The public sector has a long and successful history of developing enhanced germplasm and finished cultivars that are transferred through public release. For several reasons, such as maintaining genetic integrity, public release may not now be the
Mojdeh Bahar and Robert J. Griesbach
Mark K. Ehlenfeldt
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.
J.B. Magee, B.J. Smith, C.E. Gupton and J.M. Spiers
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.
Lian-wei Qu, Gui-mei Xing, Juan-juan Chen, Jia-jun Lei and Yan-qiu Zhang
and red flowers, respectively. Pink purple and red colors are the symbols of luck and happiness in Chinese culture. The newly released pink purple–flowered (RHS 72B) tulip cultivar Purple Jade is the first Chinese tulip cultivar registered in 2015. The
Margaret R. Pooler
The U.S. National Arboretum has released over 650 new plant cultivars since it was established in 1927. A key to the success of the plant breeding program has been the voluntary participation of universities and private nurseries in evaluating and propagating new plant material. The cooperative evaluation and stock increase programs play a critical role in the successful testing, introduction, and distribution of new cultivars of landscape trees and shrubs. These integrated cooperative programs depend on the involvement of nurserymen, researchers, botanic gardens, or individuals to evaluate potential new cultivars under diverse climatic conditions and hardiness zones, and wholesale propagation nurseries to increase stock of those cultivars destined for release.
Mark K. Ehlenfeldt
Self- and cross-fertility was evaluated in the highbush blueberry cultivars Bluegold, Duke, Legacy, Nelson, Sierra, Sunrise, and Toro, all released since 1987, by comparing them to standards of `Bluecrop' and `Rubel'. Percent fruit set increased with cross-pollination in all cultivars except `Bluecrop', which decreased by 13%. The average increase in the recently released cultivars was 43%. Fruit weight also increased in cross-pollinations for all cultivars except `Rubel', which showed a decrease of 2%. Average increase in fruit weight on cross-pollination in the recently released cultivars was 27%. Fruit set and fruit weight measurements suggest that `Duke', `Legacy', and `Nelson' could perform well in solid stands, but `Sierra' and `Toro' are more likely to need cross-pollination for best yields. Investigations were also made on a group of 10 cultivars, to evaluate whether ripening time of the pollen source cultivar had any effect on the ripening time of the fruiting parent. No single pollen source had consistent general effects on ripening, although specific combinations of females and males appeared to either hasten or delay ripening. The largest deviations were seen in delays of ripening, suggesting that poor pollination may have been the greatest factor contributing to the observed variation in ripening times.
Wendy Britton, E.J. Holcomb and David J. Beattie
Four rates of two slow-release fertilizers were tested for optimum growth of five hosta cultivars: Hosta sieboldiana `Elegans', Hosta plantaginea `Aphrodite', Hosta `Jade Scepter', Hosta `Hadspen Blue', and Hosta `Francee'. Tissue-cultured hostas from 2.5-cm plugs were planted in 6-inch (15-cm) pots filled with a commercial soilless medium, and the slow-release fertilizer was dibbled into the medium at 0, 3, 6, or 12 g/pot. The plants were maintained for 4 months. Root and shoot fresh and dry weights were recorded at the end of the experiment. In addition, foliar nutrient analysis was conducted on `Aphrodite', `Francee', and `Jade Sceptor'. Overall, hostas grew best when the medium was amended with 3 g of either Osmocote 14N-6P-11.5K or Sierrablen 17N-6P-12K slow-release fertilizer.
Robert O.M. Mwanga, Benson Odongo, Charles Niringiye, Agnes Alajo, Putri E. Abidin, Regina Kapinga, Silver Tumwegamire, Berga Lemaga, James Nsumba and Edward E. Carey
Two orange-fleshed landrace sweetpotato [ Ipomoea batatas L. (Lam.)] cultivars named ‘SPK004’ (‘Kakamega’) and ‘Ejumula’ were approved for release by the Ugandan Plant Variety Release Committee in Apr. 2004 ( Mwanga et al., 2004a ). This is the
M.K. Ehlenfeldt, A.D. Draper and J.R. Clark
contributions of Max Austin, Jim Ballingn, Creighton Gupton, Jim Moore, and Jim Spiers to testing and developing these cultivars and we thank them for contributing performance data.
Darren L. Haver and Ursula K. Schuch
The objectives of this study were to determine 1) the minimum controlled-release fertilizer (CRF) rate and the lowest constant medium moisture required to produce the highest quality plants and 2) if this production system affected quality of these plants under two postproduction light levels. Two New Guinea impatiens (Impatiens sp. hybrids) `Illusion' and `Blazon' (Lasting Impressions Series) differing in salt tolerance were grown for 42 days with a CRF at three rates (3.3, 6.6, or 9.9 g/pot) and two medium moisture levels (low or high) without leaching. The high moisture level (tension setpoints of 1 to 3 kPa) and 6.6 g of CRF/pot produced optimum biomass. Low medium moisture (tension setpoints of 4 to 6 kPa) reduced leaf area, leaf number, leaf N content, root, stem, and leaf dry masses as CRF rate increased from low to high for `Illusion'. Similar results in `Blazon' were observed as CRF rates increased from 3.3 to 6.6 g. Biomass decreased no further at the high rate of 9.9 g/pot. Biomass increased in both cultivars under high medium moisture when CRF rates increased from 3.3 to 6.6 g. Biomass of `Illusion' decreased at 9.9 g/pot, although no symptoms of salt sensitivity were observed (i.e., leaf tip burn). `Blazon' maintained a similar biomass when amended with 9.9 or 6.6 g CRF/pot, although electrical conductivity (EC) in the medium was 5.9 dS·m-1 in the upper half and 4.1 dS·m-1 in the lower half of the medium at the end of production. Growth of `Illusion' responded more favorably to postproduction light levels that were similar to those of production regardless of treatment imposed during production. Similar biomass responses occurred for `Blazon' regardless of the postproduction light level.