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On 24 Apr. 2003, 3-gallon (11.4-liter) Quercus shumardii were potted into 13.2-gallon (50-liter) containers using a standard nursery mix. Treatment design was a 3 × 2 × 2 factorial with two fertilizer placements, three irrigation methods, and two herbicide rates. Controlled-release fertilizer 17N–2.9P–9.8K was dibbled (placed 10.2 cm below the surface of the container media at potting) or top-dressed at a rate of 280 grams per container. Irrigation was applied using one of three methods: 1) a spray stake attached to a 3-gallon- (11.4-L-) per-hour pressure compensating drip emitter; 2) a surface-applied pressure-compensating drip ring delivering water at a rate of 2.3 gallons (8.9-L) per hour; and 3) the same drip ring placed 4 inches (10.2 cm) below the container substrate surface. A granular preemergent herbicide (oxyfluorfen + oryzalin) was applied at 2.0 + 1.0 lb/acre (2.24 + 1.12 kg·ha-1). At 75 days after treatment (DAT), containers with no herbicide and top-dressed fertilizer had a percent weed coverage of 46% compared to 18% for dibbled containers with no herbicide. At 180 DAT weed top dry weight was greater for top-dressed containers compared to dibbled. None of the treatments in the study had any effect on height increase. At 240 DAT, trees irrigated with drip rings at the surface had a 28% greater caliper increase among the dibbled fertilizer-treated containers. Trees irrigated with the drip ring placed below the surface and fertilizer top-dressed had the smallest caliper increase. Irrigation method had no effect on weed control in this study; however, a repeat fall application showed a significantly greater weed control with the drip ring below surface compared to the spray stake.

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The effect of fall vs. spring transplanting was tested on landscape-sized Chionanthus virginicus L. at a research farm in Blacksburg, Va. Two fall transplanting dates (11 Nov. and 1 Dec. 1994) were selected so that soil temperatures were decreasing and near 10 °C for the earlier fall date (11 Nov.) and decreasing and near 5 °C for the later fall transplanting date (1 Dec.). The spring date (14 Mar. 1995) was selected so that soil temperatures were increasing and near 5 °C. All trees were transplanted with rootballs of native soil wrapped in burlap (B&B). Fringe tree was clearly tolerant of fall transplanting. Trees transplanted on 11 Nov. had a larger leaf area 1 month after bud set the next summer and had wider canopies and more dry mass of new roots at leaf drop than trees transplanted on the other dates. Trees transplanted on 14 Mar. had less total leaf area, leaf dry mass, and lower maximum root extension into the backfill soil than trees transplanted on 11 Nov. or 1 Dec. No root growth occurred beyond the original rootball until about early July (1 month after bud set) in any treatment, suggesting that first season posttransplant irrigation regimes need to focus on rootballs, not surrounding soil areas.

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Two rootball sizes as well as a nontransplanted control were randomly assigned to Acer saccharum Marsh. (sugar maple) trees in four adjacent nursery rows at Waynesboro Nurseries in Waynesboro, Va. One size (75 cm in diameter) corresponded to the American Association of Nurserymen standards. The other rootball size was 90 cm in diameter. Trees were transplanted just before bud swell or during shoot elongation. Rootball size had no effect on height, stem diameter, or twig growth, total nonstructual leaf nitrogen content (LNC), or total stem nonstructual carbohydrate (TNC). Height growth was reduced by 81%, stem diameter growth by 71%, and twig growth by 82% for trees transplanted before bud swell compared to nontransplanted trees. LNC was 25% more on transplanted trees than on nontransplanted trees, presumably due to a dilution effect. TNC was 20% higher on transplanted compared to nontransplanted trees. Growth was severely curtailed on late-transplanted trees for all characteristics measured compared to all other treatments.

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Breeding of crapemyrtle (Lagerstroemia) in the United States has focused on developing hybrids between parents with disease or pest resistance and those with good floral characteristics. The objective of this work was to study the general and specific combining ability of several horticulturally important traits in crosses between pest-resistant parents and those with saturated flower colors. Ten crapemyrtle parents were tested in a factorial mating design including 25 of the 29 possible families. Analysis of variance revealed significant differences (P ≤ 0.05) for all traits for the general combining ability of parents. The cross between ‘Arapaho’ and ‘WHIT IV’ displayed the best specific combining ability for a desirable combination of height, leaf-out time, bloom time, and flower color based on current breeding objectives. Overall, this study revealed the importance of both additive and nonadditive genetic variability in crapemyrtle, suggesting that an integrated breeding strategy to capture both additive and dominance variance would be appropriate for producing new, improved crapemyrtle clones for the four traits evaluated.

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Root severance during field harvesting alters the water status of a tree, resulting in water stress and reduced post-transplant growth. Two experiments, using Acer rubrum L. (red maple), determined the influence of root severance at harvest on sap flow and xylem embolism. Trees 1.5–1.8 m tall (4 years old) were utilized in the first experiment, and trees 1.2–1.5 m tall (2 years old) were utilized in the second. Sap flow sensors were installed on the 4-year-old trees prior to root severance and remained on the trees until 1 week after harvest. Within 1 day after root severance sap flow was reduced and remained lower than nontransplanted (control) trees for the remainder of the experiment. Leaf stomatal conductance (Cs) of transplanted trees 1 week after root severance was lower than that of control trees, but leaf water potentials (ψ) were similar. In the second experiment, sap flow was reduced relative to control trees within 2 h after root severance. Although Cs was reduced 4 hours after root severance, ψ was not. Embolism increased within 24 hours of root severance. These results indicate that root severance quickly induces increased levels of embolism, which is associated with reduced sap flow.

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The influence of media on plant growth was investigated for five annual species. Uniform 164-cm3 liners of Tagetes erecta `Discovery Orange', Impatiens wallerana `Accent Orange', Melampodium paludosum `Showstar', Scaevola aemula `New Wonder', and Petunia axillaris `Surfinia White' were planted into 2.8-L containers on 4 Apr. 1997. The experiment was terminated after 90 days. Media included Metro-Mix 366 peat or coir, Metro-mix 700 peat or coir, and 4 pine bark : 1 sand (by volume, amended with 1.2 kg.m-3 dolomitic limestone). Plants were top-dressed with 9 g Osmocote Plus 15-9-11. Substituting coconut coir for peat moss in commercial media reduced Petunia 90 DAT foliar color ratings, Impatiens shoot dry masses, and Melampodium and Scaevola root ratings. Utilization of pine bark did not influence foliar color ratings of Tagetes, Melampodium, Petunia, or Scaevola 90 DAT. Utilization of pine bark reduced shoot dry masses of Impatiens, Melampodium, and Scaevola, and root ratings of Melampodium and Tagetes.

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Lagerstroemia indica ×fauriei `Tonto' and `Sioux' were planted in Mar. 1995. All other cultivars were planted in Oct. 1985. Plants were planted into a Ruston sandy loam on a 12 × 12 ft (3.7 × 3.7 m) spacing. Trees were pruned to develop multiple trunks. Trees are pruned annually in winter to remove any limbs smaller than 0.6 cm in diameter. Pruning cuts are made 6–8 in (15.2–20.3 cm) above prior cuts. Severe pruning is performed every 5 years. Trees were evaluated at 2-week intervals during the flowering season to determine total length of flowering and duration of good to superior flowering. Growth indices (height + width + perpendicular width)/3 were recorded after plants were dormant. Total days of flowering and floral display (0–5 with 0 representing no flowers and 5 representing superior flowering) were rated. `Muskogee' had the greatest growth index after the 2004 growing season. `Seminole' had the least. However, `Seminole' had the greatest number of flowering days. `Biloxi' had the fewest flowering days. `Tonto' had the most good to superior flowering days, while `Tuskegee' and `Muskogee' had the fewest. In 2005, `Muskogee' again had the greatest growth index, while `Sioux' had the least. `Yuma' and `Seminole' had the greatest number of flowering days, and `Biloxi' again had the fewest. `Tonto' again had the most good to superior flowering days, while `Biloxi' and `Acoma' had the fewest.

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Lagerstroemia indica x fauriei `Tonto' and `Sioux' were planted in March, 1995. All other cultivars were planted in October, 1985. Plants were planted into a Ruston sandy loam on a 12 × 12 ft (3.7 × 3.7 m) spacing. Trees were pruned to develop multiple trunks. Trees are pruned annually in winter to remove any limbs smaller than ¼ in (0.6 cm) in diameter. Pruning cuts are made 6–8 in (15.2–20.3 cm) above prior cuts. Severe pruning is performed every five years. Trees were evaluated at 2-week intervals during the flowering season to determine total length of flowering and duration of good to superior flowering. Growth indices (height + width + perpendicular width)/3 were recorded after plants were dormant. Total days of flowering and floral display (0–5 with 0 representing no flowers and 5 representing superior flowering) were rated. `Muskogee' had the greatest growth index after the 2004 growing season. `Seminole' had the least. However, `Seminole' did have the greatest number of flowering days. `Biloxi' had the fewest flowering days. `Tonto' had the most good to superior flowering days while `Tuskegee' and `Muskogee' had the fewest.

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The greenhouse and nursery industry is one of the fastest growing sectors of the region's agricultural economy; however, a major problem facing this industry is a shortage of workers, particularly skilled workers. A recent national survey of commercial nursery/landscape operations listed labor shortage as the number one limitation facing the industry at the end of 2001. The target population of this project is greenhouse and nursery workers in the Gulf South. The goal of this project is to develop and identify automated systems that can be adapted by the highly diverse greenhouse and nursery industry. Adoption of this technology will improve working conditions for greenhouse and nursery workers, increase worker retention, improve worker safety, increase worker productivity, improve skill levels, and create new jobs related to servicing the machinery and instrumentation. The Coastal Research and Extension Center, in cooperation with industry leaders representing the Gulf South, has identified several major areas of program focus. Together, we have developed a comprehensive set of production issues which will be addressed through the integration of applied mechanization technologies developed through this project.

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Bareroot Corylus colurna were grown in 7.5-liter containers from 11 Apr. until 27 June 1994. The growing medium was fritted clay. Fertility levels included no fertilization, 100 ppm N, or 200 ppm N. Plants were root pruned to remove none or one-quarter to one-half of the primary roots. Root pruning at any level resulted in decreased height, shoot, and root dry weights and number and length of new shoots. One-quarter primary root removal resulted in lower root: shoot ratios compared to plants that were unpruned. One-half primary root removal further reduced root: shoot ratios. One-half primary root removal also reduced total leaf area compared to unpruned controls. Fertilization at 200 ppm N increased leaf numbers and total leaf areas compared to plants receiving no fertilization.

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