A manageable cavity-nesting bee, Osmia aglaia Sandhouse (Apiformes: Megachilidae), was evaluated as a pollinator for cultivated red raspberry and blackberries. Floral visits by free-flying honey bees or by less numerous caged O. aglaia yielded red raspberry fruit (`Canby' and `K81-6') of equivalent size. These fruit were 30% larger (1.9 g, 70 drupelets) than fruit from unvisited flowers. Female O. aglaia readily visited flowers of all eight diverse blackberry cultivars observed. For all of these cultivated Rubus, female O. aglaia were observed to invariably collect pollen while pivoting atop the brush of pistils, maximizing opportunities for pollen transfer. Within its native geographic range in western Oregon and California, this effective native pollinator could be a sustainably managed, economical bee for cultivated cane fruit.
Angela K. Anderson and Chad E. Finn
Trailing blackberry cultivars, such as `Marion', can be traced to relatively few chance selections of Rubus ursinus Cham. & Schlecht. Wild R. ursinus offer a range of horticulturally desirable traits to breeders, from high fruit quality to improved cold hardiness. Cuttings from 460 plants, representing 20 populations in southern British Columbia, Washington, and Oregon, collected in 1993. Rooted clones were planted in 1994 in a replicated field trial to assess morphological variation. A greenhouse study was also undertaken, with 10 clones represented from each site, in two replications. Preliminary data from the greenhouse and field studies show variability in the following morphological characters: Glandular hairs; cane and prickle color; cane diameter; prickle density; internode length; leaf color, size, shape and density; and senescent leaf drop and color change. Floricane morphology will be assessed in 1995. Analysis of these data will determine relative genetic distances among the populations and enhance the understanding of the diversity available in R. ursinus.
Camila P. Croge, Francine L. Cuquel, Paula T.M. Pintro, Luiz A. Biasi, and Claudine M. De Bona
varied from 20.4 to 28.1 mg/100 g of FF. Pantelidis et al. (2007) found great variations in the levels of vitamin C in different Rubus cultivars (14.3 and 103.3 mg/100 g of FF). Deighton et al. (2000) found values between 12.3 and 16.4 mg/100 g FF in
John R. Clark
Rubus plants are rather unusual among fruit crops in that they have a perennial root system but have biennial canes. The two cane types are primocanes, or first-year canes, which are usually vegetative, and floricanes, which are the same canes
Chad E. Finn, Bernadine C. Strik, Brian M. Yorgey, and Robert R. Martin
‘Onyx’ is a new trailing blackberry ( Rubus subg. Rubus Watson) cultivar from the U.S. Department of Agriculture–Agricultural Research Service (USDA-ARS) breeding program in Corvallis, OR, released in cooperation with the Oregon Agricultural
John R. Clark and Penelope Perkins-Veazie
‘APF-45’ was introduced to broaden the choices of this innovative, primocane-fruiting blackberry ( Rubus L. subgenus Rubus Watson) type. This is the third in the University of Arkansas Prime-Ark® Brand Primocane Fruiting Blackberry cultivar line
Chad Finn and Robert Martin
Cuttings from Rubus ursinus Cham. & Schlecht, the trailing blackberry, were collected in Oregon, Washington, and British Columbia from 21 sites. The cuttings were rooted and placed in pots in the greenhouse. After the plants began to grow, leaves were harvested for ELISA testing using standard procedures. Each sample represented three clones from a site. Plants from 18 sites were represented by five samples and two sites were represented by three samples. None of the samples tested positive for the presence of raspberry bushy dwarf virus or tomato ringspot virus. Forty-four percent of the samples tested positive for tobacco streak virus. Only 33% of the sites on the Pacific coast tested positive for tobacco streak, whereas, 100% of the Cascade Mountain sites and 88% of the sites in the coastal range type environment tested positive. The only site in the Willamette Valley had no positive tests. With one exception, all of the sites that tested negative for the virus were also low elevation sites 0-90 m.
J. Cummaragunta, D.V. Schlimme, C.S. Walsh, H.J. Swartz, and A.E. Watada
In 1993, we studied the postharvest behavior of 25 Rubus genotypes. Included in the study were named cultivars from Europe and North America, advanced selections from the Univ. of Maryland Cooperative Breeding Program, species and raspberry interspecific hybrids, with R. phenicolasius, R. pungens oldhamii R sumatranus, and R parvifolius. Wide variation exists in the ethylene production rates of these genotypes. The difference between the lowest ethylene producer, R. phenicolasius, and the highest ethylene evolver, HTCC-6t (R. lasiostylus), was four orders of magnitude. Ethylene evolution rate and percentage mold were not correlated. Ethylene production and respiration rates were also measured using a flowthrough system. No single pattern was characteristic of all genotypes. Red raspberries were the highest ethylene producers and showed an ethylene and respiratory climacteric. Blackberries were low ethylene producers. Interspecific hybrids showed varied postharvest behaviors. The behavior observed in these interspecific hybrids may explain some of the conflicting reports on the postharvest behavior of blackberries and raspberries. In general heattolerant species such as blackberry, R. occidentalis, R. parvifolius exhibited lower rates of respiration and ethylene evolution than species from cool, temperate areas like R. idaeus.
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.
M.A.R. Mian, R.M. Skirvin, M.A. Norton, and A.G. Otterbacher
To study the causes of low germinability in dried blackberry seeds, seeds harvested from fresh `Thornless Evergreen' (TE) blackberry (Rubus laciniatus Willd.) were either air-dried (12, 24, 36, 48, 60, 72, 96, or 120 hours) or explanted directly onto growth-regulator-free medium after bleach disinfestation. Seeds were either cut in half before explanting or kept intact. None of the intact seeds germinated. Fewer of the halved seeds dried 12 hours or more germinated than control (fresh moist) seeds (42.7% and 54.5%, respectively). Germination decreased to <12% following >48 hours of air-drying. In a separate study, fresh seeds of TE and `Navaho' were either dried as described or held in sealed petri dishes on moist filter paper (moist treatment) for up to 60 hours. After 60 hours, germination of dried seeds of both cultivars had decreased significantly; there was no significant change in germination percentage for moist seeds. Since moist halved seeds germinated well and dried halved seeds did not, the inability of dried blackberry seeds to germinate is due to more factors than just the hard seedcoat typical of the genus.