Siskiyou

The primary goal of the US Department of Agriculture–Agricultural Research Service breeding program, in cooperation with Oregon State University, was the development of blackberry cultivars that will complement or replace Marion blackberry. While Marion fruits are ideal for processing, the plants are thorny and trailing, susceptible to winter injury, and were too soft and tender skinned for the fresh market. Black Butte variety, released in 1996, has extremely large fruit, and is early ripening and firm enough for local fresh-market sales, but it was not suitable for processing.
Siskiyou (ORUS 830-4) is early, large-fruited, stress-tolerant, and is a dual purpose berry for the fresh and processed market. Generally, trailing blackberries, such as Marion, Olallie, Boysen and Waldo, are grown in mild climates where winter temperatures do not fall below minus 17 C and they usually have very poor fruit quality if the fruit ripen when daytime temperatures are higher than 32 C. Siskiyou was widely adapted by trailing blackberry standards.
The average fruit weight for a season is about 8 g. The fruit are cylindrical and blocky. Set of the drupelets at the tip of Siskiyou fruit is not consistent. The primary fruiting season of Siskiyou is similar to that of Black Butte, it ripens its first fruit at the beginning of July. The duration of harvest season is about 30 days. Siskiyou has excellent fresh flavor but is not as strongly aromatic as Marion. Siskiyou can be mechanically harvested.

Table 1. Yield and average berry weight of Siskiyou blackberry cultivar compared to some other varieties

Cultivar	Yield, t/ha			Berry weight, g
	1995	1996	1997
Siskiyou	5.6	14.3	15.1	7.8
Black Butte	7.1	9.7	9.5	8.9
Kotata	13.0	16.8	12.9	5.0
Marion	5.9	15.0	21.2	5.0
Ranui	2.3	8.7	11.6	7.6
Waldo	7.9	20.3	24.1	6.0