1.
Denoyes-Rothan, B, et al.
(författare)
QTL analysis for resistances to Colletotrichum acutatum and Phytophthora cactorum in octoploid strawberry (Fragaria x ananassa)
2004
Ingår i: Proceedings of the XIth Eucarpia Symposium on Fruit Breeding and Genetics, Vols 1 and 2. - : INTERNATIONAL SOCIETY HORTICULTURAL SCIENCE. ; , s. 147-151
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.
2.
Gavrilets, Sergey, et al.
(författare)
The evolution of female mate choice by sexual conflict
2001
Ingår i: Proceedings of the Royal Society of London Series B. - London : The Roylal Society. - 0080-4649 .- 0962-8452 .- 1471-2954. ; 268:1466, s. 531-539
Tidskriftsartikel (refereegranskat) abstract
Although empirical evidence has shown that many male traits have evolved via sexual selection by female mate choice, our understanding of the adaptive value of female mating preferences is still very incomplete. It has recently been suggested that female mate choice may result from females evolving resistance rather than attraction to males, but this has been disputed. Here, we develop a quantitative genetic model showing that sexual conflict over mating indeed results in the joint evolution of costly female mate choice and exaggerated male traits under a wide range of circumstances. In contrast to traditional explanations of costly female mate choice, which rely on indirect genetic benefits, our model shows that mate choice can be generated as a side–effect of females evolving to reduce the direct costs of mating.
3.
Lerceteau, Estelle, et al.
(författare)
AFLP mapping and detection of quantitative trait loci (QTLs) for economically important traits in Pinus sylvestris : a preliminary study
2000
Ingår i: Molecular breeding. - : KLUWER ACADEMIC PUBL. - 1380-3743 .- 1572-9788. ; 6:5, s. 451-458
Tidskriftsartikel (refereegranskat) abstract
We have applied a two-way pseudo-testcross strategy in an analysis of Pinus sylvestris for genetic mapping and detection of quantitative trait loci (QTLs) associated with economically important traits targeted in the Swedish tree-breeding programme. Based on 94 full-sib progeny of a cross between two plus-trees from northern Sweden we generated two parental maps using AFLP markers. The female map was comprised of 94 markers assigned to 15 linkage groups giving a size of 796 cM. On the male map 155 markers were assigned to 15 linkage groups, giving a total size of 1335 cM. The recombination frequency was found to be sex-dependent, being 29.3% higher in male than in female gametes. On the female map, 12 QTLs were detected (but none for branch diameter or wood density). Three QTLs for tree height accounted for 25.8% of the total phenotypic variation of this trait. When the QTLs detected for all the traits were taken independently, the percentages of phenotypic variance ranged from 9.3% to 22.7%. The highest value was observed for frost hardiness, an important trait in northern Sweden for which a major gene seemed to be involved. A cluster of QTLs for tree height, trunk diameter and volume was located on one linkage group. On the male map, four QTLs for trunk diameter and volume were detected. Due to the reduced number of individuals under study, the results are preliminary and have to be validated on more trees.
4.
Lerceteau, Estelle, et al.
(författare)
Detection of quantitative trait loci in Pinus sylvestris L. across years
2001
Ingår i: Euphytica. - : KLUWER ACADEMIC PUBL. - 0014-2336 .- 1573-5060. ; 121:2, s. 117-122
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.
5.
Lerceteau-Köhler, Estelle, et al.
(författare)
Characterization of mixed disomic and polysomic inheritance in the octoploid strawberry (Fragaria x ananassa) using AFLP mapping
2003
Ingår i: Theoretical and Applied Genetics. - : SPRINGER-VERLAG. - 0040-5752 .- 1432-2242. ; 107:4, s. 619-628
Tidskriftsartikel (refereegranskat) 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=8x=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.
6.
Lerceteau-Köhler, Estelle, et al.
(författare)
Development of a SCAR marker linked to dominant gene conferring resistance to Colletotrichum acutatum in strawberry (Fragaria x ananassa)
2003
Ingår i: BERRY CROP BREEDING, PRODUCTION AND UTILIZATION FOR A NEW CENTURY. - : INTERNATIONAL SOCIETY HORTICULTURAL SCIENCE. ; , s. 85-91
Konferensbidrag (refereegranskat) abstract
Colletotrichum acutatum is responsible for strawberry anthracnose, one of the main disease of cultivated strawberry in the south-western area of France (60% of the French production). Anthracnose is a polycyclic disease for which no efficient disease control method has been developed. Therefore, the development of cultivars with sustainable resistance, i.e. efficient against the two pathogenicity groups, may be promising to lower both the level of damage and the use of chemicals. The objective of this study is to identify molecular markers linked to the major dominant gene conferring resistance to pathogenicity group 2 by using an approach of Bulk Segregant Analysis (BSA) and Amplified Fragment Length Polymorphisin (AFLP) markers. We identified four molecular markers, named mf1 to mf4, linked to the resistance gene to the pathogenicity group 2 of C. acutatum. Within a segregating population (back cross type) for the dominant gene, no recombination between the resistance allele and the marker mf3 was detected in 78 BC1 individuals studied. One Sequence Characterized Amplified Region (SCAR) obtained from mf4 (SCAR-mf4) provided a fast and easy test for selection of anthracnose resistant plants at early stage, with a misidentification rate of 1.3%. The evaluation of this SCAR marker in few strawberry varieties showed that only some resistant varieties possessed this marker.
7.
Lerceteau-Köhler, Estelle, et al.
(författare)
QTL analysis for fruit quality traits and resistance to Colletotrichum acutatum and Phytophthora cactorum in octoploid strawberry (Fragaria x ananassa)
2004
Ingår i: PROCEEDINGS OF THE EURO BERRY SYMPOSIUM - COST 836 FINAL WORSKHOP. - : INT SOC HORTICULTURAL SCIENCE. ; , s. 93-97
Konferensbidrag (refereegranskat) abstract
Mapping of quantitative trait loci (QTL) controlling components of strawberry (Fragaria x ananassa Duch., 2n=8x=56) fruit quality and resistance to Colletotrichum acutatum and Phytophthora cactorum can be used to provide a better understanding of the genetic control of the traits, and to develop marker assisted selection for breeders. A segregating population of 213 individuals of a cross between ‘Capitola’ and ‘CF1116’, two genotypes with many contrasting fruit quality traits, was used for genetic mapping. ‘Capitola’ was resistant to the C. acutatum pathogenicity group 1 (pg1) and to P. cactorum while ‘CF1116’ was susceptible to C. acutatum and moderately susceptible to P. cactorum. Fruit quality was evaluated on a total of 34 traits, including developmental and fruit aspect related traits, texture related traits, fruit acidity, sugars, ascorbate and amino acid concentrations. Most of the traits except the amino acid concentrations were evaluated during two successive years. Disease responses to C. acutatum (pg2) and P. cactorum were evaluated using a scale from 0 (no observed symptom) to 5 (dead plant) in two successive independent experiments. Data were analysed for putative QTLs using MapQTL. For the fruit quality traits, a total of 22 significant QTLs were detected by simple interval mapping (LOD>3.0) in the first year of analyses and 17 were detected in the second year. Only two QTLs could be detected in both years. The percentages of phenotypic variance explained by each QTL ranged from 6.5% to 16.0%. For resistances, a total of nine QTLs was detected (LOD>2.0), 4 for resistance to C acutatum and 5 for resistance to P. cactorum with the percentage of variation explained by a QTL ranging from 6.5 to 12.2%. No QTL for the P. cactorum resistance overlapped the QTLs for the C acutatum resistance.
8.
Lerceteau-Köhler, Estelle, et al.
(författare)
QTL analysis for fruit quality traits in octoploid strawberry (Fragaria x ananassa)
2004
Ingår i: PROCEEDINGS OF THE XITH EUCARPIA SYMPOSIUM ON FRUIT BREEDING AND GENETICS, VOLS 1 AND 2. - : INT SOC HORTICULTURAL SCIENCE. ; , s. 331-335
Konferensbidrag (refereegranskat) abstract
Mapping of quantitative trait loci (QTL) controlling components of strawberry (Fragaria x ananassa Duch., 2n=8x=56) fruit quality can be used to provide a better understanding of their genetic control, and to develop marker assisted selection for breeders. For this purpose, a segregating population of 213 individuals of a cross between ‘Capitola’ and CF1116, two genotypes with many contrasting fruit quality traits, was used for genetic mapping. A total of 34 traits involved in fruit quality were evaluated, including developmental and fruit aspect related traits, texture related traits, fruit acidity, sugar and ascorbate concentrations. Amino acid concentrations were quantified using one-dimensional proton NMR spectroscopy. Most of the traits except the amino acid concentrations were evaluated during two successive years. A total of 22 significant QTLs were detected by simple interval mapping (LOD > 3.0) in year 1, four on the female map and 18 on the male map, whereas 17 were detected in year 2, ten on the female map and seven on the male map. Only two QTLs could be detected in both years. When removing the year effect, 22 QTLs were observed, eight on the female and 14 on the male map. The percentages of phenotypic variance explained by each QTL ranged from 6.5% to 16.0%.
9.
Lerceteau-Köhler, Estelle, et al.
(författare)
The use of molecular markers for durable resistance breeding in the cultivated strawberry (Fragaria x ananassa)
2002
Ingår i: PROCEEDINGS OF THE FOURTH INTERNATIONAL STRAWBERRY SYMPOSIUM, VOLS 1 AND 2. - : INTERNATIONAL SOCIETY HORTICULTURAL SCIENCE. ; , s. 615-618
Konferensbidrag (refereegranskat) abstract
In France, particularly in the southwestern area, most damage to the cultivated strawberry is anthracnose, caused by Colletotrichum acutatum. Anthracnose is a polycyclic disease for which no satisfactory disease control method has been developed. Therefore, the objective of our project is to construct durable resistance by combining the different genetic components of resistance to lower both the level of damage and the use of chemicals. Genetic components will be selected by using molecular markers linked to these loci. For monogenic resistance to the pathogenicity group 2 of C. acutatum, bulk segregant analysis (BSA) combined with the AFLP markers has been developed. Four markers were found linked to the dominant gene with a recombination percentage ranging from 0 to 13.9%. For complex resistance to the pathogenicity group 1 of C. acutatum, a linkage map has been constructed in order to detect putative QTLs associated with this complex resistance. The female map was comprised of 31 SDRF (Single Dose Restriction Fragment) markers assigned to 11 linkage groups giving a total size of 392.9 cM. On the male map, 52 SDRF markers mapped on 17 linkage groups giving a total size of 406.9 cM. The work is being continued with the addition of more markers on the maps.
10.
