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ABSTRACT: Bulked segregant analysis combined with AFLPs was used to identify molecular markers linked to the Rca2 gene conferring resistance to Colletotrichum acutatum pathogenicity group 2 which causes anthracnose in the octoploid strawberry Fragaria×ananassa. DNA bulks originating from a cross between the resistant cultivar ‘Capitola’ and the susceptible cultivar ‘Pajaro’ were
screened with 110 EcoRI/MseI AFLP combinations. Four AFLP markers were found linked in coupling phase to Rca2 with recombination percentages between 0% and 17.7%. Among the four markers linked to the resistance gene, two were converted
into SCAR markers (STS-Rca2_417 and STS-Rca2_240) and screened in a large segregating population including 179 genotypes.
The Rca2 resistance gene was estimated to be 0.6cM from STS-Rca2_417 and 2.8cM from STS-Rca2_240. The presence/absence of the two
SCAR markers was further studied in 43 cultivars of F.×ananassa, including 14 susceptible, 28 resistant, and one intermediate genotype. Results showed that 81.4% and 62.8% of the resistant/susceptible
genotypes were correctly predicted by using STS-Rca2_417 and STS-Rca2_240, respectively. The 14 susceptible genotypes showed
no amplification for either SCARs. These developed SCARs constitute new tools for indirect selection criteria of anthracnose
resistance genotypes in strawberry breeding programs.
Theoretical and Applied Genetics 04/2012; 111(5):862-870. · 3.30 Impact Factor
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ABSTRACT: Fruit quality traits are major breeding targets in the Rosaceae. Several of the major Rosaceae species are current or ancient polyploids. To dissect the inheritance of fruit quality traits in polyploid fleshy fruit species, we used a cultivated strawberry segregating population comprising a 213 full-sibling F1 progeny from a cross between the variety 'Capitola' and the genotype 'CF1116'. We previously developed the most comprehensive strawberry linkage map, which displays seven homoeology groups (HG), including each four homoeology linkage groups (Genetics 179:2045-2060, 2008). The map was used to identify quantitative trait loci (QTL) for 19 fruit traits related to fruit development, texture, colour, anthocyanin, sugar and organic acid contents. Analyses were carried out over two or three successive years on field-grown plants. QTL were detected for all the analysed traits. Because strawberry is an octopolyploid species, QTL controlling a given trait and located at orthologous positions on different homoeologous linkage groups within one HG are considered as homoeo-QTL. We found that, for various traits, about one-fourth of QTL were putative homoeo-QTL and were localised on two linkage groups. Several homoeo-QTL could be detected the same year, suggesting that several copies of the gene underlying the QTL are functional. The detection of some other homoeo-QTL was year-dependent. Therefore, changes in allelic expression could take place in response to environmental changes. We believe that, in strawberry as in other polyploid fruit species, the mechanisms unravelled in the present study may play a crucial role in the variations of fruit quality.
Theoretical and Applied Genetics 01/2012; 124(6):1059-77. · 3.30 Impact Factor
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ABSTRACT: Bulked segregant analysis combined with AFLPs was used to identify molecular markers linked to the Rca 2 gene conferring resistance to Colletotrichum acutatum pathogenicity group 2 which causes anthracnose in the octoploid strawberry Fragaria x ananassa. DNA bulks originating from a cross between the resistant cultivar 'Capitola' and the susceptible cultivar 'Pajaro' were screened with 110 EcoRI/M se IAFLP combinations. Four AFLP markers were found linked in coupling phase to Rca 2 with recombination percentages between 0% and 17.7%. Among the four markers linked to the resistance gene, two were converted into SCAR markers (STS-Rca 2417 and STS-Rca 2240) and screened in a large segregating population including 179 genotypes. The Rca 2 resistance gene was estimated to be 0.6 cM from STS-Rca 2417 and 2.8 cM from STS-Rca 2240. The presence/absence of the two SCAR markers was further studied in 43 cultivars of F. x ananassa, including 14 susceptible, 28 resistant, and one intermediate genotype. Results showed that 81.4% and 62.8% of the resistant/susceptible genotypes were correctly predicted by using STS-Rca 2417 and STS-Rca 2240, respectively. The 14 susceptible genotypes showed no amplification for either SCARs. These developed SCARs constitute new tools for indirect selection criteria of anthracnose resistance genotypes in strawberry breeding programs.
Theoretical and Applied Genetics 10/2005; 111(5):862-70. · 3.30 Impact Factor
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ABSTRACT: A two-way pseudo-testcross strategy, combined with Single Dose Restriction Fragment (SDRF) marker analysis, was used for genetic mapping in the octoploid cultivated strawberry Fragaria x ananassa (2n = 8 x = 56). Based on a 113 full-sib progeny from a cross between the variety Capitola and the clone CF1116, we generated two parental maps using Amplified Fragment Length Polymorphism (AFLP) markers. Ninety two percent of the markers (727 out of 789) showed ratios corresponding to simplex markers (the majority being SDRF markers), and 8% (62 out of 789) fitted a multiplex ratio. Linkage maps were first established using SDRF markers in coupling phase. The female map comprised 235 markers distributed among 43 co-segregation groups, giving a map size of 1,604 cM. On the male map, 280 markers were assigned to 43 co-segregation groups, yielding a map size of 1,496 cM. Once the co-segregation groups were established, their association was tested using repulsion-phase markers. In total, taking into account associations representing the same linkage groups, 30 linkage groups were detected on the female side and 28 on the male side. On the female map, 68.3% of the pairwise marker linkages were in coupling versus 31.7% in repulsion phase, and the corresponding figures on the male map were 72.2% and 27.8%, respectively. In addition, both groups linked only in the coupling phase and groups linked in the repulsion phase were characterized. The observations suggest that the meiotic behavior of the F. x ananassa genome is neither fully disomic nor fully polysomic, but rather mixed. The genome may not be as completely diploidized as previously assumed.
Theoretical and Applied Genetics 09/2003; 107(4):619-28. · 3.30 Impact Factor
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ABSTRACT: A two-way pseudo-testcross strategy, combined with Single Dose Restriction Fragment (SDRF) marker analysis, was used for genetic mapping in the octoploid cultivated strawberry Fragaria × ananassa (2n = 8 x = 56). Based on a 113 full-sib progeny from a cross between the variety Capitola and the clone CF1116, we generated two parental maps using Amplified Fragment Length Polymorphism (AFLP) markers. Ninety two percent of the markers (727 out of 789) showed ratios corresponding to simplex markers (the majority being SDRF markers), and 8% (62 out of 789) fitted a multiplex ratio. Linkage maps were first established using SDRF markers in coupling phase. The female map comprised 235 markers distributed among 43 co-segregation groups, giving a map size of 1,604 cM. On the male map, 280 markers were assigned to 43 co-segregation groups, yielding a map size of 1,496 cM. Once the co-segregation groups were established, their association was tested using repulsion-phase markers. In total, taking into account associations representing the same linkage groups, 30 linkage groups were detected on the female side and 28 on the male side. On the female map, 68.3% of the pairwise marker linkages were in coupling versus 31.7% in repulsion phase, and the corresponding figures on the male map were 72.2% and 27.8%, respectively. In addition, both groups linked only in the coupling phase and groups linked in the repulsion phase were characterized. The observations suggest that the meiotic behavior of the F. × ananassa genome is neither fully disomic nor fully polysomic, but rather mixed. The genome may not be as completely diploidized as previously assumed.
Theoretical and Applied Genetics - THEOR APPL GENET. 01/2003; 107(4):619-628.
