5 research outputs found
Downy mildew resistance evaluation in 28 grapevine hybrids promising for breeding programs in Trentino region (Italy)
Downy mildew is a major grapevine disease
caused by the biotrophic oomycete, Plasmopara
viticola. Numerous disease resistance studies of diverse
Vitis germplasm have been previously carried out to
identify downy mildew resistance sources; however,
ratings were mainly reported using leaf disc in vitro
testing and foliage field assessment, or upon leaf and
cluster field evaluations. In the current study, 28 grapevine
hybrid cultivars were screened using leaf disc bioassay,
for disease resistance characterization of both
existing and wild-collected materials. 16 hybrids were
identified as highly resistant or resistant, and will serve
as relevant resistance donors in future pre-breeding and
breeding programs. All grapevine hybrids were evaluated
for foliar and cluster downy mildew resistance in an
untreated field trial over three successive years. This
study showed that the leaf disc bioassay provided some
information on the resistance level of the genotypes
under scrutiny, but it was a weak predictor of their
resistance level under field conditions on leaves and
even more on bunches. These findings are relevant to
future applications in both traditional and marker-assisted
breeding programs which promote sustainable
viticulture