• Horticultural Science & Technology
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• v.18 no.3
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• pp.360-367
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• 2000

'Yumyeong' peach has desirable characteristics of long shelf-life and specific non-melting nature with long harvesting period. However, some fruits harvested too late tend to show fruit pithiness symptom or internal breakdown. The study was conducted to investigate the differences between fruit flesh pithiness and internal breakdown symptoms, and to find out inducing factors of flesh pithiness in 'Yumyeong' peach. The incidence of flesh pithiness was higher in the fruits harvested late. Sugar and malic acid contents were not different between normal fruits and flesh pithiness fruits, but the acidity was significantly lower affected by low citric acid content in flesh pithiness fruit. In flesh pithiness fruits, calcium contents were low in both skin and flesh. Occurrence of flesh pithiness fruits was high in the years with low precipitation and high temperature for 2 months before harvest. In observations on morphological characteristics, the parts showing flesh pithiness consisted of smaller cells than the normal parts. Tonoplasts were disintegrated and the number of dead cells was high in internal breakdown fruits, while the tonoplasts were intact with contracted vacuoles in flesh pithiness fruits. Tylosises were observed in vascular tissues around the flesh pithiness, therefore, it was assumed that those tylosises restricts flesh tissue development resulting in flesh pithiness. Other varieties such as 'Fantasia' and 'Wolmi' also showed tylosis and smaller cells were observed in the flesh tissue of these cultivars, indicating abnormal growth of the flesh part. These results suggested the possibility of the occurrence of pithiness like symptoms in other peach varieties.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.545-551
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• 2010

The primary objective of this study was to determine the relationship between fruit quality characteristics and pithiness fruit occurrence for confirming occurrence factors of pithiness tissues in 'Niitaka' pears ($Pyrus$ $pyrifolia$ Nakai). Fruits were harvested 4 times in 1 week intervals from 160 days after full bloom (DAFB) to 181 DAFB. Harvested fruits were separated with the specific gravity by Archimedes laws. Also, with specific gravity level in pear fruit, sugar content, acidity, and texture profile analysis (TPA) were investigated. Final verifiability of pithiness fruit was approved by eye observation at 90 days after storage. Also, in ASS (Alcohol Soluble Solid) and AIS (Alcohol Insoluble Solid), calcium contents were investigated. Although the differences in sugar and organic acid content were not significant in fruits divided by gravity, flesh hardness was depressed in fruits that showed low gravity. These results were more conspicuous in late harvested fruits (at 174 and 181days after full bloom) which showed low gravity, representing less content of AIS content and calcium in ASS and AIS when compared with early harvest fruits. Fruits of lower gravity below 1.0 measured with dipping induced the progression of pithiness symptom up to 76%. Consequently, harvest timing is a more concise factor in pithiness fruit occurrence although those symptom also affected by storage condition. Furthermore, the cause of pithiness fruit occurrence by late harvest is due to the lower cell wall binding calcium.

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.102-107
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• 2013

BACKGROUND: Pithy pear fruit are not distinguished externally from sound fruit and thus often cause unexpected economic losses. To find out the cause of pithiness, the pithiness incidence and characteristics of Japanese pear (Pyrus pyrifolia cv. Niitaka) fruit picked from a spot frequently produced pithy fruit in an orchard were compared with those of fruit picked from another spot produced sound fruit every year. And the soil chemical properties of the two spots and mineral contents in fruit, shoots, and leaves of Japanese pear trees cultivated in the two spots were also examined. METHODS AND RESULTS: The pithiness incidence was 0, 8.8, and 11.3% at 7 days before and 0 and 7 days after optimal harvest date, respectively, in the spot frequently produced pithy fruit. Flesh firmness was significantly lower in pithy fruit than in sound fruit, while soluble solids content was slightly higher in pithy fruit than in sound fruit. Unlike other mineral contents, Ca content was significantly lower in pithy fruit than in sound fruit. These results indicate that Ca deficiency in fruit is closely associated with decrease in flesh firmness and thus pithiness development. Ca content in soil of the spot frequently produced pithy fruit was also significantly lower than that in soil of the spot produced sound fruit. However, shoots or leaves did not exhibit significant difference in Ca and/or other mineral contents between the two spots, indicating that Ca deficiency in fruit is dependent on the translocation of Ca within a plant rather than soil Ca status. Although total-N, available $P_2O_5$, K, and Ca contents were significantly lower in soil of the spot frequently produced pithy fruit than in soil of the spot produced sound fruit, Mg and Na contents and pH were not different between the soil conditions. CONCLUSION(S): Fruit maturity and Ca level in fruit are closely related to the incidence of pithiness in 'Niitaka' Japanese pear.

• Korean Journal of Agricultural Science
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• v.40 no.3
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• pp.191-196
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• 2013

This study was conducted to investigate the effect of temperature during transportation and continuing shelf-life on fruit quality and the occurrence of physiological disorder to set up the appropriate exportation temperature condition in Asian pear (Pyrus pyrifolia Nakai) 'Hanareum'. In the experiment of simulated exportation headed for USA, the fruits transported at $1^{\circ}C$ showed less weight loss than those of $5^{\circ}C$. Market temperature appeared as a key factor for keeping freshness of exported pear fruits rather than transportation temperature. Quality factors such as high flesh firmness and low incidence of fruit rot and physiological disorders including core breakdown and pithiness were attained at the fruits maintained at $18^{\circ}C$. Approximately two times higher incidence of physiological disorders and of fruit decay rates were observed in the fruits distributed at $25^{\circ}C$ than the those of $18^{\circ}C$. Therefore, temperature management during marketing resulted as an important factor for maintaining fruits quality in the process of pear fruit exportation.

• Journal of Bio-Environment Control
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• v.5 no.2
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• pp.138-144
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• 1996

This experiment was conducted to decide appropriate nutrient concentration for beet soilless culture by different nutrient concentration treatment between before and after root enlargement. Yamazaki's solution for head lettuce was used 0.5, 1, 2, 4 strength for before root enlargement and 0.5, 1, 2, 4 strength was treated after root enlargement. Root weight was good in 0.5, 1, 2 strength treatment before, then change treatment to 4 strength after root enlargement. But 4 strength treatment after root enlargement increase pithiness and root cracking. Vitamin C contents was low in 0.5 and 4 strength treatments after root enlargement. Betaxanthin and betacyanin were involved high concentration in lower nutrient concentration after root enlargement despite the treatments of before root enlargement. Therefore 1, 2 strength before root enlargement and 2 strength after root enlargement treatments is recommendable for nutrient culture of beet.

• Korean Journal of Agricultural Science
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• v.37 no.1
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• pp.13-18
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• 2010

In order to prepare the technical fundamental in production of premium quality fruits of 'Niitaka' pears, we compared the quality parameters and storability of the fruits that had various fruit set position in a cluster. The fruits set on $4^{th}$ from basal part in fruit cluster had the largest fruit size. The weight of fruits set on the higher position than $4^{th}$ from basal part in fruit cluster showed decreasing tendency. The production rates of marketable fruits which had 500g to 899g in weight were the high in $3-5^{th}$ from basal part in cluster than those in other position. The differences of fruit height and diameter which represent balanced fruit shape also showed less difference in the fruits set on $4-5^{th}$ from basal part in cluster than the fruits set closely on basal part in cluster. The fruits set on $3-4^{th}$ from basal part in cluster showed lower rate in incidence of core breakdown and pithiness disorder during 4 months of cold storage than those on the closer position to basal part in cluster.

• Food Science and Preservation
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• v.16 no.6
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• pp.838-842
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• 2009

We explored how 'Wonwhang' pear fruit quality was affected by selenium (Se) application. The fruit skin color and fruit type differed between Se-treated trees and controls. Se-treated fruits had higher potassium and Se concentrations, more fruit soluble solids, and lower acidity, compared to the controls. All Se treatments improved fruit firmness during cold temperature storage compared to the controls. Also, Se-treated fruits had greater specific gravity and minuteness, which reduced fruit pithiness and rendered test fruits denser than the controls. Overall, Se foliar application improved fruits marketability compared to the Se fertilization or Se trunk injection.

• Korean Journal of Agricultural Science
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• v.40 no.2
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• pp.79-86
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• 2013

We investigate the effect of preharvest spray of aminoethoxyvinylglycine (AVG), an inhibitor of ACC synthase activity, on fruit quality of 'Wonhwang' pear (Pyrus pyrifolia Nakai). And the effects were compared with ethephon which releasing ethylene to elucidate treatment efficacy of ethylene biosynthesis inhibitor on Asian pears. Chemicals were sprayed on 30 days before harvest with AVG (75 and 150 mg/L) and ethephon (100 mg/L), respectively. Highest flesh firmness during 21 days of shelf-life at $25^{\circ}C$ after 30 days of cold storage was attained in the fruit treated with 150 mg/L AVG (26.5N) when compared with untreated control (16.7N), while the fruits treated with 100 mg/L ethephon completely lost their marketability within 14 days of shelf-life by mass drop of firmness down to 11.6N. Low incidence of physiological disorders including pithiness and core browning were attained at the fruits treated with 150 mg/L AVG when we compared with untreated control. No occurrence of mealiness found in the fruits treated with AVG but ethephon treated fruits showed 36.4% during 14 days of shelf-life. Consequently, AVG spray at the concentration of 150mg/L on Asian pear 'Wonhwang' fruit regarded as useful preharvest management approach for keeping quality during marketing period after simulated exportation.

• Food Science and Preservation
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• v.16 no.5
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• pp.675-679
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• 2009

We investigated how Germanium (Ge) application, and the application method, affected 'Niitaka' (Pyrus pyrifolia) fruit quality in a conventional orchard. Ge-treated pears weredark yellow in color, indicating appropriate maturation. Other fruit characteristics, and weight, did not significantly differ between tests and controls. Compared to controls, fruit from Ge-treated trees had more soluble solids, a lower acid content, and fewer stone cells, which reduced fruit chewiness. Ge-treated trees showed a higher Ge concentration in fruit but a lower calcium (Ca) concentration. Other fruit mineral nutrients, includingP, K, and Mg, did not differ in level between Ge-treated fruit and controls. Ge-treated fruit showed greater firmness and a heavier specific weight during 6 months of storage, compared to control fruit. Therefore, Ge treatment reduced fruit pithiness, which can be a problem in 'Niitaka' pears. Overall, there was no significant difference between Ge-treated and control fruit qualities, but a combined Ge treatment (fertilization plus foliar application plus trunk injection) slightly improved fruit quality.

• Korean Journal of Environmental Agriculture
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• v.34 no.3
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• pp.204-209
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• 2015

BACKGROUND: Radish (Raphanus sativus L.) is cultivated worldwide and one of important vegetables in Korea where year-round production of radish is possible. Most of radishes in autumn are cultivated with double-row spacing except for Gangwon-do where sing-row spacing is predominant. However, no research has been conducted on double-row spacing in radish cultivation so far. This study was conducted to reveal the optimum double-row spacing in autumn cultivation of radish. METHODS AND RESULTS: Using top two popular autumn radish cultivars 'S' and 'C', seeds were sown in spacing between rows of $55{\times}25$, $45{\times}25$, $35{\times}25$ and $25{\times}25cm$, and that within rows of $35{\times}28$, $35{\times}25$, $35{\times}22$ and $35{\times}19cm$. Plants were harvested 58 days after sowing and leaf weight, length and number, and root weight, length sugar content and pithiness were investigated. In the spacing between rows, no significant difference was observed in leaf weight, length and number in both cultivars; however, 25 cm of spacing between rows significantly reduced the root length and weight in 'S' and 'C' cultivars, respectively. In spacing within rows, 28, 25 and 22 cm did not affect fresh root weight in both cultivars, producing appropriate radish roots of 1,500g on average. However, 19 cm of spacing within rows did not reduced fresh root weight in 'S' cultivar but did significantly in 'C' cultivar (1148.3 g). Sugar contents and pithiness of roots were also affected by spacing but its effect was very small and different between cultivars. CONCLUSION: It is suggested that optimum double-row spacing in autumn radish cultivation is 35 cm and 22 cm of spacing between and within rows, respectively, the spacing that did not reduce the yield and quality of radish roots in two popular autumn radish cultivars.