The southern highbush (Vaccinium mostly corymbosum) blueberry cultivars Jubilee, Magnolia, and Pearl River, released by the USDA in 1994, were compared with `Premier' and `Climax', two widely planted rabbiteye (V. ashei) cultivars, on the basis of flowering and harvest dates, yield, and physical and chemical quality parameters. The southern highbush cultivars flowered later and ripened at least 1 week before `Climax', one of the earliest rabbiteyes. `Pearl River' berries had less waxy “bloom” and appeared almost black when fully ripe; they had significantly less anthocyanins than the other cultivars compared. `Premier' was lower in titratable acidity and higher in sugars than the southern highbush cultivars. Although data analysis indicated statistical differences in glucose and fructose concentrations among the other four cultivars, these differences were not pronounced. Based on the quality factors used in this study, the southern highbush cultivars compared acceptably to the rabbiteye cultivars.
The water use of three mature highbush blueberry cultivars was determined during the growing season by using TDR technology. A combination of four buriable TDR waveguides at 6-, 12-, 18-, and 24-inch depth and two surface waveguides 6- and 18-inch length were installed in a 60-acre commercial `Bluejay', `Bluecrop', and `Jersey' blueberry field with four replications for each cultivar. The reference evapotranspiration (ETo) was obtained for each cultivar from three weather stations located in the vicinity of replicated waveguides. Soil moisture data were collected every 3-5 days from April to the end of September. The average daily crop evapotranspiration (ETc) was significantly different at different plant developmental stages among three cultivars; the highest daily plant water use was during the fruit development stage for all three cultivars. The crop ETc for `Bluejay' and `Elliott' can be as high as 0.35 inches per day and average 1.5 to 2 inches per week during the summer. The estimated crop coefficients at bloom, fruit development, harvest, and postharvest are 0.90, 1.51, 1.05, and 1.05 for `Bluejay'; 0.84, 1.11, 0.99, and 1.23 for `Bluecrop'; and 0.94, 1.30, 1.39, and 1.17 for `Jersey', respectively. The peak water use coincides well with the advancement of fruit maturity, suggesting irrigation scheduling should differ among early, mid, and later season highbush blueberry cultivars.
There is an increased interest in late-ripening blueberry cultivars in New Zealand and other aspects the growers are looking for in a new cultivar are late flowering to overcome early spring frost, high yield, and adaptability to medium- to low
Abstract
Hexazinone was applied as a soil drench to 1-year-old rooted hardwood cuttings of highbush (Vaccinium corymbosum L.) and rabbiteye (V. ashei Reade) blueberries in a series of greenhouse experiments. No differences in susceptibility to hexazinone were detected among 10 highbush and 3 rabbiteye cultivars growing in a fine sand soil. Two highbush and 2 rabbiteye cultivars were assayed for hexazinone tolerance in low, medium, and high organic matter soil which contained 1.3%, 3.5%, and 49.5% organic matter, respectively. Hexazinone at 1 or 2 kg/ha had no inhibitory effect on blueberry growth in the high organic matter soil, inhibited growth slightly on the medium organic matter soil and caused severe injury in the low organic matter soil. At rates of 4 and 8 kg/ha, injury was severe on the medium and low organic matter soils but very slight on the high organic matter soil.
Fifty-five highbush blueberry (Vaccinium corymbosum L.) cultivars and selections were evaluated over 2 years for their resistance to the shoot blighting phase of mummy berry disease [Monilinia vaccinii-corymbosi (Reade) Honey]. Blight incidence in 1993 ranged from 1% to 78% and differences among cultivars were significant. In 1994, infection levels were lower and ranged from 0% to 43%, again with significant differences among the entries. Several cultivars exhibited mummy berry blight resistance in both years. Ranking most resistant to less resistant were `Jersey', `Elliott', `Bluejay', `Duke', `Stanley', `Darrow', `Meader', and `Angola'. Among the cultivars consistently blightsusceptible were `Bluehaven', `Bluegold', `Northblue', `Croatan', `Northsky', `Sierra', `Harrison', `Coville', and `Murphy'. The consistent resistant reaction of certain cultivars indicates that they may be suitable as parents for introducing resistance into a breeding program. The evaluation methodology developed in these tests should be useful in screening germplasm for new sources of resistance and evaluating segregating progeny from crosses.
Self- and cross-fertility were evaluated in the highbush blueberry (Vaccinium corymbosum L.) cultivars Bluegold, Duke, Legacy, Nelson, Sierra, Sunrise, and Toro, all of which have been released since 1985, by comparing them with `Bluecrop' and `Rubel', which were used as standards. Cross-pollination increased fruit set in all cultivars except `Bluecrop', in which set was reduced 13%. The average increase among recently released cultivars was 43%. Cross-pollination also increased fruit weight for all cultivars except `Rubel'. Average increase in fruit weight with cross-pollination of the recently released cultivars was 27%. Fruit set and fruit weight measurements suggest that `Duke', `Legacy', and `Nelson' would perform satisfactorily in solid stands, and that `Sierra' and `Toro' probably need cross-pollination for maximum yields.
One-year-old rooted microshoots and 2-year-old rooted hardwood blueberry cuttings (Vaccinium corymbosum L.) were inoculated with Phomopsis vaccinii Shear using stem flap, stem freeze, needle pierce, and leaf tear wounding techniques. The needle pierce was the simplest method that produced high infection rates. Nine northern-adapted cultivars were placed in a factorial experiment to measure their infection resistance. Microshoots and hardwood cuttings of `Elliott' and `Bluetta' survived the longest and had the lowest mortality rate. Phomopsis vaccinii was reisolated successfully from inoculated shoots of all cultivars.
Released in 2004 by the University of Georgia and U.S. Dept. of Agriculture, `Vernon' is an early season rabbiteye blueberry (Vaccinium ashei Reade), having large fruit size, good yields and excellent plant vigor. `Vernon', tested as T-584, was selected in 1990 at the Coastal Plain Experiment Station in Tifton, Ga. from a cross of T-23 × T-260. `Vernon' fruit ripens early with the cultivar Climax in south Georgia, and few days before `Premier'; however, `Vernon' flowers 5 to 10 days after the standard cultivars. On average over a 6 year period, `Vernon' yielded 5.8 kg/plant per season, compared to 3.1 and 4.5 kg/plant for `Climax' and `Premier', respectively. Berry stem scar, color, firmness, and flavor of the new cultivar are good to excellent. Berry size of `Vernon' is considerably large, averaging 2.05 g/berry over 4 locations in 2003, compared to only an average weight of 1.56 g/berry for `Climax'. `Vernon' berries are firmer than `Premier'. Propagation of the new cultivar is easily accomplished from softwood cuttings. Chill hour requirement is estimated to be in the range of 500 to 550 hours (<7 °C). `Vernon' should be planted with other rabbiteye blueberry cultivars with a similar time of bloom to provide optimum pollination. Propagation rights are controlled by Georgia Seed Development Commission, 2420 S. Milledge Avenue, Athens, GA 30606 (for more information go to www.gsdc.com).
The effects of pollination treatments on fruit set and five berry characteristics [mass, diameter, number of apparently viable seeds (well-developed, plump with dark seed coat), total seed number (includes apparently viable and partially developed seeds), and harvest date] were examined on three highbush blueberry cultivars. Pollination treatments included unpollinated, open pollinated, emasculated, and three hand pollinations that used pollen from the same flower, from the same cultivar, or from a different cultivar. Berries matured earliest and were smallest with the most apparently viable seeds in `Northland', `Patriot' had the greatest fruit set and smallest seed number, and `Bluecrop' matured the latest. Fruit set was greater, berry size larger, seed number smaller, and maturation later in 1990 than 1991. For all three cultivars, berries were generally smallest, latest maturing, and had the fewest seeds when pollination was prevented and were largest with the most seeds and earliest maturing in open visitation. Emasculation resulted in berries similar to those from unpollinated flowers. For berry characteristics, cross-pollination was of benefit for `Patriot' and possibly `Northland' but not `Bluecrop'. Thus, commercial highbush blueberry planting designs must be based on the pollination requirements of the particular cultivar. `Northland' berries almost always had seeds, while `Patriot' showed high levels and `Bluecrop' low levels of parthenocarpy.
, PYO, and home use. Origin Dr. Frederick V. Coville was the founder of the USDA blueberry breeding program (which began in 1911) and he is credited for 15 cultivars developed from crosses made during his lifetime ( Mainland, 2012 ). He has also been