Blackberry - Prime-Ark Freedom, (APF-153T)


Blackberry named ‘Prime-Ark® Freedom’, (APF-153T)



‘Prime-Ark® Freedom’ (to be U.S plant patented as ‘APF-153T’), is the world’s first primocane-fruiting thornless blackberry (Rubus L. subgenus Rubus Watson) commercial introduction. It is intended primarily as a home garden or local-market plant. This is the fourth in the University of Arkansas Prime-Ark® Brand Primocane Fruiting Blackberry cultivar line.  This unique type of blackberry fruits on current-season canes (primocanes) and second-season canes (floricanes), potentially providing for two cropping seasons, both traditional summer fruits in addition to late summer to fall production. In addition to having thornless canes, this new introduction has very large fruits with good flavor, and is very early ripening on floricanes, the earliest of all Arkansas blackberries. Fruit does not exhibit exceptional postharvest storage potential however, and ‘Prime-Ark® Freedom’ is not recommended for the shipping market.

Type:  Erect, thornless, primocane-fruiting

Ripe Date:  In 2011 at the California test site where ‘Prime-Ark® Freedom’ began harvest approximately 10-15 Aug. with harvest extending into early October. This performance could also be of particular importance in more northern areas of the U.S. in that late-ripening fruit of primocane blackberries may be frost damaged in the upper Midwest or similar climates.  Additionally, the early harvest date for ‘Prime-Ark® Freedom’ provides for a longer harvest season of this blackberry type since  ‘Prime-Ark® 45’ has an average first ripe date range of late August to early September at Watsonville. 

Berry Characteristics:  Average floricane berry weight of ‘Prime-Ark® Freedom’ was near 9 g in the FRS replicated trial (Table 1), significantly larger than all other entries. This is a very noteworthy attribute and one that will greatly enhance its desirability as either a home garden or local sales cultivar as large fruit is preferred by many consumers. For primocane berries, weight in Arkansas was slightly less for ‘Prime-Ark® Freedom’ compared to the floricane fruits of the same cultivar, and was significantly larger than that for ‘Prime-Ark® 45’.  In California, primocane berry weight was observed to be much higher than that found in Arkansas, just over 16 g in 2011 and 13 g in 2012.

Fruit of ‘Prime-Ark® Freedom’ is elongated to blocky, and attractive with a glossy, black finish. Fruit shape varies on primocanes, and can be reduced in glossiness and color due to heat in Arkansas but is uniform in more suitable environments (J.R. Clark, personal observation).  Also observed in Arkansas were numerous double fruits on primocanes, more common than seen on ‘Prime-Ark® 45’, and this is thought to be related to high temperatures during flower development. Soluble solids concentration for floricane fruits over 2 years averaged 10.4% for ‘Prime-Ark® Freedom’, slightly lower than ‘Prime-Ark® 45’ (11.4%) and similar to ‘Natchez’. Soluble solids values for ‘Prime-Ark® Freedom’ primocane fruits from the California test site were 10.8% in 2011 and 11.0% in 2012. Flavor ratings for ‘Prime-Ark® Freedom’ averaged 7.8, the same as for ‘Prime-Ark® 45’, higher than for ‘Natchez (7.0) but lower than ‘Ouachita’ (8.8) and ‘Osage’ (8.3).  Flavor comments over the years in both Arkansas and California indicated berries were routinely sweet in flavor (as supported by the soluble solids content over 10%) although occasionally were noted as tart in California. Field firmness ratings averaged 7.8 for ‘Prime-Ark® Freedom’, the same as ‘Natchez’ but lower than that of the other cultivars.

Postharvest Performance:  Postharvest evaluations for floricane fruits stored for 7 d at FRS indicated variable performance for ‘Prime-Ark® Freedom’ (Table 3). For all years, ‘Prime-Ark® Freedom’ had either significantly or numerically lower overall ratings compared to ‘Prime-Ark® 45’, indicating limited shipping potential. 

Plant Characteristics: Canes of ‘Prime-Ark® Freedom’ are very erect, similar to ‘Ouachita’ and more erect than ‘Natchez’. Vigor rating of ‘Prime-Ark®’ Freedom’ was low in the FRS plants established in the poor site, but showed good vigor on a more appropriate site at the Station. In California the plants were observed to be very vigorous.  No orange rust [caused by Gymnoconia nitens (Shwein.) F. Kern & H.W. Thurston] was observed on ‘Prime-Ark® Freedom’ in any evaluations, even though infected plants were seen within 30-50 m of data collection plots in each year of evaluation. ‘Prime-Ark® Freedom’ berries or canes have not been observed to be susceptible to anthracnose at FRS where a single spray of lime sulfur was applied. Reaction of ‘Prime-Ark® Freedom’ to rosette/double blossom [Cercosporella rubi (Wint.) Plakidas] has not been conducted as this disease did not occur at any of the test sites. It is hoped that is has resistance to this disease as exhibited by other Arkansas thornless blackberry cultivars.

‘Prime-Ark® Freedom’ is an exciting development as it is the first thornless plant of this blackberry type released for commercial introduction in the world. Its potential to produce two crops each year, both being early to very early in ripening, is another unique attribute of this cultivar. Its exceptional fruit size should make it a very noteworthy blackberry for home gardeners or local-market growers.

For a list of licensed propagators click here.



Patent Information:
App Type Country Serial No. Patent No. File Date Issued Date Expire Date
Plant United States 14/120,553 PP26,990 6/3/2014 8/2/2016 3/5/2035
Fruit Crops
For Information, Contact:
Bryan Renk
Associate Director for Technology Commercialization
University of Arkansas TCO
John Clark
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