Articles
GENETIC ANALYSIS OF DOWNY MILDEW RESISTANCE DERIVED FROM MUSCADINIA ROTUNDIFOLIA
Article number
603_57
Pages
451 – 456
Language
English
Abstract
Bulked segregant analysis was employed to identify molecular markers linked to a gene that confers downy mildew resistance to the muscadine grape.
The level of resistance to downy mildew of a BC2 segregating population was estimated by visual notation after inoculation of leaves on whole plant.
The broad-sense heritability of the trait was estimated at 0.88. Polymorphism revealed with RAPD (151 primers), ISSR (13 primers) and SSR (208 loci) was screened between two bulks produced by separately pooling the individual DNAs from the six most resistant and the six most susceptible plants.
By analysis of variance, 1 RAPD, 4 ISSR and 8 SSR were shown to have a significant effect upon the level of resistance.
Twelve of these markers were mapped on the same linkage group and cover a 45 cM long region.
The identification of a QTL of resistance was confirmed by interval mapping.
This QTL accounted for 73 % of the observed variation and 83% of the genetic variation.
These results strongly suggest that the identified QTL corresponds to a unique major gene conditioning the muscadine grape downy mildew resistance, which we have named Rp1.Moreover, Rpv1 was shown to be tightly linked to the dominant gene confering resistance to powdery mildew, Run1.
The level of resistance to downy mildew of a BC2 segregating population was estimated by visual notation after inoculation of leaves on whole plant.
The broad-sense heritability of the trait was estimated at 0.88. Polymorphism revealed with RAPD (151 primers), ISSR (13 primers) and SSR (208 loci) was screened between two bulks produced by separately pooling the individual DNAs from the six most resistant and the six most susceptible plants.
By analysis of variance, 1 RAPD, 4 ISSR and 8 SSR were shown to have a significant effect upon the level of resistance.
Twelve of these markers were mapped on the same linkage group and cover a 45 cM long region.
The identification of a QTL of resistance was confirmed by interval mapping.
This QTL accounted for 73 % of the observed variation and 83% of the genetic variation.
These results strongly suggest that the identified QTL corresponds to a unique major gene conditioning the muscadine grape downy mildew resistance, which we have named Rp1.Moreover, Rpv1 was shown to be tightly linked to the dominant gene confering resistance to powdery mildew, Run1.
Authors
D. Merdinoglu, S. Wiedeman-Merdinoglu, P. Coste, V. Dumas, S. Haetty, G. Butterlin, C. Greif
Keywords
Muscadinia rotundifolia, Vitis vinifera, resistance, downy mildew, Plasmopara viticola, powdery mildew, molecular marker, genetic mapping.
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