| 1. |
- Crouzillat, D, et al.
(författare)
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Theobroma cacao L : A genetic linkage map and quantitative trait loci analysis
- 1996
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Ingår i: Theoretical and Applied Genetics. - : SPRINGER. - 0040-5752 .- 1432-2242. ; 93:1-2, s. 205-214
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Tidskriftsartikel (refereegranskat)abstract
- A genetic linkage map of Theobroma cacao (cocoa) has been constructed from 131 backcross trees derived from a cross between a single tree of the variety Catongo and an F1 tree from the cross of Catongo by Pound 12. The map comprises 138 markers: 104 RAPD loci, 32 RFLP loci and two morphologic loci. Ten linkage groups were found which cover 1068 centimorgans (cM). Only six (4%) molecular-marker loci show a significant deviation from the expected 1:1 segregation ratio. The average distance between two adjacent markers is 8.3 cM. The final genome-size estimates based on two-point linkage data ranged from 1078 to 1112 cM for the cocoa genome. This backcross progeny segregates for two apparently single gene loci controlling (1) anthocyanidin synthesis (Anth) in seeds, leaves and flowers and (2) self-compatibility (Autoc). The Anth locus was found to be 25 cM from Autoc and two molecular markers co-segregate with Anth. The genetic linkage map was used to localize QTLs for early flowering, trunk diameter, jorquette height and ovule number in the BC1 generation using both single-point ANOVA and interval mapping. A minimum number of 2-4 QTLs (P<0.01) involved in the genetic expression of the traits studied was detected. Coincident map locations of a QTL for jorquette height and trunk diameter suggests the possibility of pleiotropic effects in cocoa for these traits. The combined estimated effects of the different mapped QTLs explained between 11.2% and 25.8% of the phenotypic variance observed in the BC1 population.
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| 2. |
- Denoyes-Rothan, B, et al.
(författare)
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QTL analysis for resistances to Colletotrichum acutatum and Phytophthora cactorum in octoploid strawberry (Fragaria x ananassa)
- 2004
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Ingår i: Proceedings of the XIth Eucarpia Symposium on Fruit Breeding and Genetics, Vols 1 and 2. - : INTERNATIONAL SOCIETY HORTICULTURAL SCIENCE. ; , s. 147-151
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Konferensbidrag (refereegranskat)abstract
- Colletotrichum acutatum and Phytophthora cactorum are two of the most important pathogens of strawberry in Europe, and particularly in France. The characterization of quantitative trait loci (QTL) controlling resistances to these two pathogens would allow a better knowledge of the genetic architecture of these resistances in order to develop durable resistance. A pseudo-testcross strawberry population derived from the cross between Capitola and CF1116 was used for detecting QTLs associated with C. acutatum and P cactorum resistances. One hundred and eighty five individuals were inoculated with C. acutatum by dipping cold stored plants in a conidial suspension adjusted to 2.10(6) conidia per ml. They were also inoculated separately with P cactorum by inserting an agar disk containing mycelium into the crown. Each inoculation was conducted twice. Putative QTLs for resistance to C acutatum and P cactorum were identified by Interval Mapping (Mapmaker-QTL) using a LOD threshold of 2.
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| 3. |
- Lerceteau, Estelle, et al.
(författare)
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Detection of quantitative trait loci in Pinus sylvestris L. across years
- 2001
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Ingår i: Euphytica. - : KLUWER ACADEMIC PUBL. - 0014-2336 .- 1573-5060. ; 121:2, s. 117-122
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Tidskriftsartikel (refereegranskat)abstract
- In an earlier study, we reported the characterisation of quantitative trait loci (QTLs) for economically important traits related to wood production for a specific year of measurement. However, validating the detected QTLs across years is important for any strategy for marker-assisted selection (MAS). Therefore, we evaluated the consistency of the QTLs across four years in 9 to 12 year-old trees. Data related to tree height were analysed in two ways. The total height was used to characterise QTLs likely to be useful in MAS, and the increment values to evaluate growth regulation. Among the 11 QTLs detected, 4 were found in both the 1996 and 1997 evaluations. QTL numbers and locations related to total height were found to be highly stable. However, the QTL effects progressively changed in successive years, following either an increasing, decreasing or curvilinear trend. Depending on their specific trends, some QTLs may not be expressed at all later in maturity, or they may be expressed at a higher level. This will have direct consequences on the applicability of molecular markers in early screening programs, since a study at the mature stage may also be required. More variation in QTL number and effect was observed relating to height increment than to total height, indicating significant differences in gene expression during the growth periods involved.
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| 4. |
- Lerceteau, Estelle, et al.
(författare)
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Properties of AFLP markers in inheritance and genetic diversity studies of Pinus sylvestris L.
- 1999
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Ingår i: Heredity. - : BLACKWELL SCIENCE LTD. - 0018-067X .- 1365-2540. ; 82:3, s. 252-260
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Tidskriftsartikel (refereegranskat)abstract
- We analysed the properties of AFLP markers in Pinus sylvestris. Using primers with three selective nucleotides, the AFLP protocol produced large numbers of amplified bands and could only be used with a restricted number of primer combinations. Replacement of the EcoRI + 3 primer by an EcoRI + 4 primer halved the number of bands, facilitating analysis. The inheritance of all but about 8.4% of the amplified bands has been confirmed to be Mendelian. We compared band patterns among selected P. sylvestris trees from northern Sweden, two Asian species of Pinus and one species from the genus Picea. The dendrogram obtained was generally concordant with the taxonomic data, although the genetic similarity values between trees from different genera did not entirely follow accepted inter- and intraspecific relationships. This deviation was less pronounced using primer combinations that generated fewer bands. More than 69.1% of the bands that were polymorphic in two P. sylvestris trees or 29 of their F-1 progeny were in a pseudo-testcross configuration and thus were useful for the development of a linkage map for each parent. These markers have been analysed in four other crosses, and 83% of the bands could be mapped in at least one cross. Depending on the level of heterozygosity of the parents, the efficiency of such mapping will vary, but the AFLP technique appears to be a powerful way to generate, very quickly, large numbers of markers that are useful for constructing and comparing linkage maps.
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