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Mapping QTL associated with Verticillium dahliae resistance in the cultivated strawberry (Fragaria × ananassa).

Antanaviciute L, Šurbanovski N, Harrison N, McLeary KJ, Simpson DW, Wilson F, Sargent DJ, Harrison RJ - Hortic Res (2015)

Bottom Line: Average wilt scores were significantly associated with multiple QTL, which were mostly significant across all years.A clear and statistically significant relationship was observed between resistant, tolerant and susceptible material and the total number of markers present in the different resistance classes.These markers are abundant in the cultivated strawberry germplasm indicating that, despite the large number of markers, clear genetic gain is possible through marker-assisted breeding.

View Article: PubMed Central - PubMed

Affiliation: East Malling Research, New Road, East Malling , Kent ME19 6BJ, UK.

ABSTRACT
A biparental cross of octoploid strawberry segregating for resistance to Verticillium dahliae, the causative agent of Verticillium wilt, was screened under field conditions for three seasons. Average wilt scores were significantly associated with multiple QTL, which were mostly significant across all years. Markers significantly associated with the traits were used to screen material with known wilt resistance and susceptibility phenotypes. A clear and statistically significant relationship was observed between resistant, tolerant and susceptible material and the total number of markers present in the different resistance classes. In field situations resistance QTL appear to behave in an additive manner. These markers are abundant in the cultivated strawberry germplasm indicating that, despite the large number of markers, clear genetic gain is possible through marker-assisted breeding.

No MeSH data available.


Related in: MedlinePlus

Plot of the relationship between mean wilt score of individuals binned by marker number (error bars are 95% confidence intervals), for phenotypic data of three years (minimum of ten individuals per bin). A clear and consistent increase in wilt resistance is seen across all years with increasing marker number. However, the level of wilt resistance observed depends upon the disease pressure for that year. 2009 was the most severe year for disease, followed by 2011 and then 2010. For comparison mean wilt scores of ‘Redgauntlet’ and ‘Hapil’ in 2009 were 3.1 and 8.1, respectively). Linear regression analysis of the relationship was performed and the gradient and intercept are shown for each year.
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fig6: Plot of the relationship between mean wilt score of individuals binned by marker number (error bars are 95% confidence intervals), for phenotypic data of three years (minimum of ten individuals per bin). A clear and consistent increase in wilt resistance is seen across all years with increasing marker number. However, the level of wilt resistance observed depends upon the disease pressure for that year. 2009 was the most severe year for disease, followed by 2011 and then 2010. For comparison mean wilt scores of ‘Redgauntlet’ and ‘Hapil’ in 2009 were 3.1 and 8.1, respectively). Linear regression analysis of the relationship was performed and the gradient and intercept are shown for each year.

Mentions: In order to understand whether there were effects of QTL significant in only one year or across multiple years, an analysis was carried out where the mapping population was binned into groups containing up to two markers, three markers, all the way to nine markers, ensuring a minimum of ten genotypes per bin. Markers for which the presence allele was in coupling with the QTL were selected, as these were the only markers considered suitable for validation of QTL in the wider germplasm. In several cases (those marked with a suffix M1 in Table 2) these were not the most strongly associated marker with the QTL. 95% confidence intervals were calculated for the average phenotypic wilt scores in each bin by non-parametric bootstrapping within binned groups of individuals. A clear linear decline in disease susceptibility was observed with the increase in number of wilt markers, per genotypic bin (Figure 6). This was observed across all years, with the gradient of the slope and the intercept on the y axis both associated with the level of disease pressure in that year. Hence, the slope was steepest in 2009, then 2011 and last 2010, which was the year with the lowest disease pressure.


Mapping QTL associated with Verticillium dahliae resistance in the cultivated strawberry (Fragaria × ananassa).

Antanaviciute L, Šurbanovski N, Harrison N, McLeary KJ, Simpson DW, Wilson F, Sargent DJ, Harrison RJ - Hortic Res (2015)

Plot of the relationship between mean wilt score of individuals binned by marker number (error bars are 95% confidence intervals), for phenotypic data of three years (minimum of ten individuals per bin). A clear and consistent increase in wilt resistance is seen across all years with increasing marker number. However, the level of wilt resistance observed depends upon the disease pressure for that year. 2009 was the most severe year for disease, followed by 2011 and then 2010. For comparison mean wilt scores of ‘Redgauntlet’ and ‘Hapil’ in 2009 were 3.1 and 8.1, respectively). Linear regression analysis of the relationship was performed and the gradient and intercept are shown for each year.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595976&req=5

fig6: Plot of the relationship between mean wilt score of individuals binned by marker number (error bars are 95% confidence intervals), for phenotypic data of three years (minimum of ten individuals per bin). A clear and consistent increase in wilt resistance is seen across all years with increasing marker number. However, the level of wilt resistance observed depends upon the disease pressure for that year. 2009 was the most severe year for disease, followed by 2011 and then 2010. For comparison mean wilt scores of ‘Redgauntlet’ and ‘Hapil’ in 2009 were 3.1 and 8.1, respectively). Linear regression analysis of the relationship was performed and the gradient and intercept are shown for each year.
Mentions: In order to understand whether there were effects of QTL significant in only one year or across multiple years, an analysis was carried out where the mapping population was binned into groups containing up to two markers, three markers, all the way to nine markers, ensuring a minimum of ten genotypes per bin. Markers for which the presence allele was in coupling with the QTL were selected, as these were the only markers considered suitable for validation of QTL in the wider germplasm. In several cases (those marked with a suffix M1 in Table 2) these were not the most strongly associated marker with the QTL. 95% confidence intervals were calculated for the average phenotypic wilt scores in each bin by non-parametric bootstrapping within binned groups of individuals. A clear linear decline in disease susceptibility was observed with the increase in number of wilt markers, per genotypic bin (Figure 6). This was observed across all years, with the gradient of the slope and the intercept on the y axis both associated with the level of disease pressure in that year. Hence, the slope was steepest in 2009, then 2011 and last 2010, which was the year with the lowest disease pressure.

Bottom Line: Average wilt scores were significantly associated with multiple QTL, which were mostly significant across all years.A clear and statistically significant relationship was observed between resistant, tolerant and susceptible material and the total number of markers present in the different resistance classes.These markers are abundant in the cultivated strawberry germplasm indicating that, despite the large number of markers, clear genetic gain is possible through marker-assisted breeding.

View Article: PubMed Central - PubMed

Affiliation: East Malling Research, New Road, East Malling , Kent ME19 6BJ, UK.

ABSTRACT
A biparental cross of octoploid strawberry segregating for resistance to Verticillium dahliae, the causative agent of Verticillium wilt, was screened under field conditions for three seasons. Average wilt scores were significantly associated with multiple QTL, which were mostly significant across all years. Markers significantly associated with the traits were used to screen material with known wilt resistance and susceptibility phenotypes. A clear and statistically significant relationship was observed between resistant, tolerant and susceptible material and the total number of markers present in the different resistance classes. In field situations resistance QTL appear to behave in an additive manner. These markers are abundant in the cultivated strawberry germplasm indicating that, despite the large number of markers, clear genetic gain is possible through marker-assisted breeding.

No MeSH data available.


Related in: MedlinePlus