It has been shown that perennial woody plants exhibit marked seasonal changes in nutrient content, carbon metabolism, and organ development. A knowledge of seasonal nutrient allocation and temporal accumulation patterns can be useful in the development of fertilization regimes that reflect the biology of a tree crop. Maintenance of optimum leaf nutrient status is an important priority in pecan cultural practice. However, a systematic evaluation of nutrient resorption is lacking in pecan. In this work, seasonal changes in nutrients and carbohydrates were evaluated in pecan trees grown under orchard conditions. In addition, resorption efficiencies of eight pecan cultivars were evaluated. Significant levels of resorption were observed in all essential elements, but cultivar differences were not significant. Seasonal patterns of nutrient and carbohydrate content in leaf, stem, and shoot tissue, will be presented as well as a structural evaluation of abscission zone formation.
Tehryung Kim and Hazel Y. Wetzstein
A.M. Armitage and Meg Green
The University of Georgia trial garden has been in existence since 1982, and the method of evaluation and distribution of taxa has evolved over the years. Annual and perennial taxa are evaluated systematically, over the entire season, providing season-long summaries for each one. Annuals are evaluated every 2 weeks, and scores are based on plant performance, including foliar health, flower numbers and the appearance of disease and insect damage. Perennials are evaluated similarly, however flowering time, flowering persistence and height in the landscape are also noted. Summaries for each taxon are presented in tabular and graphic form. Many new crops have been evaluated and introduced to the floriculture industry. New crops are placed in the horticulture gardens and evaluated by garden personnel and by commercial growers and landscapers. Plants have been distributed free of charge to propagators and growers, resulting in rapid market acceptance of successful taxa.
Li-Hong Gao, Mei Qu, Hua-Zhong Ren, Xiao-Lei Sui, Qing-Yun Chen, and Zhen-Xian Zhang
Single-slope, energy-efficient solar greenhouses in China use solar energy as the sole source of light and heat for winter crop production in the region between latitudes 32°N and 43°N. The use of solar greenhouses has greatly reduced energy demand and carbon dioxide (CO2) emissions. Solar greenhouses are the best structure for growing winter horticultural crops in China, and have been adopted by countries such as Japan, Korea, and Russia. Increased proliferation of efficient solar greenhouses in China may contribute to solving worldwide problems such as the energy crisis and global climate change. This article summarizes the structure, function, application, and ecological benefits of energy-efficient, single-slope solar greenhouses in China, based on 20 years of systematic studies. We hope this technology can be applied to regions of similar climate to help reduce energy consumption and CO2 emissions.
Chengyan Yue, Zata Vickers, Jingjing Wang, Neil O. Anderson, Lauren Wisdorf, Jenna Brady, Michele Schermann, Nicholas Phelps, and Paul Venturelli
The present study systematically investigated the effects of warehouse and greenhouse aquaponic growing conditions on consumer acceptability of different basil cultivars. A total of 105 consumers rated their liking of three basil cultivars (Nufar, Genovese, and Eleonora), each grown in three conditions (aquaponically in a greenhouse, aquaponically in a warehouse, both with Cyprinus carpio, Koi fish, and grown in soilless medium). We used linear random effect models to investigate consumer preferences for attributes of basil plants grown in different environments by controlling for individual-specific random effects. Participants generally liked the soilless medium–grown and greenhouse aquaponically grown basil plants more than the warehouse aquaponically grown plants. The soilless medium–grown basil had the highest appearance liking and flavor intensity, followed by the greenhouse aquaponic grown and then by the warehouse aquaponic grown. Aquaponically grown cultivars were rated less bitter than soilless medium–grown cultivars.
C.J. Simon and N.F. Weeden
The ribosomal genes of the two crab apple (Malus) genotypes White Angel' and `Robusta 5' were characterized to determine the extent of between- and within-genotype heterogeneity. Initial investigations with a cloned sequence of soybean rDNA failed to detect some Malus intergenic spacer region fragments. An alternative probing method that used electrophoretically purified Malus rDNA was developed. Double-digests of total genomic DNA with combinations of 13 restriction endonucleases identified the positions of 35 restriction sites. Restriction site polymorphism was observed both between and within the crab apple genotypes. Ribosomal DNA from White Angel' was cloned in phage and plasmid vectors and mapped with 11 enzymes. The region of the spacer causing length heterogeneity was identified. These clones should be useful as genetic markers and for examining population dynamics and systematic of Malus and closely related taxa.
John L. Maas, John M. Enns, Stan C. Hokanson, and Richard L. Hellmich
1 Research Plant Pathologist. 2 Horticulturist. 3 Research Geneticist. 4 Research Entomologist. We are grateful to M. Alma Solis, Research Entomologist, Systematic Entomology Laboratory. ARS. USDA, Beltsville, for insect identifications, and
Thomas E. Marler and Leah E. Willis
We are grateful to C. Hubbuch for systematic guidance in defining the list of species for this survey and to P. Andersen, B. Dehgan, and T. Walters for evaluation and suggestions for improving the manuscript. The cost of publishing this paper was
Introductory Horticulture at Illinois State University is approved for inclusion in the University Studies Program. This program is comprised of courses whose content is considered of general importance to the educated layperson, rather than to the specialist in the field. Departments may use the University Studies Program as a means of attracting students to the field. This has been done with fair success with Introductory Horticulture. Because the course must provide personal enrichment, be broad in scope, offer a systematic design for further learning, and assure a breadth of knowledge and understanding, this course has been designed to focus on the economies of the various horticultural industries, how they are related to the socioeconomic history of the various regions of the country and how the marketing of horticultural products and enterprises affects the personal life of individuals. Acceptance of this approach has been two-fold: first: student evaluations are positive, a steady enrollment has been maintained, and the course has steadily provided 10% to 15% of new Horticulture students, and second: the University Studies review committee has twice affirmed the “tenure” of Introductory Horticulture in spite of increasingly stringent guidelines that discourage many traditional science courses.
E.H. Simonne, J.T. Eason, J.A. Pitts, and J.T. Owen
Bell pepper (Capsicum annuum L.) fruit are typically green in color at the immature stage, 1/3 and 2/3 colored during ripening, and red at maturity. However, this sequence does not apply to new varieties with immature colors of white or purple, intermediate colors of brown or black, and mature colors of yellow or orange. The study of physiological changes during ripening in such cultivars requires the description of color changes. Therefore, color changes of new bell pepper varieties were evaluated by subjective description and objective measurement of L, a, and b. Color changes were described with a five-color stage scale. L, a, and b were affected significantly by variety (P < 0.01), and a and b were affected significantly by color stage (P = 0.95, 0.01, and 0.01 for L, a, and b, respectively). Location and cultivar*location had no significant effect. For each cultivar, differences in a and b values defined color stages that were clearly identifiable. When plotted, color measurements (a and b) were in good agreement with the verbal descriptions. Therefore, measurements of L, a, and b are not systematically necessary when referring to bell pepper colors.
C. Richer-Leclerc and J.-A. Rioux
The “Réseau d'esssais des plantes ligneuses ornementales du Québec” (REPLOQ) is a research project initiated in 1982 with the mandate to elaborate, develop and coordinate a cooperative research project to evaluate the winter hardiness of ornamental plants. Systematic evaluation trials provided information on growth potential and hardiness of woody trees and shrubs evaluated over a five year period in the principal growing regions of Québec. Zonal range covered was 2 to 5b in the Canadian system. Adequate field testing is critical for new introductions and, since 1984, more than 400 species and cultivars have been introduced in 8 evaluation sites. Results were published on several forms: technical factsheets provide cultural and production recommendations for the species and cultivar evaluated in each climatic zone. Propagation methods as well as their potential for ornamental purpose were described. In the 1984 plantation, Malus baccata and Quercus macrocarpa showed a similar potential for acclimation, but Malus baccata could be produced advantageously in any area, while the production potential of Quercus macrocarpa was enhanced by the summer heat of the wannest region. In this group of plants, Acer saccharinum was the species with the greatest number of plants suffering winter damage and could not be grown without risk anywhere in the area studied. Acer platanoides was severely damaged in the coldest of the eight evaluation sites and should not be cultivated there.