"‘UCONNAM012’ (Ground Hug®) and ‘UCONNAM165’ (Low Scape Mound®): Two Low-growing Cultivars of Black Chokeberry (Aronia melanocarpa)" published on Apr 2024 by American Society for Horticultural Science.
Japanese barberry (Berberis thunbergii DC.) is a widespread invasive plant that remains an important landscape shrub represented by ornamental, purple-leaved forms of the botanical variety atropurpurea. These forms differ greatly in appearance from feral plants, bringing into question whether they contribute to invasive populations or whether the invasions represent self-sustaining populations derived from the initial introduction of the species in the late 19th century. In this study we used amplified fragment length polymorphism (AFLP) markers to determine whether genetic contributions from B. t. var. atropurpurea are found within naturalized Japanese barberry populations in southern New England. Bayesian clustering of AFLP genotypes and principal coordinate analysis distinguished B. t. var. atropurpurea genotypes from 85 plants representing five invasive populations. While a single feral plant resembled B. t. var. atropurpurea phenotypically and fell within the same genetic cluster, all other naturalized plants sampled were genetically distinct from the purple-leaved genotypes. Seven plants from two different sites possessed morphology consistent with Berberis vulgaris (common barberry) or B. ×ottawensis (B. thunbergii × B. vulgaris). Genetic analysis placed these plants in two clusters separate from B. thunbergii. Although the Bayesian analysis indicated some introgression of B. t. var. atropurpurea and B. vulgaris, these genotypes have had limited influence on extant feral populations of B. thunbergii.
Experiments were conducted on tissue proliferation (TP) development and in vitro and ex vitro growth of tissues from plants with (TP+) and without TP (TP-). In 1993 the increase in TP in one-, two-, and three-yr-old `Holden' and `Besse Howells' was 3%, 52%. and 32% and 10%, 26% and 21%, respectively. No differential mortality was observed. Shoot tip cultures initated from TP+ and TP- `Montego' showed 10-12 mo were required for miniaturiziation and multiplication in TP- shoot tips and 4 mo in TP+ shoot tips. TP- cultures require 10 uM 2-iP for normal shoot proliferation; whereas TP+ cultures had to be transferred to hormone-free medium after 6 mo to maintain normal shoot morphology. Cutting propagation from TP- and TP+ plants older than 5 yr, showed persistence of morphological aberrations associated with TP+ plants.
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.
The effect of shading during nursery production on the growth, foliage color, and foliar chlorophyll content of container-grown Kalmia latifolia cultivars was investigated. Five cultivars were grown under 40% shade, 60% shade, or full sunlight for a 2-year production cycle. During the first year of production, there were no significant differences in measured growth characteristics for most cultivars in response to light treatment. Shade improved foliar color by decreasing lightness (L*), decreasing chroma, and changing hue angle from a yellow-green to a darker green. Foliar chlorophyll concentration increased under shade. In the second year of the production cycle, the response of foliar color and chlorophyll concentration to shade was similar to that observed in year 1. Plant size, number of branches, leaf area, leaf dry mass, and stem dry mass decreased linearly with increasing shade in year 2. Although shading improves foliar color, it probably should not be employed for container production of Kalmia latifolia in cool, northern production areas due to reduced plant growth during year 2. Shade may be useful in the first year of production to enhance foliar color without reducing shoot growth.
Cannabis ( Cannabis sativa ) grown for flowers containing cannabinoids requires all female plants, which are susceptible to seed set from exposure to pollen. Created triploids demonstrated reduced seed production compared with diploids in field and greenhouse studies in which plants were challenged with pollen from males. In the field, seed production as a percent of floral biomass ranged from 6.7% to 18.0% for triploids and from 52.6% to 57.1% for diploids. The photoperiod-insensitive triploid genotype ‘Purple Star’ × ‘Wilhelmina’ had 98.5% fewer filled (containing a developed embryo) seeds than the photoperiod-insensitive diploid genotype ‘Tsunami’ × ‘Wilhelmina’. In the greenhouse, triploid ‘Wife’ had 99.5% fewer filled seeds than diploid ‘Wife’. Plant growth and flower production were similar with eight triploid and seven diploid genotypes evaluated over three greenhouse studies. There were a few superior triploid and diploid genotypes; however, their performance was more likely attributable to the parental cultivar combination than ploidy level. The optimal cross direction for producing triploid seed in large quantities is tetraploid × diploid because the diploid × tetraploid cross exhibits triploid block caused by endosperm paternal excess. Colchicine-induced tetraploid parent plants should be tested over a prolonged period to eliminate cryptic chimeral mixoploids or tetraploid plants should be derived from seed produced by crossing two colchicine-induced putative tetraploid plants to ensure that seeds from tetraploid × diploid crosses will be triploid. The latter approach is necessary for photoperiod-insensitive cultivars because a prolonged period of ploidy testing is not possible for these plants. These findings indicate that triploid plants have significantly reduced fertility and are a suitable alternative to diploids in situations in which pollen exposure is possible.
This study reports the development, characterization, and cross-species transferability of 20 genomic microsatellite markers for Aronia melanocarpa , an important nutraceutical fruit crop. The markers were developed with Illumina paired-end genomic sequencing technology using DNA from Professor Ed cultivar that was originally collected from the wild in New Hampshire. The markers were highly polymorphic and transferable to Aronia arbutifolia and Aronia prunifolia genomes. The average number of alleles per locus was 9.1, 4.5, and 5.6 for A. melanocarpa , A. arbutifolia , and A. prunifolia , respectively. The polymorphism information content (PIC) of loci ranged from 0.38 to 0.95 for all taxa, with an average of 0.80, 0.68, and 0.87 for A. melanocarpa , A. arbutifolia , and A. prunifolia , respectively. This is the first study to develop microsatellite markers in the Aronia genus. These markers will be very useful in studying the genetic diversity and population structure of wild Aronia and expediting the breeding efforts of this emerging fruit crop through marker-assisted selection.
Abstract Outdoor-grown, containerized, Aronia melanocarpa (Michx.) Ell. and Rhododendron ‘Roseum Elegans’ were grown atop soil-filled boxes that had been recessed into a grassed field in separate studies. Aronia were fertilized with either a single application of controlled-release fertilizer (CRF) or a split application of CRF separated by 36 days. Rhododendron were supplied a single application of CRF and either a standard or excessive irrigation volume on each irrigation day. Soil samples were taken in 30 cm (12 in) layers to a depth of 90 cm (36 in) beneath containers at 14-day intervals and soil NO3-N concentrations were determined. Accumulation of NO3-N was immediate in the 0—30 cm (0–12 in) layer for both species with accumulation of NO3-N in the deeper soil layers occurring later. Split application of a CRF was somewhat effective at reducing NO3-N accumulation at specific times and in specific soil layers, but reductions were not as substantial as studies on NO3-N concentrations in leachate have indicated. The large irrigation volumes used in the irrigation volume study resulted in NO3-N moving rapidly through the soil profile beneath containers.
