environmental harm, resulting in losses of $35 billion annually ( Pimentel et al., 2005 ). Due to the overall damage associated with invasive plants, more attention has been placed on invasive (i.e., exotic or non-native) weeds and their impacts. Although
S. Christopher Marble
John C. Beaulieu, Maureen A. Tully, Rebecca E. Stein-Chisholm and Javier M. Obando-Ulloa
.69 and 260.93) were significantly higher than their controls (222.42 and 51.26), respectively ( Table 4 ). This may be the result of citrus pulp and cloud containing most of the monoterpenes ( Brat et al., 2003 ; Radford et al., 1974 ) and the ability of
Rajeev Arora and Lisa J. Rowland
understanding the cellular basis of cold acclimation (CA) or cold hardening has been one of the major approaches in the past few decades to study plants’ response to subfreezing temperatures. CA is the genetic ability of many species such as temperate-zone woody
David L. Coffey
Results from a three-year cultivar evaluation study indicate that Chinese cabbage production is feasible in Tennessee, but may require special attention to bacterial disease control. Individual head weight and projected yields of both the heading (pe tsai) and the nonheading (pak choy) forms compared well to those reported from areas where it is adapted and widely grown. Additional research is needed to identify appropriate planting dates and slow-bolting cultivars, especially for spring production. The ability to achieve predictable and profitable spring and fall production of this specialty crop is essential for establishing markets and promoting Chinese cabbage as a reliable crop that can be incorporated readily into vegetable production systems.
Jean M. Larson and Emily Hoover
Formative evaluation (pretesting) can lead to better working exhibits in public gardens. While many botanical gardens and arboreta will attest to the importance of using formative evaluation, it has not been used to develop exhibits for consumers with diverse disabilities. At the Clotilde Irvine Sensory Garden of the University of Minnesota Landscape Arboretum (Chanhassen, Minn.) we are interested in developing exhibits that meet the needs of audiences with disabilities. To that end in 2000, four comprehensive interpretive exhibits were pretested before the final exhibits were installed within the Clotilde Irvine Sensory Garden to determine the exhibits ability to teach concepts to all regardless of disability. The evaluation indicated these exhibits were physically accessible, but needed attention in specific areas to enhance their inclusiveness.
Edmund M. Tavernier and Robin G. Brumfield
The greenhouse, nursery, and sod (GNS) sector in the United States accounted for $10 billion in gross sales or 5% of gross farm receipts, in 1998. Despite its significant economic contributions, the sector receives little attention from policymakers. Part of the problem lies in the absence of empirical economic analysis that addresses the impact of the sector on the U.S. economy. The absence of such analysis places the sector at a disadvantage when agricultural policies are designed to address agricultural imbalances, such as farm income problems, and hinders the ability of the sector to lobby for policies favorable to GNS producers. This study provides estimates of the economic impacts of the GNS sector on the U.S. economy and quantifies the linkages between the GNS sector and other economic sectors. The results show that the sector contributed over $26 billion and $17 billion in output and value added economic activity, respectively, and over 438,000 jobs.
Justin R. Morris
The moderate consumption of red wine, grapes, raisins, and grape juice has a demonstrably positive effect on human health. Scientifically conducted surveys have shown that the effects of moderate intake of red wine reduces circulatory disease. Legislative efforts on labeling red wine to show the scientific evidence of this statement are receiving favorable attention. The antioxidant resveratrol, present in the skins of the grape in any of its various forms, is believed to be the agent primarily responsible for the healthful benefits demonstrated. It has been shown to affect lipid metabolism in higher mammals. Studies of resveratrol content in a variety of wine grapes are being performed at the Univ. of Arkansas, as well as at other institutions. Red wine (in contrast to white wine and other alcoholic beverages) reduces clotting ability and increases levels of high-density lipoproteins (“good” cholesterol), which diminishes the risk of coronary problems. Grape skin extract, red wines, and red juice appear to enhance the ability of blood vessels to resist vasoconstriction and to contribute to antithrombotic activity. In laboratory tests, several known antioxidants in wine out-performed vitamin E, the current best-known dietary antioxidant.
Kimberly H. Krahl and William M. Randle
Petunia hybrida Vilm. is one of the major bedding plants grown worldwide, and, like most bedding plants, is grown primarily for its seasonal floral display. While increased floral and reflowering capacity have been the focus of breeding programs for many ornamental species, floral longevity has received little direct attention. Increased floral longevity would enhance the value of any crop grown for floral effect. In this study, four parental genotypes (two with short flower life, two with long flower life) were crossed in a partial diallel mating design to create six F1 families. The F1 individuals were then selfed and backcrossed to the appropriate parents to create F2 and backcross families. Data from parental and F1 genotypes were analyzed to determine general and specific combining ability for floral longevity in petunia. Results indicated the presence of significant additive gene effects and nonsignificant nonadditive gene effects for floral longevity in this germplasm. However, aberrant F2 and backcross family means were observed in all families. For each family, F2 and backcross means were lower than expected given normal Mendelian segregation. Further experiments will be necessary to elucidate the causes for the deviate F2 and backcross family means before specific recommendations for selecting for increased floral longevity in petunia can be made.
Massimo Tagliavini and Bruno Marangoni
grateful to W. Drahorad, O. Failla and D. Porro for useful information on soil conditions and specific management techniques in apple orchards in the Adige Valley. We thank D. Scudellari for his continuous ability to bring grower needs to our attention and
Vinod Kumar, Aref Abdul-Baki, James D. Anderson and Autar K. Mattoo
Cover crop management in growing horticultural produce has attracted attention for reducing soil erosion and limiting the input of synthetic fertilizers and pesticides. Hairy vetch (Vicia villosa Roth.), one of the cover crops, exhibits desirable attributes such as high N fixing ability, biomass quality, adaptability to low temperatures, resistance to pests, and fitness in vegetable production, particularly in rotation with tomatoes. The interactions between the cover crop mulch and the tomato plant in the field plots result in delayed leaf senescence and increased disease tolerance. The mechanisms underlying these interactions are largely unknown. Limits in pursuing these studies year-round in the field—growing season and complexity and variability of the field environment—could be circumvented if the observed responses of tomato plants to hairy vetch mulch in the field could be reproduced under greenhouse conditions. We have tested tomato plants for two years in the greenhouse using soil residues brought from field plots where respective cover crops had been previously grown. Treatments were a) bare soil from a fallow, weed-free field plot, b) soil from a field plot that had been planted into a rye cover crop, and c) soil from a field plot that had been planted into a hairy vetch cover crop. Pots with soil from the rye or vetch field plots were further topped with rye or vetch residues, respectively, after transplanting the tomato plants. Additional N was applied to 50% of the plants in each treatment. In the greenhouse, cover crop residue-supplemented tomatoes exhibited high vigor, higher marketable yield and delayed senescence compared to those grown in bare soil. All treatments responded favorably to additional N from commercial fertilizers. Delayed leaf senescence correlated with the accumulation of rubisco large subunit and chitinase, two proteins central to photosynthesis and pathogenesis, respectively. This study shows that the responses of tomato plants to cover crops seen in the field can be mimicked under greenhouse conditions.