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  • Author or Editor: Wol Soo Kim x
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Consumers in the United States. and the European Union prefer to purchase medium-sized and symmetrical pears, while most Koreans prefer fruit that is as large as possible. This study was carried out to determine the effect of fruit loading, thinning time, and water management at full bloom stage on the number of seed and size and shape of fruit. As fruit loading increased and the time of fruit thinning was delayed, there was a decrease in fruit weight. The rate of fruit weight under 450 g was 41.7% in the treatment of 30% increase of fruit loading compared to control. There was an increasing tendency of symmetry fruits as the increase of fruit loading. By water stress treatment for 30 days after full bloom, a lot of medium sized fruit were harvested. The rate of symmetrical fruits was increased from the fruit, which held nine to ten seeds per fruit as well as uniformed seed development. Therefore, these results suggested that the number of seed s per fruit showed a close relationship to fruit shape, but water stress and fruit thinning time did not affect the fruit shape.

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Foliar sprays of TIBA inhibited the growth of apple seedlings, and induced bitter pit of field grown `Golden Delicious' fruit. Total Ca levels were significantly decreased in the stems and leaves of apple seedlings, and in fruit peel. Foliar sprays of NAA increased total Ca content in shoots of apple seedlings. The Ca levels in the roots of seedlings were affected less by TIBA and/or NAA sprays than that of shoots. Irrigation after TIBA treatment inhibited apple seedling growth, and decreased total Ca content in shoots and roots, while NAA increased the growth and Ca content in the seedlings. TIBA via lanolin mixture to the shoot inhibited growth, and decreased the Ca content in shoots and roots of apple seedlings. NAA via lanolin mixture did not affect growth, whereas it increased the Ca content in the shoots of apple seedlings.

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The energized water, Bio Green Water (BG water) was manufactured through a series of processes: tap water, purification, adding catalysts, spectra energy imprinting, filtering, BG water. BG water was supplied at four times at 3-week interval to the bench soil of green peppers (`Nokwang') in the plastic film house. BG water-treated green pepper showed the reduced plant highs compared to the control, although there were no difference in the number of nodes and leaves between the BG water treatment and the control. This was attributed to shorter internode length by the treatment. The BG water treatment significantly increased fruit weight, length, and diameter and decreased abnormally curved fruit. The treatment also increased harvested fruit numbers and yields outstandingly. Postharvest, the green peppers harvested from the treated plants were not changed in green color; however, fruit in the control were gradually discolored to dark brown.

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Many trials to supply selenium to fruit have been carried out since tests have confirmed selenium's role as a medical substance. Supplying selenium in orchards by soil and foliar application was not effective because of loss from rainfall. In order to increase selenium absorption by fruit, this study carried out tree trunk injections during the growing season. Selenium solutions in concentrations of 5, 10, 25, and 50 mg·L–1 were supplied to `Niitaka' pear (Pyruspyrifolia) trees by trunk injection (1.5 L/tree) four times at 15-day intervals from June 2004.

The treatment with 50 mg·L–1 selenium showed necrosis symptoms at leaf-margins after secondary treatment and toxicity as abnormally red fruit skin color. Fruit weight and leaf area were decreased by selenium treatments, while severe symptoms appeared with higher selenium concentrations. Hunter values `a' and `b' in fruit skin color were increased by selenium treatment in comparison to the control. The selenium treatment showed lower soluble solids by as much as 1.2%, and higher fruit firmness. Selenium concentration in pear fruit was increased by trunk injection with a 5 mg·L–1 solution. The bound selenium in pear fruit after 3 months of storage in cold room conditions was very high, but free selenium was low.

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During the early spring, embolism symptoms may be observed on the leaves of kiwi trees after a severe, cold winter. The morphological character of embolism in young leaves in early spring is typically parachute shaped, at the basal part of kiwi shoots. Deformed leaves were observed at the beginning stage of development. To test the factors, we used water stress, low temperature, and xylem bubble treatments on kiwi vines during the winter season. Low temperature treatments on trees were carried out in a –15 °C chamber for 0, 12, 24, and 48 hours. For the xylem bubble treatment, the trees were injected with 3.5 MPa compressed air at –15 °C for 24 hours. For water stress treatments, the trees were not irrigated until dry soil conditions reached as little as 50% soil moisture. Treated kiwi trees planted in plastic pots (20 cm × 25 cm) were moved into the growth chamber at 25 °C with 12 hours of light, and the rate of deformed leaf symptoms was observed. In all treatments, deformed leaves were observed and bud burst rates were lower than for the control. Therefore, we confirmed that the main factors for deformed leaves were low temperature, xylem bubbles, and water stress.

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Recently, the acreages Japanese apricot have been increased for being known of the medical functions. However, the increase of tree height, overgrowing trees and light deficiency at the bottom of canopy induced the poor fruit quality and higher labor charges. This study was conducted to assess the effects of training time, angle and length of water sprout on tree growth, the shoot-curbing, and the occurrence of new shoot for 2 years. Water sprouts were trained on 5, and 25 June, and 15 July with three varying angles of 30°, 45° and 60°, and cut at three lengths (50, 80, 110_) after harvest. Compared to control, the treatment on June 25 showed the highest values of 76%, 82% of internode and shoot length respectiely. In the treatment of training angle, shoot length was 71% in both 30° and 45° but heavily limited to 36% in 60° with comparing to control. The occurrence of shoots showed 18.1, 24.6, and 36.3 in treatment of 50, 80 and 110 cm, respectively, and in 80 cm, the number of shoot with diameter more than 0.5 mm, which is suitable for bearing mother branch, was higher. The best result was obtained in method of branch training with 45° and heading-back 80 cm at height on 15 June for the renewal of lateral branch.

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This experiment was carried out to investigate the effective cutting methods and media for hardwood cuttings in `Sunaga Wase' peach (Prunus persica L.). Using 1-year-old peach stems out of winter pruning, the cutting stems were procurred through several steps on 16 Feb. 1995 and 1996. i) Cut 30 cm in length by pruning scissors and bundled to 10 stems; ii) 1-cm bottom part of cutting stem dipped into IBA (1000 ppm solution) for 5 s and then powdering with Captan WP; iii) upper part of cutting stem coated with Topsin paste; iv) standing the bundled cutting stems in the cutting bench filled with cutting media; v) the temperature maintained at 20 ± 1°C under the level of cutting media by bottom heating and at 5 to 10°C above the media level. Among the cutting media, vermiculite showed the highest rooting percentage, as much as 93.2%, followed by Jiffy pot and rockwool cube. High transplanting survival percentage under field conditions was obtained by the treatment of vermiculite of media + cutting duration for 35 days. Although the treatment of cutting duration for 55 days showed very high percentage of rooting, such as 96.4% in vermiculite, 78.3% in Jiffy pots, and 83.3% of rockwool cube, their percentage of nursery survival after transplanting were reduced remarkably less than 10% in nursery fields covered with black polyethylene film. The nursery trees obtained from each treatment were characteristically 136 to 146 cm in tree height and 22.9 to 26.8 cm in trunk diameter.

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In order to investigate the super-density planting in peach orchards, the experiment was carried out using nursery trees out of hardwood cuttings in `Sunaga Wase' peach (Prunus persica L.). The nursery trees were planted with various planting densities of 1 × 0.5 m (20,000 trees/ha), 1 × 1 m (10,000 trees/ha), 2 × 0.5 m (10,000 trees/ha), 2 × 1 m (5,000 trees/ha), and 6 × 5 m (330 trees/ha) as traditional density on 22 Mar. 1995. As soon as fruit harvest in mid-July, the peach trees were pruned by thinning and heading-back the shoots to induce the new shoot as well as to limit the tree height and lower the canopy. During the second year after planting, nursery cutting trees yielded the most peach fruits from the planting density of 1 × 0.5 m, as much as 14.37 t, which was 14 times higher than the 6 × 5 m of traditional density, followed by 2 × 0.5 m, 1 × 1 m, 2 × 1 m, and 6 × 5 m, respectively. According to summer pruning just after harvest, remaining vegetative buds burst and then the new shoot grew very vigorously in several days. The floral bud differentiation on the new shoots was lower, as much as 32.2%, than that of 77.9% in no-pruning shoots. There were no differences in fruit characteristics among various planting densities.

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Germanium has been reported as a mineral element affecting plant cell metabolism. Many trials to supply germanium to fruit have been carried out since tests have confirmed germanium's role as a medical substance. Supplying germanium to orchards by soil and foliar application was not effective because of loss from rainfall. Also, tree injection with germanium solution required the insertion of a tube to the tree xylem at each injection site. In order to increase germanium absorption by fruit, this study carried out the postharvest dipping of fruit into germanium solution. `Niitaka' pear (Pyruspyrifolia) fruit was treated with two types of germanium, GeO (inorganic type) and Ge-132 (organic type), in a concentration of 50 mg·L–1 just after harvest in early Oct. 2004. Flesh browning after peeling the fruit was delayed by germanium treatment, and polyphenoloxidase (PPO) activities were lowered. Postharvest potentials were maintained at high levels for fruit firmness, physiological disorders, and decayed fruit during cold storage at 0 to 1 °C for 2 months. Antioxidant and some phenolic compounds were higher than those of control fruit.

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Dark browning of fruit skin of Japanese pear `Niitaka' (Pyrus pyriforia) is a physiological disorder during storage. Very higher rates of dark browning were observed in bagged pears, and in the orchards under higher humidity during the maturing season. Also the factors, such as higher humidity and lower temperature in storage room increase the dark browning. Dark browning is a different physiological disorder with the sugerficial scold of apples, which associated with conjugated trienes, oxidation products of alpha-farnesenes. The dark browning was controlled by dipping the harvested pears into 1,000 ppm diphenylamine (DPA) solution for 5 seconds before storage.

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