Theoretical and Applied Genetics (Theor Appl Genet)
Founded in 1929 as "Der Züchter" a German journal for theoretical and applied genetics. In 1966 its direction changed from national to international and from plant breeding to genetics and breeding research. The title changed in 1968 to "Theoretical and Applied Genetics". Edited by H. Stubbe from 1946 to 1976 by H. F. Linskens 1977 to 1987 and by G. Wenzel from 1988. TAG will publish original articles in the following areas: Genetic and physiological fundamentals of plant breeding Applications of plant biotechnology Theoretical considerations in combination with experimental data
Journal Impact: 4.72*
Journal impact history
|2016 Journal impact||Available summer 2017|
|2015 Journal impact||4.72|
|2014 Journal impact||4.52|
|2013 Journal impact||4.17|
|2012 Journal impact||4.12|
|2011 Journal impact||4.06|
|2010 Journal impact||2.67|
|2007 Journal impact||3.30|
|2005 Journal impact||2.55|
|2004 Journal impact||4.04|
|2003 Journal impact||2.23|
Journal impact over time
|Website||Theoretical and Applied Genetics (TAG) website|
|Other titles||Theoretical and applied genetics (Online), TAG, TAG, theoretical and applied genetics|
|Material type||Document, Periodical, Internet resource|
|Document type||Internet Resource, Computer File, Journal / Magazine / Newspaper|
Publications in this journal
- [Show abstract] [Hide abstract] ABSTRACT: Key message: Here we report the production of a set of wheat - Aegilops speltoides Robertsonian translocations covering all Ae. speltoides chromosome arms except the long arm of the homoeologous group 4 chromosome. Aegilops speltoides of the Poaceae family is the most probable donor of the B and G genomes of polyploid Triticum species and also an important source of resistance to diseases and pests of wheat. Previously, we reported the production of a complete set of T aestivum-Ae. speltoides chromosome addition lines and a set of disomic S(B/A)-genome chromosome substitution lines. The isolation of compensating Robertsonian translocations (RobTs) composed of alien chromosome arms translocated to homoeologous wheat chromosome arms is the important next step to exploit the genetic variation of a wild relative of wheat. Here, we report the development of molecular markers specific for the S-genome chromosomes and their use in the isolation of a set of 13 compensating wheat-Ae. speltoides RobTs covering the S genome of Ae. speltoides except for the long arm of chromosome 4S. Most of the RobTs were fully fertile and will facilitate mapping of genes to specific chromosome arms and also will accelerate the introgression of agronomically useful traits from Ae. speltoides into wheat by homologous recombination.
- [Show abstract] [Hide abstract] ABSTRACT: Key message: This study revealed a complex genetic architecture of male floral traits in wheat, and Rht-D1 was identified as the only major QTL. Genome-wide prediction approaches but also phenotypic recurrent selection appear promising to increase outcrossing ability required for hybrid wheat seed production. Hybrid wheat breeding is a promising approach to increase grain yield and yield stability. However, the identification of lines with favorable male floral characteristics required for hybrid seed production currently poses a severe bottleneck for hybrid wheat breeding. This study therefore aimed to unravel the genetic architecture of floral traits and to assess the potential of genomic approaches to accelerate their improvement. To this end, we employed a panel of 209 diverse winter wheat lines assessed for male floral traits and genotyped with genome-wide markers as well as for Rht-B1 and Rht-D1. We found the highest proportion of explained genotypic variance for the Rht-D1 locus (11-24 %), for which the dwarfing allele Rht-D1b had a negative effect on anther extrusion, visual anther extrusion and pollen mass. The genome-wide scan detected only few QTL with small or medium effects, indicating a complex genetic architecture. Consequently, marker-assisted selection yielded only moderate prediction abilities (0.44-0.63), mainly relying on Rht-D1. Genomic selection based on weighted ridge-regression best linear unbiased prediction achieved higher prediction abilities of up to 0.70 for anther extrusion. In conclusion, recurrent phenotypic selection appears most cost-effective for the initial improvement of floral traits in wheat, while genome-wide prediction approaches may be worthwhile when complete marker profiles are already available in a hybrid wheat breeding program.
- [Show abstract] [Hide abstract] ABSTRACT: Key message: A method based on a multi-task Gaussian process using self-measuring similarity gave increased accuracy for imputing missing phenotypic data in multi-trait and multi-environment trials. Multi-environmental trial (MET) data often encounter the problem of missing data. Accurate imputation of missing data makes subsequent analysis more effective and the results easier to understand. Moreover, accurate imputation may help to reduce the cost of phenotyping for thinned-out lines tested in METs. METs are generally performed for multiple traits that are correlated to each other. Correlation among traits can be useful information for imputation, but single-trait-based methods cannot utilize information shared by traits that are correlated. In this paper, we propose imputation methods based on a multi-task Gaussian process (MTGP) using self-measuring similarity kernels reflecting relationships among traits, genotypes, and environments. This framework allows us to use genetic correlation among multi-trait multi-environment data and also to combine MET data and marker genotype data. We compared the accuracy of three MTGP methods and iterative regularized PCA using rice MET data. Two scenarios for the generation of missing data at various missing rates were considered. The MTGP performed a better imputation accuracy than regularized PCA, especially at high missing rates. Under the 'uniform' scenario, in which missing data arise randomly, inclusion of marker genotype data in the imputation increased the imputation accuracy at high missing rates. Under the 'fiber' scenario, in which missing data arise in all traits for some combinations between genotypes and environments, the inclusion of marker genotype data decreased the imputation accuracy for most traits while increasing the accuracy in a few traits remarkably. The proposed methods will be useful for solving the missing data problem in MET data.
- [Show abstract] [Hide abstract] ABSTRACT: Key message: We fine mapped the Xa4 locus and developed a pyramided rice line containing Xa3 and Xa4 R - alleles and a cold-tolerance QTL. This line will be valuable in rice breeding. Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a destructive disease of cultivated rice. Pyramiding BB resistance genes is an essential approach for increasing the resistance level of rice varieties. We selected an advanced backcross recombinant inbred line 132 (ABL132) from the BC3F7 population derived from a cross between cultivars Junam and IR72 by K3a inoculation and constructed the mapping population (BC4F6) to locate the Xa4 locus. The Xa4 locus was found to be delimited within a 60-kb interval between InDel markers InDel1 and InDel2 and tightly linked with the Xa3 gene on chromosome 11. After cold (4 °C) treatment, ABL132 with introgressions of IR72 in chromosome 11 showed lower survival rate, chlorophyll content, and relative water content compared to Junam. Genetic analysis showed that the cold stress-related quantitative trait locus (QTL) qCT11 was located in a 1.3-Mb interval close to the Xa4 locus. One line, ABL132-36, containing the Xa3 resistance allele from Junam, the Xa4 resistance allele from IR72, and the cold-tolerance QTL from Junam (qCT11), was developed from a BC4F6 population of 250 plants. This is the first report on the pyramiding of Xa3 and Xa4 genes with a cold-tolerance QTL. This region could provide a potential tool for improving resistance against BB and low-temperature stress in rice-breeding programs.
- [Show abstract] [Hide abstract] ABSTRACT: Key message We developed and validated a robust marker toolkit for high-throughput and cost-effective screening of a large number of functional genes in wheat. Abstract Functional markers (FMs) are the most valuable markers for crop breeding programs, and high-throughput genotyping for FMs could provide an excellent opportunity to effectively practice marker-assisted selection while breeding cultivars. Here we developed and validated kompetitive allele-specific PCR (KASP) assays for genes that underpin economically important traits in bread wheat including adaptability, grain yield, quality, and biotic and abiotic stress resistances. In total, 70 KASP assays either developed in this study or obtained from public databases were validated for reliability in application. The validation of KASP assays were conducted by (a) comparing the assays with available gel-based PCR markers on 23 diverse wheat accessions, (b) validation of the derived allelic information using phenotypes of a panel comprised of 300 diverse cultivars from China and 13 other countries, and (c) additional testing, where possible, of the assays in four segregating populations. All KASP assays being reported were significantly associated with the relevant phenotypes in the cultivars panel and bi-parental populations, thus revealing potential application in wheat breeding programs. The results revealed 45 times superiority of the KASP assays in speed than gel-based PCR markers. KASP has recently emerged as single-plex high-throughput genotyping technology; this is the first report on high-throughput screening of a large number of functional genes in a major crop. Such assays could greatly accelerate the characterization of crossing parents and advanced lines for marker-assisted selection and can complement the inflexible, high-density SNP arrays. Our results offer a robust and reliable molecular marker toolkit that can contribute towards maximizing genetic gains in wheat breeding programs.
- [Show abstract] [Hide abstract] ABSTRACT: Key message: Dominant glandless gene Gl 2 (e) was fine-mapped to a 15 kb region containing one candidate gene encoding an MYC transcription factor, sequence and expression level of the gene were analyzed. Cottonseed product is an excellent source of oil and protein. However, this nutrition source is greatly limited in utilization by the toxic gossypol in pigment glands. It is reported that the Gl 2 (e) gene could effectively inhibit the formation of the pigment glands. Here, three F2 populations were constructed using two pairs of near isogenic lines (NILs), which differ nearly only by the gland trait, for fine mapping of Gl 2 (e) . DNA markers were identified from recently developed cotton genome sequence. The Gl 2 (e) gene was located within a 15-kb genomic interval between two markers CS2 and CS4 on chromosome 12. Only one gene was identified in the genomic interval as the candidate for Gl 2 (e) which encodes a family member of MYC transcription factor with 475-amino acids. Unexpectedly, the results of expression analysis indicated that the MYC gene expresses in glanded lines while almost does not express in glandless lines. These results suggest that the MYC gene probably serves as a vital positive regulator in the organogenesis pathway of pigment gland, and low expression of this gene will not launch the downstream pathway of pigment gland formation. This is the first pigment gland-related gene identification in cotton and will facilitate the research on glandless trait, cotton MYC proteins and low-gossypol cotton breeding.
- [Show abstract] [Hide abstract] ABSTRACT: Key message: Using next-generation DNA sequencing, it was possible to clarify the genetic relationships of Avena species and deduce the likely pathway from which hexaploid oat was formed by sequential polyploidization events. A sequence-based diversity study was conducted on a representative sample of accessions from species in the genus Avena using genotyping-by-sequencing technology. The results show that all Avena taxa can be assigned to one of four major genetic clusters: Cluster 1 = all hexaploids including cultivated oat, Cluster 2 = AC genome tetraploids, Cluster 3 = C genome diploids, Cluster 4 = A genome diploid and tetraploids. No evidence was found for the existence of discrete B or D genomes. Through a series of experiments involving the creation of in silico polyploids, it was possible to deduce that hexaploid oat likely formed by the fusion of an ancestral diploid species from Cluster 3 (A. clauda, A. eriantha) with an ancestral diploid species from Cluster 4D (A. longiglumis, A. canariensis, A. wiestii) to create the ancestral tetraploid from Cluster 2 (A. magna, A. murphyi, A. insularis). Subsequently, that ancestral tetraploid fused again with another ancestral diploid from Cluster 4D to create hexaploid oat. Based on the geographic distribution of these species, it is hypothesized that both the tetraploidization and hexaploidization events may have occurred in the region of northwest Africa, followed by radiation of hexaploid oat to its current worldwide distribution. The results from this study shed light not only on the origins of this important grain crop, but also have implications for germplasm collection and utilization in oat breeding.
- [Show abstract] [Hide abstract] ABSTRACT: Key message: Trigenomic Brassica allohexaploids synthesized from three crossing strategies showed diploidized and non-diploidized meiotic behaviors and produced both euploid and aneuploid progenies during successive generations, revealing the distinct subgenome stabilities (B > A> C). Three cultivated allotetraploid Brassica species (Brassica napus, B. juncea, B. carinata) represent the model system of speciation through interspecific hybridization and allopolyploidization, but no Brassica species at higher ploidy level exists in nature. In this study, Brassica allohexaploids (2n = 54, AABBCC) were artificially synthesized using three crossing strategies, and had combinations of the genomes from the extant allotetraploids and diploids (B. rapa, B. oleracea and B. nigra). The chromosome numbers and complements of these allohexaploids and the self-pollinated progenies of successive generations (S0-S7) were determined using multicolor fluorescent in situ hybridization that distinguished the chromosomes of three constituent genomes from each other. Both euploid and aneuploid progenies were identified. The most aneuploids maintained all B- and A-genome chromosomes and variable number of C-genome chromosomes, suggesting that genome stability was B > A > C. In the extreme case, loss of whole set of C-genome chromosomes led to the production of B. juncea-type progeny. Some aneuploid progenies had the same number of chromosomes (2n = 54) as the euploid, but the simultaneous loss and gain of A- and C-genome chromosomes. The diploidized and non-diploidized meiotic behaviors co-occurred in all allohexaploid individuals of consecutive generations. The aberrant chromosome pairing and segregation mainly involved the chromosomes of A and C genomes, which resulted in aneuploidy in self-pollinated progenies. The mechanisms for the differential stability of three genomes and the stabilization of the new allohexaploids are discussed.
- [Show abstract] [Hide abstract] ABSTRACT: Key message: Genetically stable deletion lines of Agropyron cristatum chromosome 6P in common wheat background were generated, which allowed for physical mapping of 255 6P-specific STS markers and leaf rust resistance gene(s). Chromosomal deletion lines are valuable tools for gene discovery and localization. The chromosome 6P of Agropyron cristatum (2n = 4x = 28, PPPP) confers many desirable agronomic traits to common wheat, such as higher grain number per spike, multiple fertile tiller number, and enhanced resistance to certain diseases. Although many elite genes from A. cristatum have been identified, their chromosomal locations were largely undetermined due to the lack of A. cristatum 6P deletion lines. In this study, various A. cristatum 6P deletion lines were developed using a wheat-A. cristatum 6P disomic addition line 4844-12 subjected to (60)Co-γ irradiation as well as an Aegilops cylindrica gametocidal chromosome. Twenty-six genetically stable A. cristatum 6P deletion lines in the genetic background of common wheat were obtained, and their genetic constitutions were elucidated by genomic in situ hybridization (GISH) and sequence-tagged site (STS) markers specific to A. cristatum chromosome 6P. Moreover, 255 novel chromosome 6P-specific STS markers were physically mapped to 14 regions of chromosome 6P. Field evaluation of leaf rust resistance of various deletion lines and BC1F2 populations indicated that the A.cristatum chromosome 6P-originated leaf rust resistance gene(s) was located in the region 6PS-0.81-1.00. This study will provide not only useful tools for characterization and utilization of wheat materials with alien chromosomal segments, but also novel wheat germplasms potentially valuable in wheat breeding and improvement.
- [Show abstract] [Hide abstract] ABSTRACT: Key message: Soybean quantitative trait loci for ozone response. Ground-level ozone reduces yield in crops such as soybean (Glycine max (L.) Merr.). Phenotypic variation has been observed for this trait in multiple species; however, breeding for ozone tolerance has been limited. A recombinant inbred population was developed from soybean genotypes differing in tolerance to ozone: tolerant Fiskeby III and sensitive Mandarin (Ottawa). Plants were exposed to ozone treatment for 5 days in greenhouse chambers followed by visual scoring for foliar injury. Mean injury score in the mid-canopy was 16 % for Fiskeby III, and 81 % for Mandarin (Ottawa). Injury scores were lower in younger leaves for both parents and progeny, compared to scores in the older leaves. Segregation was consistent with multigenic inheritance. Correlation coefficients for injury between leaf positions ranged from 0.34 to 0.81, with the closer leaf positions showing the greater correlation. Narrow sense heritability within an ozone treatment chamber was 0.59, 0.40, 0.29, 0.30, 0.19, and 0.35 for the 2nd, 3rd, 4th, 5th, 6th, and combined 3rd-5th main stem leaf positions (numbered acropetally), respectively, based on genotypic means over three independent replications. Quantitative trait loci (QTL) analysis showed that loci were associated with distinct leaf developmental stages. QTL were identified on Chromosome 17 for the 2nd and 3rd leaf positions, and on Chromosome 4 for the 5th and 6th leaf positions. Additional loci were identified on Chromosomes 6, 18, 19, and 20. Interacting loci were identified on Chromosomes 5 and 15 for injury on trifoliate 4. The ozone sensitive parent contributed one favorable allele for ozone response.
- [Show abstract] [Hide abstract] ABSTRACT: Key message: A targeted amplicon-based genotyping-by-sequencing approach has permitted cost-effective and accurate discrimination between ryegrass species (perennial, Italian and inter-species hybrid), and identification of cultivars based on bulked samples. Perennial ryegrass and Italian ryegrass are the most important temperate forage species for global agriculture, and are represented in the commercial pasture seed market by numerous cultivars each composed of multiple highly heterozygous individuals. Previous studies have identified difficulties in the use of morphophysiological criteria to discriminate between these two closely related taxa. Recently, a highly multiplexed single nucleotide polymorphism (SNP)-based genotyping assay has been developed that permits accurate differentiation between both species and cultivars of ryegrasses at the genetic level. This assay has since been further developed into an amplicon-based genotyping-by-sequencing (GBS) approach implemented on a second-generation sequencing platform, allowing accelerated throughput and ca. sixfold reduction in cost. Using the GBS approach, 63 cultivars of perennial, Italian and interspecific hybrid ryegrasses, as well as intergeneric Festulolium hybrids, were genotyped. The genetic relationships between cultivars were interpreted in terms of known breeding histories and indistinct species boundaries within the Lolium genus, as well as suitability of current cultivar registration methodologies. An example of applicability to quality assurance and control (QA/QC) of seed purity is also described. Rapid, low-cost genotypic assays provide new opportunities for breeders to more fully explore genetic diversity within breeding programs, allowing the combination of novel unique genetic backgrounds. Such tools also offer the potential to more accurately define cultivar identities, allowing protection of varieties in the commercial market and supporting processes of cultivar accreditation and quality assurance.
- [Show abstract] [Hide abstract] ABSTRACT: Key message: A novel R gene was mapped to a locus on chromosome 11 from 30.42 to 30.85 Mb, which was proven to be efficient in the improvement of rice blast resistance. Rice blast is a devastating fungal disease worldwide. The use of blast resistance (R) genes is the most important approach to control the disease in rice breeding. In the present study, we finely mapped a novel resistance gene Pi65(t), conferring a broad-spectrum resistance to the fungus Magnaporthe oryzae, using bulked segregant analysis in combination with next-generation sequencing technology. Segregation in a doubled haploid (DH) population and a BC1F2 population suggested that resistance to blast in Gangyu129 was likely conferred by a single dominant gene, designated Pi65(t); it was located on chromosome 11 from 30.20 to 31.20 Mb using next-generation sequencing. After screening recombinants with newly developed molecular markers, the region was narrowed down to 0.43 Mb, flanked by SNP-2 and SNP-8 at the physical location from 30.42 to 30.85 Mb based on the Nipponbare reference database in build 5. Using the software QTL IciMapping, Pi65(t) was further mapped to a locus between InDel-1 and SNP-4 with genetic distances of 0.11 and 0.98 cM, respectively. Within this region, 4 predicted R genes were found with nucleotide binding site and leucine-rich repeat (NBS-LRR) domains. We developed molecular markers to genotype 305 DH lines and found that InDel-1 was closely linked with Pi65(t). Using InDel-1, a new rice variety Chuangxin1 containing Pi65(t) was developed, and it is highly resistant to rice blast and produces a high yield in Liaoning province of China. This indicated that Pi65(t) could play a key role in the improvement of rice blast resistance.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.