• Journal of Plant Biotechnology
• /
• v.32 no.1
• /
• pp.45-50
• /
• 2005

Virus-free stocks was produced by the combination of the heat treatment of virus infected plant and shoot-tip grafting (STS). To produce virus-free stocks, the plants infected with citrus viruses were used for virus-free stock production using the modified method of STG in thermotherapy at $40^{\circ}C$ for 16 hours in the light, and at $30^{\circ}C$ for 8 hours of darkness for 4 weeks. Trifoliate orange (P. trifoliata) were used as rootstock seedling for STG. Percentages of virus-free stocks against citrus tristeza virus (CTV), satsuma dwarf virus (SDV) and citrus tatter leaf virus (CTLV) were $75.7\%,\;100.0,\%\;82.6\%$ respectively. Shoot tip size for successful STG were as small as possible. Less than $0.3\;\cal{mm}$ of shoot tips gave the hight efficiency of virus free plants but survival rates were low. And, survival rate after shoot-tip culture was analyzed and the rates were dependant on the cultivars; Yuzu cultivar showed the hight survival rate ($74.6\%$) and early satsuma mandarin (Iwasagi) was $13.3\%$ as the lowest cultivar. But citrus trees were not succeed to grown, turned brown, and died.

• The Plant Pathology Journal
• /
• v.26 no.4
• /
• pp.353-359
• /
• 2010

In order to control postharvest spoilage of satsuma mandarin fruits, rhizobacteria were isolated from soil samples. The Pantoea agglomerans strain 59-4 (Pa 59-4) which suppresses the decay of mandarin fruit by green and blue mold, was tested for the control efficacy and its mode of action was investigated. Pa 59-4 inhibited infection by green and blue mold on wounded mandarins, which were artificially inoculated with a spore suspension of Penicillium digitatum and P. italicum with control efficacies of 85-90% and 75-80%, respectively. The biocontrol efficacy was increased by raising the concentration of cells to between $10^8$ and $10^9\;cfu/ml$, and pretreatment with the antagonist prevented subsequent infection by green mold. The population of Pa 59-4 was increased more than 10 fold during the 24 hr incubation at $20^{\circ}C$, indicating that colonization of the wound site might prevent the infection by green mold. Despite poor antifungal activity, the Pa 59-4 isolate completely inhibited the germination and growth of P. digitatum spores at $1{\times}10^8\;cfu/ml$. We argue that the control efficacy was mediated by nutrient competition. Overall, the effective rhizobacterium, Pa 59-4, was shown to be a promising biocontrol agent for the postharvest spoilage of mandarin fruits by green and blue mold.

• Journal of Bio-Environment Control
• /
• v.7 no.2
• /
• pp.130-138
• /
• 1998

This experiment was conducted to study the effect of ethephon(100mg.L$^{-1}$ ) and calcium carbonate (10000mg.L$^{-1}$ ) on the acceleration of peel coloration of ‘Miyagawa Early’ Satsuma Mandarin in the plastic house. The foliar application treatments were conducted once. twice or 3 time at intervals of 15 days from degreening of the fruit apex. Peel coloration of a value by spraying ethephon ＋ clef-non was increased with treatment frequency. The a/b values ran similar to this trend. As a result of this, peel coloration was accelerated by foliar application of ethephon ＋ clef-non. Glucose and fructose did not differ significantly among foliar application frequencies. Sucrose and total sugar increased as foliar application frequency increased, but there was no significant di(ference among foliar application frequency group. The brix values were higher than 12˚BX in all treatments. However, a distinct difference between the control Brix value and the values for the treatment groups was found only in the level 3 frequency group.

• Journal of Bio-Environment Control
• /
• v.7 no.4
• /
• pp.276-282
• /
• 1998

This experiment was carried out to elucidate the effect of ethychlozate foliar application on the fruit quality of Miyagawa Early Satsuma Mandarin in the plastic house. Ethychlozate(100mg.L$^{-1}$ ) was applied to the fruit at 100, 115 and 145 days after full bloom stage. The fruit was divided into four frequency level groups, with the control group receiving no Ethychlozate treatment and the level 3 group receiving all three applications. Peel coloration by a value Increased as application frequency increased. The a/b value trend was seen to be similar to this, but the b value ran contrary to the a value trend. Glucose contents of the fruit juice did not differ statistically among the application frequency levels but the fructose level was seen to be higher with increasing application frequency. Sucrose showed a similar trend to fructose in that it had a tendency to increase as application frequency increased. As a result of this, total sugar increased naturally with application frequency. The average Brix level among all treatment groups was higher than the average Brix level in the control group but Brix level did not differ significantly among application frequency levels. Acidity had a tendency to increase as application frequency increase, but there was no statistical difference found.

• Applied Biological Chemistry
• /
• v.41 no.2
• /
• pp.141-146
• /
• 1998

In order to determine the optimmum harvest time of Citrus unshiu Marc. var. miyagawa and C. unshiu Marc. var. okitsu produced in Cheju, citrus fruits sampled at packing houses or harvested directly on citrus tree in south and north area of Cheju were analyzed. The fruits were grown in size till middle of October, and soluble solids were increased continuously after that. The fruits size were different by positional directions on the tree, the quality of citrus fruits in central southern positions on the tree was good for fresh fruit consumptions. Compared with only the quality of citrus fruits as a factor of soluble solids, total sugar, pH, and color index, the optimum harvest time were supposed to be reasonable at late of November for C. unshiu Marc. var. okitsu, and at early of December for C. unshiu Marc. var. miyagawa. The results obtained from citrus fruits sampled at packing houses were supposed to be not suitable for determing the optimum harvest time, because of storage after harvest at ordinary harvesting time.

• Journal of Bio-Environment Control
• /
• v.10 no.2
• /
• pp.118-119
• /
• 2001

This experiment was carried out to examine the effects of foliar applications of 100 mg.L$^{-1}$ ethephon mixed with different calcium formulae (10,000 mg.L$^{-1}$ Clef-non, 2,000 mg.L$^{-1}$ Cell-bine, 2,000 mg.L$^{-1}$ Hicalux, and 2,000 mg.L$^{-1}$ calcium acetate monohydrate) on the rind coloration, defoliation and fruit quality of satsuma mandarin cultivated in the plastic greenhouse. Foliar applications of ethephon alone or in mixture with either Clef-non, Cell-bine, Hicalux or calcium acetate monohydrate demonstrated that increased 'a'value of peel chromaticity as compared to the control. The treatments encouraged fruit colour and allowed the harvest date to be predicted. The defoliation ratio decreased considerably by foliar applications of ethephon mixed with Cell-bine or Hicalux. The sugar content of fruit increased by 1.6, 1.54, and 1.54$^{\circ}$Bx with the foliar applications of ethephon, ethephon+Clef-non, and ethephon+Cell-bine, respectively. With the foliar applications of ethephon in mixture with Cell-bine, fruit coloration was accelerated. defoliation was delayed, and fruit quality was improved.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.16 no.3
• /
• pp.21-25
• /
• 1987

In order to obtain a basic understanding of the storage of Satsuma mandarin sacs, the canned sacs were stored at room temperature from Feb. 20 to June 20(4 months), after dipping in chlorine solution and pasteurization as a pretreatment before canning. In general, the brix, acidity and pH of the sacs were almost not affected by the chlorine treatment ana a variety of pasteurization temperatures during storage. The broken rate was apperently increased by chlorine treatment, especially in the early stage of storage. However, the broken sacs were partially recovered in the end of storage. The contents of total carotenoid were almost not decreased by the conditions of the pretreatments during storage. The contents of vitamin C were sharply decreased between 3rd and 4th month of storage time on all sample. As a result, the decrement of vitamin C in canned sacs was caused by storage temperature rather than the condition of the pretreament.

• Food Science and Preservation
• /
• v.19 no.1
• /
• pp.7-11
• /
• 2012

This study was conducted to determine the effects of the humidity and gas composition on the quality of satsuma mandarins during their heat treatment, in an effort to reduce their acidity. To come up with different humidity and gas conditions, various plastic films were used. The fruits were wrapped with an 18-${\mu}m$ high-density polyethylene (HDPE) punched film, a 30-${\mu}m$ low-density polyethylene (LDPE) film, or a 100-${\mu}m$ LDPE film just before treatment at $30^{\circ}C$ for 55 hours. After heat treatment, the titratible acidity (TA) was significantly reduced while the soluble-solid content (SSC) showed no differences, which resulted in increased SSC/TA ratios in all the treatments. The fruits that were not wrapped with a film, however, which had low RH, developed higher ethanol and acetaldehyde contents than those wrapped with an 18-${\mu}m$ HDPE punched film, which had high RH and a similar gas composition. Among the films, the higher the $CO_2$ concentration in the film was, the more the ethanol and acetaldehyde contents increased, which induced more off-flavor. It was thus concluded that high humidity and normal gas composition are favorable conditions for heat treatment to reduce the acidity of satsuma mandarins.

• The Plant Pathology Journal
• /
• v.36 no.1
• /
• pp.106-110
• /
• 2020

Citrus mosaic sadwavirus (CiMV) is a closely related virus with the Satsuma dwarf virus (SDV) along with Navel orange infectious mottling virus (NIMV), Natsudaidai dwarf virus (NDV), and Hyugagatsu virus (HV). The present study found that the typical symptoms of CiMV-infected citrus fruits include the appearance of dark blue speckles or ringspots on fruit rinds and the browning of oil glands in the spots as rind coloring began. As rind coloring progressed, the spots gradually faded, whereas the browning of the oil glands worsened to the point that the tissues surrounding the oil glands became necrotic. In very early satsuma mandarins (Citrus unshiu 'Miyamoto Wase') and 'Setoka' cultivar (C. hybrid 'Setoka') of late-maturity citrus, the symptomatic fruits were eventually dropped. And in early satsuma mandarin (C. unshiu 'Miyakawa Wase'), the peel hardness of the virus-infected fruit (1,618.3 ± 305.5, g-force) was more than twice as hard as that of the healthy fruit (636.5 ± 39.1, g-force). The ratio of flesh weight to total fruit weight was higher for the healthy fruit (77.3 ± 1.7%) than for the infected fruit (70.7 ± 0.6) and peel puffing was more severe in the infected fruit (2.9 ± 0.4 mm) than in the healthy fruit (0.9 ± 0.2 mm). The soluble solids content in infected citrus fruits was less values than the healthy fruit by 0.5-1.5 °Brix. These findings reveal that CiMV infection on citrus trees reduces the fruit quality of citrus.

• Applied Biological Chemistry
• /
• v.42 no.2
• /
• pp.147-151
• /
• 1999

Quality characteristics of Satsuma mandarin (Citrus unshiu Marc. var. okitsu) harvested in early December according to production areas and sea level altitude of Cheju were investigated. Soluble solids and flesh ratio were $9.06{\sim}12.98,\;77.32{\sim}81.27%$ on citrus fruits harvested in orchards located below 100 m sea level (lower area), and were $10.16{\sim}12.26,\;75.00{\sim}81.55%$ in orchards 150 m sea level altitude (higher area), respectively. Acid content of citrus juice was $0.83{\sim}1.21%$ in fruits harvested in lower area, and was $0.94{\sim}1.34%$ in higher area except Hankyung-myun area. The differences of soluble solids and acid contents by harvesting periods for 10 days were 0.91 and 0.82 for soluble solids; 0.15 and 0.13% for acid contents, respectively. In proportion to late harvesting, Brix/acid ratio and fruit quality were improving. Soluble solids of fruits harvested from lower area were higher than those of fruits from higher area, but acid contents were lower in fruits from lower area than in fruits from higher area. In sensory evaluation on fruit appearence, the differences between two altitudes were not clear, but panelists marked higher points on fruits harvested in main production areas, Seogwipo-si and Namwon-eup which are southern areas. Fruit quality harvested in Seogwipo-si areas showed better quality than fruits from other harvested areas.