquan Zhang ◽  
Laibin Zhao ◽  
Shoufen Dai ◽  
Aili Li ◽  
...  
Keyword(s):  
Bread Wheat ◽  
Hexaploid Wheat ◽  
Gene Pool ◽  
Breeding Strategy ◽  
Synthetic Hexaploid Wheat ◽  
Synthetic Hexaploid

Genetic variation for quality traits in synthetic wheat germplasm

2008 ◽  
Vol 59 (5) ◽  
pp. 406 ◽  
Author(s):  
Daryl Mares ◽  
Kolumbina Mrva
Keyword(s):  
Genetic Variation ◽  
Bread Wheat ◽  
Polyphenol Oxidase ◽  
Genetic Defect ◽  
Synthetic Hexaploid Wheat ◽  
Quality Traits ◽  
Colour Stability ◽  
Wheat Cultivars ◽  
Late Maturity ◽  
Synthetic Hexaploid

Synthetic hexaploid wheats offer breeders ready access to potentially novel genetic variation associated with the D genome of Aegilops tauschii. In order to assess the application of this germplasm to wheat quality improvement, collections of primary and derived synthetic hexaploid wheat lines were surveyed for traits that determine colour and colour stability in Asian noodles and the frequency of a genetic defect know as late maturity α-amylase (LMA). The range of variation was then compared with bread wheat and durum wheat cultivar collections. Primary synthetics contained substantial genetic variation for quality traits associated with colour and colour stability of Asian noodles including near-zero extremes for polyphenol oxidase and lipoxygenase. These extremes represent a significant advantage compared with current bread wheat cultivars and are similar to the best durum wheats. While alternative strategies for reducing polyphenol oxidase and lipoxygenase are available, the synthetics nevertheless provide a useful resource for wheat breeders attempting to develop improved wheat cultivars for the Asian noodle market. Unfortunately, however, most primary synthetics were prone to late maturity α-amylase and mature grain contained unacceptably high levels of α-amylase. Elimination of this genetic defect, or selection within breeding populations for low or non-LMA, is both time consuming and labour intensive and presents a significant obstacle to exploitation of variation for other traits. As proof of concept, near-zero polyphenol oxidase (PPO) lines, free from LMA, were recovered from backcross populations involving a high LMA primary synthetic.

scholarly journals Allopolyploidization Enhances Genetic Recombination of the Ancestral Diploid Genome in the Evolution of Wheat

2020 ◽  
Author(s):  
Hongshen Wan ◽  
Jun Li ◽  
Shengwei Ma ◽  
Fan Yang ◽  
Liang Chai ◽  
...  
Keyword(s):  
Hexaploid Wheat ◽  
Genetic Recombination ◽  
Recombination Frequency ◽  
Aegilops Tauschii ◽  
Synthetic Hexaploid Wheat ◽  
Evolutionary Potential ◽  
D Genome ◽  
Diploid Genome ◽  
Synthetic Hexaploid ◽  
The Impact

Abstract Background: Genetic recombination produces different allelic combinations potentially, providing new variations to the selection pools for domestication. Allopolyploidization increases evolutionary potential of the hexaploid common wheat by taking its advantages of heterosis and gene redundancy. May there be any relationship between allopolyploidization and genetic recombination? To study the impact of allopolyploidization on genetic recombination in different ancestral genomes of wheat, we generated synthetic hexaploid wheat by crossed tetraploid Triticum turgidum with diploid Aegilops tauschii to simulate its evolutionary hexaploidization process. Results: Using Wheat Breeder’s Genotyping Array, the genotypes of F2 individuals were investigated in both tetraploid (A1A1B1B1 x A2A2B2B2) and their synthetic hexaploid wheat derived populations (A1A1B1B1DD x A2A2B2B2DD). And the genotypes of the diploid population (D1D1 x D2D2) and their synthetic hexaploid wheat derived population (AABBD1D1 x AABBD2D2) were obtained with DArT-Seq™ technology. Based on genotypes of F2 populations, the genetic recombination frequency of homologous chromosome were consequently calculated in ancestral tetraploid AABB (4x), diploid DD (2x) and their synthetic hexaploid AABBDD (6x) plants, respectively. The recombination frequency of the ancestral diploid genome DD from Aegilops tauschii was found enhanced significantly more than 2 folds after their hexaploidization, while no significant changes was found in their ancestral tetraploid genome AABB via hexaploidization.Conclusions: Allopolyploidization enhancing genetic recombination of the ancestral diploid genome is found to increase the evolutionary potential of wheat, which is beneficial for wheat to conquer their narrow origination of D genome, quickly spread and make it a major crop of the world.

scholarly journals Genetic Contribution of Synthetic Hexaploid Wheat to CIMMYT’s Spring Bread Wheat Breeding Germplasm

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Umesh Rosyara ◽  
Masahiro Kishii ◽  
Thomas Payne ◽  
Carolina Paola Sansaloni ◽  
Ravi Prakash Singh ◽  
...  
Keyword(s):  
Bread Wheat ◽  
Hexaploid Wheat ◽  
Wheat Breeding ◽  
Synthetic Hexaploid Wheat ◽  
Genetic Contribution ◽  
Spring Bread Wheat ◽  
Synthetic Hexaploid ◽  
Breeding Germplasm
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