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Jianfeng Liu, Bowen Yang, Yuetong Ming, Yuchu Zhang, and Yunqing Cheng

Rubus idaeus is a red-fruited species of Rubus L. and has remarkable economic and cultural value. This genus is distributed over both the hemispheres and is commonly cultivated in temperate regions ( Sønsteby and Heide, 2009 ). Its berry has

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Horacio E. Alvarado-Raya, Rebecca L. Darnell, and Jeffrey G. Williamson

Interest in off-season production of red raspberry ( Rubus idaeus L.) is increasing as a result of the high demand for a limited supply ( Darnell et al., 2006 ; Knight et al., 1996 ; Pritts et al., 1999 ; Schloemann, 2001 ) and the resultant

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Justine E. Vanden Heuvel, J. Alan Sullivan, and John T.A. Proctor

Treatments of either staked (stabilized) or not staked (control, freestanding) canes were applied to Rubus idaeus L. `Boyne' and `Regency' during the 1997 and 1998 seasons to determine the effect of stabilizing fruiting canes in a windy environment. Treatments were applied in late April of each year, and canes were removed following harvest for growth analysis. Stabilizing (staking) floricanes increased yield per cane in `Boyne' by 68% and in `Regency' by 189%, primarily through increases in fruit number per cane. Leaf area of the staked canes was 41% larger for `Boyne' and 159% for `Regency' than that of the control canes, suggesting that more leaf area was retained for photosynthesis, resulting in greater yield. Primocane diameter in `Boyne' and primocane height in `Regency' were also increased by staking, but floricane structure was unaffected.

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Helena Mathews, C. Cohen, W. Wagoner, J. Kellogg, V. Dewey, and R. Bestwick

We have developed efficient plant rageneration and transformation systems for red raspberry (Rubus idaeus L.). We have successfully introduced a gene for controlling biosynthesis of ethylene into raspberry for the first time. Leaf and petiole segments were co-cultivated with disarmed Agrobacterium strains EHA 101 or 105 containing plasmids pAG5420, pAG 1452 or pAG1552. The plasmids encoded gene sequences for S-adenosylmethionine hydrolase (SAM ase) driven by the fruit specific or wound and fruit specific tomato SE8 or E4 promoters. SAM ase catalyses the conversion of S-adenosylmethionine (SAM) to methylthioadenosine (MTA) and homoserine which can reenter the methionine recycling pathway. SAM is therefore not available for the synthesis of 1-am inocyclopropane carboxylic acid (ACC), the metabolic precursor for ethylene biosynthesis. Initial shoot regenerants were mostly chimeras containing transformed and non-transformed cells. Solid clones of pure transgenics were developed by repeated culture of leaf, petiole and nodal explants of primary regenerants on higher stringency selection medium. Transformants were screened on medium with kanamycin, geneticin or hygromycin depending on the selection marker gene NPTII or hpt. Genomic integration of transgenes were confirmed by Southern hybridization. Transgenic plants of cultivars Canby, Meeker and Chilliwack have been transplanted to the greenhouse for fruit set and further evaluation of transgenic traits.

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David C. Percival, John T.A. Proctor, and J.P. Privé

Rubus idaeus L. cv. Heritage raspberries were placed in controlled environment chambers (25°C, 14-hour photoperiod, 2.0 kPa vapor pressure deficit, CO2 concentration of 380 mol·m-2·s-1) to study the effects of drought stress on leaf gas exchange and stem water potential. Whole-plant photosynthesis (Pn) and transpiration were sensitive to drought stress and gradually decreased from the second day of the study until rehydration. Stomatal aperture feed-back regulation was present during the initial 48 hours of the study with transpiration rates dropping in response to a decrease in stem water potential. Spatial differences were also present with leaf Pn, and stomatal and CO2 conductance values of the younger, distal (i.e., closer to the apex) leaves decreasing at a faster rate than the older, proximal leaves (i.e., close to crown). Evidence of increased mesophyll resistance to drought stress was apparent with ci either remaining constant or increasing, while Pn and carboxylation efficiency simultaneously decreased. Protection of the underlying photochemistry was evident with parahelionastic leaf movements which resulted in a reduction in the effective leaf area and subsequent heat load. Therefore, an optimum balance between water loss and ci existed, and an alteration in these rates represented a stomatal conductance adjustment to match the intrinsic photosynthetic capacity rather than just a causal relationship.

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Brenner L. Freeman, Janet C. Stocks, Dennis L. Eggett, and Tory L. Parker

cultivar, across the season, and between storage treatments. Materials and Methods Raspberry collection. Six cultivars of Rubus idaeus L. raspberries (‘Autumn Bliss’, ‘Caroline’, ‘Jaclyn’, ‘Joan J’, ‘Polana’, and ‘Polka’) grown on a 20 acre farm in Utah

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Julie Graham, Mary Woodhead, Kay Smith, Joanne Russell, Bruce Marshall, Gavin Ramsay, and Geoff Squire

Red raspberry ( Rubus idaeus ) is cultivated on a large scale and has frequent sympatric wild populations in the Tayside area of the United Kingdom. The high potential for gene flow between these populations has encouraged the study of the

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Marvin Pritts

Primocane-fruiting raspberries ( Rubus idaeus L.) produce new canes (primocanes) from buds on the roots or from basal buds on older canes or the crown. Flowers are initiated on these primocanes regardless of daylength and when field-grown can

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Pauliina Palonen and Katriina Mouhu

Red raspberry ( Rubus idaeus ) has a relatively low harvest index, i.e., the relationship of harvestable crop to vegetative growth. When cultured in plastic tunnels or greenhouses, cane growth of raspberry plants is even more vigorous than in the

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Stephen F. Klauer, J. Scott Cameron, and Chuhe Chen

With the advent of new rotary-head mechanical harvesters, it is now possible to machine-harvest a wider raspberry canopy. In Spring 1996, a trial was established in a grower's field in Lynden, Wash., comparing raspberries trained to two top wires with a 70-cm spread (split trellis) to the conventional single top wire system. Within the split trellis, increases in leaf number per cane (97%), and leaf area per cane (55%) were not reflected in a concomitant increase in total leaf dry weight per cane (35%). Leaf dry weight per fruit weight was 11% less within the split trellis. These data suggest that the canopy is more efficient with this type of trellis. Increases in estimated yield per cane (49%) and projected yield per acre (50%) associated with the split trellis were due to increases in berry number per cane (47%). Fruit number per meter of lateral was 35% greater within the split trellis. Greatest enhancements to yield components were in the upper parts of the canopy where canes were tied over. Since there were no differences in lateral numbers or lateral lengths between the two systems, this increased productivity was due to increased floral expression, enhanced fruit set, increases through Spring bud initiation or any combination thereof. In both trellis systems, the longest laterals occurred on the middle third of the cane and decreased in length progressively towards the tip of the cane. Primocane lengths were shorter (20%) and diameters were smaller (10%) and more uniform in the split trellis system.