Black Pearl

Black Pearl (ORUS 1380-1) is a thornless trailing blackberry cultivar from the Department of Agriculture - Agricultural Research Service breeding program in Corvallis, released in cooperation with the Oregon State University Agricultural Experiment Station and the Washington State University Agricultural Research Center, United States. Black Pearl is adapted to machine harvesting and has yield and processed fruit quality very similar to world-known blackberry cultivar Marion. It is one of three thornless varieties which are being released simultaneously - Black Diamond, Black Pearl and Nightfall blackberry. These cultivars was intended to replace Marion variety, which hasn't good post-harvest characteristics. Black Pearl is thornless blackberry variety, but primocanes have some thorns on the basal. These thorns are soft and smooth. Also child canes from root are thorny. Black Pearl harvest begins at the few days of July, peaks in early July and is largerly done by the third week of July in south regions. Fruits of Black Pearl are similar in shape to Marion berries, they are a medium long conic and can have a blunt tip. Flavor is excellent. Fruit firmness is sufficient for machine harvesting and transportation. Yield is very similar to Marion, average berry weight is 6 g. Winter hardiness is about -13 C. Black Pearl blackberry has sufficient resistance to different diseases.

Table 1. Comparison table of Black Pearl, Nightfall, Silvan, Black Diamond, Marion, Waldo and Siskiyou blackberry cultivars at the North Willamette Research and Extension Centre, Oregon State University

Cultivar	Fruit weight, g	Yield, kg/ha
	2001-2003	2001	2002	2003	Avg.
Black Pearl	6.2	26969	14373	15505	18949
Nightfall	6.2	42447	13405	20962	25604
Silvan	6.2	31757	16811	21845	23351
Black Diamond	5.8	29281	15568	19001	21283
Marion	5.1	26380	13021	18397	19266
Waldo	5.5	25849	11000	17286	18045
Siskiyou	6.9	20969	9854	9359	13394

Table 2. Harvest season date, yield and fruit weight

Cultivar	Fruit weight, g	Fruit yield, kg/ha	2003 Harvest season
			5%	50%	95%
Black Pearl	6.1	15038	July 6	July 16	August 8
Waldo	4.8	23579	July 14	August 1	August 26
Marion	4.8	19896	July 9	July 14	July 28
Kotata	4.4	13323	July 6	July 18	July 28