). There are many highbush blueberry cultivars grown in the northwestern United States ( Strik et al., 2014 ), some of which are reported to have more variability in berry weight and fruit set than others (e.g., ‘Liberty’ and ‘Draper’). Our objectives were
; Smittle and Miller, 1988 ). However, a number of new cultivars have been released since these studies were undertaken and little work has been done to optimize the postharvest keeping quality of ‘Elliott’ blueberry fruit, the latest-ripening cultivar grown
As part of a program to develop transgenic highbush blueberry (Vaccinium corymbosum L.) cultivars, studies were conducted to determine optimum conditions for high-efficiency shoot regeneration from leaf explants of in vitro propagated, commercially important, tissue culture-recalcitrant `Bluecrop' shoot cultures. The effects of pretreatments, growth regulators, and age of explant source on shoot organogenesis were investigated. A maximum of 98% shoot regeneration and 10 shoots regenerating per leaf explant occurred when explants of 2-week-old shoot cultures were incubated in the dark (for a total of 14 days) on pretreatment medium #1 containing 2.6 μM NAA and 5 μM TDZ for 4 days, next on pretreatment medium #2 containing 2.6 μM NAA and 7 μM zeatin riboside for 3 days, then on regeneration medium containing 1 μM TDZ for 6 weeks, and last on medium without growth regulators for 10 days. No shoot regeneration occurred if explants were incubated without exposure to pretreatments before incubation on regeneration medium. There were no significant differences in percentage of regeneration or the number of shoots regenerating per explant from leaf explants derived from either 1-, 2-, or 3-week-old shoot cultures. Shoot production per explant on 1 μM TDZ was about three times that on either 0.5 μM TDZ or 20 μM zeatin riboside, and nine times that on 5 μM TDZ.
Fifteen highbush (or highbush hybrid) blueberry cultivars (Vaccinium corymbosum Linnaeus), two rabbiteye blueberry cultivars (V. ashei Reade), and one southern lowbush (V. darrowi Camp) selection from the wild were examined using seventeen 10-base RAPD and seven 15- to 18-base SSR-anchored primers (primers comprised of SSR motifs) in polymerase chain reactions (PCRs). Fifteen RAPD and three SSR markers resulting from these reactions were chosen to construct a DNA fingerprinting table to distinguish among the genotypes included in this study. Similarity values were calculated based on 132 RAPD and 51 SSR bands, and a dendrogram was constructed based on the similarity matrix. The V. ashei cultivars and V. darrowi selection grouped out separately from the V. corymbosum cultivars as expected. However, estimates of relative genetic similarity between genotypes within the V. corymbosum group did not agree well with known pedigree data and, thus, indicated that RAPD and SSR data did not accurately assess the genetic relationships of cultivars within this species.
from Michigan Blueberry Growers Association and Abbott Laboratory. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to
1 Professor and berry research leader, NWREC. 2 Senior research assistant, NWREC. The authors appreciate the support of the Oregon Blueberry Commission, Fall Creek Farm & Nursery, Lowell, Ore. and Oregon Blueberry Farms, Silverton, Ore.
Thirty-three Vaccinium corymbosum selections and cultivars were artificially inoculated with spores of Colletotrichum gloeosporioides in the green fruit stage. Fruit was harvested when ripe and incubated under high-humidity conditions for 1 week, before evaluation. A wide range of susceptibility to anthracnose fruit-rot was found, ranging from 8% to 85%. Among the most-resistant cultivars were: `Elliott' (8%), `Murphy' (8.3%), `Stanley' (13%), and `Weymouth' (16.9%). Among the most-susceptible cultivars were: `Bluetta' (85%), `Spartan' (82.7%), `June' (69.9%), and `Northblue' (69.5%). Uninoculated checks had a maximum of 6% infection.
Ornamental blueberries are increasing in popularity in southern landscaping due to their attractive foliage and also since they provide food and serve as attractants to birds and other wildlife. `Native Blue', tested as MS611, resulted from a cross of two native diploid Vaccinium darowii clones, Florida 4B X US 799. US 799 was selected from seedlings grown from open-pollinated seed collected by Dr. Paul Lyrene in Ocala National Forest, Florida. The Cross was made by Dr. Arlen Draper and selected in the greenhouse in 1987. Plants of `Native Blue' are low growing, compact, and finely branched with small, glaucous leaves and are quite typical of V. darowii. In test plots in Mississippi, the plants set many small berries and after four years have have grown to a height of approximately 18 inches. Desireable characteristics include beautiful pastel foliage, hardy and vigorous plants producing much fruit that are attractive to native birds.
Blueberry fruit were harvested at commercial maturity from variety trials and shipped overnight to UC Davis. Fruit quality was evaluated upon receipt and after 6 and 20 days of cold storage at 0.5 °C in air shelf life. Firmness, external color, soluble solids, and titratable acidity were measured. Sensory evaluations were conducted by trained tasters to rate the blueberries for crispness, mealiness, sweetness, tartness, blueberry flavor, and off-flavors at harvest and again after 21 days of storage. Many of the blueberries increased in firmness during cold storage. Firmness at harvest tended to be softer in `Santa Fe' and `Jewel' and firmer in `Star'. Sensory data also found `Sharpblue' and `Southmoon' to be more firm; however the objective measurements did not agree. Overall, `Saphire' was low in sugars and acids, and `Jewell' and `Star' were high in acids. `Misty' and `Sharpblue' were consistently high in sugars and acids. Overall objective fruit quality ratings were highest for `Misty', `Sharpblue', and `Southmoon', and lowest for `Santa Fe'. Blueberry flavor was rated highest in `Jewell', `Star', and `Sharpblue', and lowest in `Santa Fe', `Saphire', `Misty', and `Emerald'. These data indicate that blueberry flavor may be closely tied to acid content, as most of the high-flavor varieties had high acid and many of the low-flavor varieties had low acid. Over 3 years, the varieties consistently rated highest for overall objective quality were `Misty' and `Southmoon'. `Star' was rated high for overall quality in 2 years and moderate in 1. `Jewell', `Star', and `Sharpblue' were rated highest in flavor. `Santa Fe' was ranked low in flavor quality in 2 out of 3 years. Selection of variety appears to have a strong influence on the sensory quality of the blueberries marketed.
Infestations of Botrytis blossom blight (Botrytis cinerea) can reduce yields in commercial blueberry fields in the Pacific Northwest. In 1993, environmental conditions during blueberry flowering were ideal for the development of Botrytis. Individual plants were evaluated in a replicated highbush blueberry culture/advanced selection trial (42 clones, 5 reps, 3 plants) in Aurora, Ore. Each plant was evaluated for damage due to Botrytis using a subjective scoring system (1= all flower clusters on plant appear blighted, 5= many blossoms blighted, 9= no blossoms blighted). Many clones showed very little injury. The following clones showed the greatest injury, in decreasing order of severity, NC 2678, `Bluechip', `Bounty', G-805, `Nelson', G-224, `Berkeley', `Sierra', and `Bluegold'. In addition, Botrytis damage was scored on the field collection of Vaccinium at the National Clonal Germplasm Repository. Data from this nonreplicated study will also be presented.