Comparison of 'Marion' to thornless blackberry genotypes as individually quick-frozen and puree products

The trailing blackberries (Rubus sp. L.), particularly 'Marion', are the primary blackberries grown for the processing market and they are largely machine harvested. While 'Marion' is well known for its processed fruit quality, particularly flavor, aroma, and perception of low seediness, it has spines (thorns) that can be dislodged when machine harvested and end up in the product. A primary goal of the USDA-ARS blackberry breeding program in Corvallis is the development of cultivars that are comparable to 'Marion' in fruit quality but are spineless (thornless). Nine thornless selections were compared with four standard cultivars as individually quick-frozen (IQF) and puree products in a blind evaluation. Each sample was scored panelists from the blackberry industry and research program. IQF samples were scored for appearance, color, seediness, flavor, and overall quality by 21 panelists and purees were scored for color, flavor, aroma, and overall quality by 25 panelists. Both panels used a 9 point hedonic scale (1 = dislike extremely, 5 = neither like nor dislike, 9 = like extremely). With the exception of color, there were significant differences among all genotypes for all traits evaluated in the IQF and pureed products. ORUS 1380-1 was ranked similar to 'Marion' and significantly better than 'Waldo', in overall quality of the IQF product. In puree form, ORUS 1843-1 and ORUS 1843-3 had the highest ranking in overall quality, but were only both statistically different from ORUS 1489-2. For pureed product flavor, ORUS 1843-1 was the highest rated selection but was not statistically different from 'Marion'. While ORUS 1843-1 and ORUS 1843-3 hold great promise, they are from a cross between wild collected Rubus ursinus Cham. & Schit. and 'Waldo' and as a result have some negative characteristics of the native species, particularly small fruit size. The puree quality of NZ 912811-1, NZ 9351-4 and ORUS 1380-1 was similar to 'Marion' and these genotypes offer promise as thornless replacements for 'Marion'.