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To characterize the in vitro behavior of Rhododendron `Montego' with tissue proliferation (TP) to cytokinin and auxin, comparisons were made of normal [TP(–)], dwarf TP [TP(+) dwarf], and long TP [TP(+) long] shoot cultures. On basal medium TP(–) and TP(+), long shoots failed to multiply and had a low relative growth rate (RGR) of 0.1, whereas TP(+) dwarf shoots produced 31.8 shoots per tip, with most shoots being <5 mm long, and RGR was 0.3. Addition of 15 μm 2iP to basal medium induced the production of more than six shoots per TP(–) tip and doubled their RGR; TP(+) long shoots produced 16.8 shoots, most <5 mm long, and had an RGR of 0.3; TP(+) dwarf shoots produced only 16% as many shoots as on basal medium, but still exhibited an increase in RGR. Leaves from TP(–) and TP(+) sources failed to produce shoots on basal medium, but 74% of TP(–) leaves formed shoots when cultured on 1 μm IBA and 30 μm 2iP. TP(+) leaves were able to form shoot meristems on media containing only 5 μm 2iP (26% of explants), but these meristems failed to elongate into shoots. Calli from TP(–) leaves, TP(+) leaves, and TP(+) tumors grown on medium containing 10 μm NAA and 15 μm 2iP had higher RGRs than the same calli on basal medium during the first 8 weeks of culture. Over time, RGR decreased in both TP(–) and TP(+) leaf calli, but increased in TP(+) tumor callus. The increased RGR resulted from differentiation of shoot meristems on 85% of the calli between week 4 and week 8. Our results suggest that TP(+) tissues have altered hormone metabolism or sensitivity that leads to dramatic differences in in vitro behavior and probably contributes to tissue proliferation observed in whole plants. Chemical names used: 6-(γ,γ-dimethylallylamino) purine (2iP); indole-3-butyric acid (IBA); α-naphthaleneacetic acid (NAA).

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The growth of the ornamental plant industry has rapidly increased over the past several years, creating a strong demand for well-trained graduates and industry workers. It is vital for a person entering this industry to have a solid and broad plant material background. The best ways to learn, sell, and teach plants are through visual materials. Currently, there are few cost-effective resources that provide a person with all the visual information needed to learn plants. To better serve the students and industry workers, the Univ. of Connecticut has developed a free multimedia ornamental plant database on the World Wide Web. The plant database focuses on plants for the New England area (USDA zone 6 and lower). This website brings detailed textual information, thousands of pictures, and audio pronunciations together in one complete package. Plant characteristic information (textual and pictorial) consists of habitat, habit and form, summer foliage, autumn foliage, flowers, fruit, bark, culture, landscape uses, liabilities, ID features, propagation, and cultivar/variety. The major factors and decision processes involved in developing an educational Web site, with emphasis on usability and accessibility are considered. The target audience for this Web site is students as well as the nursery and landscape industry workers, agricultural consultants, extension personnel, landscape architects, and the gardening public.

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Japanese barberry (Berberis thunbergii DC.) is a popular ornamental shrub used in garden and urban landscaping. Currently there are over 60 B. thunbergii cultivars in the market. To better distinguish its cultivars, we used the amplified fragment length polymorphism (AFLP) technique to develop DNA marker profiles for 59 cultivars and hybrids. These markers were used to authenticate the trueness-to-name of B. thunbergii cultivars in production and in the market, control for intracultivar genetic variants, and develop a molecular key to identify cultivars approved for importation in Canada. Polymorphic markers from seven primer combinations were able to clearly differentiate 57 of 59 cultivars evaluated. Two cultivars, Aurea and Aurea Nana, could not be differentiated because they had identical marker profiles. Among the 274 plants tested, 263 were confirmed to be true-to-name and correctly labeled, whereas 11 plants could not be confirmed true-to-name. Seven of the 20 cultivars evaluated exhibited detectable intracultivar genetic variation. ‘Crimson Pygmy’ had the highest number of plants exhibiting genetic variability. Overall, nursery producers and retailers do not appear to be mixing or mislabeling cultivars. A molecular key developed from a subset of 25 markers was able to accurately identify and differentiate the 11 B. thunbergii cultivars approved for importation in Canada. This key could be used in a cultivar verification program to facilitate international trade of B. thunbergii cultivars where wheat rust is a concern.

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While japanese barberry (Berberis thunbergii DC.) is an acknowledged invasive plant naturalized throughout the eastern and northern U.S., the danger posed by its popular horticultural forms is unknown and controversial. This work analyzed the reproductive potential and seedling growth of four ornamental genotypes important to the nursery industry. Fruit and seed production was quantified in 2001, 2002, and 2003 for multiple landscape plants of B.t. var. atropurpurea, `Aurea', `Crimson Pygmy', and `Rose Glow'. The average number of seeds produced per landscape specimen ranged from lows of 75 and 90 for `Aurea' and `Crimson Pygmy' to 2968 for var. atropurpurea and 762 for `Rose Glow'. Seed production relative to canopy surface area for `Rose Glow' was similar to `Aurea' and `Crimson Pygmy' and all three cultivars were less prolific than var. atropurpurea in this regard. Cleaned and stratified seeds from var. atropurpurea, `Crimson Pygmy' and `Rose Glow' showed an average greenhouse germination rate of 70% to 75%, while `Aurea' yielded 46% germination. A subpopulation of seedlings from each genotype accession was grown further outdoors in containers for a full season to ascertain seedling vigor and development. The vigor of 1-year-old seedlings, as measured by dry weight of canopy growth, for progeny derived from `Aurea' (0.70 g) and `Crimson Pygmy' (0.93 g) was significantly less than var. atropurpurea (1.20 g) and `Rose Glow' (1.33 g). These results demonstrate that popular japanese barberry cultivars express disparate reproductive potential that, after further study, may be correlated with invasive potential. Some popular commercial cultivars may pose significantly less ecological risk than others.

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The shade-tolerant, variegated grass Hakonechloa macra `Aureola' is a valuable ornamental. In an experiment replicated in two growing seasons, Hakonechloa plants were fertilized at each irrigation (fertigation) with factorial combinations of three fertilizer formulations (N:P molar ratios 5:1, 10:1, and 20:1) at five N concentrations (2, 4, 8, 16, and 32 mmol·L-1), along with an unfertilized control, to determine the effect of N:P ratio and N concentration on vegetative growth and to establish fertility guidelines for production. Root dry weight and tiller bud growth increased slightly as N:P ratio increased. Fertilizer N concentration of 16 mmol·L-1 promoted the most shoot growth, whereas the number of tiller buds and root growth were greatest at 2 and 4 mmol·L-1 N. No interaction occurred between N:P ratio and fertilizer concentration. Results indicate that an N concentration of 8 mmol·L-1, with an N:P ratio of 10:1 or 20:1 is optimal for production of Hakonechloa. At this fertilizer concentration, the mean electrical conductivity of extracts obtained by a solution displacement extraction (pour-through) procedure was 2.3 ± 0.45 dS·m-1 (mean ± standard deviation). Tissue nutrient concentrations of N, P, K, Ca, and Mg were (in mg·g-1): 24.0, 2.8, 14.3, 2.1, and 2.1, respectively. In a concurrent study, Hakonechloa plants were grown in pine bark: peat: sand mix with dolomitic lime added at 0, 1.2, 3.6, and 9.5 kg·m-3 producing pH ranging from ≈4.5 to 7.2. Growth of Hakonechloa was greatest with no lime (pH 4.5) and declined markedly as the rate of lime increased. Concentrations of N, P, and K in shoot tissue were greatest at a pH between 4.5 and 5.6 (0 and 1.2 kg·m-3 dolomitic lime). These findings clearly support recommending production of Hakonechloa in soilless potting mix with pH ≈4.5 and constant fertigation with N at 8 mmol·L-1.

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Funding reductions have left many Extension field and specialist positions unfilled when they are vacated. In New England, severe economic downturns have made this situation acute and have forced Extension programs to find innovative and more efficient ways of delivering information to clientele groups. The nursery and landscape industries comprise a major agricultural sector in New England whose needs must be met to maintain agriculture in the region. Yankee Nursery Quarterly was developed as a regional effort to draw upon nursery and related expertise from the six New England states. Yankee Nursery Quarterly provides information in the areas of nursery and Christmas tree production, landscaping, arboriculture, garden center operation and turfgrass four times annually. The publication format deviates from the standard 8 ½″ by 11″ size and uses 2 color printing, a four-column layout and black and white photography to provide a recognizable, informative and visually appealing product.

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Winged euonymus [Euonymus alatus (Thunb.)] is an important landscape shrub that has demonstrated its potential to be invasive in numerous states across the central and northern United States. Nine cultivars were evaluated for their potential to produce fruits and seeds in a randomized, replicated field planting. Seeds from all cultivars were evaluated for germination rate and initial survival in a deciduous woodland. Seeds collected from ‘Compactus’ were also sown in five natural environments (full sun meadow, edge of woods, moist woods, dry woods, pine woods) to determine which habitat types support its germination and establishment. Seed production for cultivars varied from 981 to 6090 seeds per plant. The dry deciduous woods and pine woods were the only environments that supported significant germination rates that could be as high as 37.8%. Seedling survival was at least 77% in the deciduous dry woods and at least 55% in the pine woods. In the first replication, establishment rates for cultivars in the dry deciduous woods ranged from a low of 6.5% for ‘Odom’ Little Moses™ to a high of 42.5% for ‘Monstrosus’. In the second replication, all cultivars achieved over 30% establishment and most exceeded 40% establishment. An estimate of the annual seedling contribution per plant per cultivar was calculated by combining seed production data with establishment data for each cultivar. This estimate was predicted to range from 588 to 3763 and therefore none of the nine cultivars evaluated should be considered non-invasive based on our findings. Our findings show that germination and seedling survival rates are high for E. alatus and because the species is long-lived, cultivars will likely have to be completely seed-sterile to be considered non-invasive according to demographic models.

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