Articles
CLONAL SELECTION IN GRAPEVINE: INTERACTIONS BETWEEN GENETIC AND SANITARY STRATEGIES TO IMPROVE PROPAGATION MATERIAL
Article number
528_106
Pages
703 – 712
Language
Abstract
Clonal selection is considered a very important tool for grapevine genetic improvement.
The best results are obtained when sanitary and genetic selection are carried out at the same time in order to propagate only clones naturally free from harmful viruses or made virus-free by artificial techniques.
Clonal selection is based on genetic variability within cultivars.
Possible explanations of this variability may be the polyclonal origin of cultivars and the accumulation of genetic mutations in their genotypes.
On the other hand, virus diseases contribute to increase the phenotypical variability within grapevine populations.
How much of the phenotypical variability within a population is due to genotype and how much to virus presence is still not clear.
Experiments showing that morphological and agronomical differences among clones exist regardless of their virological status are discussed in the paper.
However, many evidences are reported confirming that the overall performances of clones are improved after sanitation.
In general, vegetative vigour is always increased, whereas all the other parameters are modified depending on the virus.
Up to now, the best results were achieved by GLRaVs eradication.
Healthy vines showed higher physiological activity than infected plants of the same clone, once free from GLRaV-3 as well as from GLRaV-1. The grape quality was enhanced without any yield increase by eliminating GLRaV-3 and also wine quality was improved according to sensory evaluations.
In the case of GLRaV-1 elimination, yield was increased without penalizing quality parameters.
On the contrary, the advantages of GFLV artificial sanitation are more questionable due to the consequent dramatic increase of vine vigour.
In order to maintain the existing genetic variability within a cultivar, a clonal selection methodology not only based on sanitation approaches is highly recommended.
Nevertheless the clonal material has to be free from viruses such as GFLV, GLRaV-1, GLRaV-3 and GVA whose detrimental effects are clearly demonstrated.
However the presence of other ‘minor’ viruses might be accepted in the clonal material in order to allow a greater impact of genetic selection.
The best results are obtained when sanitary and genetic selection are carried out at the same time in order to propagate only clones naturally free from harmful viruses or made virus-free by artificial techniques.
Clonal selection is based on genetic variability within cultivars.
Possible explanations of this variability may be the polyclonal origin of cultivars and the accumulation of genetic mutations in their genotypes.
On the other hand, virus diseases contribute to increase the phenotypical variability within grapevine populations.
How much of the phenotypical variability within a population is due to genotype and how much to virus presence is still not clear.
Experiments showing that morphological and agronomical differences among clones exist regardless of their virological status are discussed in the paper.
However, many evidences are reported confirming that the overall performances of clones are improved after sanitation.
In general, vegetative vigour is always increased, whereas all the other parameters are modified depending on the virus.
Up to now, the best results were achieved by GLRaVs eradication.
Healthy vines showed higher physiological activity than infected plants of the same clone, once free from GLRaV-3 as well as from GLRaV-1. The grape quality was enhanced without any yield increase by eliminating GLRaV-3 and also wine quality was improved according to sensory evaluations.
In the case of GLRaV-1 elimination, yield was increased without penalizing quality parameters.
On the contrary, the advantages of GFLV artificial sanitation are more questionable due to the consequent dramatic increase of vine vigour.
In order to maintain the existing genetic variability within a cultivar, a clonal selection methodology not only based on sanitation approaches is highly recommended.
Nevertheless the clonal material has to be free from viruses such as GFLV, GLRaV-1, GLRaV-3 and GVA whose detrimental effects are clearly demonstrated.
However the presence of other ‘minor’ viruses might be accepted in the clonal material in order to allow a greater impact of genetic selection.
Authors
F. Mannini
Keywords
Grapevine, clone, virus, heat-treatment, yield, must, wine
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