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David J. Chalmers, Preston K. Andrews, Kevin M. Harris, Ewen A. Cameron, and Horst W. Caspari

The design of a type of drainage lysimeter, as tested with trees of Pyrus serotina Rehder var. culta Rehder `Hosui' is described. All lysimeter operations and monitoring of irrigation and drainage volumes were managed by a “multi-tasking” controller/datalogger. It was possible to apply different irrigation levels to each of three sets of four random lysimeters. Evapotranspiration (ET) was calculated using a conservation of water equation, with differences between irrigation inputs and drainage outputs corrected for changes in soil-water content. ET ranged between 3.3 and 10.7 liters/tree per day in well-watered, noncropped trees in late Summer and Fall 1990. These rates correspond to ET of 0.13 to 0.43 liter·cm-2·day-1 and 0.96 to 3.10 liters·m-2·day-1 on trunk cross-sectional area and canopy area bases, respectively. The correlation coefficient between ET and Class A pan evaporation was >0.9 during this period. Weekly crop coefficients for the well-watered trees averaged 0.52 when calculated on a canopy-area basis. When irrigation was withheld for 18 days, the crop coefficient declined to 0.38. There were no differences in ET between trees growing in the two soil profiles, despite significant differences in soil water distribution.

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Wol-Soo Kim, Jung-An Jo, and Soon-Ju Chung

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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Wol-Soo Kim* and Jin-Ho Choi

The stone cells are observed in the process of lignifications of tissues in flesh of pear as a depressing factor of fruit quality. These studies were carried out to search the effect of stone cells on fruit quality, to investigate the anatomical characteristics, such as formative period and distribution of stone cell, to seek forming causes. During the growing seasons of 2002 and 2003, samples for anatomical investigations were taken periodically in Pyrus pyriforia cv. Niitaka, P. communis cv. Bartlett and P. ussiriansis cv. Yari. The morphology of stone cell in the fruit flesh was observed by using optical microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). By optical microscope, stone cell observed first from 14 days after full bloom. The adjacent cells to stone cell was first showed spherical type on initial forming stage but showed radial form at 90 days after full bloom. The shape of stone cell inspected by SEM was like a cluster and its size was various. By using TEM, components of stone cell, such as nucleus and vacuole, and secondary cell wall thickening were observed, so it could consider that the stone cell is living thing. The largest amount of stone cell clusters existed beneath fruit skin.

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Wol-Soo Kim and Jung-An Jo

Many trials to supply germanium to fruit have been carried out since tests have confirmed germanium's role as a medical substance. Supplying germanium in orchards by soil and foliar application was not effective because of loss from rainfall. In order to increase germanium absorption by fruit, this study carried out tree trunk injections during the growing season. Two types of germanium, GeO (inorganic type) and Ge-132 (organic type), in concentrations of 5, 10, 25, and 50 mg·L–1 were supplied to `Niitaka' pear trees by trunk injection (1.5 L/tree), four times at 15-day intervals from June 2004. The treatment with 50 mg·L–1 GeO showed decreased fruit weight, but 50 mg·L–1 Ge-132 showed no difference to the control and other treatments. Fruit lenticels were increased in size by all of the Ge treatments in comparison to control fruit. Soluble solids as well as Hunter value `a' of the fruits of all Ge treatments were higher than that of the control. Flesh browning after peeling the fruit was delayed by the 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.

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Wol-Soo Kim, Jung-An Jo, Soon-Ju Chung, Kil-Yong Kim, and Hyun Sug Choi

The shells of crab, shrimp, beetles, etc., could be decomposed by chitinase to chitin, calcium, and protein, respectively. We incubated the mixture solution of 1.5 kg crab shell, 1.5 kg multinutrient, 2 kg compost with microorganisms to decompose the chitin substance, 3 kg sugar, and 700 L water at room temperature for 7 days. During the incubation, aeration with an air pump was essential. We sprayed the chitin-incubated solution (CIS) after filtering to `Niitaka' pear (Pyrus pyrifolia) trees at 15-day intervals from May to Sept. 2004. Leaf area, leaf thickness, leaf specific weight, and chlorophyll contents were increased by the treatment with CIS. In fruit characteristics, fruit weight, soluble solids, fruit firmness, and Hunter values “a” and “b”were increased by the CIS treatment. Flesh browning after peeling the fruit was delayed by the CIS treatment, and polyphenoloxidase (PPO) activities were lowered.

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Wol-Soo Kim and Jung-An Jo

Pear (Pyrus pyrifolia) fruits of `Whangkeumbae' were produced from the organic orchard at Yongam, southwestern Korea, which was managed by spraying with chitin incubated solution (CIS) 15 times from petal fall stage, mid-April to late August, to control pests and diseases during the growing season. The CIS contained about 50 kinds of chitin digestive and/or effective microorganisms and other organic/inorganic biologically active substances by incubating the mixtures at 30 °C for 7 days. The soil had standard levels of chemical and physical properties in Korea, as well as 3.0% to 4.0% organic matter. The organic fruits showed higher soluble solid contents, and fruit firmness was increased in comparison to conventional fruits. The organic fruit skin changed in color from yellow to brown, and black spot occurred; however, there was no difference in flesh tissues in terms of colors and textures. The phenolic compounds were significantly increased in organic fruits and leaves, with especially higher levels for fruit skin than for flesh tissues. Free radical levels dropped sharply in organic fruit, but slowly in conventional fruits. The results showed that the organic pear fruits have higher levels of antioxidant activity, and also showed the phenomena related to the change in fruit skin color from yellow to brown.

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Ashok K. Ghosh, Lewis N. Lukens, David M. Hunter, and Judith N. Strommer

The genus Pyrus (pear) includes species and cultivars of great diversity. We have tested the feasibility of a polyacrylamide gel eletrophoresis (PAGE)-based +/– simple sequence repeat (SSR) screen as a means of defining relationships amongst pears of commercial importance in North America. The screen included 28 pear accessions, including economically important cultivars, numbered selections from breeding programs and interspecific hybrids. It relied on 18 SSR primer pairs, each of which produced polymorphic banding patterns in all the genotypes examined. Fragments were scored for presence or absence within genotypes. The results show that amplification and analysis of a small number of SSR loci enable identification of cultivars and reasonable definition of genetic relationships in North American pears. Seven primer pairs were sufficient to distinguish the 28 pear cultivars. Analyses using both distance and parsimony criteria grouped cultivars in a manner consistent with known pedigrees and sites of origin.

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Wol-Soo Kim, Tae-Hyun Kim, Soon-Ju Chung, and Hyun Suk Choi

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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Chad E. Finn and John R. Clark

incognita and M. floridensis) , similar to Nemaguard and Flordaguard, respectively; suggested for armillaria root rot infested sites. PEAR—ASIAN Joseph D. Postman USDA-ARS National Clonal Germplasm Repository, Corvallis, OR Sooyoung. A

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Esmaeil Fallahi, Bahar Fallahi, Michael J. Kiester, and Shahla Mahdavi

not precocious and productive. In an attempt to improve pollination, precocity, and productivity in fire blight–tolerant ‘Magness’ pear, asian pear trees were used as a pollinizer ( Walsh et al., 2015 ). In this process, they found that asian pears