More than 300 red raspberry cultivars and selections were screened for raspberry (Rubus idaeus L.) bushy dwarf virus (RBDV), tobacco streak virus (TSV), and tomato ringspot virus (TomRSV) using enzyme-linked immunosorbent assay in three naturally infected breeding program selection plots at Corvallis, Ore. All genotypes tested negative for TSV and TomRSV. The RBDV incidence in primocane-fruiting cultivars and selections was 67%; in floricane-fruiting genotypes, it was 34%. The pattern of RBDV infection in the field showed no discernible trend. The high incidence may have been due to use of infected parents, propagation of infected genotypes, and pollen transmission. `Willamette', considered to be immune to the common strain of RBDV, along with 14 clones that had been in the field 10 years or longer, tested negative. The high incidence of RBDV in the breeding plots may provide an opportunity to identify resistant parents for breeding programs. An early seedling screening method for RBDV susceptibility is desirable to eliminate highly susceptible genotypes from the program and maintain a lower incidence of RBDV within the breeding plots.
M.M. Stahler, F.J. Lawrence and R.R. Martin
Chad Finn, Kirsten Wennstrom, Janessa Link and Jill Ridout
Sixteen western black raspberry (Rubus leucodermis Douglas ex Torrey & A. Gray) populations, collected from through out the Pacific Northwest, and `Munger', the most widely grown black raspberry (R. occidentalis L.) cultivar, were established in 1994 in a replicated trial in Corvallis, Ore. In 1996 and 1997 the seedlings were evaluated for date of budbreak, flowering date, ripening date, fruit size, and disease tolerance. Fruit within a replication were pooled for evaluation of pH, soluble solids, titratable acidity, and anthocyanin content. The plants were vigorous and had produced solid hedges by the time evaluation commenced. The populations were significantly different within each year for all traits except for anthocyanin content in 1996. Rubusleucodermis populations were identified that broke bud and ripened fruit earlier or later than `Munger'; however, all flowered with or sooner than `Munger'. Despite the fact that R. occidentalis is native to eastern North America and R. leucodermis to the West, `Munger' was much less affected by foliar and cane diseases than the R. leucodermis populations. Several populations were as vigorous as `Munger'. `Munger' had fruit that were 30% larger than the mean for any R. leucodermis population. Generally, R. leucodermis had higher pH and lower titratable acidity than `Munger', but many populations had similar soluble solids; lower acidity may partly explain the blandness of R. leucodermis fruit compared with `Munger'. Despite the lighter appearance of R. leucodermis, the anthocyanin levels of some populations were higher than `Munger'. Rubusleucodermis may be a source of earlier fruiting, later budbreak, and vigor when used in breeding but careful selection for fruit size (for the fresh market), acidity (for the processing market), and disease resistance must be done. Rubus leucodermis may also be an excellent source of raspberry bushy dwarf virus (RBDV) resistance in black and red raspberry breeding programs.
Patrick P. Moore, Wendy Hoashi-Erhardt, Bruce Barritt, Thomas Sjulin, Jo Ann Robbins, Chad E. Finn, Robert R. Martin and Michael Dossett
from Botrytis cinerea L. in harvests in WSU–Puyallup plots ( Table 1 ). Grafting tests indicated that ‘Cascade Gold’ was resistant to raspberry bushy dwarf virus. The unknown virus that was detected in ‘Cascade Gold’ in 1992 was identified as
Michael Dossett, Chaim Kempler and Hugh Daubeny
transmission of raspberry bushy dwarf virus (RBDV) conferred by its wild parent, Kanata-B. Root rot and raspberry bushy dwarf virus are two of the biggest disease issues limiting raspberry production around the world ( Hall et al., 2009 ). In addition, aphid
Patrick P. Moore, Wendy Hoashi-Erhardt, Chad E. Finn, Robert R. Martin and Michael Dossett
fresh market use. It is root rot [ Phytophthora rubi (W.F. Wilcox & J.M. Duncan) W.A. Man in‘t Veld] tolerant and resistant to the common strain of Raspberry bushy dwarf virus (RBDV). Because of its adaptation to machine harvest, high yield, tolerance
Mark M. Bray, John R. Clark and Rose C. Gergerich
Latent infection of Blackberry yellow-vein associated virus (BYVaV) in `Chickasaw' blackberry has been reported. However, plants with characteristic leaf symptoms, such as vein yellowing, chlorotic mottling, and oak-leaf patterns, have tested positive for BYVaV using reverse-transcription polymerase chain reaction. Experiments were initiated to determine if the symptoms expressed in BYVaV infected `Chickasaw' were caused by mixed virus infections. BYVaV, a recently identified crinivirus, was evaluated for synergistic interactions with Tobacco ringspot virus (TRSV), Tomato ringspot virus (ToRSV), and Raspberry bushy dwarf virus (RBDV). `Chickasaw' blackberry plants infected with BYVaV (single infection) were used as receptor plants to establish mixed virus infections with TRSV and ToRSV transmitted by nematodes and RBDV transmitted by bottle grafts. Characteristic symptoms of multi-virus infection will be presented and discussed.
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.
M. Joseph Stephens, Peter A. Alspach, Ron A. Beatson, Chris Winefield and Emily J. Buck
The Pacific northwestern (PNW) region of the United States is well known for production of machine-harvested red raspberries (Rubus idaeus) for process markets. The cultivar Meeker, developed in the 1960s, is well suited to this area and for machine-harvesting, but it is susceptible to raspberry bushy dwarf virus and root rot caused by Phytophthora rubi. Despite the efforts of several breeding programs, ‘Meeker’ is still the predominant cultivar for commercial production in the PNW. One of the major difficulties with breeding new berry fruit cultivars is the time-consuming nature of collecting fruit yield and quality data on large seedling populations. For fruit yield, visual scoring assessment methods are commonly used for seedling populations, but these may be poor predictors of yield. Consequently, visual scores for yield can result in less genetic improvement and thus can adversely affect successful cultivar development. Total yield measured by hand-harvesting is labor-intensive and does not assess machine-harvestability, but machine-harvesting is not practical to measure on individual plants. In this study we set out to see if we could bulk machine-harvest full-sib family plots for among-family selection and use yield component data on individuals within the plots for within-family selection. Using best linear unbiased predictors, we estimated machine-harvest yield breeding values for our individual seedlings and found higher genetic gain per generation using estimated individual machine-harvest breeding values (7.6%) than using hand-harvested breeding values (6.5%). Implications for breeding machine-harvest red raspberries are discussed.
Patrick P. Moore and Jo Ann Robbins
A crumbly fruited clone of `Centennial' red raspberry (Rubus idaeus L.) had fewer drupelets per fruit and smaller fruit than normal-fruited `Centennial'. Although there was more abortive pollen in the crumbly clone of `Centennial', there was no difference in drupelet set between the two `Centennial' clones when used as paternal parents. Thus, in `Centennial', the mechanism causing crumbly fruit was primarily a maternal effect. There was no evidence of disease as a cause of the crumbly fruited `Centennial' clone and observations were consistent with a somatic mutation.
Mark M. Bray, John R. Clark and Rose Gergerich
In 2004, two surveys were conducted to assess the presence of four viruses in marketable blackberry nursery stock. The U.S. survey consisted of dormant nursery stock received from 11 nurseries in the southern, southeastern, midwestern, northeastern, and Pacific northwestern regions of the U.S. The second survey was focused only on Arkansas licensed propagating nurseries with samples collected during the growing season. Samples were tested using reverse transcription–polymerase chain reaction or enzyme-linked immunosorbent assay for the presence of Blackberry yellow vein associated virus (BYVaV), Raspberry bushy dwarf virus (RBDV), Tomato ringspot virus (ToRSV), and Tobacco ringspot virus (TRSV). Of the total samples in the U.S. survey, there were 9% that tested positive for virus infection. Ninety percent of the positives were infected with BYVaV. Forty percent of these were detected in `Triple Crown', 40% in `Chickasaw', and 20% in `Apache'. The remaining 9% of the total positive virus samples were infected with TRSV and 100% of these were in `Triple Crown'. No viruses were found on any samples of `Chester Thornless'. In the Arkansas survey, 11% of the total samples tested positive for virus. Of these, 50% were infected with BYVaV.
The percent infected with BYVaV was distributed evenly among `Apache', `Chickasaw', and `Kiowa'. The other 50% of the infected samples were positive for TRSV (67% `Apache', 33% `Chickasaw'). There was one mixed infection of BYVaV and TRSV detected in `Apache'. These findings indicate that BYVaV is the most prevalent virus found in nursery stock and that the occurrence of BYVaV is not restricted to a single region or cultivar.