Agriculture Reference
In-Depth Information
The most immediate threats to blackcurrant production are pest- or pathogen-
based. The blackcurrant gall mite (
Cecidophyopsis ribis
Westw.) causes rapid de-
cline in crop yields, partly due to its role as a vector of blackcurrant reversion virus
(BRV). This renders bushes sterile within two years. The incidence of mites has
risen in recent years, mainly due to the withdrawal of many control chemicals, and
the long-term sustainability of production depends largely on the development of
resistant cultivars. Sources of resistance to both the mite and the virus are available:
genes
Ce
from gooseberry (Knight et al.
1974
) and
P
from
R. nigrum
var.
sibiricum
(Anderson
1971
) both confer resistance to
C. ribis
, although the resistance conferred
by
Ce
is thought to be more robust. Molecular markers for
Ce
-based resistance are
routinely used for identification of new resistant seedlings (Brennan et al.
2009
),
and similar markers for gene
P
have been reported by Mazeikiene et al. (
2012
). BRV
resistance from
Ribes dikuscha
has been used by breeders, notably in the cultivars
'Golubka' and 'Ben Gairn', although the genetic control of resistance is unclear.
Foliar diseases of importance on blackcurrant include mildew (
Sphaerotheca
mors-uvae
), leafspot (
Drepanopeziza ribis
), Septoria leafspot (
Septoria ribis
) and
white pine blister rust (
Cronartium ribicola
). Resistance is available for most of
these diseases within the
Ribes
genepool, and increasingly breeders are focusing
on the production of resistant cultivars as chemical control methods become more
restricted (Brennan et al.
2008
).
The major pests of
Ribes
apart from gall mite include the leaf-curling midge
(
Dasineura tetensii
Rübs.), which has increased in importance and distribution in
recent years. Other problems are caused by clearwing (
Synanthedon tipuliformis
)
in many production areas, especially New Zealand, and sawfly (
Nematus ribesii
),
the latter being particularly serious on gooseberry. Many currant and gooseberry
growers are now looking into Integrated Pest and Disease Management strategies
for effective control of these problems.
Future Challenges and Opportunities
Environmental resilience is likely to become an important factor in the sustain-
ability of
Ribes
production, especially blackcurrant, in northern areas, due to the
reduced levels of chilling during recent winters. This has led to erratic budbreak in
some cultivars with a high chilling requirement, and if the trend continues as a result
of a changing climate then selection for more resilient cultivars will be required
(Jones et al.
2012
), although earlier budbreak has already increased the risk of frost
damage at flowering time in some northern areas.
The diverse array of health-beneficial compounds in
Ribes
fruits, especially
blackcurrant, gives opportunities for an expanded market for these fruits. Current
studies are looking at bioavailability of these compounds in human nutrition,
together with their activity against specific health issues.
Some emerging pest and disease problems require some attention from breeders;
blackcurrant clearwing (
Synanthedon tipuliformis
) has become a major problem in
New Zealand on all currants and may already be found in drier and warmer areas
of Europe; and stem dieback caused by
Phomopsis
spp. is increasingly problem-
