Neil C. Bell, Bernadine C. Strik, and Lloyd Marti
Primocanes were cut at ground level at one-month intervals from late April to late July 1991 and 1992. An uncut control was included. Four canes per plant were trained either in August or the following February, the others being removed and measured. Yield data were collected and yield components measured in 1992 and 1993. Cane diameter, main cane length and branch cane length per plant generally declined with later suppression date. Consequently, yield per meter of cane declined with later suppression date. However, cane number and total plant main cane length were greater for all suppression treatments and percent budbreak increased with later suppression date. As a result, April- and May-suppressed plants had increased-yields compared to control plants in both 1992 and 1993, as did June-suppressed plants in 1993. August-trained plants had significantly higher yields than February-trained in both years, primarily because of increased budbreak. The basal section of canes was the most productive, because of increased budbreak and branch cane production.
Bernadine C. Strik, John R. Clark, Chad E. Finn, and M. Pilar Bañados
blackberries produce primocanes from buds at the base of floricanes at the crown or from buds on roots, whereas trailing and semierect types only produce new primocanes from buds on the crown. With the exception of the primocane-fruiting erect types, primocanes
M.A. Norton and R.M. Skirvin
Chimeral `Thornless Evergreen' (CTE), (Rubus laciniatus Willd.) somaclones selected in 1983 and field planted in 1985 were reexamined in 1992 for various vegetative and reproductive characteristics. Two major types of thornless (prickle-free) plants, intermediate-sized (`UI 6-6' = `Everthornless') and dwarf (`UI 6-4'), originally selected from a chimeral thornless parent plant, were compared with thorny plants. The intermediate and dwarf somaclones have maintained their distinctive habits over 7 years' growth in the field, indicating that their growth habits are stable and not a transient effect of tissue culture. Although the thornless somaclones remained thornless, the degree and type of prickle-like structures varies considerably, indicating that the thornless gene (S te) does not entirely suppress the production of prickles, but apparently alters their development. Increasing suppression was directly related to increasing dwarfism, suggesting a link between thornlessness and internode length.
Fumiomi Takeda and Jorge Soria
many long lateral canes rooted at their tips (e.g., tip layering) for production of long-cane plants of trailing ‘Siskiyou’ and semierect ‘Triple Crown’ blackberry. Materials and methods The stock plants used in the study were nursery-matured trailing
Javier Fernandez-Salvador, Bernadine C. Strik, and David R. Bryla
rates and appropriate soil pH ( Kuepper et al., 2003 ), and do not address different sources of N fertilizer or possible response differences among blackberry types [e.g., erect, semierect, and trailing types ( Finn and Strik, 2014 ; Strik and Finn
F. Takeda, B. C. Strik, and J. R. Clark
Western trailing blackberries (e.g., `Boysen' and `Marion') are grown in Oregon. USDA-released semi-erect thornless blackberries (e.g., `Chester Thornless') and erect, thorny blackberries (e.g., `Cherokee') from Arkansas are grown across the United States from the mid-Atlantic coast region to Oregon. Flower bud development in several blackberry cultivars growing at three sites (Arkansas, Oregon, and West Virginia) was studied. In buds of `Boysen' and `Marion' blackberries from Oregon, sepal primordia were first observed in September and November, respectively. Further floral bud development continued into January. Sepal development in `Cherokee' buds occurred in November in Oregon and in December in Arkansas. At all subsequent sampling dates, the development was more advanced in Oregon than in Arkansas. Buds of `Chester Thornless' blackberry from all three sites remained undifferentiated until spring. Preliminary findings indicated that the time of flower bud initiation varied considerably among the cultivars examined. The results suggest that floral bud development in blackberry, once initiated, is continuous, but periods of low temperature can arrest bud development.
Fumiomi Takeda and David Handley
A combination of simple cultural practices, a modified rotatable crossarm (RCA) trellis system, and covering plants with insulation material in winter overcame the lack of cold hardiness in trailing blackberries that have been established at Kearneysville, W.Va. After tying canes to trellis wires and rotating the cross-arms to below horizontal, tied canes were close to the ground, allowing them to be covered with protective materials, such as floating rowcover and polyethylene plastic during winter. Covers were removed in early spring and the canes remained in the horizontal orientation until bloom, which promoted flowering laterals to grow upright. After bloom, the cross-arm was rotated beyond vertical to position the fruit on one side of the row and improve harvest efficiency. In Jan. and Feb. 2005, the daily minimum temperatures under the FRC+PE covers were about 3 °C higher than in the open. The covers also provided protection against the wind. Tissue damage in protected trailing blackberries was significantly less than for unprotected plants. `Siskiyou' plants in covered plots produced 3 to 5 times more fruit than plants in the open. Harvesting of `Siskiyou' fruit occurred during the red raspberry harvest season or 2 to 3 weeks earlier than for eastern blackberries. Our findings suggest that trailing blackberries can grow satisfactorily and produce fruit if the adverse effect of low temperatures and winds is mitigated with our trellis system and winter protection method. If practical cultural techniques for improving their winter survival become available, there is a potential for early-season high-quality blackberry production in the mid-Atlantic coast region.
P. Perkins-Veazie, C. Finn, and E. Baldwin
Oregon produces most of the processing blackberries in the United States. `Marion' blackberry (Rubus hybrid) is a trailing, thorny plant type with fruit highly prized for its unique flavor and superior processing quality. Blackberries developed in other parts of the United States grow well in Oregon but differ in flavor from `Marion' fruit. `Marion' blackberry plants are thorny and highly susceptible to freeze injury; growers desire a thornless, higher yielding, and more winter tolerant plant with similar fruit flavor and quality. This experiment was done to identify volatiles unique to `Marion' that may be incorporated into new germplasm. Forty-two volatile peaks were identified in blackberries using headspace gas chromatography and known standards. Ethylacetate and trans-2-hexenol were present in very low amounts and nerilidol was present in an unusually high amount in fresh `Marion' homogenates relative to other blackberry cultivars. Nerilidol is a volatile commonly associated with raspberry flavor and may come from the raspberry germplasm in the breeding background of `Marion'. It appears that the flavor of `Marion' fruit results from proportional differences in several volatile compounds rather than the presence of volatiles unique to this cultivar.