Quantitative trait loci detection of Edwardsiella tarda resistance in Japanese flounder Paralichthys olivaceus using bulked segregant analysis

Our objectives were to identify randomly amplified polymorphic DNA (RAPD) markers associated with quantitative trait loci (QTL) for sucrose, total soluble solids (TSS), and sucrose percentage of total sugars (SPTS) using bulked segregant analysis in an F2 population from the melon (Cucumis melo L.) cross of `TAM Dulce' (high sugars) × TGR1551 (low sugars) in a greenhouse experiment, and confirm the associations of RAPD markers with QTL for these sugar traits in an F2 population from the different cross of `Deltex' (high sugars) × TGR1551 in a field experiment. Continuous distributions for sucrose, TSS, and SPTS were observed in the F2 populations indicating quantitative inheritance for the traits. Significant positive correlations were found between sucrose and TSS or SPTS. Nine RAPD markers were detected to be significantly associated with QTL for sucrose in the F2 population of the `TAM Dulce' × TGR1551 cross in the greenhouse based on simple linear regression. Five unlinked markers associated with QTL were significant in a stepwise multiple regression analysis where the full model explained 39% of the total phenotypic variation for sucrose. Five and seven of the nine RAPD markers associated with QTL for sucrose were also observed to be significantly associated with QTL for TSS and SPTS, respectively, suggesting that in this cross three sugar traits are controlled by the same QTL. Five RAPD markers were confirmed in the F2 population of the `Deltex' × TGR1551 cross in the field to be consistently associated with QTL for three sugar traits. Significant associations of andromonoecious (a) with both sucrose and TSS were consistently expressed in our populations under greenhouse and field environments. These RAPD and floral markers associated with the sugar synthesis QTL identified and confirmed here could be useful in melon breeding for improving the mature fruit sweetness.

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Detection of quantitative trait loci associated with leaf rust resistance in bread wheat

Genome ◽

10.1139/g97-036 ◽

1997 ◽

Vol 40 (2) ◽

pp. 253-260 ◽

Cited By ~ 30

Author(s):

H. M. William ◽

D. Hoisington ◽

R. P. Singh ◽

D. González-de-León

Keyword(s):

Quantitative Trait Loci ◽

Leaf Rust ◽

Quantitative Trait ◽

Rust Resistance ◽

Bulked Segregant Analysis ◽

Recombinant Inbred Lines ◽

Leaf Rust Resistance ◽

Common Disease ◽

The Third ◽

Trait Loci

Leaf rust, caused by Puccinia recondita Rob. ex Desm., is a common disease in wheat. The objective of this study was to develop molecular markers associated with the quantitative trait loci (QTLs) putatively conferring durable leaf rust resistance in Triticum aestivum L. em. Thell. A population of 77 recombinant inbred lines (RILs) developed from 'Parula' (resistant) and 'Siete Cerros' (moderately susceptible) was used. Bulked segregant analysis was done using random amplified polymorphic DNAs (RAPDs) with DNA enriched for low-copy sequences using hydroxyapatite chromatography. Out of 400 decamer primers screened, 3 RAPD markers were identified between the bulk of the most resistant and the bulk of the most susceptible lines. These were cloned and used as probes on the RILs in Southern hybridizations. Two probes revealed two tightly linked loci. One-way analysis of variance showed that these two loci, and another revealed by the third probe, were linked to QTLs controlling leaf rust resistance based on data taken from 2 years of replicated field trials. Cytogenetic analysis placed the two tightly linked loci on the long arm of chromosome 7B. The third probe detected loci located on the short arms of chromosomes 1B and 1D. It is suggested that the QTL detected on 7BL may well be homoeoallelic to Lr34.Key words: bulked segregant analysis, RAPDs, RFLPs, DNA enrichment, leaf rust, QTL.

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Mapping Freeze Tolerance Quantitative Trait Loci in a Citrus grandis × Poncirus trifoliata F1 Pseudo-testcross Using Molecular Markers

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.128.4.0508 ◽

2003 ◽

Vol 128 (4) ◽

pp. 508-514 ◽

Cited By ~ 32

Author(s):

Courtney A. Weber ◽

Gloria A. Moore ◽

Zhanao Deng ◽

Fred G. Gmitter

Keyword(s):

Quantitative Trait Loci ◽

Quantitative Trait ◽

Bulked Segregant Analysis ◽

Random Amplified Polymorphic Dna ◽

Freeze Tolerance ◽

Interval Mapping ◽

Poncirus Trifoliata ◽

Linkage Maps ◽

Sequence Characterized Amplified Region ◽

Trait Loci

Mapping quantitative trait loci (QTL) associated with freeze tolerance was accomplished using a Citrus grandis (L.) Osb. × Poncirus trifoliata (L.) Raf. F1 pseudo-testcross population. A progeny population of 442 plants was acclimated and exposed to temperatures of -9 °C and -15 °C in two separate freeze tests. A subpopulation of 99 progeny was genotyped for random amplified polymorphic DNA (RAPD), cleaved amplified polymorphic sequence (CAPS), sequence characterized amplified region (SCAR), and sequence tagged site (STS) markers to produce a linkage map for each parent. Potential QTL were identified by interval mapping, and their validity was corroborated with results from means comparison (t test), one-way analysis of variance (F test), and bulked segregant analysis (BSA). Multiple analytical methods provided evidence supporting putative QTL and decreased the probability of missing significant QTL associated with freeze tolerance. QTL with a large effect on freeze tolerance were located on both the Citrus and Poncirus linkage maps. In addition, clusters of markers with significantly different means between marker present and absent classes indicating minor QTL that contribute smaller effects on the level of tolerance were found on the linkage maps of both species.

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