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Common wheat
About: Common wheat is a research topic. Over the lifetime, 3584 publications have been published within this topic receiving 71113 citations. The topic is also known as: common wheat.
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TL;DR: The present review summarizes the available data on wheat-alien transfers conferring resistance to diseases and pests and should be useful for further directed chromosome engineering aimed at producing superior germplasm.
Abstract: Wild relatives of common wheat, Triticum aestivum, and related species are an important source of disease and pest resistance and several useful traits have been transferred from these species to wheat. C-banding and in situ hybridization analyses are powerful cytological techniques allowing the detection of alien chromatin in wheat. C-banding permits identification of the wheat and alien chromosomes involved in wheat-alien translocations, whereas genomic in situ hybridization analysis allows determination of their size and breakpoint positions. The present review summarizes the available data on wheat-alien transfers conferring resistance to diseases and pests. Ten of the 57 spontaneous and induced wheat-alien translocations were identified as whole arm translocations with the breakpoints within the centromeric regions. The majority of transfers (45) were identified as terminal translocations with distal alien segments translocated to wheat chromosome arms. Only two intercalary wheat-alien transloctions were identified, one induced by radiation treatment with a small segment of rye chromosome 6RL (H25) inserted into the long arm of wheat chromosome 4A, and the other probably induced by homoeologous recombination with a segment derived from the long arm of a group 7 Agropyron elongatum chromosome with Lr19 inserted into the long arm of 7D. The presented information should be useful for further directed chromosome engineering aimed at producing superior germplasm.
841 citations
680 citations
TL;DR: In this article, the VRN-1 gene was sequenced and all the accessions had large deletions within the first intron, which overlap in a 4-kb region and showed high sequence conservation among the different recessive alleles.
Abstract: The broad adaptability of wheat and barley is in part attributable to their flexible growth habit, in that spring forms have recurrently evolved from the ancestral winter growth habit. In diploid wheat and barley growth habit is determined by allelic variation at the VRN-1 and/or VRN-2 loci, whereas in the polyploid wheat species it is determined primarily by allelic variation at VRN-1. Dominant Vrn-A1 alleles for spring growth habit are frequently associated with mutations in the promoter region in diploid wheat and in the A genome of common wheat. However, several dominant Vrn-A1, Vrn-B1, Vrn-D1 (common wheat) and Vrn-H1 (barley) alleles show no polymorphisms in the promoter region relative to their respective recessive alleles. In this study, we sequenced the complete VRN-1 gene from these accessions and found that all of them have large deletions within the first intron, which overlap in a 4-kb region. Furthermore, a 2.8-kb segment within the 4-kb region showed high sequence conservation among the different recessive alleles. PCR markers for these deletions showed that similar deletions were present in all the accessions with known Vrn-B1 and Vrn-D1 alleles, and in 51 hexaploid spring wheat accessions previously shown to have no polymorphisms in the VRN-A1 promoter region. Twenty-four tetraploid wheat accessions had a similar deletion in VRN-A1 intron 1. We hypothesize that the 2.8-kb conserved region includes regulatory elements important for the vernalization requirement. Epistatic interactions between VRN-H2 and the VRN-H1 allele with the intron 1 deletion suggest that the deleted region may include a recognition site for the flowering repression mediated by the product of the VRN-H2 gene of barley.
591 citations
01 Jan 1966
TL;DR: The discovery that the 21 different chromosomes of common wheat fall into seven homoeologous groups of three (Sears, 1952, 1954) was based primarily on the ability of each tetra-some to compensate for the nullisome of each of the other two chromosomes of the same group.
Abstract: The discovery that the 21 different chromosomes of common wheat (Triticum aestivum L.) fall into seven homoeologous groups of three (Sears, 1952, 1954) was based primarily on the ability of each tetra-some to compensate for the nullisome of each of the other two chromosomes of the same group. Supporting evidence has come from the finding of Okamoto and Sears (1962) that the pairing in haploids is largely between chromosomes belonging to the same homoeologous group, and from the work of Riley and Kempanna (1963), who found only pairing of homoeologues when increased pairing was induced by the absence of chromosome 5B.
579 citations