(Ribes nigrum)

History and background

A relative newcomer as a cultivated crop, European black currant is native to northern Europe and north and central Asia. The first historical reference to this fruit was in the 17th century, when it became known more as a medicinal fruit than one useful for culinary purposes. It was discovered to have a soothing effect on sore throats, which is now attributed to its high vitamin C content.

Unlike gooseberry, European black currant does not exhibit a wide range of attributes in either plant or fruit, but this is changing as plant breeders are looking at other ribes species to infuse resistance to a variety of plant diseases. The challenge is keeping the clear, crisp taste of the nigrum species. Black currant has become a popular and widely grown fruit in Europe but is relatively unknown in North America. Eaten fresh, it is an acquired taste, but its uses as an ingredient is almost limitless. Rich in color, nutrients and flavor, it can be used in sophisticated foods, drinks and desserts.

Black currant may be the most nutritious fruit of all. While most superfruits are high in specific nutrients, black currant is exceptional in the full range of nutritional components. Data from USDA (reference below) shows that volume-for-volume in terms of minerals compared to blueberry, it has nine times the calcium, five times the iron, four times the magnesium, nearly five times the phosphorous and four times the potassium; in terms of vitamins, it has 18 times the vitamin C and four times as much vitamin A. Black currant also has more than twice the anthocyanin content (second only to aronia) and twice the flavanols of blueberry. A study at the University of Glasglow (Borges et al, 2010) found that black currants had a higher antioxidant capacity and anthocyanin content than blueberries, rasperries, cranberries and red currants.

Observations at Carandale Farm

When selections were made 10 years ago for observation in the Carandale test plot, growers attempted to find cultivars representing a range of characteristics. Fruit and plant characteristics are not nearly as variable as they are for gooseberry, so four cultivars were considered adequate. Following is information and observations about the selections. All were planted in 2003.

‘Ben Lomand’ was selected for its reported high fruit quality and high content of vitamin C. As a bonus, it was also said to have winter hardiness, resistance to late-spring frosts, even ripening (good for machine harvesting), high yields, large fruit and long hang time. It was said to be susceptible to white pine blister rust, but somewhat resistant to powdery mildew and leaf spot diseases.

Observations verify most of these claims, except it does experience more defoliation than expected, indicating susceptibility to leaf spot. This is not unexpected, since resistance can vary from location to location and disease strains involved. ‘Ben Lomand’ has shown signs of white pine blister rust (WPBR) as advertised. Plants were received from Nourse Farms and adapted well. They have been high yielding and the fruit large, firm and uniformly ripening with an intense flavor. The plants are upright, 4-5 feet tall, and would be easy to machine harvest. Black currants have relatively high nutrient requirements. Plant vigor has declined somewhat in recent years, suggesting a need for more fertility. Fruit size, quality, yield, uniform ripening and ease of machine harvest all contribute to making ‘Ben Lomand’ a an economically sustainable fruit crop.

‘Ben Sarek’ was selected for trial because it was said to have a milder flavor more acceptable as a fresh fruit. It was also said to resist leaf spot, mildew and WPBR. It has been observed to have about the same amount of leaf defoliation from these diseases as ‘Ben Lomand’. Plants were received from Nourse Farms and adapted well. The bushes are small and compact, making them easy to manage. Yields are high for the size of the bush, but the overall yield is less than ‘Ben Lomand’ because of the bush size difference. The fruit is at least as large and perhaps somewhat larger than ‘Ben Lomand’. It is also milder when fully ripe, but probably not enough to make much difference. The fruit also has a tendency to drop when fully ripe, which would make machine harvesting more difficult.

A couple of years after planting, individual canes started showing blight symptoms. They would wilt without evidence of cane bore activity. ‘Ben Sarek’ seemed to be the only cultivar affected. After several years of diligent removal of affected canes, the plants seem to have recovered. ‘Ben Sarek’ has some good qualities as a home garden plant and perhaps for commercial pick-your-own, but its softer fruit, dropping tendency and smaller plant size (restricting yield) may limit it as an economically sustainable commercial fruit crop.

‘Titania’ was selected for testing because of its reported disease resistance. It is considered to be immune (or at least highly resistant) to WPBR and other leaf diseases. This reputation has been confirmed in the test plot. Plants were purchased from Nourse Farms. The plant is vigorous, reaching heights of 6 feet. It matures quickly. Fruit is large, similar to ‘Ben Lomand’, but has a milder flavor. Yield potential is high, and the bush is suitable for machine harvest. Flowering and ripening seasons are similar to ‘Ben Lomand’. The vigorous plants can be a bit unruly and branches can break form snow and fruit load.

‘Titania’ appears to be good all-around cultivar. It may not be outstanding in any particular area, but it has no significant flaws. It has the best blend of quality, flavor, sweetness and disease resistance of the four cultivars. It is also suitable for both hand and machine harvest and seems to have as much resistance to spring frosts as any cultivar tested. Observations indicate that ‘Titania’ could be an economically sustainable addition to an integrated planting system

‘Swedish Black’ was selected because it was said to be less acidic and sweeter than most other varieties while retaining a characteristic flavor. It was included to determine its potential for fresh consumption. Plants came from One Green World. They grew well the first season, but did not stool out like other cultivars. They started fruiting the second season. Leaf disease symptoms appeared before harvest, and the fruit was small, sparse and lacked good flavor. They obviously had little disease resistance.

Fruit quality has improved with minimal pesticide intervention, and the plants continue to survive after 10 years, but ‘Swedish Black’ is not a good candidate for commercial fruit under conditions at the test site. In fact, it would be hard to recommend the cultivar for most applications. Even in years when disease conditions were not a factor, fruit quality and yield were not distinctive. The continuing lack of renewal canes makes it difficult to maintain plant vigor, even in the absence of leaf diseases.

Discussion

Of the cultivars tested, ‘Ben Lomand’ and ‘Titania’ appear to have potential as economically sustainable fruit crops. As components of an integrated cropping system, they would benefit from the symbiotic relationships with other fruit crops.

References

USDA Agricultural Research Service Nutrient Data Library: black currants and blueberries

Borges, G., A. Degenevre, W. Mullen and A. Crozier. 2010. “Identification of Flavonoid and Phenolic Antioxidants in Black Currants, Blueberries, Raspberries, Red Currants, and Cranberries.” J. Agric. Food Chem., 2010, 58 (7), pp 3901–3909. <http://pubs.acs.org/doi/abs/10.1021/jf902263n#citing>, accessed 6/21/13.

Northern Hardy Fruit Evaluation Project: Black Currant information. From the Carrington Research Extension Center, North Dakota State University.

There is an excellent discussion about black currant in the summer 2004 edition of Pomona, pg. 55-71. Subjects include flavor, nutrition and disease resistance. See the North American Fruit Explorers website for this issue.

This article was posted in Ribes.