ISHS Acta Horticulturae 585: VIII International Rubus and Ribes Symposium
BLACKCURRANT RESEARCH TRIALS IN THE PROVINCE OF QUEBEC, CANADA WITH SPECIAL REFERENCE TO FOLIAR DISEASES |
| Authors: | H. Rousseau, M. Roy, J. Coulombe |
| Keywords: | White pine blister rust, powdery mildew, cultivar collection, agronomy trials, Cronartium ribicola, Drepanopeziza ribis, Sphaerotheca mors-uvae |
| Abstract:
The commercially grown cvs. ‘Ben Alder’, ‘Ben Lomond’, ‘Ben Nevis’, ‘Ben Sarek’ and ‘Titania’ were evaluated along with 39 cultivars and selections from the Canadian Clonal Genebank and 45 selections from IRDA Breeding Program. White Pine Blister Rust (WPBR) was the most prominent disease causing severe defoliation of most cultivars investigated. Amidst commercial cultivars, ‘Ben Alder’ was the most affected with 63 % of the under leaf surface covered with uredinia by mid-August, a few days following harvest. Cv. ‘Ben Lomond’ showed an intermediate susceptibility with 24 % of the leaves affected. Cvs. ‘Ben Nevis’ and ‘Ben Sarek’ expressed a high level of resistance with only 5 % of the leaves affected and cv. ‘Titania’ was rust resistant. Seven of the cultivars from the Canadian Clonal Genebank and 21 of our selections were rust resistant. Powdery mildew, grey mould, anthracnose and septoria leaf spots were also present in the fields at degrees that did not necessitate fungicide treatments. Plant spacing at 55, 70, 85 and 100 cm within rows for both cvs. ‘Ben Alder’ and ‘Ben Lomond’ were compared. For cv. ‘Ben Alder’, yield per bush did not vary but it improved for cv. ‘Ben Lomond’ with increased plant spacing. Mean weights of fruit did not vary with these spacings (for cv. ‘Ben Alder’ 105 g; for cv. ‘Ben Lomond’ 163 g). At bud break, many fields remain covered with snow and as a result, machine pruning while plants are still dormant proved difficult. Machine pruning in autumn was compared to machine pruning in spring. Although machine pruning in autumn did not reduce subsequent yield, we observed a decrease in the incidence of foliar diseases with machine pruning in the spring. | |
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