Blackberry Cultivar Trial - UKREC - 2004
Joe Masabni, Dwight Wolfe, June Johnston, and Hilda Rogers, Department of Horticulture, UKREC

Blackberry (Rubus spp.), a native plant, grows well in Kentucky. Improved blackberry cultivars offer a high income-per-acre crop for Kentucky agricultural producers looking to diversify production. Blackberries have lower establishment and labor costs than many horticultural enterprises. This experiment was begun to evaluate the performance of newer blackberry cultivars in western Kentucky’s climate.

In the spring of 2000, a blackberry cultivar trial was established at the University of Kentucky Research and Education Center, Princeton, KY. The experimental design consisted of five cultivars (Apache, Arapaho, Chickasaw, Kiowa, and Navaho) and five5 replications arranged in a randomized complete block design. The Five5 rows or replications, each consisting of five5 cultivars per row, were spaced 14 ft apart. Rows were 70 ft long with 10 ft for each cultivar and a 5 ft grass buffer areas between cultivars to serve as a buffer. Six plants were spaced 2 ft apart within each plot. Plants looked fine throughout the season 2000 season. In the spring of 2001, all Navaho plants started to develop symptoms of Tobacco Ring Spot Virus. These plants were removed during the fall of 2001 after laboratory confirmation of the virus infection. During the growing season of 2002, Chickasaw plants developed systems of Impatiens Necrotic Spot Virus in 2002, and were subsequently removed in the fall of 2002 after completion of removed that fall, after harvest.

Plots were harvested from 18 June through 1 August in 2002, from 26 June through 4 August in 2003, and from June 17 to July 30 in 2004. Harvesting was done every 2 to 6 days as dictated by the ripening quality of the berries days, depending on berry ripeness. Yield and berry size (weight of 25 berries per plot) measurements were collected at each harvest, and the total yield and average berry size calculated (Table 1).

Results and Discussion

All blackberries cultivars ripened a couple of weeks earlier in 2004 than in 2003. In addition, yields in 2004 were more than double those observed in 2003, for cultivars Apache and Kiowa (Table 1). In general, the plants were healthy and grew well. The drop in yields in 2003in 2003 compared to 2002 could be attributed to excessive pruning in fall of 2002 of excessive fall pruning of canes infested with the rednecked cane borer.

Arapaho is an early ripening variety, but yielded significantly less fruit with significantly small berry size (as measured by average weight per berry) than Apache and Kiowa, for all three years that fruit has been harvested from this trial. Conversely, Apache tends to be the last to ripen but has yielded the most fruit. Kiowa and Chickasaw were intermediate between Apache and Arapaho in yield and ripening date, in 2002, and Kiowa was intermediate in yield in 2003 and 2004.In terms of berry size,

Table 1. Yield parameters of the blackberry cultivar trial established in 2000 at UKREC, Princeton, Kentucky.

¹ Cultivars listed in descending order of ‘Yield’ column.
² Chickasaw variety was pulled out in 2003.