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The influence of cultivar and isolate on the susceptibility of red raspberry canes to Didymella applanata
Author(s) -
PEPIN H. S.,
WILLIAMSON B.,
TOPHAM PAULINE B.
Publication year - 1985
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1985.tb03123.x
Subject(s) - cultivar , biology , plant stem , inoculation , shoot , horticulture , axillary bud , plant disease resistance , botany , explant culture , biochemistry , gene , in vitro
SUMMARY The internodes of young canes of a single red raspberry selection were inoculated in the field with 32 isolates of Didymella applanata from diverse localities throughout the British Isles. All isolates were pathogenic but differed in virulence estimated by lesion length; their origin and virulence were not related. Four petioles on young canes of seven cultivars were inoculated in the glasshouse with 13 of the isolates. The axillary buds at treated nodes were shorter and the emergence of lateral shoots was substantially less than at non‐inoculated nodes in all seven cultivars. Although there were significant cultivar × isolate interactions, these were small in comparison to the effects of inoculation, cultivar and position of the treated node. The cultivar × isolate interactions between eight cultivars and 14 isolates were also studied in the field by inoculation of petioles and the internodes of young canes. Joint regression analysis of bud and lesion lengths revealed significant cultivar × isolate interactions but no discontinuous variation in the expression of disease was found. A principal components analysis using % nodes infected, % reduction in bud length and % lateral shoot failure confirmed the relationship between these variates and gave three vectors. The first (83.3% of variation) named the ‘resistance’ vector described the relative resistance or susceptibility of cultivars, the second ‘tolerance’ vector (13.4%) described the variation due to relative tolerance or intolerance of these genotypes and the third a ‘bud response’ vector accounted for only 3.3% of the variation.