• Korean Journal of Soil Science and Fertilizer
• /
• v.46 no.6
• /
• pp.525-529
• /
• 2013

As most of citrus, shiranuhi mandarin ((Citrus unshiu ${\times}$ C. sinensis) ${\times}$ C. reticulata) mainly use the trifoliate orange (Poncirus trifoliata) as its rootstock which has dwarf and cold hardness in Korea. However, recently, scion root was observed in 'Shiranuhi' mandarin tree grafted onto the trifoliate orange. This study was carried out to find out effects of scion root occurrence on the fruit quality, flowering and yield of shiranuhi mandarin. For the experiment, we selected six farmers who have outbreak of scion root in their Shiranuhi mandarin orchards and surveyed the difference of fruit quality of shiranuhi mandarin hybrid between scion root and control (trifoliate orange root). In the results, flowering was severely decreased in scion root trees compared to control. As a result of survey of 174 Shiranuhi mandarins, 160 trees were proved to be scion root, and had less flowering. Fruiting of scion root also severely dropped compared to control and thus, yields of scion root (6.4 kg) reduced by 24% compared to control (26.7 kg). The fruit size, weight and soluble solid contents of scion root were significantly reduced, but there were no differences in acid contents and coloring of fruit. From the results, we concluded that scion root had negative influence on flowering, fruit size and the yields of Shrinanuhi mandarin hybrid.

• Korean Journal of Plant Resources
• /
• v.32 no.6
• /
• pp.677-682
• /
• 2019

Hand leaf thinning for improvement of fruit coloration and quality is one of the most labor-consuming works in Korean apple cultivation. The study was aimed at investigating whether foliar application of two chelate compounds (Cu-EDTA, Fe-EDTA) could defoliate effectively 'Hongro'/M.9 apple leaves and enhance fruit coloration and quality. At 30 days before harvest, foliar spray with two chelate compounds defoliated significantly the apple leaves. Chelate treatments did not affect the leaf chlorophyll content. High concentration of chelates decreased drastically photosynthetic rate of true leaves, and then it stayed in low levels, whereas low levels of chelates reduced sharply the photosynthetic rate but it was gradually restored over time. Cu-EDTA regardless of its concentration triggered higher defoliation compared to Fe-EDTA. Consequently, higher defoliation improved light interception of fruits and accumulated more anthocyanin. Particularly, Cu-EDTA could target mainly fruit cluster leaves which affect directly light interception of the fruits, i.e. more selective defoliants compared to Fe-EDTA. However, 3% Cu-EDTA rather defoliated excessively, accompanying with reduction of fruit weight and soluble solids. Therefore, our results suggest that 1% Cu-EDTA which defoliates properly the fruit cluster leaves could improve coloration and quality of 'Hongro'/M.9 apple fruits.

• 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 Practical Agriculture & Fisheries Research
• /
• v.13 no.1
• /
• pp.47-69
• /
• 2011

The purpose of this study is to suggest strategies for vitalizing Jeju citrus export-specialized organization. To achieve the goal, the research has been focused on the establishment and standardization for fruit production practices that can keep a steady supply of high quality citrus fruit for export market, and followed by systematization of farms using the practices. According to the research findings, it is desirable that the high quality fruit production manual such as the Global GAP must be established, developed and prepared to train farm households. The establishment of the high quality fruit production manual is focused on the items as follows : 1) labor productivity enhancement by structural improvement of farm layout, 2) the practices for high-sugar-fruit production such as thinning out, irrigation and drainage system, and mulching with a poromeric sheet 3) productivity enhancement and quality improvement of fruit by cultivar improvement and virus-free nursery trees, 4) standardization of cultural practices throughout the citrus fruit production.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.6
• /
• pp.1009-1016
• /
• 2012

The purpose of this study was to determine the effects of organic fertilizers on soil properties and growth and quality of melon. Organic fertilizer was applied in soil at the rate of 0, 0.5, 1, 2N according to Rural Development Administration guideline in Korea. The fertilizer had no effects on plant growth-rate parameters, including plant height, leaf number, and leaf size. There were minor effects on the fruit quality parameters such as fruit weight, fruit length, fruit width, placenta and seed weights, sugar content, and starch content. Ascorbic acid level was decreased as fertilizer level was increased. The level of nitrate in groundwater increased with increased levels of N.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.77.4-77
• /
• 2001

The quality of agricultural products is classified with various factors which are measured and determined by destructive and/or nondestructive method. NIR spectrum analysis method is used to determine internal qualities such as a brix and an acidity. CCD color camera is used to measure external quality like color and a size of fruit. today, nondestructive methods are widely researched. The quality and the garde of fruit loaded into a cup automatically and measured in real time by camera and NIR system is determined by internal and external factors. This paper proposes modified boundary tracking algorithm which detects the contour of fruit´s color image and make chain code faster than conventional method ...

• Food Science and Preservation
• /
• v.1 no.1
• /
• pp.9-14
• /
• 1994

Soluble solids($^{\circ}$Brix), acid content and edible part ratio of Citrus unshiu collected at sorting Places in south Cheju area wee more lowered, and peel thickness was more thickened with increasing fruit size. Compared to early variety of Citurs unshiu(C. unshiu Miyakawa Mar), peel thickness of medium variety of Citurs unshiu(C. unshiu Hayashi Mar) was more thickened, and edible part ratio was more lowered with increasing fruit size. Soluble solids of medium variety of Citurs unshiu were lowered, and acid contents were increased compared to early variety. Processing properties for pressing concentrated juice was good for early variety of Citurs unshiu, especially on fruit diameter of 50-65mm. Soluble solids, acid contents and juice ratio were decreased with increasing peel thickness. The quality properties for fresh fruit with peel thickness had a good correlation on early variety of Citurs unshiu, and these data are supposed to be applied to the quality evaluation of Citurs unshiu produced in Cheju.

• Food Science and Preservation
• /
• v.16 no.3
• /
• pp.305-310
• /
• 2009

This study was conducted using 8-year-old 'Niitaka' (Pyrus pyriforia) pear trees to investigate the effect of different organic fertilizers on fruit quality and level of total phenolicsin a conventionally managed orchard. Trees were treated with one of five different fertilizers: 1) control (60 g of chemical fertilizer [16N-11P-12K] per tree) 2) rice bran (RB, 10 kg per tree); 3) coffee bran compost (CBC, 10 kg per tree); 4) chitin-incubated compost (CIC, 10 kg per tree); or 5) RCC (RB+CBC+CIC, 30 kg per tree). Soluble solid content, hardness, and titratable acidity were significantly higher in fruit from RCC-treated trees compared with fruit from trees exposed to other treatments. Overall, control fruit had smaller stones and lower calcium concentration than had organically fertilized fruit. Also, control fruit showed a reduced level of total phenolic compounds and lower antioxidant activity in both peel and flesh than did organically fertilized fruit. Compost-treated trees yielded fruit of enhanced edibility and with longer shelf-life owing to a reduction in stone size and increased calcium concentration, respectively. Overall, fruit from trees treated with organic fertilizers was of higher quality and had greater antioxidant levels compared with fruit from trees treated with chemical fertilizer.

• Korean Journal of Agricultural Science
• /
• v.49 no.3
• /
• pp.421-430
• /
• 2022

Crop load management in apple trees is important for achieving optimum productivity and crop value. Hence, we investigated the influence of different crop loads on the fruit quality, mineral content, and yield of the 'RubyS' apple variety. After 4 weeks of full bloom, the crop load was adjusted by hand thinning to different (5, 10, and 15 fruits·cm^-2) trunk cross-sectional areas (TCSA), representing low, medium, and high crop loads. The low crop load increased the fruit size and weight, the development of the red-blushed area, and the peel color a^* at harvest; however, it reduced the total number of fruits·tree^-1 and yield compared with that of the other crop loads. The medium crop load improved the fruit weight, flesh firmness, and soluble solids content and reduced the fruits·tree^-1 but did not affect the fruit size and yield. However, there were no significant differences in the titratable acidity and starch index among the crop loads. The fruit mineral content (phosphorus and potassium) was higher in the low and medium crop loads compared to the high crop load. However, the nitrogen, calcium, and magnesium contents in the fruits were not affected by the crop loads. Overall, this study suggests that a low crop load improves the fruit size and weight, but its effect on the quality and fruit mineral content is similar to that of a medium crop load. Therefore, the optimum crop load level for the 'RubyS' apple trees was approximately 10 fruits·cm^-2 TCSA.

• Korean Journal of Plant Resources
• /
• v.37 no.4
• /
• pp.401-410
• /
• 2024

This study was undertaken to elucidate the effects of virus and viroid infections on the growth of trees and the attributes of fruit quality in 'Hongro' apples. Trials were initiated using virus-infected, viroid-infected, combined virus/viroid-infected, and uninfected apple trees in an experimental apple orchard at the National Institute of Horticultural and Herbal Science in 2019. The growth of each tree was measured annually and compared between virus-free and virus/viroid-infected trees. Fruits were harvested from all apple trees, and selected attributes of fruit quality, including yield, weight, firmness, titratable acidity, and anthocyanin content, were determined in September 2021-2022. The results revealed significant differences among virus-free trees and those infected with either virus, viroid, or a combination of virus and viroid. Infection with viral and viroid diseases led to reductions in tree height (14.0%), trunk area (23.1%), fruit yield (65.0%), fruit weight (34.4%), and anthocyanin content (39.8%), while increasing fruit firmness (33.2%) and titratable acidity (39.8%), respectively. We anticipate that our research findings will also be beneficial for apple virus and viroid disease control, as well as apple cultivation management.