Code:
OIV
453
Name: Cluster: degree of resistance to downy mildew
Category:
,
GROUP OF CHARACTERISTICS,
ORGAN
Subcategory:
DOWNY MILDEW,
BIOTIC RESISTANCE - FUNGUS,
BUNCH
Code: OIV 453
Name: Cluster: degree of resistance to downy mildew
Category: , GROUP OF CHARACTERISTICS, ORGAN
Subcategory: DOWNY MILDEW, BIOTIC RESISTANCE - FUNGUS, BUNCH
Primay descriptor priority list
For a quick characterisation of varieties the Genres CT 96 No81 - partners compiled a Primary description priority list. The list encompasses 14 priority one primary descriptors. The chosen descriptors show a good discriminating power between varieties. Most of them are easy to score.
Description
The resistance of grapevine varieties to downy mildew (Plasmopara viticola) is to be observed under field trials over several years without the use of chemical plant protection and/or resistance inductors. The different mildew symptoms are to be assessed on all the clusters from 4 – 6 vines in two stages, if possible: about 3 weeks after the flowering onset and before veraison. 1 to 3 = A very high percentage – if not all – of clusters strongly affected or killed with serious consequences for the vintage. 5 = 20-30 % of clusters attacked with distinct consequences for the vintage. 7 to 9 = No attack or only some clusters slightly attacked without consequence for the vintage. Notes 3 and 7 can be applied when assessment is difficult. The symptoms should be evaluated considering the climatic conditions, that could influence the evolution of the disease, and, possibly, on plants without any biotic or abiotic stresses.Level expression
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