Blackberry Breeding is Booming

The time is ripe for breeding and growing blackberries. Growth in blackberry marketing has been spurred by improvements on the market and local sales at farmers’ markets and other retail venues.

“As a new crop to many areas of the world, blackberries share many similarities to red raspberries, and as raspberry production develops in an area, blackberries often follow,” says John R. Clark, a horticulture professor at the University of Arkansas who heads up one of the largest public efforts in blackberry breeding in the world. “However, blackberries are less expensive to produce than red raspberries because they do not have to be replanted as often and commonly do not have as many pest control inputs.”

Advancements In Blackberries

Cultivar improvements include blackberries that ship better, ripen earlier, ripen later, taste better, and are thornless. “Fueled by an improved set of parents and traits to utilize and an increased interest among growers and consumers, blackberry breeders are in a great position to breed exceptional new cultivars,” Clark says.

While improved blackberry plants are more often high-yielding and thornless, making them easier for growers to manage, other factors important in breeding exceptional blackberry cultivars include:

• Fruit Quality. “Regardless of whether fruit is processed or used fresh, quality traits of primary interest in breeding include fruit flavor, color, firmness, ease of removal of the fruit at harvest, and seediness,” Clark says. “Enhancing the sweetness, along with reduced acidity and astringency levels, is the most important opportunity for improving the consumption of blackberries produced in the U.S.”

• Fruit Size. Advancements in fruit size have been substantial in blackberry breeding. Although it is important, excellent size has been attained in parents for breeding and is much easier to achieve than in years past, Clark says.

• Pest Resistance. A few advances in blackberry pest resistance have been achieved recently, while other concerns loom as potential problems, including double blossom/rosette, a serious disease in the Southeastern U.S. However, thornless varieties are resistant to this disease. Concern over viruses is also increasing as planting area expands in the South, including Blackberry yellow vein associated virus and Blackberry Virus X.

Exciting Release This Year

On the horizon, new floricane-fruiting developments and the innovative primocane-fruiting technology developed by the University of Arkansas will allow blackberry production to be extended into fall months, when blackberry quality and quantity is typically limited. This will round out the yearly production of domestic and import fruit to keep high-quality berries in good supply year-round, according to Clark.

“The University of Arkansas intends to release the first primocane-fruiting variety with commercial shipping quality this year, with the hope that this and subsequent releases will expand options for growers and enhance quality to consumers,” he says.

Advantages of primocane fruiting include later-season fruiting period; the potential to schedule production based on primocane management; the potential for two crops on the same plant in the same year (floricane followed by primocane); reduction in pruning costs by mowing of canes (primocane crop only); avoidance of winter injury; and avoidance of rosette/double blossom occurrence.

“One of the first major problems encountered was the damaging effects of heat (85°F and above for multiple days) on the flowers, leading to small, low-quality fruit. If grown in more moderate climates, such as in the Willamette Valley of Oregon or coastal California, primocane bloomtime is later and at a more desirable temperature, and berry size, quality, and plant yields are much better,” Clark says. “Currently, moderate summer heat environments are recommended for this new type of blackberry.”