Cuticular waxes were analyzed on abaxial and adaxial leaf surfaces of three Hosta genotypes differing in leaf surface glaucousness; the glossy-leaved Hosta plantaginea, the glossy-leaved Hosta lancifolia, and the glaucous-leaved Hosta `Krossa Regal'. All three hosta had their highest total leaf wax quantity in the spring soon after full leaf expansion. The major wax constituent class on these hosta was primary alcohols, comprising up to 84.6% of the total wax. Many hosta leaves had unusually high C24 length primary alcohols, especially in the spring. However, the dominant chain length in this alcohol class varied with development and genotype. A unique class of ß-diketones were present on the glaucous `Krossa Regal', comprising as much as 28.7% of the total waxes on abaxial leaf surfaces in the summer. Interestingly, these ß-diketones were only 0.9% of total waxes on adaxial leaf surfaces of `Krossa Regal' in the summer. Studies are under way to determine whether the dramatic seasonal changes in the waxy leaf coatings described in this report are associated with biotic and abiotic stress resistance in hosta.
Matthew A. Jenks, Carole H. Gaston, Mark S. Goodwin, Jessie A. Keith, Rebecca S. Teusink, and Karl V. Wood
Jessie Keith, Carole H. Gaston, and Matthew A. Jenks
Hosta variants for epicuticular waxes were selected based on variation in surface glaucousness, from highly glaucous to highly glossy. In an effort to determine seasonal variation in hosta waxes, gas-chromatography mass-spectrometry was used to perform detailed chemical analysis of the adaxial and abaxial leaf blade waxes four times points during the growing season, early spring, mid-spring, mid-summer, and autumn. These studies revealed that in all variants, the total wax loads increased dramatically during the period of leaf expansion in the spring, dropped roughly five fold by midsummer, and then accumulated slightly above summer levels into the fall season. The dominant wax constituent class on all hosta cultivars was primary alcohols. Changes in these alcohols were primarily responsible for seasonal changes in total wax load. In some variants, the shorter chain length alcohols were unusually high compared with alcohol distributions normally found on other plants. Besides primary alcohols, significant amounts of acids, aldehydes, and alkanes, were also found and shown to vary during the growing season. A possible association between these seasonal changes in wax profiles and hosta resistance to slugs is discussed.
Stephen J. Stringer*, Arlen Draper, and James M. Spiers
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.
Ouina C. Rutledge and Patricia S. Holloway
The germination, establishment, survival, and public preference of four wild-flower seed mixes were evaluated in relation to irrigation and seasonal sowing date. The mixes included two commercial nonindigenous wildflower mixes, a commercial mix with indigenous and nonindigenous wildflowers, and an experimental mix composed exclusively of Alaska native wildflowers. The two latter mixes were sown with and without `Tundra' glaucous bluegrass (Poa glauca). The two nonindigenous mixes exhibited the greatest seedling establishment during the first season. Fall sowing and irrigation during seed germination significantly increased species establishment for all mixes. In the second season, 11 nonindigenous species did not reappear, whereas all of the indigenous species reappeared. The experimental mix had the greatest species richness of the six mixes in the second season. The addition of grass to the mixes did not significantly affect wildflower species richness in either the first or second season. Survey respondents preferred the nonindigenous wildflower mixes to those containing Alaska native wildflowers because of a greater mix of colors that appeared earlier in the first season than the other mixes. Alaska native species recommended for wildflower mixes include Polemonium acutiflorum, Lupinus arcticus, Hedysarum mackenzii, Arnica alpina, and Aster sibiricus.
Michael C. Long*, Stephen L. Krebs, and Stan C. Hokanson
Forty deciduous azalea (Rhododendron sp.) cultivars from commercial sources were evaluated for powdery mildew (Microsphaera sp.) resistance. Plants were established in two duplicate field plantings in Ohio and Minnesota and evaluated in 2002 and 2003. Plants were scored using a disease symptom rating based on the percent of leaf area infected, evaluating both ab- and adaxial leaf surfaces. Highly significant differences were found for cultivar, location, year, cultivar × location and cultivar × year for disease severity. Calendulaceum × speciosum, `Fragrant Star', `Garden Party', `Late Lady', `Millennium', `Parade', and `Popsicle' showed no powdery mildew symptoms in both locations. Another group of plants with only minimal symptoms (<25% leaf area affected) included `Jane Abbott', `Magic', `Northern Hi-Lights' and `Snowbird'. The symptom-free cultivars exhibited glaucous foliage, suggesting a potential, common resistance mechanism. The mean scores for the abaxial and adaxial leaf surfaces were 2.34 and 1.64, respectively, although four cultivars had more disease symptoms on the adaxial surface. `Arneson Gem' showed nearly a two-point difference between abaxial and adaxial scores. Evaluations of azalea powdery mildew susceptibility should consider both leaf surfaces and use the highest score as the best estimate of host resistance.
S.J. Stringer, J.M. Spiers, and A.D. Draper
Two new southern highbush blueberry cultivars, `Dixieblue' and `Gupton', will provide growers with new blueberry cultivars having excellent fruit quality that ripen relatively early in the season, during the profitable early fresh-market window. Berries of `Dixieblue' are light blue, medium in size, and their flat shape makes them most attractive. `Gupton' is very productive and berry quality is also excellent. The performance of these cultivars represent an improvement over most currently available southern highbush blueberry cultivars due to 1) their durability and performance on both upland and sandy soils endemic to the Gulf Coast and 2) consistent production of high quality fruit that will meet the demand for early ripening fresh-market blueberries. The new rabbiteye blueberry cultivar, `DeSoto', represents an improvement over currently available rabbiteye blueberry cultivars for late-season production. `DeSoto' produces medium-to-large fruit having excellent color, flavor, and firmness Plants of `DeSoto' are productive, vigorous but semi-dwarf, upright and spreading. It's semi-dwarf growth habit, which is unique among currently grown rabbiteye blueberries, results in bushes that attain a maximum height of about 2 meters upon maturity, reducing the necessity of top-pruning that is required for all other cultivars. `DeSoto' blooms two to three weeks later than early-to-mid season cultivars such as `Climax' and `Tifblue', providing insurance against late-spring freezes. Similarly, its fruit mature 21 to 14 days or more, respectively after these same cultivars. `DeSoto' will provide niche market blueberry growers with a new cultivar having productivity, plant vigor, fruit quality, and very late ripening period that will extend their marketing season. The new evergreen ornamental blueberry, `Native Blue', is low growing, compact and finely branched with small glaucous leaves, traits that are quite typical of V. darowii. `Native Blue' has beautiful foliage that changes color in different seasons. Mature leaves are darker green while newer growth exhibits a light pinkish hue that changes to a bluish green. Other desirable characteristics of `Native Blue' are its dwarf growth habit, hardy and vigorous growth, and its capacity for a high level of fruit production that serves as an attractant to birds and other wildlife. `Native Blue' will provide southeastern U.S. nurserymen, landscapers, and homeowners with a novel and beautiful new ornamental shrub that will complement plantings of azaleas, camellias, crepe myrtles, etc.
Sheng-Xi Liao, Xian-Jie Mi, Ai-Zhong Liu, Kun Li, Zhen-Yin Yang, and Bo Tian
glaucous green leaves on the upper side of the shoots ( Farjon, 2005 ; Fu et al., 1999 ). As a result of its glaucous green leaves and beautiful shape, Chinese Incense-cedar has been introduced into many gardens or parks worldwide as an ornamental tree. In
D. Scott NeSmith and Mark K. Ehlenfeldt
height of 1.2 m with a canopy width of more than 0.6 m on 3-year-old plants grown in acidic soil (pH less than 5.2) with pine bark amendment. The non-glaucous foliage is attractive during the spring and summer months having an upper leaf surface color of
Yulia A. Kuzovkina and Lorenzo Vietto
woman from Perm” in Russian. ‘Podarok Sud`by`’. A hybrid of S. babylonica × S. × pendulina ‘Elegantissima’ reaching 12 m in height. It is a green-barked weeping tree with a broad crown and cascading branches. Foliage is green above with glaucous
has a moderately vigorous growth rate, leaves glaucous up to 8.0 × 3.5 cm., margin toothed especially towards the apex, often flushed with red when emerging, stems reddish brown to shining brown, flowers densely clustered in large corymbs (7-16 × 6