• Journal of Bio-Environment Control
• /
• v.28 no.1
• /
• pp.55-65
• /
• 2019

The effects of stigma removal from floral organ and treatment of auxin on those regions were evaluated on the fruit growth and quality in strawberry (Fragaria ananassa Duch.). The removal of stigma reduced the fruit weight, fruit length, and fruit width, while fruit growth declined as the number of removed stigma increased. The removal of stigma also resulted in reduced fruit firmness, sugar content, and total anthocyanin content, and decreased value of Hunter a for red color and increased value of Hunter b for yellow. The number of seeds deceased as the regions of removed stigma increased. The treatment of auxin on the region of removed stigma improved fruit size, while it reduced fruit firmness, sugar content, and anthocyanin content. The delay in fruit ripening was observed from both stigma removal and auxin treatment. The incidence of malformed fruits increased as the regions with removed stigma increased. The treatment of auxin also promoted fruit malformation.

• Korean Journal of Environmental Agriculture
• /
• v.39 no.4
• /
• pp.360-367
• /
• 2020

BACKGROUND: The productivity and quality of blueberry (Vaccinium ashei Reade) greatly depend on the number of fruits in a plant. Especially, fruit set more than appropriate number negatively affects productivity and marketability due to the increased number of small fruits and delayed harvest time. This study was conducted to investigate proper timing and concentration for applying chemical blossom thinners such as ammonium thiosulfate (ATS) and UREA. METHODS AND RESULTS: ATS at 1.25% and 1.50%, and UREA at 6% and 8% were applied in four developmental stages, bud swell, pink bud, full bloom and petal fall. Fruit thinning rate was calculated based on the number of fruits harvested divided by that of flowers before applying blossom thinners. Ratios of leaf to flower and leaf to fruit were calculated based on the number of fully developed leaves in 25 days after full blossom divided by that of flowers or fruits, respectively. Chemical injury of leaves was investigated by calculating the number of leaves with chemical injury divided by the total number of leaves. Fruit thinning rates were 48% and 66% for UREA treatments at 6% and 8%, respectively, and 49% and 62% for ATS treatments at 1.25% and 1.50%, respectively, in the full bloom stage. In the petal fall stage, fruit thinning rates were 18% and 24% for UREA treatments at 6% and 8%, respectively, and 49% and 35% for ATS treatments at 1.25% and 1.50%, respectively. Leaf to fruit ratio (L/FR) increased by 109% and 188% compared to leaf to flower ratio in ATS treatments at 1.25% and 1.50%, respectively, and L/FR increased 93 and 196% in UREA treatments at 6% and 8%, respectively, in the full bloom stage. In the petal fall stage, leaf to fruit ratio increased by 60% to 100% in ATS treatments, but did not significantly differ from the control in UREA treatments. Fruit harvest was delayed in all treatments of all developmental stages except for 1.5% ATS and 6% UREA treatments at the petal fall stage, whose fruit harvest was two or three days faster than the control. CONCLUSION: The application of ATS and UREA for blossom thinning should be in the petal fall and full bloom stages for early and late harvest, respectively. Considering chemical injury, integrated harvesting and fruit size, however, it is appropriate to apply ATS at 1.5% in the petal fall stage to increase fruit productivity and quality in blueberry.

• Korean Journal of Plant Resources
• /
• v.27 no.6
• /
• pp.701-706
• /
• 2014

Three highbush blueberries (Vaccinium corymbosum cvs. Bluecrop, Coville, and Northland) grown in an open field and in a rain shelter were compared to evaluate the potential benefits of rain-sheltering systems on growth and fruit quality. Shrubs grown in rain shelter flowered 5-14 days earlier and were in full bloom earlier than those in the open field. All three cultivars set fruit by nearly 90% of flowers when they were grown in the open field, but was markedly reduced when they were grown in the rain shelter, to approximately 50% for 'Bluecrop' and 'Coville'. Fruit sets ratio of 'Northland' grown in the in the rain shelter was 14.5. Fruit from greenhouse-grown 'Northland' were larger, heavier, and had more seeds per berry. Soluble sugar content (SSC) of fruits varied both with the cultivars and growing conditions. SSC of fruits grown in the greenhouse was higher in 'Bluecrop' compared to that grown in the field, but this pattern was reversed in 'Northland'. Titratable acid was significantly higher in fruits from rain shelter-grown shrubs of both 'Bluecrop' and 'Northland' than in fruits from open field-grown shrubs (P < 0.05), although there was no difference in TA with respect to growing conditions for 'Coville'. The number of seed per fruit, fruit length and diameter, weight, SSC, and TA were similar in 'Coville' shrubs grown in the open field and the rain shelter. Fruit firmness of 'Bluecrop', 'Coville', and 'Northland' was higher in the rain shelter than in the open field. 'Coville' and 'Northland' fruits harvested in the open field had higher blue chroma than those harvested in the rain shelter. However, this pattern was reversed for 'Bluecrop'. On the whole, sheltering from rain affected most fruit characteristics of the three cultivars differently. Therefore, suitable blueberry cultivars for the rain shelter should be chosen by purpose.

• Journal of Biosystems Engineering
• /
• v.37 no.4
• /
• pp.252-257
• /
• 2012

Purpose: The net rind pattern and color of melon surface are important for a high market value of melon fruits. The development of the net and color are closely related to the changes in shape, size, and maturing. Therefore, the net and color characteristics can be used indicators for assessment of melon quality. The goal of this study was to investigate the possibility of estimating melon soluble solids content (SSC) and firmness by analyzing the net and color characteristics of fruit surface. Methods: The true color images of melon surface obtained at fruit equator were analyzed with 18 color features and 9 texture features. The partial least squares (PLS) method was used to estimate SSC and firmness in melons using their color and texture features. Results: In sensing melon SSC, the coefficients of determination of validation (${R_v}^2$) of the prediction models using the color and texture features were 0.84 (root mean square error of validation, RMSEV: 1.92 $^{\circ}Brix$) and 0.96 (RMSEV: 0.60 $^{\circ}Brix$), respectively. The ${R_v}^2$ values of the models for predicting melon firmness using the color and texture features were 0.64 (RMSEV: 4.62 N) and 0.79 (RMSEV: 2.99 N), respectively. Conclusions: In general, the texture features were more useful for estimating melon internal quality than the color features. However, to strengthen the usefulness of the color and texture features of melon surface for estimation of melon quality, additional experiments with more fruit samples need to be conducted.

• Journal of Bio-Environment Control
• /
• v.7 no.4
• /
• pp.330-335
• /
• 1998

To investigate the effect of soil water control on yield and quality of musk melon in plastic film house, irrigation points were treated with -10, -20, -30, -50 and -100 kPa by 10mm dripping each time at fruit developing and ripening stage, respectively. Fresh weight of stem and leaves was not significant among irrigation points, but percentage of dry matter was highest at -100kPa and lowest at -10kPa. Marketable yield was not different among -50kPa, -100kPa, -30kPa and -20kPa and lowest at -10kPa. Sugar content of the flesh fruit at ripening stage was 15.1 $^。/Brix at -50kPa and 14.4 $^。/Brix at -10kPa Therefore, optimum irrigation point at ripening stage of fruit is -50kPa by 10mm dripping each time. time.

• The Korean Journal of Food And Nutrition
• /
• v.33 no.2
• /
• pp.159-166
• /
• 2020

Melon is a fruit consumed and grown globally because of the sweet taste and pleasant aroma. The purpose of this study was to determine the quality characteristics and antioxidant activities of melon jams added with various fruits such as apple, aronia, blueberry, grape, kiwi, passion fruit, and peach. We determined quality characteristics such as pH, total acidity, antioxidant activity, content of total anthocyanin, polyphenol and tannin, respectively. The 100% melon jam as the control was the highest pH and lowest total acidity, whereas mixed jams with melon and passion fruit showed opposite results. The mixed jams with melon and aronia of the total anthocyanin, the polyphenol contents, tannin, and ABTS radical scavenging activities, were markedly higher than those of the control and other samples (p<0.001), followed by the mixed jams with melon and blueberry. In the taste sensing analysis, mixed jams with melon and passion fruit revealed higher richness and lower aftertaste-bitterness and aftertaste-astringency than the commercial strawberry jam and other samples. Thus, jams mixed with various fruits, in particular, aronia, blueberry, and passion fruit were superior to the 100% melon jam in terms of physiological activity and palatability.

• Korean Journal of Agricultural Science
• /
• v.39 no.4
• /
• pp.503-509
• /
• 2012

This research aimed to investigate the effect of preharvest spray of aminoethoxyvinylglycine (AVG) on fruit quality of 'Nagasawa Hakuho' peach (Prunus persica Batsch). The efficacy of various concentrations of AVG (75 and 150 mg/L), which inhibits the ethylene biosynthesis, was evaluated under field conditions. Treatments were performed 21, 14 and 7 days before harvest, respectively. Fruit weight, flesh firmness, soluble solids content, acidity, ethylene production, respiration rate and skin color difference were determined at harvest time and during shelf-life at $25^{\circ}C$. Results indicated that the most appropriate timing of AVG spraying was 21 days before harvest at the concentration of 75 mg/L as shown higher firmness at harvest time and lower ethylene production and respiration rate during shelf-life. Spraying of AVG during near harvest period (14 to 7 days before harvest) inhibited fruit growth slightly, independent of concentration and did not affect fruit quality in 'Nagasawa Hakuho' peach.

• Korean Journal of Environmental Agriculture
• /
• v.41 no.4
• /
• pp.245-251
• /
• 2022

BACKGROUND: Selection an suitable light source is essential in the year-round production of horticultural crops in closed production systems such as plant factory with controlled environments. This study was investigated to confirm the effects of artificial light sources on growth of cherry tomato'CF Jelly'(Lycopersicon esculentum var.) under high-pressure sodium lamps (HPS), metal-halide lamps (MH), and LEDs. METHODS AND RESULTS: Light intensity of the light sources was controlled at 220±30 µmol/m²/s with 12 hrs of photoperiod for a day. Flower development was significantly faster in HPS and MH treatments compared to the LEDs. There was no significant difference between the leaf number and leaf shape under the HPS and MH treatments. Reproductive growth of cherry tomato was significantly promoted by the LEDs treatment of blue plus red lights. Fruit yield per plant also increased under the LEDs compared to the others. CONCLUSION(S): Growth, flowering, and fruit setting of the cherry tomato were accomplished by the artificial lights under plant factory conditions. The HPS treatment showed negative effect on fruit quality in terms of blossom-end rot incidence compared to the LEDs or MH treatment. Effect of the LEDs on promotion of fruit weight and yield was also proved. Additional research should be carried out for improving sugar metabolism or decreasing disease in the fruits under plant factory system using only artificial lights.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.25 no.4
• /
• pp.84-89
• /
• 2024

Light is an important component among which plays a crucial role in determining the production and quality of fruit trees. Since the disturbance of light directly leads to reduced photosynthetic efficiency, their damage can be increased especially in fruit trees such as Japanese apricots with a short growing time. In this study, we investigated how the effects of shading condition can affect the production and quality of Japanese apricots according to increased damages by light disturbance in the main orchard complex. The average photosynthetically active radiation (PAR) level in Japanese apricots was rapidly dropped as the shading time was increased compared to the control (304 μmol/m²/s) and the PAR level decreased to 142 μmol/m²/s after shaded for eight hours. The maximum photosynthetic efficiency, with a PAR value of 900 to 1,000 μmol/m²/s, corresponds to the time period without shading and the time period with 2 hours of shading, and these times range from 11 a.m. to 3 p.m. And the time period for shading for 4 hours was from 1:00 p.m. to 2:00 p.m., and under conditions of shading for 6 and 8 hours, the effect was a low amount of light. There was no difference in the weight of Japanese apricots during 2 hours shading time, however, it was significantly reduced as shading time were increased. The difference of the acid content and L/D ratio was not significant on shading time, but the SSC was decreased as times going on. In conclusion, our results indicate that the shading for more than 2 hours make negative effects to decrease the weight and SSC and the yield and affects directly to drop in fruit quality.

• Korean Journal of Environmental Agriculture
• /
• v.38 no.3
• /
• pp.166-172
• /
• 2019

BACKGROUND: Increase in the ratio of small berries in blueberry production decreases the farmers' profits due to weakening market competitiveness and lowering harvest efficiency. One of the reasons for increased small berries is over fruit-load. For improving productivity and competitiveness of blueberry in Korea, hand-thinning can be applied to increase fruit quality before the developing adequate chemical thinning methods. This study was conducted to investigate the proper timing and methods for floral buds thinning in rabbiteye blueberry. METHODS AND RESULTS: Eight years old bushes of rabbiteye bluberries 'Brightwell' as a primary cultivar and 'Powderblue' as a pollinizer were used for this study. Fruit size distribution by leaf-to-fruit ratio was investigated by counting the number of leaves and fruits in canes of 127 'Brightwell' plants whose fruit set varied. Fifty percent of flowers/floral buds were removed in four different floral buds stages such as bud swell, late pink bud, full bloom, and petal fall, and the consumed time for thinning and fruit characteristics were recorded to investigate the effect and proper timing of floral buds thinning. Fruit weight and soluble solids content tended to increase in proportion to leaf-to-fruit ratio and the production of the number of fruits less than 13 mm in diameter decreased when leaf-to-fruit ratio was more than 2.5. Manual floral buds thinning by hands was fastest in full bloom stage and slowest in bud swelling stage. In all cultivars, fruit size was significantly smaller in non-thinning treatment than thinning, and there was, however, no significant difference in total fruit yield. The number of fruits less than 13 mm in diameter increased in both cultivars as floral buds thinning was delayed. Consumed time for picking 90% berries out of total berries per bush was shortest in full bloom stage thinning in 'Brightwell' and bud swelling, full bloom thinning in 'Powderblue'. These were 25 and 20 days faster than no thinning, respectively. CONCLUSION: Although the effect of floral buds thinning varied depending on the cultivars, our results confirmed that floral buds thinning was effective for the early intensive harvesting and the increase of the large fruit ratio and the harvesting productivity. Also, in order to increase thinning efficiency, it is recommended to remove the flower buds before the full bloom stage.