Galling and reversion disease incidence in a range of blackcurrant genotypes, differing in resistance to the blackcurrant gall mite (Cecidophyopsis ribis) and blackcurrant reversion disease
At. Jones et al., Galling and reversion disease incidence in a range of blackcurrant genotypes, differing in resistance to the blackcurrant gall mite (Cecidophyopsis ribis) and blackcurrant reversion disease, ANN AP BIOL, 133(3), 1998, pp. 375-384
An assessment was made of the response of 10 blackcurrant genotypes, differ
ing in resistance to the agent of blackcurrant reversion disease (BRD) and
to its gall mite vector, in field trials in Scotland and Finland over 5 yr.
At each location, the 10 genotypes were planted in plots containing infect
or plants with high inoculum levels of the two organisms. In Scotland, the
infector plants contained large numbers of gall mites (Cecidophyopsis ribis
) and were infected with the European (E) form of BRD; in Finland, infector
plants contained a different species of gall mite (C. spicata) and the sev
ere Russian form (R) of BRD. As expected, at both sites, almost all plants
of cvs Ben Alder, Ben Lomond, Ben Tirran, Ojebyn and an SCRI selection F4/1
/66, which are susceptible to gall mite and BRD, became infested with each
of these organisms. However, in Scotland but not in Finland, 58% of cv. Oje
byn plants were affected by BRD. The cv. Foxendown, which contains gene Ce
that confers apparent immunity to C. ribis, was free from galls and failed
to develop distinctive BRD symptoms at both sites. The cvs Rus and Neosypaj
uscajaija, which contain gene P which is reported to confer resistance to C
. ribis, were infested more slowly by mites than the mite-susceptible genot
ypes and showed a smaller number of galls per plant. Also, they were infect
ed with BRD more slowly than some mite-susceptible genotypes although by th
e end of the experiment, most plants were affected by BRD. All plants of cv
s Golubka and Ben Gairn, which are resistant to the agent of BRD, remained
free from distinct BRD symptoms at both sites despite the fact that plants
contained galls. These data indicate the superiority of gene Ce over gene P
for resistance to gall mites with the added benefit that the virtual immun
ity to gall mites provided by gene Ce provides a high level of protection a
gainst infection with BRD. The relative merits of these different forms of
resistance to gall mites and BRD in blackcurrant are discussed in relation
to present control methods for these two organisms and in the light of rece
nt findings of different species of eriophyid mites on Ribes species.