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1.
BMC Plant Biol ; 19(1): 333, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31370789

RESUMO

BACKGROUND: Wheat grains contain gluten proteins, which harbour immunogenic epitopes that trigger Coeliac disease in 1-2% of the human population. Wheat varieties or accessions containing only safe gluten have not been identified and conventional breeding alone struggles to achieve such a goal, as the epitopes occur in gluten proteins encoded by five multigene families, these genes are partly located in tandem arrays, and bread wheat is allohexaploid. Gluten immunogenicity can be reduced by modification or deletion of epitopes. Mutagenesis technologies, including CRISPR/Cas9, provide a route to obtain bread wheat containing gluten proteins with fewer immunogenic epitopes. RESULTS: In this study, we analysed the genetic diversity of over 600 α- and γ-gliadin gene sequences to design six sgRNA sequences on relatively conserved domains that we identified near coeliac disease epitopes. They were combined in four CRISPR/Cas9 constructs to target the α- or γ-gliadins, or both simultaneously, in the hexaploid bread wheat cultivar Fielder. We compared the results with those obtained with random mutagenesis in cultivar Paragon by γ-irradiation. For this, Acid-PAGE was used to identify T1 grains with altered gliadin protein profiles compared to the wild-type endosperm. We first optimised the interpretation of Acid-PAGE gels using Chinese Spring deletion lines. We then analysed the changes generated in 360 Paragon γ-irradiated lines and in 117 Fielder CRISPR/Cas9 lines. Similar gliadin profile alterations, with missing protein bands, could be observed in grains produced by both methods. CONCLUSIONS: The results demonstrate the feasibility and efficacy of using CRISPR/Cas9 to simultaneously edit multiple genes in the large α- and γ-gliadin gene families in polyploid bread wheat. Additional methods, generating genomics and proteomics data, will be necessary to determine the exact nature of the mutations generated with both methods.


Assuntos
Edição de Genes/métodos , Genes de Plantas/genética , Gliadina/genética , Glutens/genética , Triticum/genética , Proteína 9 Associada à CRISPR , Sistemas CRISPR-Cas , Eletroforese em Gel de Poliacrilamida , Glutens/imunologia , Melhoramento Vegetal/métodos , Plantas Geneticamente Modificadas , Alinhamento de Sequência
2.
Planta ; 250(3): 971-977, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31256257

RESUMO

MAIN CONCLUSION: In spite of the limited investment in orphan crops, access to new technologies such as bioinformatics and low-cost genotyping opens new doors to modernise their breeding effectively. Innovation in plant breeding is imperative to meet the world's growing demand for staple food and feed crops, and orphan crops can play a significant role in increasing productivity and quality, especially in developing countries. The short breeding history of most orphan crops implies that genetic gain should be achievable through easy-to-implement approaches such as forward breeding for simple traits or introgression of elite alleles at key target trait loci. However, limited financial support and access to sufficient, relevant and reliable phenotypic data continue to pose major challenges in terms of resources and capabilities. Digitalisation of orphan-crop breeding programmes can help not only to improve data quality and management, but also to mitigate data scarcity by allowing data to be accumulated and analysed over time and across teams. Bioinformatics tools and access to technologies such as molecular markers, some of them provided as services via specific platforms, allow breeders to implement modern strategies to improve breeding efficiency. In orphan crops, more marker-trait associations relevant to breeding germplasm are generally needed, but implementing digitalization, marker-based quality control or simple trait screening and introgression will help modernising breeding. Finally, the development of local capacities-of both people and infrastructure-remains a necessity to ensure the sustainable adoption of modern breeding approaches.


Assuntos
Produção Agrícola/métodos , Produtos Agrícolas , Melhoramento Vegetal/métodos , Biologia Computacional , Produtos Agrícolas/genética , Genoma de Planta/genética
3.
Nat Commun ; 10(1): 2982, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-31278256

RESUMO

Hybrid rice breeding for exploiting hybrid vigor, heterosis, has greatly increased grain yield. However, the heterosis-related genes associated with rice grain production remain largely unknown, partly because comprehensive mapping of heterosis-related traits is still labor-intensive and time-consuming. Here, we present a quantitative trait locus (QTL) mapping method, GradedPool-Seq, for rapidly mapping QTLs by whole-genome sequencing of graded-pool samples from F2 progeny via bulked-segregant analysis. We implement this method and map-based cloning to dissect the heterotic QTL GW3p6 from the female line. We then generate the near isogenic line NIL-FH676::GW3p6 by introgressing the GW3p6 allele from the female line Guangzhan63-4S into the male inbred line Fuhui676. The NIL-FH676::GW3p6 exhibits grain yield highly increased compared to Fuhui676. This study demonstrates that it may be possible to achieve a high level of grain production in inbred rice lines without the need to construct hybrids.


Assuntos
Mapeamento Cromossômico/métodos , Grão Comestível/genética , Vigor Híbrido/genética , Oryza/genética , Melhoramento Vegetal/métodos , Cromossomos de Plantas/genética , Locos de Características Quantitativas/genética
4.
Nat Commun ; 10(1): 2562, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31189898

RESUMO

Cadmium (Cd) accumulation in rice grain poses a serious threat to human health. While several transport systems have been reported, the complicity of rice Cd transport and accumulation indicates the necessity of identifying additional genes, especially those that are responsible for Cd accumulation divergence between indica and japonica rice subspecies. Here, we show that a gene, OsCd1, belonging to the major facilitator superfamily is involved in root Cd uptake and contributes to grain accumulation in rice. Natural variation in OsCd1 with a missense mutation Val449Asp is responsible for the divergence of rice grain Cd accumulation between indica and japonica. Near-isogenic line tests confirm that the indica variety carrying the japonica allele OsCd1V449 can reduce the grain Cd accumulation. Thus, the japonica allele OsCd1V449 may be useful for reducing grain Cd accumulation of indica rice cultivars through breeding.


Assuntos
Cádmio/metabolismo , Grão Comestível/metabolismo , Proteínas de Membrana/metabolismo , Oryza/metabolismo , Poluentes do Solo/metabolismo , Alelos , Asparagina/genética , Cádmio/análise , Membrana Celular/metabolismo , Grão Comestível/química , Humanos , Proteínas de Membrana/genética , Mutação de Sentido Incorreto , Oryza/química , Oryza/genética , Filogenia , Melhoramento Vegetal/métodos , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Polimorfismo de Nucleotídeo Único , Poluentes do Solo/análise , Valina/genética
5.
Plant Sci ; 285: 122-131, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203876

RESUMO

Domestication and subsequent breeding have eroded genetic diversity in the modern chickpea crop by ˜100-fold. Corresponding reductions to trait variation create the need, and an opportunity, to identify and harness the genetic capacity of wild species for crop improvement. Here we analyze trait segregation in a series of wild x cultivated hybrid populations to delineate the genetic underpinnings of domestication traits. Two species of wild chickpea, C. reticulatum and C. echinospermum, were crossed with the elite, early flowering C. arietinum cultivar ICCV96029. KASP genotyping of F2 parents with an FT-linked molecular marker enabled selection of 284 F3 families with reduced phenological variation: 255 F3 families of C. arietinum x reticulatum (AR) derived from 17 diverse wild parents and 29 F3 families of C. arietinum x echinospermum (AE) from 3 wild parents. The combined 284 lineages were genotyped using a genotyping-by-sequencing strategy and phenotyped for agronomic traits. 50 QTLs in 11 traits were detected from AR and 35 QTLs in 10 traits from the combined data. Using hierarchical clustering to assign traits to six correlated groups and mixed model based multi-trait mapping, four pleiotropic loci were identified. Bayesian analysis further identified four inter-trait relationships controlling the duration of vegetative growth and seed maturation, for which the underlying pleiotropic genes were mapped. A random forest approach was used to explore the most extreme trait differences between AR and AE progenies, identifying traits most characteristic of wild species origin. Knowledge of the genomic basis of traits that segregate in wild-cultivated hybrid populations will facilitate chickpea improvement by linking genetic and phenotypic variation in a quantitative genetic framework.


Assuntos
Cicer/genética , Genes de Plantas/genética , Melhoramento Vegetal/métodos , Teorema de Bayes , Cicer/crescimento & desenvolvimento , DNA de Plantas/genética , Domesticação , Estudos de Associação Genética , Ligação Genética/genética , Hibridização Genética/genética , Locos de Características Quantitativas/genética , Característica Quantitativa Herdável , Sementes/crescimento & desenvolvimento
6.
Nat Commun ; 10(1): 2738, 2019 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-31227696

RESUMO

The breeding of cereals with altered gibberellin (GA) signaling propelled the 'Green Revolution' by generating semidwarf plants with increased tiller number. The mechanism by which GAs promote shoot height has been studied extensively, but it is not known what causes the inverse relationship between plant height and tiller number. Here we show that rice tiller number regulator MONOCULM 1 (MOC1) is protected from degradation by binding to the DELLA protein SLENDER RICE 1 (SLR1). GAs trigger the degradation of SLR1, leading to stem elongation and also to the degradation of MOC1, and hence a decrease in tiller number. This discovery provides a molecular explanation for the coordinated control of plant height and tiller number in rice by GAs, SLR1 and MOC1.


Assuntos
Regulação da Expressão Gênica de Plantas/fisiologia , Giberelinas/metabolismo , Oryza/fisiologia , Proteínas de Plantas/metabolismo , Brotos de Planta/fisiologia , Grão Comestível , Giberelinas/genética , Mutação , Melhoramento Vegetal/métodos , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Proteólise , Transdução de Sinais/fisiologia
7.
Plant Cell Physiol ; 60(6): 1274-1283, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31056666

RESUMO

As an important industrial feedstock, wax esters (WEs) have been used as lubricants in a number of technical processes. There is however currently no large-scale biological source for WE production and alteration in metabolic pathways of plant oils for producing WEs could be attractive to the commercial markets. Here, we present the breeding results of long-term studies on successful development of new crambe lines producing WEs through genetic engineering and cross breeding. The transgenic crambe lines producing WEs at over 25% of the total seed oil were first generated by introduction of the jojoba WE biosynthetic genes ScFAR and ScWS. Further improvement of the lines aiming at improving oxidative stability of WEs was achieved through introducing the CaFAD2-RNAi gene into these lines by crossing. The hybrid lines possessed similar agronomic traits to the wild type and a stable level of WEs over several generations, suggesting a high potential of crambe as an industrial crop for WE production.


Assuntos
Crambe (Planta)/metabolismo , Engenharia Metabólica , Melhoramento Vegetal , Óleos Vegetais/metabolismo , Crambe (Planta)/genética , Genes de Plantas , Engenharia Genética , Óleos Industriais , Engenharia Metabólica/métodos , Melhoramento Vegetal/métodos , Plantas Geneticamente Modificadas , Sementes/metabolismo , Ceras/metabolismo
8.
Plant Sci ; 283: 135-146, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128683

RESUMO

The genetic basis of domestication and improvement remains largely unknown in sorghum as a typical multiple-origins species. In this study, the F2 and F3 populations derived from a cross between Sorghum virgatum and domesticated sorghum were used to study the genetic architecture of domestication- and improvement-related traits. We found that human selection had greatly reshaped sorghum through the Quantitative Trait Loci (QTLs) with large genetic effects in the traits of harvest, plant architecture and grain taste including the reduction of shattering, few branches, short plant stature and the removal of polyphenols from seed. The expansion of seed width was selected to improve the yield through accumulating small-effect QTLs. Two major QTLs of plant height (QTI-ph1 and dw1) were narrowed down into 24.5-kilobase (kb) and 13.9-kb, respectively. DNA diversity analysis and association mapping of dw1 gene suggested the functional variant (A1361 T) might originate from the same event not long time ago. Our results supported that parallel phenotypic changes across different species during domestication and improvement might share the same genetic basis, QTL × QTL interactions might not play an important role in the reshaping of traits during sorghum domestication and improvement, and offered new views on transgressive segregation and segregation distortion. Our study greatly deepens our understandings of the genetic basis of sorghum domestication and improvement.


Assuntos
Domesticação , Característica Quantitativa Herdável , Sorghum/genética , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Genes de Plantas/genética , Genoma de Planta/genética , Melhoramento Vegetal/métodos , Locos de Características Quantitativas/genética , Sementes , Sorghum/anatomia & histologia
9.
Plant Sci ; 283: 202-210, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128690

RESUMO

Salinity is one of the most frequent limiting conditions in pasture production for grazing livestock. Legumes, such as Lotus spp. with high forage quality and capable of adapting to different environments, improves pasture performance in restrictive areas. In order to determine potential cultivars with better forage traits, the current study assess the response to salt stress of L. tenuis, L. corniculatus and a novel L. tenuis x L. corniculatus accession. For this purpose, chlorophyll fluorescence, biomass production, ion accumulation and anthocyanins and proanthocyanidins levels have been evaluated in control and salt-treated plants PSII activity was affected by salt in L. tenuis, but not in L. corniculatus or hybrid plants. Analyzed accessions showed similar values of biomass, Na+ and K+ levels after salt treatment. Increasing Cl- concentrations were observed in all accessions. However, hybrid plants accumulate Cl- in stems at higher levels than their parental. At the same time, the levels of anthocyanins considerably increased in L. tenuis x L. corniculatus stems. Chloride and anthocyanin accumulation in stems could explain the best performance of hybrid plants after a long saline treatment. Finally, as proanthocyanidins levels were no affected by salt, L. tenuis x L. corniculatus plants maintained adequate levels to be used as ruminant feed. In conclusion, these results suggest that hybrid plants have a high potential to be used as forage on salt-affected lands. High Cl- and anthocyanins accumulation in Lotus spp. stems seems to be a trait associated to salinity tolerance, with the possibility of being used in legume breeding programs.


Assuntos
Lotus/metabolismo , Antocianinas/metabolismo , Clorofila/metabolismo , Hibridização Genética , Lotus/crescimento & desenvolvimento , Lotus/fisiologia , Melhoramento Vegetal/métodos , Potássio/metabolismo , Estresse Salino , Plantas Tolerantes a Sal , Sódio/metabolismo
10.
Genetica ; 147(2): 205-216, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31054007

RESUMO

Information about population structure and genetic relationships within and among wild and brazilian Coffea arabica L. genotypes is highly relevant to optimize the use of genetic resources for breeding purposes. In this study, we evaluated genetic diversity, clustering analysis based on Jaccard's coefficient and population structure in 33 genotypes of C. arabica and of three diploid Coffea species (C. canephora, C. eugenioides and C. racemosa) using 30 SSR markers. A total of 206 alleles were identified, with a mean of 6.9 over all loci. The set of SSR markers was able to discriminate all genotypes and revealed that Ethiopian accessions presented higher genetic diversity than commercial varieties. Population structure analysis indicated two genetic groups, one corresponding to Ethiopian accessions and another corresponding predominantly to commercial cultivars. Thirty-four private alleles were detected in the group of accessions collected from West side of Great Rift Valley. We observed a lower average genetic distance of the C. arabica genotypes in relation to C. eugenioides than C. canephora. Interestingly, commercial cultivars were genetically closer to C. eugenioides than C. canephora and C. racemosa. The great allelic richness observed in Ethiopian Arabica coffee, especially in Western group showed that these accessions can be potential source of new alleles to be explored by coffee breeding programs.


Assuntos
Coffea/genética , Repetições de Microssatélites , Polimorfismo Genético , Coffea/classificação , Genótipo , Técnicas de Genotipagem/métodos , Técnicas de Genotipagem/normas , Filogenia , Melhoramento Vegetal/métodos
11.
Plant Sci ; 284: 9-15, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31084883

RESUMO

Genomic Best Linear Unbiased Prediction (GBLUP) in tree breeding typically only uses information from genotyped trees. However, information from phenotyped but non-genotyped trees can also be highly valuable. The single-step GBLUP approach (ssGBLUP) allows genomic prediction to take into account both genotyped and non-genotyped trees simultaneously in a single evaluation. In this study, we investigated the advantage, in terms of breeding value accuracy and bias, of including phenotypic observation from non-genotyped trees in a standard tree GBLUP evaluation. We compared the efficiency of the conventional pedigree-based (ABLUP), GBLUP and ssGBLUP approaches to evaluate eight growth and wood quality traits in a Eucalyptus hybrid population, genotyped with 33,398 single nucleotide polymorphisms (SNPs) using the EucHIP60k. Theoretical accuracies, predictive ability and bias were calculated by ten-fold cross validation on all traits. The use of additional phenotypic information from non-genotyped trees by means of ssGBLUP provided higher predictive ability (from 37% to 75%) and lower prediction bias (from 21% to 73%) for the genetic component of non-phenotyped but genotyped trees when compared to GBLUP. The increase (decrease) in the prediction accuracy (bias) became stronger as trait heritability decreased. We concluded that ssGBLUP is a promising breeding tool to improve accuracies and bias over classical GBLUP for genomic evaluation in Eucalyptus breeding practice.


Assuntos
Eucalyptus/genética , Madeira/genética , Eucalyptus/anatomia & histologia , Eucalyptus/crescimento & desenvolvimento , Estudos de Associação Genética , Estudo de Associação Genômica Ampla , Melhoramento Vegetal/métodos , Característica Quantitativa Herdável , Madeira/anatomia & histologia , Madeira/crescimento & desenvolvimento
12.
Theor Appl Genet ; 132(3): 627-645, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30824972

RESUMO

KEY MESSAGE: The integration of new technologies into public plant breeding programs can make a powerful step change in agricultural productivity when aligned with principles of quantitative and Mendelian genetics. The breeder's equation is the foundational application of quantitative genetics to crop improvement. Guided by the variables that describe response to selection, emerging breeding technologies can make a powerful step change in the effectiveness of public breeding programs. The most promising innovations for increasing the rate of genetic gain without greatly increasing program size appear to be related to reducing breeding cycle time, which is likely to require the implementation of parent selection on non-inbred progeny, rapid generation advance, and genomic selection. These are complex processes and will require breeding organizations to adopt a culture of continuous optimization and improvement. To enable this, research managers will need to consider and proactively manage the, accountability, strategy, and resource allocations of breeding teams. This must be combined with thoughtful management of elite genetic variation and a clear separation between the parental selection process and product development and advancement process. With an abundance of new technologies available, breeding teams need to evaluate carefully the impact of any new technology on selection intensity, selection accuracy, and breeding cycle length relative to its cost of deployment. Finally breeding data management systems need to be well designed to support selection decisions and novel approaches to accelerate breeding cycles need to be routinely evaluated and deployed.


Assuntos
Melhoramento Vegetal/métodos , Plantas/genética , Setor Público , Marcadores Genéticos , Padrões de Herança/genética , Polimorfismo de Nucleotídeo Único/genética , Seleção Genética
13.
Plant Biol (Stuttg) ; 21(5): 935-941, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30907053

RESUMO

The declining native orchid Himantoglossum adriaticum H. Baumann is a European endemic of priority interest (92/43/ EEC, Annex II). Northern Italian populations of H. adriaticum are small and isolated, with depressed seed set. Given the important implications for plant population conservation, we tested the hypothesis that artificial pollen transfer (hand-pollination) and outbreeding between populations increases fruit set and seed germination percentage. The background fruit set and in vitro germination rates were determined for ten reference populations. An artificial cross-pollination experiment included (a) pollen transfer from one large population to two small and isolated populations; (b) pollen transfer between two small but not isolated populations; (c) within-population pollen transfer (control). All seeds were sown on a modified Malmgren's medium and cultured in a controlled environment. Germination percentage was compared using a Kruskal-Wallis anova. The background fruit set (mean = 18%) and germination (<5%) rates were consistently low across populations. Fruit set after hand-pollination was consistently 100%. Pollen transfer from the largest population to smaller populations resulted in an increase in total germination ranging from 0.9% to 2.9%. The largest increase in germination occurred between small-sized and less isolated populations (from 1.7% to 5.1%). The results of pollen transfer between the small populations are particularly encouraging, as the mean increase in germination was almost four times that of the control. Outbreeding can be considered a valuable tool to increase genetic flow and germination in natural populations, limit the accumulation of detrimental effects on fitness driven by repeated breeding with closely-related individuals, thereby increasing the possibility of conservation of rare or endangered species.


Assuntos
Germinação , Orchidaceae/fisiologia , Melhoramento Vegetal , Polinização , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Germinação/fisiologia , Melhoramento Vegetal/métodos
16.
Nat Commun ; 10(1): 1216, 2019 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-30872580

RESUMO

Efficient crop improvement depends on the application of accurate genetic information contained in diverse germplasm resources. Here we report a reference-grade genome of wild soybean accession W05, with a final assembled genome size of 1013.2 Mb and a contig N50 of 3.3 Mb. The analytical power of the W05 genome is demonstrated by several examples. First, we identify an inversion at the locus determining seed coat color during domestication. Second, a translocation event between chromosomes 11 and 13 of some genotypes is shown to interfere with the assignment of QTLs. Third, we find a region containing copy number variations of the Kunitz trypsin inhibitor (KTI) genes. Such findings illustrate the power of this assembly in the analysis of large structural variations in soybean germplasm collections. The wild soybean genome assembly has wide applications in comparative genomic and evolutionary studies, as well as in crop breeding and improvement programs.


Assuntos
Genoma de Planta/genética , Melhoramento Vegetal/métodos , Locos de Características Quantitativas/genética , Soja/genética , Evolução Biológica , Variações do Número de Cópias de DNA , Domesticação , Genômica/métodos , Genótipo , Anotação de Sequência Molecular , Peptídeos/genética , Proteínas de Plantas/genética , Translocação Genética/genética
17.
BMC Plant Biol ; 19(1): 109, 2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30894127

RESUMO

BACKGROUND: Two-line hybrid rice with high yield potential is increasingly popular and the photo- and temperature-sensitive male sterile line is one of the basic components for two-line hybrid rice breeding. The development of male sterile lines through conventional breeding is a lengthy and laborious process, whereas developing thermo-sensitive genic male sterile (TGMS) lines for two-line hybrid breeding by editing a temperature-sensitivity gene by CRISPR/Cas9 is efficient and convenient. RESULTS: Here, thermo-sensitive genic male sterility (TGMS) was induced by employing the CRISPR/Cas9 gene editing technology to modify the gene TMS5. Two TGMS mutants, tms5-1 and tms5-2, both lacking any residual T-DNA, were generated in the indica rice cultivar Zhongjiazao17 (cv. YK17) background. When grown at a sub-optimal temperature (22 °C), both mutants produced viable pollen and successfully produced grain through self-fertilization, but at temperatures 24 and 26 °C, their pollen was sterile and no grain was set. F1 hybrids derived from the crosses between YK17S (tms5-1) and three different restorer lines outperformed both parental lines with respect to grain yield and related traits. CONCLUSION: The YK17S generated by CRISPR/Cas9 system was proved to be a new TGMS line with superior yield potential and can be widely utilized in two-line hybrid breeding of indica rice.


Assuntos
Sistemas CRISPR-Cas , Oryza/genética , Melhoramento Vegetal/métodos , Infertilidade das Plantas/genética , Proteínas de Plantas/genética , Quimera , Mutagênese , Oryza/fisiologia , Plantas Geneticamente Modificadas , Pólen/genética , Pólen/crescimento & desenvolvimento , Temperatura Ambiente
18.
Mol Genet Genomics ; 294(3): 789-810, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30887144

RESUMO

Upland cotton (Gossypium hirsutum L.) race stocks may possess desirable traits for the genetic improvement of cotton. Quantitative trait locus (QTL) analysis can assist in uncovering new alleles from unadapted race stocks. In this study, three sets of chromosome segment introgression lines (ILs) were developed from three backcrosses (BC3) between three race stocks, G. hirsutum races latifolium accs. TX-34 and TX-48 and punctatum acc. TX-114, as donor parents and Texas Marker-1 (TM-1) as the recurrent parent. Based on a total of 452 polymorphic simple sequence repeat (SSR) markers in BC3F2 genotyping, 149, 150 and 184 ILs were obtained from TM-1 × TX-34, TM-1 × TX-48 and TM-1 × TX-114, respectively. The average introgressed chromosomal segment length was 12.7 cM, and the total genetic distance was 3268 cM covering approximately 73.4% of the Upland cotton genome. The BC3F2, BC3F2:3 and BC3F2:4 progeny, which produced the ILs, were evaluated for yield and fibre quality traits. A total of 128 QTLs were detected, each of which explained 1.6-13.0% of the phenotypic variation. Thirty-five common QTLs related to eight traits were detected. Six QTL clusters were found on five chromosomes. Thirty-eight QTLs were previously unreported, and they may be footprints of cotton domestication. Domestication or artificial selection by humans successfully eliminated most unfavourable QTLs (21/38); however, some favourable QTLs (17/38) are not present in modern cultivars, demonstrating the importance of race stocks for improving cotton cultivars. The 26 elite ILs developed could be used to improve the yield and fibre quality components simultaneously. These results provide information on desirable QTLs for cotton improvement.


Assuntos
Fibra de Algodão/normas , Genes de Plantas/genética , Gossypium/genética , Locos de Características Quantitativas/genética , Biomassa , Mapeamento Cromossômico/métodos , Cromossomos de Plantas/genética , Cruzamentos Genéticos , Domesticação , Genoma de Planta/genética , Gossypium/classificação , Gossypium/crescimento & desenvolvimento , Melhoramento Vegetal/métodos , Seleção Genética
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