Prime-Ark Freedom blackberry variety

Prime-Ark Freedom (also known as APF-153T) is the world’s first commercially released thornless primocane-fruiting blackberry. This is the fourth in the University of Arkansas Prime-Ark Brand Primocane Fruiting Blackberry cultivar line following the release of Prime-Jan and Prime-Jim in 2004 and Prime-Ark 45 in 2009. All of the prior-released primocane-fruiting cultivars are thorny.
This type of blackberry fruits on current-season canes (primocanes) and on 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 variety produces very large berries with good flavor and is very early ripening on floricanes.
Fruit of Prime-Ark Freedom does not exhibit exceptional postharvest storage potential but it is not recommended for the shipping market due the berries have low firmness.
The average primocanes length is about 2-2.5 m. Primocanes are low vigorous, without thorns, very erect. Prime-Ark Freedom berries are large-sized, average weight of berry is about 9-12 g. Color is glossy black.
Each plant produces groups of berries, like bunch of grapes. The first yield starts forming at primocanes in the beginning of June and continues three to four weeks. During this first harvest season, Prime-Ark Freedom intensively produces floricanes, which soon begin to bloom. Floricanes are thornless. This is the second harvest season, which continues up to the middle of October.
After the end of the second harvest season Prime-Ark Freedom requires winter shelter from winter cold wind and other unfavourable conditions, because the declared cold hardiness of this blackberry variety is moderate, about minus 13..17 C, but the many growers note that real hardiness is about minus 18..20 when using covering.
Plants like sun placement, but it is observed that at high air temperature (over 31..33 C) pollination cardinally reduces.

Table 1. Comparison table of floricane and primocane yield of two primocane-fruiting and three floricane-fruiting blackberry - Natchez, Osage, Ouachita, Prime-Ark 45 and Prime-Ark Freedom

Cultivar	Yield, kg/ha
	2011	2012	2013
Floricane harvests
Prime-Ark Freedom	6258	10740	17529
Natchez	19773	19448	-
Osage	13681	14461	-
Ouachita	12076	15716	-
Prime-Ark 45	7866	13238	23501
Primocane harvests
Prime-Ark Freedom	-	911	2893
Prime-Ark 45	-	214	3663

Table 2. Comparison table of floricane and primocane averaged fruit weight of two primocane-fruiting and three floricane-fruiting blackberry - Natchez, Osage, Ouachita, Prime-Ark 45 and Prime-Ark Freedom

Cultivar	Berry weight, g/pcs
	2011	2012	2013
Floricane harvests
Prime-Ark Freedom	9.2	8.7	12.6
Natchez	7.6	7.3	-
Osage	5.0	5.1	-
Ouachita	5.5	5.8	-
Prime-Ark 45	5.5	5.4	6.2
Primocane harvests
Prime-Ark Freedom	-	7.5	8.8
Prime-Ark 45	-	4.8	5.8

Table 3. Сomparison table of Prime-Ark Freedom (APF-153T), Natchez, Osage, Ouachita and Prime-Ark 45 (APF-45) blackberries by floricanes parameters

Main features	Cultivar
	APF-153T	Natchez	Osage	Ouachita	APF-45
2011
Flowering date on floricane
10% bloom	April 13	April 2	April 19	April 27	April 20
50% bloom	April 16	April 20	April 25	May 4	April 26
Floricane harvest date
First	May 28	June 6	June 9	June 13	June 6
Peak	June 6	June 13	June 20	June 28	June 18
Last	June 20	July 7	July 25	July 25	July 18
2012
Flowering date on floricane
10% bloom	March 26	April 2	April 2	April 5	March 27
50% bloom	April 1	April 4	April 5	April 11	April 2
Floricane harvest date
First	May 6	May 17	May 21	May 24	May 17
Peak	May 21	May 29	May 29	June 5	May 29
Last	June 8	June 25	June 25	June 28	June 28
Fruit (rating scale of 1 to 10 where 10 is the best)
Firmness	7.6	7.8	8.2	8.6	8.2
Flavor	7.6	7.0	8.2	8.6	7.6
Soluble solids, %	9.7	11.3	11.8	11.6	10.8