2 research outputs found
Quantitative trait loci affecting pathogen resistance and ripening of grapevines
Grapevines (Vitis vinifera L.) form the basis of
viticulture, and are susceptible to diseases such as downy
mildew (Plasmopara viticola) and powdery mildew (Erysiphe necator). Therefore, successful viticulture programs
require the use of pesticides. Breeding for resistance is the
only eco-friendly solution. Marker-assisted selection is currently widely used for grapevine breeding. Consequently,
traits of interest must be tagged with molecular markers
linked to quantitative trait loci (QTL). We herein present
our findings regarding genetic mapping and QTL analysis of resistance to downy and powdery mildew diseases
in the progenies of the GF.GA-47-42 (‘Bacchus’ × ‘Seyval’) × ‘Villard blanc’ cross. Simple sequence repeats and
single nucleotide polymorphisms of 151 individuals were
analyzed. A map consisting of 543 loci was screened for
QTL analyses based on phenotypic variations observed in
plants grown in the field or under controlled conditions. A
major QTL for downy mildew resistance was detected on
chromosome 18. For powdery mildew resistance, a QTL was identified on chromosome 15. This QTL was replaced
by a novel QTL on chromosome 18 in 2003 (abnormally
high temperatures) and 2004. Subsequently, both QTLs
functioned together. Additionally, variations in the timing of the onset of veraison, which is a crucial step during
grape ripening, were studied to identify genomic regions
affecting this trait. A major QTL was detected on linkage
group 16, which was supplemented by a minor QTL on
linkage group 18. This study provides useful information
regarding novel QTL-linked markers relevant for the breeding of disease-resistant grapevines adapted to current climatic conditions