Variety breeding and selection in the British Isles is all run from the Scottish Crop Research Institute at Invergowrie near Dundee.
“We now routinely select varieties with increased levels of anthocyanins, especially delphinidins, which give the blackcurrant fruit and juice its rich purple colour. Some older varieties are relatively low in anthocyanins, but more recent varieties such as ‘Ben Alder’ are particularly high in these compounds, which are thought to confer major health benefits to the consumer. Future varieties will extend this attribute even further, since high anthocyanin content is one of the core characteristics sought by the blackcurrant industry, for both natural colour and health reasons. By combining high levels of desirable anthocyanins with good colour stability in the juice, the currently available varieties offer consumers and producers the ideal berry for healthy products.”
Dr Rex Brennan, Fruit Breeding Group Director.
The mainstay of the blackcurrant industry for many years was the variety `Baldwin’. Of unknown origin, `Baldwin’ is thought to be over 150 years old, and whilst generally outclassed now in terms of agronomic performance, it is still grown on a reduced scale today. `Baldwin’ has a mild flavour, and reasonable levels of vitamin C, but it is very susceptible to many foliar diseases, including mildew, and the flowers are extremely sensitive to damage by spring frosts. There are several other very old varieties that can still be found in small quantities today, including `Lee’s Prolific’ (from 1860), `Boskoop Giant’ (1880) and `Wellington XXX’ (1913).
The first of the `Ben’ varieties bred at the Scottish Crop Research Institute was `Ben Lomond’, released in 1975. This variety still occupies a significant proportion of the UK acreage, and was released as a high-yielding type with delayed flowering to avoid damaging spring frosts at flowering time. This was achieved by the introduction of plant material from Northern Scandinavia into the SCRI programme, thereby combining high yield potential and consistency. The introduction of `Ben Lomond’ into commercial blackcurrant growing was a pivotal event in the development of modern blackcurrant varieties, and for many years `Ben Lomond’ was the leading UK variety in both acreage and performance. `Ben Lomond’ has a high winter chilling requirement, and its performance in southern parts of England may be affected after mild winters. Although resistant to mildew when released, `Ben Lomond’ is now highly susceptible to this disease.
Released in 1989, Ben Alder offers very high levels of anthocyanins, together with a typical blackcurrant flavour. From a cross between `Ben More’ and `Ben Lomond’, this variety also has a more upright habit that is more amenable to mechanical harvesting. It has fairly small berries, held close to the stems, and again has later flowering, like `Ben Lomond’.
The late flowering character is most obvious in the variety `Ben Tirran’, released in 1990. From a complex cross involving the old variety `Seabrooks Black’, `Ben Lomond’ and SCRI hybrids with some redcurrant ancestry, `Ben Tirran’ is the latest of all the `Ben’ varieties in both flowering and ripening. It is fairly high in vitamin C, and its later ripening provides a means of extending the harvest. Yields of `Ben Tirran’ are consistently high throughout the UK.
`Ben Hope’ was released in 1998, because of its high yields, good flavour profile and especially because of its reduced susceptibility to gall mite (`big bud’). Estimates made in field trials at East Malling Research have shown `Ben Hope’ to be up to 30 times more resistant to gall mite than other commonly-available varieties, making `Ben Hope’ a valuable asset at a time when control measures for gall mite are increasingly limited. The variety derives from a complex cross, including `Westra’ (a form of the old variety `Westwick Choice’, but with a very upright habit that is passed on to `Ben Hope’) and a hybrid with some gooseberry ancestry (from whence the relative resistance to gall mite is obtained). There are several hybrids from SCRI with complete resistance to gall mite currently in trials, but at the present time the combination of positive characteristics mean that `Ben Hope’ is the most widely-grown variety in the UK and throughout Europe, for both large-scale commercial growing and gardens.
`Ben Gairn’, also released in 1998, is the only current UK variety with resistance to reversion virus, a disease which renders the plant sterile and therefore non-fruiting. The resistance is derived from a Russian variety, `Golubka’, which was crossed at SCRI with `Ben Alder’ to produce `Ben Gairn’, and should enable the life expectancy of plants and plantations to be extended. This variety is very early in both flowering and ripening.
`Ben Avon’ and `Ben Dorain’ are sister seedlings from a cross between `Ben Alder’ and `Ben Lomond’, giving high yields, upright growth habit and very good fruit/juice quality. Released in 2003, these varieties show differences in their local adaptation, so that `Ben Dorain’ performed best in trials in the West Midlands and Scotland, whilst `Ben Avon’ was better in East Anglia. The higher vitamin C content of these varieties makes them useful alternatives to `Ben Alder’ and `Ben Tirran’.
In addition to varieties bred for the commercial juicing market, there are several varieties bred at SCRI for the PYO and amateur markets. For these markets, growth habit and juice quality is not as crucial as for processing, and there is a preference for large berries with sweeter flavour. The main varieties are `Ben Sarek’, `Ben Connan’ and the as yet-unreleased `Big Ben’; the latter is currently in trials within Europe including at the Royal Horticultural Society, and has the largest and sweetest berries compared to other types. `Ben Sarek’ and `Ben Connan’ both have reasonable habit and high yields.
At the moment, the most widely grown and popular variety for home growing is 'Ben Hope'.