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Understanding the fruit ripening mechanism is critical for fruit quality improvement. Although postharvest ethylene application is known to enhance the onset of fruit ripening, the exact mechanisms remain unclear. In this study, a gel-based proteomic analysis was performed to investigate the changes in protein profiles during the ripening of exogenous-ethylene-treated kiwifruit (Actinidia deliciosa) cultivars ‘Hayward’ and ‘Garmrok’. Based on comparative two-dimensional gel electrophoresis, most of the proteins were aggregated in exogenous-ethylene-treated kiwifruit compared to the untreated kiwifruit. Consequently, 90 and 106 proteins were differentially expressed in ‘Hayward’ and ‘Garmrok’ kiwifruit, respectively. Among the successfully identified proteins by matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry, the 50% in ‘Hayward’ kiwifruit and 60% in ‘Garmrok’ kiwifruit were associated with ripening. Also, 18% and 10% of proteins were associated with defense response in ‘Hayward’ and ‘Garmrok’ kiwifruit, respectively. The other major proteins were related to protein biosynthesis and photosynthesis/Calvin cycle during kiwifruit ripening. We used bioinformatics analysis to determine the interactions between identified proteins, and this proteomic approach provided insights into biological pathways and molecular functions in postharvest ripening of exogenous-ethylene-treated kiwifruit.

Genotyping-by-sequencing (GBS) was used to investigate the genetic diversity and population structure of kiwifruits (Actinidia spp.). Using single nucleotide polymorphisms detected by GBS, phylogenetic tree and population structure were constructed for 89 kiwifruit accessions including Korean native A. arguta. The kiwifruit accessions were clearly divided into two groups in the phylogenetic tree. These groups were characterized by the presence or absence of hairs on pericarp. In the population structure analysis, the peak of delta K was detected at K = 5, suggesting that the 89 kiwifruit accessions were divided into five clusters. Each cluster represented A. chinensis, A. deliciosa, A. eriantha with wild accessions, female A. arguta, and male A. arguta. The result of the population structure supported the genetic background of each accession. We also performed genetic diversity analysis of A. arguta accessions. Consequently, A. arguta accessions were characterized by sex and 13 A. arguta accessions, occupying 33.3% of the total collection, were selected as a core set for use as germplasm to develop disease and cold stress resistant cultivars in future kiwifruit breeding programs. These results suggest that GBS approach is suitable for genetic diversity analysis of kiwifruits. Moreover, our results could be applied in kiwifruit breeding program to develop disease and cold stress resistant cultivars using Korean native A. arguta. Particularly, the developed Korean native A. arguta core set will be used as breeding materials for crop improvement strategies.

Kiwifruit has been cultivated in southern coastal regions of Korea since late 1970s. New cultivars have been successively released in recent years. In this study, we investigated major disease and pest incidences in new kiwifruit cultivars 'Goldone', 'Redvita' and 'Garmrok' at open field in Sacheon for 3 years and rain-proof field in Jeju for 2 years. For the bacterial canker, the 3 new cultivars showed more disease occurrence in Sacheon but rare in Jeju. For leaf spot disease, compared to disease incidence of 20% on 'Hayward' in Sacheon, cv. 'Garmrok' had high incidence about 60% but cv. 'Goldone' and cv. 'Redvita' had low incidence less than 20%. However, in Jeju, diseases incidences of all the new cultivars were lesser than 20%. In the case of Hemiptera, many Halyomorpha halys and Nezara antennata appeared in Sacheon but in Jeju Plautia stali was dominated. Isolated bacterial canker pathogen was identified as Pseudomonas syringae pv. actinidiae biovar 3. Leaf spots pathogens were Phomopsis sp., Phoma sp., Fusarium tricinctum and Alternaria alternata. This study shows the disease information on new kiwifruit cultivars and the adequate disease managements will be required.

Chitosan, a natural polysaccharide derived from the deacetylation of chitin, has a great potential for a wide range of applications. As an edible coating material chitosan, has been reported to be highly effective in extending the postharvest life of many crops while reducing moisture loss, respiration, ethylene production, ripening, softening, controlling the decay, and maintaining fruit quality, along with storability. This review discussed the applications of chitosan and its potential effects on the postharvest life and quality attributes of kiwifruit. The application of chitosan, the possible mechanisms of action, and its perspectives as a coating material for kiwifruit are discussed.

블루베리의 주요 품종군은 북부형(Vaccinium corymbosum L.), 남부형(Vaccinium corymbosum hybrid)하이부쉬 블루베리와 래빗아이 블루베리(Vaccinium ashei Reade)로 나뉜다. 이들 품종군은 공통 적으로 배수성이 좋은 산성토양과 뿌리털이 없는 천근성 뿌리구조로, 보비력과 양분이용이 매우 취약한 환경을 가지고 있다. 따라서 본 연구는 시비효율성 증대를 위하여 래빗아이 블루베리의 생육특성에 미 치는 관비효과를 구명하고자 수행하였다. 시험장소는 경남 남해에 소재한 국립원예특작 과학원 남해출 장소 시설포장에서, 2013년 4년생 ‘Brightwell’(V.ashei Reade)레빗아이 블루베리 품종을 완숙유기물(피 트모스) 30%(v/v)혼합된 토양에 재식하여 수행하였다. 시비는 오레곤 주립대학에서 제공하는 표준시비 량 14g plant -1 의 관행시비와 4수준의 관비를 처리하여 양분흡수량과 수체생육 그리고 과실특성을 조사 하였다. 시비방법에 따른 수체생육과 과실생산량은 관비시비가 효과적이었으며, 관비수준별 시비효과는 표준시비량의 50%처리가 가장 효과적이었다. 처리별 엽중 질소함량은 표준시비량의 50% 관비처리가 14.4g kg -1 으로 가장 높았으나, 200% 관비구는 11.5 g kg -1 으로 가장 낮았다. 처리별 엽중 인산함량은 유의차가 나타나지 않았으나, 칼리와 칼슘 그리고 마그네슘함량은 표준시비량의 50%관비처리에서 가장 높았으며, 시비량의 증가는 엽중 무기성분 함량을 낮추는 경향을 나타냈다. 처리별 수관면적은 관행시 비가 4.86 m 3 으로 가장 낮은 수준을 보였으며, 50% 관비처리가 9.61 m 3 로 가장 높았다. 이와같이 50% 관비처리의 높은 시비효과는 각각 3,650 g plant과 12,849 g plant을 나타낸 건물중과 과실생산량에서 도 유사한 경향이었다. 한편 시비방법과 관비수준에 따른 과실의 안토시아닌과 당 그리고 산함량 등 과 실품질은 일정한 경향을 나타내지 않았다.

BACKGROUND: This study was conducted to investigate the effect of the unexpected early loss of leaves on a newly-bred kiwifruit on the regrowth of axillary buds the current season and the early growth and development the following year. METHODS AND RESULTS: The vines were defoliated on Jul. 18, Aug. 16, and Sep. 17 in 2012 and on Jul. 16, Aug. 13, and Sep. 12 in 2013. The vines were defoliated 0 (control), 50, and 100% of the total number of leaves on a vine. The regrowth of axillary buds at 30 days after defoliation increased in proportion to defoliation degrees regardless of the defoliated time. Defoliation the previous season did not influence percent budbreak the next season. Percentage of floral shoots of the control vines was 27.4%, each bearing 2-3 flowers. In those vines defoliated 100% in August and September, however, percent floral shoots and number of flowers significantly reduced. CONCLUSION(S): Defoliation in July, August, and September didnot affect percent budbreak the following year regardless of degrees of defoliation. A 100% defoliation in August and September significantly reduced flowering the following year compared to the control; that in August resulted in no floral buds at all.

Peach and nectarine cultivars have been released worldwide according to regional preference and local adaptability. However, few reports have provided statistical analyses and comprehensive comparisons of Eastern and Western cultivars. In this study, 22 phenotypic characteristics of 120 peach and nectarine cultivars collected from various countries were examined to determine their diversity and relationships. Based on phenological traits, Western cultivars bloomed earlier than Eastern cultivars, with no difference in ripening time. Fruit shape of Eastern cultivars was close to oblate, while fruit weights were similar. In addition, higher soluble solids concentration (SSC) and lower titratable acidity were observed in Eastern cultivars. In health benefit traits, such as total flavonoid concentration, total phenol concentration, and antioxidant capacity, there was no difference between Eastern and Western type. Positive correlation between chilling unit (CU) and latitude of origin was also found. In addition, the CU was closely associated with flowering date. Relationships among the phenotypic characteristics were also found. Ripening date showed significant and positive correlations with fruit development period, fruit weight, and SSC. In general, cultivars with late ripening times tend to produce high-quality fruit with a sweet taste and large size. The evaluation of a large number of cultivars from various regions with phenotypic variability could provide valuable information on regional preference or local adaptability.

Pectin methylesterases (PMEs) mediate demethylesterification of pectic polysaccharides such as homogalacturonan, a major component of the primary plant cell wall, in the apoplasm. The PMEs are implicated in a number of developmental processes, including pollen development and pollen tube growth, through the fine tuning of the methylesterification status of pectin. In this study, we isolated a full-length cDNA (KiwiPME1) encoding PME from kiwifruit and characterized its molecular features. Analyses of the primary protein structure and gene structure revealed that KiwiPME1 encodes a pre-pro-PME protein that is predicted to localize to the outside of the cell and belongs to group 2 (formerly type 1). The KiwiPME1 expression was highly detected in pollen grains of kiwifruit but not in vegetative tissues investigated. Expression pattern analysis of KiwiPME1 among different floral tissues of male and female plants revealed that KiwiPME1 was expressed specifically in the stamens of flower buds in male and female plants, whereas its expression was detected only in the stamens of male plants when the flowers opened. Expression analysis of KiwiPME1 promoter fused to the GUS reporter gene in Arabidopsis displayed a very similar pattern to that in kiwifruit. Our study suggests that the cell wall-localized KiwiPME1 is likely implicated in the pollen development and pollen tube growth of a dioecious species kiwifruit.

Floral Bud Cold Hardiness and Cultural Safety Zone in Rabbiteye Blueberry Cultivars Hong-Lim Kim, Yong-Bum Kwack, Jeom-Hwa Han, Pill-Kyung Oh, Won-Byoung Chae, Seong-Cheol Kim, Mok-Jong Kim and Jin-Gook Kim, (Namhae Sub‐Station, NIHHS, RDA, Namhae 668‐812, Korea, Fruit Research Division, NIHHS, RDA, Suwon 440-706, Korea, Vegetable Research Division, NIHHS, RDA, Suwon 440‐706, Korea, Department of Horticulture, Gyeongsang National University, Jinju 660‐701, Korea)

Received: 18 September 2014 / Revised: 10 November 2014 / Accepted: 12 November 2014 Copyright c 2014 The Korean Society of Environmental Agriculture This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Accumulated nutrient reserves provide an important energy source for deciduous fruit trees in their initial growth and development the following spring. This study investigated the effect of mid-season defoliation on the growth and accumulation of carbohydrate reserves of kiwifruit vines in Korea. The ‘Goldrush’ (Actinidia chinensis) vine was used for this experiment, following de-blossoming in spring. The vines were artificially defoliated to varying degrees at 1 month intervals from Jul. 15 to Oct. 14. The degree of defoliation was 0 (control), 25, 50, 75, and 100%. From Jul. 15 to Sep. 15, the dry weight of kiwifruit vines with 50% or more defoliation was reduced as compared to the control. In particular, 75 and 100% defoliation on Aug. 16 resulted in decrease of 79.2 and 83.1 g from the control vines (145.6 g), respectively. Defoliation on Aug. 16 decreased both the aboveground and underground dry weight of the vines. Most carbohydrate reserve of the young vines (which did not have fruit) accumulated in the roots. Defoliation on Aug. 16 and Sep. 15 reduced the accumulation of carbohydrate reserves, which was correlated with a decline in vine dry weight. For vines with 75% or more defoliation on Aug. 16 and Sep. 15, about less than half amount of starch accumulated in the roots as compared to the control (4.3 g per vine). In contrast, the accumulation of soluble sugars was not significantly influenced by defoliation, except for vines with 75% or more defoliation on Aug. 16. In conclusion, 75% or more defoliation on Aug. 16 and Sep. 15 has a negative impact on the growth and carbohydrate reserve of a new cultivar, ‘Goldrush’.

In May 2014, sclerotinia rot symptoms caused by Sclerotinia sclerotiorum were observed on stored kiwifruit in Jinju, South Korea. The symptoms appeared as soft, water-soaked lesions on fruit covered with a white mycelium. The morphological characteristics and the internal transcribed spacer sequences of rRNA of the pathogen isolated from the sclerotinia rot showed it to be S. sclerotiorum. This was confirmed by performing a pathogenicity test with pure cultures of S. sclerotiorum and by reisolating S. sclerotiorum from artificially inoculated kiwifruits. Our results should help promote a better understanding of the diseases that affect kiwifruit and improve practices for postharvest disease control in the kiwifruit industry.

BACKGROUND: Kiwifruit, which was introduced to Korea in late 1970s, is a warm-temperate fruit tree, whose leaves are easily damaged by wind because of their large size. To produce high quality fruits, efficient windbreak is necessary to protect leaves until harvest. In Korea, typhoons from July onwards usually influence the production of kiwifruit. Damages from typhoons include low fruit quality in the current year and low flowering ratio the following year. This study was conducted to investigate the effect of early defoliation of kiwifruit vines from July to October on the regrowth of shoot axillary buds the current year and bud break and flowering the following year. METHODS AND RESULTS: Scions of kiwifruit cultivar 'Goldrush' were veneer grafted onto five-year-old Actinidia deliciosa rootstocks, planted in Wagner pots (13L) and grown in a rain shelter. Kiwifruit leaves in the proximity of leaf stalk were cut by lopping shears to simulate mechanical damage from typhoon since only leaf stalks were left when kiwifruit vines were damaged by typhoons. Kiwifruit vines were defoliated from July 15 to October 14 with one monthintervals and degrees of defoliation were 0, 25, 50, 75 and 100%. All experiments were conducted in the rain shelter and replicated at least five times. Defoliation in July 15 resulted in a high regrowth ratio of 20-40% regardless of degree of defoliation but that in August 16 showed only 5.8% of regrowth ratio in the no defoliation treatment; however, more than 25% of defoliation in August 16 showed 17-23% of regrowth ratio. In September 15, regrowth ratio decreased further to less than 10% in all treatments and no regrowth was observed in October 14. Percent bud break of all defoliation treatments were not significant in comparison to 64.7% in no defoliation except for 42.1% and 42.9% in 100% defoliation in July 15 and August 16, respectively. Floral shoot in the no defoliation treatment was 70.2% and defoliation of 50% or less resulted in the same or increased floral shoot ratio in July 15, August 16, and September 15; however, defoliation in October 14 showed no difference in all treatments. In flower number per floral shoot, 2-3 flowers appeared in no defoliation and only 1 flower was observed when the vines were defoliated more than 50% in July 15 and September 15. In October 14, contrary to the floral shoot ratio, flower number decreased with increased defoliation. CONCLUSION(S): Therefore, it is suggested that dormancy of 'Goldrush' axillary buds, was started in August and completed in October. The effect of defoliation on bud break of axillary buds the following year was insignificant, except for 100% defoliation in July 15 and August 16. From July 15 to September 15, floral bud ratio was significantly reduced when more than 50% of leaves were defoliated compared to no defoliation. Also, the number of flowers per flower-bearing shoot the following year decreased by less than 50% when compared to no defoliation, and this decrease was more prominent in September 15 than July 15 and August 16.

In Korea, kiwifruit is grown within a limited region on the southern coast where the climate is warm. Since the yellow - fleshed kiwifruit variety, ‘Hort16A’, first became commercially available, we have focused on breeding additional yellow - fleshed kiwifruits. Here, we describe the cultivar ‘Goldone’, which originated from ‘Red Princess’ and is characterized by red coloration around the fruit core. Conventional field crosses were performed in 2003, and permission for final release of ‘Goldone’ was obtained in 2011. This cultivar is very productive, with an average fruit weight of 129 g, which is 39% heavier than that of the cultivar ‘Hayward’. ‘Goldone’ is harvested in late October, approximately 165 - 170 days after anthesis. In general, ‘Goldone’ has approximately eight flowers per fruiting shoot; these flowers must be thinned before blooming for commercial production. ‘Goldone’ was registered at the Korean Seed & Variety Service in 2014 for plant variety protection rights (grant no. 4835).

BACKGROUND: The fruit quality and flowering characteristics of Kiwifruit (A. deliciosa cv. Hayward) in the following year is known to be affected by the extent and timing of defoliation of the current year. In korea, the production of kiwi, which is a perennial, straggling deciduous warm-temperate fruit, is often restricted by wind damage due to typhoons resulting to defoliation at the middle season of its growing period. In this paper, we report the effect of the different timing of defoliation and severities at the current season to the kiwifruit quality. METHODS AND RESULTS: Twenty seven-year-old 'Hayward' trees grown under polyethylene film rain-shelter were defoliated in different days from August to September at seven day-intervals. In each day, 0, 25, 50, 75 and 100% of leaves were removed from the trees. Fruits from each treatment were classified into four floating types (L: lying in bottom, S: standing on bottom, F: floating and SF: floating at the surface of water) by submerging them into tap water. Defoliation of kiwifruit trees in August and September caused air holes in locules of inner pericarp. Increased number of air hole in locules of a fruit was observed in floating types F and SF, and most of the air holes were located in stem end. The defoliation of trees in August significantly reduced the ratio of L-floating type fruits, which have the least number of locule air holes. The extent of defoliation also affected the distribution of the four types, the more leaves removed, the less L-floating type fruits harvested. The weight of fruits from trees defoliated in August was lower than that of fruits from September. Soluble solids content decreased as the number of locule air holes increased. Negative correlations were observed between the extent of defoliation and the weight and soluble solids content of fruits. CONCLUSION: Early defoliation effect on kiwifruit locule air hole occurrence and fruit quality were more severe in August than in September. And also if the defoliation severity is over 25%, severe fruit quality reduction expected to happen due to increase of fruit locule air hole in the inner pericarp.

A new promising kiwifruit, 'Halla Gold' variety with yellow flesh and being harvested in October, was developed at the Agricultural Research Center for Climate Change, National Institute of Horticultural and Herbal Science, Rural Development Administration, Korea in 2007. This variety was derived from the seedling population crossed between Actinidia chinensis cv. Golden Yellow and A. chinensis cv. Songongu in 1997. It was selected out of 2,971 seedlings. Characteristic trials were carried out from 2001 to 2003. After the selection, adaptability test was also conducted at kiwifruit orchards in Jeju Island from 2003 to 2007. Shoots of 'Halla Gold' sprout slightly stronger than those of 'Jecy Gold' but weaker than 'Hort16A' and the color of leaf is green. Fruit shape is oblong and fruit skin color is yellowish-dark green without hair. The average weight of fruit is 106.3 g. Fruit has a moderate size soft core, yellow pericarp, and fragile and juicy flesh. Soluble solids content is Brix and acidity is 1.4%. The harvesting time is about 10 days earlier than 'Jecy Gold' and about 20 days ahead of 'Hort16A'. The storage life is about 90 days at . This variety can be recommended for cultivating at low land area bellow 100 m sea level in Jeju Island or under shelter to prevent disease and cold injury.

The soil moisture has an important effect on growth and development of highbush blueberry (HB), mainly because the root system, devoid of root hairs, is superficial. Moreover, the texture and organic matter content of Korean soil is different from the main producing counties, such as USA and Canada. To facilitate the growth and development of HB and long-term maintenance of productivity, the research related to soil moisture condition in Korea should be the priority. This study was performed to investigate the growth properties of the HB in various soil moisture conditions in order to determine the irrigation trigger point and optimum soil water potential. The texture of soil used in this experiment was loam. For the experiments, the soil was mixed with peatmoss at a rates 30% (v/v). Irrigation was scheduled at -3, -4, -5, -8, -15 and -22 kPa soil water potential then investigated leaf macronutrient, bush growth, and fruit properties. The leaf K content of HB showed the same trend in the soil water potential, but Leaf P and Mg content was highest in -5 and -22 kPa, respectively. The productivity and growth amount of HB showed the peak at the range of -4~-8 kPa as normal distribution pattern, and greatly decreased at above -15 kPa. Total dry weight and Cane diameter were highest at -4 kPa, plant width, fruit weight and yield were highest at -5 kPa, and plant height, cane number and shoot tension were highest at -8 kPa. Soluble solids content showed same trend in the soil water potential, but titratable acidity, anthocyanins and total polyphenols were not significantly different. Therefore, the optimal soil water potential for the development and a maximum production of HB were a range of -4~-8 kPa, and the recommended ideal irrigation trigger point was within -15 kPa.