The Horticulture Journal
Online ISSN : 2189-0110
Print ISSN : 2189-0102
Volume 87 , Issue 4
Showing 1-13 articles out of 13 articles from the selected issue
ORIGINAL ARTICLES
  • Kazuhiro Matsumoto, Tomomichi Fujita, Saki Sato
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 443-451
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: February 22, 2018
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    The evaluation of storability for the type 2 red-fleshed apple ‘Kurenainoyume’ is essential to expand its consumption for table and processing use, as the cultivation area of this cultivar has extended year by year. There is also little available information whether cold storage affects the skin and flesh coloration of ‘Kurenainoyume’ (type 2 apples). In the present study, we evaluated the effect of 1-methylcyclopropene (1-MCP) treatment on the storability of bagged and non-bagged fruit for respective table and processing use over 3 years. Furthermore, we determined the maximum storage duration of both bagged and non-bagged fruit with 1-MCP. No change was observed in the soluble solid content during cold storage regardless of 1-MCP and bagging treatments. The malic acid content, flesh firmness, and skin and flesh coloration decreased with longer storage duration, but the decrease in these parameters was alleviated by 1-MCP treatment. Without 1-MCP, the storage duration of both bagged and non-bagged fruit to maintain flesh firmness and coloration at acceptable levels was about 90 days after harvest (DAH). With 1-MCP, bagged fruit for table use could be stored for about 180–210 DAH with no severe decrease in flesh firmness. Non-bagged fruit for processing use could also be stored for the same duration as bagged fruit, but the flesh firmness severely deteriorated. Although cooling treatment during the fruit growing stage improved flesh coloration, we found that cold storage did not promote this factor.

  • Kazuhiro Matsumoto, Tomomichi Fujita, Saki Sato, Takaya Moriguchi
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 452-461
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: March 13, 2018
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    ‘Kurenainoyume’ is a newly released type 2 red-fleshed apple with pinkish flesh color. In our previous study, we revealed the effects of light condition on red coloration of the skin, flesh, and core of ‘Kurenainoyume’ apple fruit. In this study, we investigated the effects of temperature, shading, defoliation, and crop load on red coloration of the flesh. Low temperature improved flesh coloration; apples subjected to cooling treatment at 5°C or 10°C showed higher a* values of the Lab color space than the control (without cooling treatment), in a temperature-dependent manner. Low temperature reduced the soluble solid content to a lesser extent in some years, whereas fresh weight, malic acid content, and flesh firmness were not affected. Thus, the importance of temperature for flesh coloration was confirmed, similar to its effect on skin coloration. When the trees were covered with cheesecloth with a 50% shading rate from August 1 (82 days after full bloom: DAFB) to October 28 (170 DAFB), flesh coloration was negatively affected, and fresh weight, soluble solid, and malic acid contents were reduced relative to the control treatment (without shading). We also investigated the effects of defoliation (one-seventh of the control) and crop load (two- or threefold the crop load of the normal case control) on flesh coloration. Both defoliation and over crop load also decreased a* values, but their effects on the parameters related to fruit quality were not clear. Because all the treatments of shading, defoliation, and crop load relate to the efficiency of photosynthesis and the distribution of photosynthetic assimilates, our results also demonstrated that photosynthetic assimilates (carbohydrates) were one of the crucial factors affecting flesh coloration.

  • Kazuhiro Matsumoto, Toru Kobayashi, Tomoaki Kougo, Tomomichi Fujita, S ...
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 462-473
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: March 13, 2018
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    We investigated the effect of fruit bagging treatment using three kinds of paper bags differing in light permeability on the red coloration of skin, flesh, and core in type 2 red-fleshed ‘Kurenainoyume’ apples by comparison with type 1 ‘Goshogawara’ apples. Skin coloration of both ‘Goshogawara’ and ‘Kurenainoyume’ was affected by light and the effect was more marked in ‘Kurenainoyume’ than ‘Goshogawara’. In contrast, the effect of fruit bagging treatment on the red coloration of the core was limited in ‘Goshogawara’, while core coloration was not observed in ‘Kurenainoyume’ type 2 apples. Flesh coloration was observed even under dark conditions in both cultivars, and the light tended to enhance the flesh coloration to some extent in both cultivars. Since fruit bagging treatment is a prerequisite for ‘Kurenainoyume’ to prevent cork spot-like physiological disorder (CSPD) in the skin, we optimized the fruit bagging treatment conditions using a light impermeable double-layered paper bag (2-layer bag), considering both prevention of CSPD and the red coloration of ‘Kurenainoyume’ skin and flesh. Bag-removal at 25, 35, and 45 days before harvest (DBH), resulted in good skin and flesh coloration without CSPD incidence. Moreover, there was no significant difference in fresh weight, soluble solid, or malic acid contents compared with the non-bagging control. Therefore, we recommend bag-removal from 25 to 45 DBH for ‘Kurenainoyume’ as a practical cultivation technique.

  • Ittetsu Yamaga, Shigekazu Nakamura
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 474-480
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: April 18, 2018
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    In the present study, we examined the effect of blue LED irradiation on production of phytoalexin scoparone in wounded satsuma mandarin fruit as a result of fungal infections, as well as the effect of tape-type blue LED on fruit decay during long-term storage (from December to April) in an actual storage room. The blue LED treatment reduced the rate of fruit decay compared to that of dark treatment in wounded fruits. The decay rate of LED irradiated fruit was 13.3%, while that of non-irradiated fruit was 51.1%. In wounded fruits, blue LED treatment resulted in significantly higher scoparone contents than dark treatment. Intact (non-wounded) fruits had low scoparone contents, irrespective of blue LED irradiation. In an examination of changes in total fruit decay rate during storage using tape type-blue LED, the total decay rate was not significantly different between the LED-treated and untreated fruits until 64 days after storage (36 days after starting LED irradiation). On the other hand, at 92 and 120 days after the start of storage, total fruit decay under blue LED treatment was significantly lower compared to the untreated control. The tape-type blue LED (10 μmol·m−2·s−1) did not affect either the fruit quality analyzed (soluble solid content, titratable acidity, specific gravity, percentage of flesh) or the rind color. These results indicate that blue light induces scoparone production in wounded satsuma mandarin, and because of this, along with other putative factors, tape-type blue LED irradiation reduces mandarin fruit decay during long-term storage.

  • Issei Asakura, Yoichiro Hoshino
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 481-489
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: May 22, 2018
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    Actinidia kolomikta (Maxim. & Rupr.) Maxim., a wild kiwifruit relative native to East Asia, has several desirable characteristics, such as strong cold tolerance, precocity, and high levels of vitamin C, and has therefore attracted horticultural interest. In this study, the interspecific cross compatibility of the diploid Actinidia kolomikta with one cultivated species [A. deliciosa (A. Chev.) C. F. Liang & A. R. Ferguson], three native Actinidia species [A. arguta (Siebold & Zucc.) Planch. ex Miq., A. polygama (Siebold & Zucc.) Maxim., and A. rufa (Siebold & Zucc.) Planch. ex Miq.], and one endemic variety [A. arguta (Siebold & Zucc.) Planch. ex Miq. var. hypoleuca (Nakai) Kitam.], was evaluated to see if interspecific hybridization using A. kolomikta could improve edible Actinidia crop breeding programs. There was no fruit setting two weeks after anthesis in the tested cross combinations when A. kolomikta was the male parent. In contrast, all five crosses using A. kolomikta as the female parent produced 100% fruit setting two months after pollination. The crosses with different ploidy levels such as combinations between diploid A. kolomikta and hexaploid A. deliciosa, or diploid A. kolomikta and tetraploid A. arguta, produced a few viable seeds. In contrast, the crosses with diploid species such as A. arguta var. hypoleuca, A. polygama, and A. rufa, produced many viable seeds and seedlings. From these results, the cross compatibilities of A. kolomikta with the other tested species were categorized as follows: no fruit setting (A. arguta × A. kolomikta and A. polygama × A. kolomikta); fruit setting with few viable seeds (A. kolomikta × A. arguta and A. kolomikta × A. deliciosa); and normal fruit setting with viable seeds (A. kolomikta × A. arguta var. hypoleuca, A. kolomikta × A. polygama, and A. kolomikta × A. rufa). These results could be a basis for future edible Actinidia crop breeding programs using A. kolomikta and interspecific hybridization.

  • Taku Yano, Akiyoshi Morisaki, Shun-ichiro Ito, Masaharu Kitano
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 490-498
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: July 21, 2018
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    To predict the seasonal vegetative growth of potted seedlings of Satsuma mandarin, the effects of initial plant conditions (age, shoot pruning), environment (greenhouse, greenhouse + shading, open-field culture), and pot size on growth were researched for 1.5–2.5 years. The growth pattern was evaluated using a curve fitting with the 4-parameter logistic (4L) model, biomass allocation, and classical (interval) growth analysis, and a generalized linear model analysis based on thermal time (tt). Growth delays from shoot pruning were confirmed by growth trajectories with the 4L model based on tt. Plant growth was positively affected by enlarging the pot size (from 20-L to 45-L), while shading significantly suppressed the growth of 45-L potted Satsuma mandarin seedlings in the greenhouse. In the growth analysis, the relative growth rate was not always determined by the net assimilation rate (NAR), which included both shoot-pruning and pot size effects. To predict the plant mass of Satsuma mandarin seedlings (MP), we proposed several generalized linear models using a log link function assuming that MP followed a Gamma-distribution. The best model to predict MP was selected based on Akaike information criterion (AIC) values, and contained explanatory variables for initial plant biomass, NAR, specific leaf area (SLA), leaf mass ratio (LMR), pot size, and tt. Some simpler models excluding NAR, but including SLA and/or LMR as explanatory variables, were more useful than a model lacking growth analysis parameters (NAR, SLA, and LMR).

  • Takashi Kawai, Fumiya Matsumori, Hidemi Akimoto, Naoki Sakurai, Ken Hi ...
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 499-507
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: July 14, 2018
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    Split pit in peach (Prunus persica (L.) Batsch) fruit is an internal disorder that can have adverse effects on fruit quality and shelf stability. As it is difficult to distinguish split-pit fruit from normal fruit by appearance, a nondestructive detection method is desirable to determine accurately the timing of split-pit occurrence and remove unwanted fruit from trees. In our recent study, we used an acoustic vibration method for the nondestructive detection of split pit in harvested peach fruit. Here, we demonstrate that this method can be used to detect split pit in unpicked peach fruit. Time-course monitoring of growing fruit revealed that the ratio of the third (f3) to the second (f2) resonant frequency (f3/f2), which is an indicator of split pit in harvested fruit, abruptly increased in unpicked split-pit fruit from early June to early July. In contrast, the f3/f2 values of normal fruit remained low until harvest in late July. The increase in f3/f2 values of split-pit fruit was observed in early June (stage II of fruit growth) and/or from late June to early July (stage III of fruit growth), suggesting that, at least under the experimental conditions in the current study, pit splitting occurred at these two different timings. Split-pit fruit detection rate at harvest increased towards the end of the second split-pit occurrence and split pit could be predicted with high accuracy thereafter. These results collectively suggested that the timing of split-pit occurrence in unpicked peach fruit could be predicted accurately by measuring f3/f2 values and unwanted fruit with split pit could be distinguished from normal fruit on trees. We discuss the possible applications of the nondestructive acoustic vibration method in combination with fruit thinning and the future use of this method in research aiming to develop effective prevention methods or resistant cultivars with reduced split pit.

  • Megumu Takahashi, Yuka Nakano, Hidekazu Sasaki
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 508-515
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: July 07, 2018
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    Lateral heads, which generate after the harvest of an apical head of broccoli (Brassica oleracea L. var. italica), are generally small and have a low market value. Our purpose in this study was to increase the yield of broccoli from April to May, when domestic broccoli production is low, by removing excess branches (dubbed the “L-shaping” process) and growing one or two large and marketable lateral heads with the cultivar ‘Yumehibiki’. First, we demonstrated that transplanting seedlings in late-January and early-February to a field covered by plastic mulch and tunnels enabled apical heads and marketable lateral heads to be harvested in April and May, respectively. The number of marketable lateral heads reached a maximum 81% of that of apical heads. Next, we derived the base temperature (BT; °C), effective heat unit summation (EHUS; °C·day) from transplanting to apical head harvest, and additional EHUS from apical head harvest to lateral head harvest. They were 1.76°C, 747°C·day, and 254°C·day in 2016, and 1.74°C, 675°C·day and 204°C·day in 2017, respectively. The favorable timing for transplanting to result in the highest marketable yield was estimated as when the average temperature reached 4.0°C, but was less than 7.1°C. Finally, we characterized the lateral branches that were most likely to produce marketable lateral heads. The branches that produced marketable heads showed significantly higher values for thickness of branch, length of branch, and number of leaves on branch than those that produced nonmarketable heads, although the diameters of the developing heads on the branches were not significantly higher. Further analysis revealed that the leaf area was also significantly higher in marketable lateral heads than in nonmarketable heads. Taken together, the possibility of a substantial increase in yield during the broccoli off-crop season by using L-shaped ‘Yumehibiki’ was demonstrated in this study.

  • Wenkai Yan, Yuqi Zhang, Yating Zhang, Ruifeng Cheng, Yi Zhang, Qichang ...
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 516-523
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: August 03, 2018
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    Light is one of the most limiting factors affecting plant growth in greenhouses. Recently, supplementary artificial light has been widely used in greenhouse production in winter or on overcast days when solar radiation is weak. However, plant responses to supplementary artificial light in a Chinese Solar Greenhouse (CSG) and the economic feasibility of the lighting strategy are poorly understood. The tomato, one of the most widely produced and consumed vegetables in the world, was tested in this study. A CSG was divided into three sections, and three treatments were arranged. They were top lighting with HPS lamps (TL), TL plus inter-lighting with LEDs (TL+IL), and control treatment without artificial light, respectively. We showed that supplementary artificial light improved the uniformity of light distribution from the south to north end of the CSG, and increased the average greenhouse temperature by ~1–1.4°C. Tomato yield was increased by 21.8% and 32.9% in TL and TL+IL, respectively, compared with that of the control. The higher yield under supplementary artificial light resulted from a larger number of ripe fruits rather than bigger fruit size. Moreover, fruit quality was improved by supplementary artificial light as indicated by a higher total soluble sugar content. There were no significant differences in total biomass production or total soluble sugar content in leaves, as well as fruits, between TL and TL+IL treatments, but TL+IL further stimulated fruit maturation compared with TL. Although supplementary artificial light confers an advantage in terms of tomato growth, it is not economically feasible as 28.8 kWh electricity was required to increase the tomato yield by 1 kg in the CSG. Therefore, it is important to find solutions to increase the efficiency of supplementary artificial light in the CSG.

  • Runch Tuntipaiboontana, Chatuporn Kuleung, Vipa Hongtrakul
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 524-531
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: April 11, 2018
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    For their exceptional beauty and great variety, waterlilies of the genus Nymphaea are popular ornamental plants worldwide. To improve their appealing traits, breeders worldwide have attempted intrasubgeneric and intersubgeneric cross-breeding and succeeded in producing new varieties. Molecular markers have become standard practice in the breeding process and for accurate variety identification. With increasing knowledge about transposable elements in eukaryotic genomes, retrotransposon-based markers have been developed for various plant species and were sometimes found to be more informative than conventional marker methods. Due to the lack of information about retrotransposons in waterlilies, this study aimed to confirm the presence and analyze the diversity of the Ty1-copia retrotransposons, which have been well studied and used to develop markers in many plants. 133 sequences of a conserved domain in the reverse transcriptase gene of Ty1-copia elements were isolated from 13 varieties of waterlilies and found to be homologous to either Ale, Angela, or TAR lineages. Sequences homologous to the Ale lineage were found to be abundant and diverse. Those homologous to the Angela lineage were found to be very conserved, but scarce. Those homologous to the TAR lineage were relatively conserved and were found in ample amounts. Furthermore, the results indicate that those homologous to the Angela or TAR lineages are more conserved to their counterpart in other plants than those homologous to the Ale lineage. From this study, 3 groups of Ty1-copia elements were found to be suitable candidates for development of retrotransposon-based markers for waterlilies in the future.

  • Yoshikuni Kitamura, Tetsuya Hattori, Kaori Mogami, Takashi Fudano, Mar ...
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 532-540
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: April 25, 2018
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    Hydrangea (Hydrangea spp.) flower buds usually differentiate from the end of summer through autumn, but some cultivars can also produce flower buds in spring. In the present study, we selected cultivars with high potential for such unseasonable flower bud production in Japan by evaluating the flower bud production on pinch-treatment-induced axillary shoots. We also examined the pinching time and the difference between the two shoot types: previously formed shoots that developed from buds formed in the previous autumn and basal shoots that formed in the current spring. We found that ‘Christmas’, ‘Endless Summer’, and ‘Rosea’ had the highest frequencies of unseasonable flower bud production on the axillary shoots of previously formed shoots (90.0%, 80.0%, and 90.0%, respectively) and basal shoots (90.0% for all three cultivars). When the buds were pinched in mid-April, the axillary shoots that formed on both shoot types flowered from early July to mid-August, which was approximately 1 month later than for seasonably produced flower buds in the same cultivars. In 2011, 98.0%, 90.5%, and 84.0% of the axillary shoots that developed on previously formed shoots flowered in ‘Christmas’, ‘Endless Summer’, and ‘Rosea’, respectively, while in 2012, 63.2%, 54.9%, and 75.3% flowered, respectively. Similar values were seen for the basal shoots, with the exception of ‘Christmas’ in 2011 and ‘Endless Summer’ in 2012, which both had lower flowering rates than previously formed shoots. In ‘Rosea’, flower bud differentiation started just after the pinch treatment, and the frequency of flower bud production decreased when the pinch treatment was conducted after late April. Thus, ‘Christmas’, ‘Endless Summer’, and ‘Rosea’ were considered to have high potential for unseasonable flowering following pinch treatment in early spring. However, unseasonable flower bud production may often be suppressed in pinched basal shoots.

  • Olga Tejeda-Sartorius, Libia Iris Trejo-Téllez, María de los Ángeles A ...
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 541-548
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: June 15, 2018
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    We carried out a comparative study on the effect of mineral fertilizers and biofertilizers on the nutrient concentration of Laelia anceps Lindl. subsp. anceps (Orchidaceae) seedlings. The first nutrient solution (Min-Fert) was prepared with commercial mineral fertilizers (Peters Professional® 30N-10P-10K); the second one (Biofert) from Nutro® commercial biofertilizer; and the third with a combination of mineral sources and biofertilizers (Min-Fert + Biofert). Mineral fertilization promoted significant differences in N concentration in leaves and roots. Also, it increased K and the concentration of some micronutrients in the roots. The phosphorous concentration increased in pseudobulbs and roots with the Min-Fert and Min-Fert + Biofert. Biofertilization increased the N concentration in pseudobulbs, and Min-Fert + Biofert increased the Ca and Mg concentration in the roots, as well as the concentration of Fe and Cu in pseudobulbs and Cu in the leaves. Interestingly, Min-Fert significantly increased the nutrient concentration in the roots in comparison to the other tissues. We demonstrated that the use of biofertilizers in L. anceps subsp. anceps (alone or as a supplement to mineral fertilization), represents an alternative to reduce production costs and mitigate the negative impacts of mineral fertilization on the environment.

  • Yoshikuni Kitamura, Takafumi Watanabe, Yukari Kato, WeiWei Teoh, Keiko ...
    Type: Original Articles
    2018 Volume 87 Issue 4 Pages 549-556
    Published: 2018
    Released: October 24, 2018
    [Advance publication] Released: June 19, 2018
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    Information about mechanical reinforcement of decorative organs could help development of a novel technique that would give flowers with robust floral organs and broadly contribute to postharvest flower preservation. Hydrangeas (Hydrangea spp.) exhibit remarkable characteristics in terms of mechanical reinforcement of decorative sepals. Although decorative sepals at the flowering stage shrink when they are desiccated, decorative sepals after flowering maintain their shape even after desiccation. In this study, the lignifications of the vein cells in decorative sepals were analyzed using phloroglucinol/HCl-staining. The microstructure of the cell wall was analyzed using transmission electron microscopy (TEM). The three-dimensional structure of vein cells was analyzed using serial block-face scanning electron microscopy (SBF-SEM). Tubular- and spindle-shaped dead cells with a lignified pitted secondary cell wall were observed around the vessel elements in decorative sepals after flowering. These cells were observed as living cells without a secondary cell wall in the veins of decorative sepals at flowering and in fully expanded leaves. Further, 10 hydrangea cultivars were analyzed for development of mechanical reinforcement in vein cells, and some of them were compared by desiccation testing. Decorative sepals of a cultivar lacking those cells exhibited shrinkage after flowering when they were desiccated. In conclusion, dead cells with a lignified pitted secondary cell wall contribute to the reinforcement of veins in decorative sepals of hydrangeas and become sclerified parenchyma cells. Axial parenchyma sclerifying in veins after flowering is essential for robust hydrangea floral organs and represent a new type of mechanical reinforcement tissue in plant decorative floral organs.

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