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  • Author or Editor: D. Himelrick x
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Rooted rabbiteye blueberry cuttings were transplanted to 15 cm pots containing either builders sand or 80% sand 20 peatmoss v/v (1% OH). Five different herbicides were applied at the high and low recommended rates. Terbacil at 1.4 or 2.9 kg/ha a.i. caused a 72% mortality while 1.8 or 3.6 kg/ha a.i. application of norflurazon caused a 53% mortality. Root volume, weight, top weight, and leaf chlorophyll concentrations were reduced by terbacil treatment. Oryzalin at 2.7 kg/ha a.i. or norflurazon at 3.6 kg/ha a.i. reduced root and top weight and chlorophyll. Napropamide at 2.2 kg/ha a.i. reduced top weight and chlorophyll. Two good choices for young plants appear to be simazine at 1.8 kg/ha a.i. and napropamide.

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Two cultivars of blackberry (Rubus sp.) were propagated in July under intermittent mist by rooting 2-node softwood stem cuttings. Differences in root development among cultivars were evident with the thornless erect cultivar, `Navaho', producing a better root system than the thorny erect cultivar, `Cheyenne'. Treatment of `Navaho' with 3000 and 8000 ppm indolebutyric acid (IBA) in water and treatment of `Cheyenne' with 8000 ppm IBA in water and 3000 ppm IBA in talc improved rooting.

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Poultry and coal production are two major industries concentrated in north-central Alabama. Standard surface coal mine reclamation procedures were compared to procedures utilizing poultry litter in an 3.24-ha mine site. Three 0.4-ha plots amended with litter at rates of 25, 50, and 100 mt/ha, were compared to a plot with mineral fertilizer (13N–13–P13K) at standard reclamation rates of 672 kg/ha, and a plot receiving no fertilizer or litter. All plots were amended with ground limestone and disced in 31 cm. A mix of fescue, lespedeza, rye, and clover was broadcast over all plots uniformly. Eight tree species; northern red oak, nuttall oak, willow oak, red maple, yellow poplar, royal paulownia, loblolly pine, and eastern red cedar were planted in all plots at 1482 trees/ha. Forage yields (1995–96) in litter-amended plots were two to three times higher than statewide hay production averages. High litter rates have had no negative effects on ground cover, tree survival, or ground water nitrates (NO3). This project demonstrates broiler litter use as an organic-matter amendment in a self-sustaining reclamation success.

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Four year old `Loring' peach trees on `Lovell' rootstock were treated with single applications of 0, 50, and 100 ppm GA3 alone and in combination with 100 ppm ethephon on 15 November 1988, 1989, and 1990 to determine the effect on bloom delay the following spring. Flower bud number was not affected by any of the treatments the next spring. Ethephon had the greatest effect on bloom delay the following spring. The 50 and 100 ppm GA3 treatments resulted in a slight delay of bloom. The combination of 50 and 100 ppm GA3 and 100 ppm ethephon resulted in less of a bloom delay than ethephon alone but greater than the GA3 treatments alone. Fruit set was increased by ethephon treatments in 1989 and 1991 but not in 1990. Ethephon treatments delayed fruit maturity whereas GA3 did not. Total fruit yield for 1989, 1991, and the three year average was not effected by treatments. However, in 1990 50 ppm GA3 resulted in the highest yields. Ethephon treatments reduced the average fruit weight in 1990 and 1991 but not in 1989 or the three year average.

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Own-rooted four-year-old kiwifruit plants (Actinidia deliciosa) protected by a Reese clip-on styrofoam insulation trunk wrap, or microsprinkler irrigation, sustained less freeze injury than unprotected plants under field conditions at temperatures as low as -17.8C. Trunk splitting occurred on the plants but no injury was detected on canes, buds, or shoots in the canopy of the plants. Unprotected plants had more trunk splitting and at greater heights than protected plants. New canes developed from suckers of cold-injured plants and developed a filled canopy the following season.

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The surfactant “Surfactant WK” (dodecyl ether of polyethylene glycol) was applied to peach trees [Prunus persica (L.) Batsch] at full bloom over 3 years. Blossoms died rapidly so that within 2 days dead blossoms could be distinguished easily from live blossoms or set fruit. There were strong (R 2 > 0.87), linear correlations between concentration of “Surfactant WK” applied and percent blossoms removed and fruit set, which were similar over the 3 years. Trees were hand-thinned according to commercial practices after treatment. There was similar cropload, fruit weight, and yield across treatments at harvest indicating no negative effects by the chemical on productivity. There was only slight limb damage at the highest concentrations of “Surfactant WK,” which overthinned blossoms. We recommend that based on the effectiveness, consistency, and lack of significant phytotoxicity, “Surfactant WK” be reevaluated as a thinning chemical for peach trees.

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Changes in the activities of sucrose-metabolizing enzymes as related to ontogeny and ripening were studied in fruit mesocarp tissues of watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai, cvs. A.U. Producer and Sweet Scarlet]. The levels of soluble sugars and the activities of sucrose synthase (SS; EC 2.4.1.13), sucrose-phosphate synthase (SPS; EC 2.4.1.14), and invertase (INV; EC 3.2.1.26) were measured. The temporal pattern of these enzymes relative to the levels of soluble sugars were similar for both cultivars. `Sweet Scarlet' was characterized by having higher INV and SPS activities, while SS activities tended to be similar in both cultivars during fruit development. During later stages of ripening, `Sweet Scarlet' tended toaccumulate reducing sugars, while `AU Producer' tended to accumulate sucrose and therefore had lower sucrose-cleaving enzyme activity. Results indicate that SPS and INV appear to play a prominent role in carbohydrate metabolism in developing and ripening tissues of watermelon.

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Abstract

Strawberries (Fragaria Xananassa Duch.) classified as day-neutrals (‘Hecker’ and ‘Tristar’), Junebearers (‘Redchief’ and ‘Guardian’), and everbearers (‘Ourown’ and ‘Ozark Beauty’) were grown at a constant 21°C under 16 hour long days (LD), 9 hour short days (SD), or 9 hours with the dark period interrupted by 3 hours of low-level incandescent radiation [night interruption (NI)]. Flowering of day-neutrals was unaffected by photoperiod; Junebearer flowering was inhibited under NI and LD compared to SD; flowering of everbearers was promoted by LD compared to SD. Runner production was greatest for all types under LD, followed by NI then SD. Everbearers produced more runners than the other types. Effects of photoperiod on total, nonstructural carbohydrates varied with photoperiodic type and tissue sampled. The 3 types of strawberries were grown also under SD and NI under day/night temperature regimes of 18°/14°, 22°/18°, 26°/22°, and 30°/26°C. With number of inflorescences and runners and total dry weight per plant, significant photoperiod × temperature × type interactions were found. Results indicate that current classification of strawberry cultivars into photoperiodic type is inadequate.

Open Access

Twelve peach [Prunus persica (L.) Batsch] seedling rootstocks [Lovell, Nemaguard, Flordaguard, 14DR51, five Guardian™ (BY520-9) selections, and three BY520-8 selections] budded with `Cresthaven' were planted in 1994 and evaluated through 2000 to determine performance under commercial management practices. Mesocriconema xenoplax population densities were above the South Carolina nematicide treatment threshold of 50 nematodes/100 cm3 of soil after 1996. However, symptoms of peach tree short life (PTSL) were not observed. Tree mortality was less than 14% through 1999, with most of the dead trees exhibiting symptoms consistent with Armillaria root rot. About 13% of the surviving trees in 1999 were removed in 2000 due to symptoms of phony peach. There were no differences in tree mortality among rootstocks. Tree growth, photosynthesis, and suckering varied among rootstocks, but leaf conductance, internal CO2, and leaf transpiration did not. Foliar calcium, magnesium, iron, and phosphorus varied among rootstocks, but all were within the range considered sufficient for peach trees. Fruit yield varied among rootstocks, but yield efficiency did not, indicating that higher yield corresponded with larger trees. Bloom date did not vary among rootstocks, but harvest date was advanced as much as 2 days for some rootstocks, compared to Lovell. Fruit weight varied among rootstocks but skin color, flesh firmness, and soluble solids content were similar. All rootstocks performed satisfactorily for commercial peach production.

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The yellow passionfruit (Passiflora edulis f flavicarpa Degener), a perennial vine grown in the tropics and subtropics, was successfully grown as an annual crop in a temperate zone. Fruit maturity was hastened by ethephon treatments to allow harvest before the mean date of the first killing frost. Maturity was advanced in a linear manner with application rates of 150, 300, and 600 ppm ethephon. Total yield was not affected by ethephon treatment; however, cull fruit producing no juice increased with increasing rates of ethephon, thereby reducing marketable yields. Soluble solids and ascorbic acid contents of the juice were not affected by ethephon treatment. Purple passionfruit (Passiflora edulis Sims) did not produce blossoms.

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