The Horticulture Journal
Online ISSN : 2189-0110
Print ISSN : 2189-0102
ISSN-L : 2189-0102
Advance online publication
Displaying 1-10 of 10 articles from this issue
  • Naoki Hiraiwa, Hisayo Yamane, Soichiro Nishiyama, Ryutaro Tao
    Article type: Original Articles
    Article ID: SZD-017
    Published: 2025
    Advance online publication: February 05, 2025
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Supplementary material

    Fruit sensory characteristics are crucial in terms of decision-making for fruit production and breeding. However, due to the relatively short consumption history of blueberries in the Japanese market, their sensory characteristics have yet to be characterized by Japanese consumers. Over three years, Japanese consumer panels evaluated preferences and sensory attributes of 34 blueberry cultivars such as rabbiteye blueberry (Vaccinium virgatum Aiton) and highbush blueberry (V. corymbosum L.), including both northern highbush blueberry and southern highbush blueberry. The preferences and sensory attributes were rated using the general labeled magnitude scale (gLMS) method. The consumer panels recognized variations in sensory attributes and expressed their preferences for taste and texture. Overall liking was strongly correlated with texture liking (r = 0.66), sweetness (r = 0.58), and flavor intensity (r = 0.42), but weakly with firmness (r = 0.22) and not correlated with sourness or a rough feeling. Additionally, significant interaction effects between perceived and ideal taste intensities on overall liking were found, with sourness perception having a more pronounced effect. The results also suggested potential differences in blueberry preference between Japanese and U.S. consumer panelists. Furthermore, sensory attributes were well correlated with corresponding instrumentally measured taste and texture traits, supporting the usefulness of biochemical and mechanical measurements for evaluating blueberry quality characteristics, particularly texture. This study revealed that blueberry fruit preference was largely determined by sweetness intensity and texture preference, with sourness preference also having a significant influence. There is potential to satisfy Japanese preferences, especially regarding texture. The findings provide valuable insights into Japanese consumer preferences for blueberries and offer a roadmap for consumer-oriented cultivar selection and breeding.

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  • William Viera, Takashi Shinohara, Chino Iyooka, Naoki Terada, Atsushi ...
    Article type: Original Articles
    Article ID: QH-150
    Published: 2025
    Advance online publication: February 04, 2025
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    Fruit consumption is highly recommended due to its health benefits. Passiflora species are a good source of vitamins and antioxidant compounds such as carotenoids that are associated with a reduction in cellular oxidative processes, as well as against cardiovascular diseases and cancer development. As a result, purple passion fruit (P. edulis) and yellow passion fruit (P. edulis f. flavicarpa) are economically important crops that are cultivated based on the demand for their flavor and nutraceutical properties. The objective of this study was to determine the components of carotenoids and sugars in the pulp juice of passion fruit. Two Ecuadorian yellow passion fruit strains (‘INIAP 2009’ and ‘POR1’), one Ecuadorian purple passion fruit variety (‘Gulupa’) and two Asian hybrid cultivars (P. edulis × P. edulis f. flavicarpa; ‘Summer Queen’ and ‘Ruby Star’) were used for this research. The results showed that ‘POR1’ had high acidity and contained all carotenoids, but had the lowest amount of vitamin C, whereas ‘INIAP 2009’ had high contents of organic acids, vitamin C and β-cryptoxanthin. ‘Gulupa’ had the lowest acidity, α-carotene and citric acid content, but the highest amount of glucose, fructose, malic acid and vitamin C; this variety also showed high values of β-carotene and β-cryptoxanthin. On the other hand, ‘Summer Queen’ had high sucrose, malic acid, α and β-carotene and good amount of vitamin C, while ‘Ruby Star’ had high amounts of α-carotene, β-cryptoxanthin and citric acid, but low vitamin C content. These results can be used for further breeding programs focused on improving passion fruit quality.

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  • Hisashi Kondo, Takayuki Yoshizaki, Yuta Hashimoto, Satoru Yamamoto
    Article type: Original Articles
    Article ID: QH-162
    Published: 2025
    Advance online publication: February 04, 2025
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    The cultivation of ‘Muscat Bailey A’ for fresh consumption is popular in western Japan, but growers are facing issues with poor coloration of grape berries partly due to insufficient cooling of nighttime temperatures. To ameliorate the coloration defects in ‘Muscat Bailey A’ grapes grown with gibberellin treatment for seedlessness under high nighttime temperatures, and to improve the color characteristics of red wine made from these grapes, the effectiveness of agricultural materials aimed at correcting poor coloration was tested on grape berries intentionally subjected to conditions that induce poor coloration in 2017 and 2018. Inactivated yeast derivatives, shochu lees filtrate, and proteolytic enzymes were sprayed on leaves, and fertilizer containing optically active abscisic acid (S-ABA) was sprayed on clusters during veraison as agricultural materials that could potentially improve fruit characteristics such as grape skin color and the hue of wine. After veraison, the grapes were grown under conditions in which the nighttime temperature was kept above 25°C. The L*, a*, and b* values of these grape skins were determined using colorimetry. Low L* values, indicating darker berry coloration, and notable decreases in hue angle, suggesting a shift towards red and purple hues, were observed after treatment with S-ABA-containing fertilizer. The absorbance of wine made from the grapes described above was measured spectrophotometrically. A significant difference in the color characteristics of the wine was observed for various absorbance indices (A420 representing yellow, A520 representing red-purple, and A520, at pH 1.0 as an indicator of total anthocyanins). The tannin content in the wine from S-ABA-treated grapes was significantly higher compared to the control. However, no differences were observed in taste among these wines. Comprehensive analysis by LC-MS confirmed that mainly levels of malvidin, petunidin (both purple-colored anthocyanins), and peonidin (a red-colored anthocyanin) compounds had increased. These results suggest that S-ABA-containing fertilizer works effectively in alleviating the poor coloration of ‘Muscat Bailey A’ clusters grown under high nighttime temperature conditions and in improving coloration of the wine made from these grapes.

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  • Kazunori Takeda, Toru Sugita, Yusuke Haraguchi, Hiroshi Matsunaga, Jun ...
    Article type: Original Articles
    Article ID: SZD-010
    Published: 2025
    Advance online publication: February 04, 2025
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    Supplementary material

    Soilborne pest and disease management is one of the most important challenges in the cultivation of sweet bell pepper, sweet pepper, and chili pepper (Capsicum annuum L.). In Japan, the nematode Meloidogyne incognita is a soilborne pest responsible for considerable economic losses. Unfortunately, although F1 rootstock cultivars resistant to M. incognita infestation have been developed, resistance-breaking populations of M. incognita have emerged that can attack these cultivars. To address this issue through crossbreeding, breeding materials that are resistant to the new populations of resistance-breaking nematodes are needed. Here, we obtained 288 Capsicum germplasms from the NARO Genebank (Japan) and screened them for resistance to infestation by normal nematodes (strain Mi-Nishigoshi), resistance-breaking nematodes (‘LS 2341’-derived strain), and nematodes collected from 14 sweet pepper fields in Miyazaki Prefecture, Japan. Two of the germplasms, ‘NuMex Bailey Piquin’ and ‘PM 217-1-3’, showed strong resistance to all of the M. incognita tested and were used for progeny testing. ‘NuMex Bailey Piquin’ was selected as the parental line for a new F1 rootstock with resistance to a wide range of nematodes, including resistance-breaking nematodes. Since segregation of resistance was observed in ‘NuMex Bailey Piquin’, we selected one line named ‘J159’ among the selfing population of ‘NuMex Bailey Piquin’ to fix the resistance to the resistance-breaking nematode. We then evaluated the nematode resistance of ‘J159’ F1s crossed with the doubled haploid line ‘KLDH89’, which is resistant to bacterial blight, normal nematodes, and pepper mild mottle virus (pathotype P1,2), but not to resistance-breaking nematodes. The ‘KLDH89 × J159’ cross not only showed high resistance to resistance-breaking nematodes, but also high yield when used as a rootstock. It is registered in Japan under the rootstock cultivar name ‘Dai-Hinata’.

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  • Shoki Ochiai, Takanori Ishii, Erika Kamada
    Article type: Original Articles
    Article ID: SZD-007
    Published: 2025
    Advance online publication: January 11, 2025
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION

    Spinach for processing use should be systematically harvested according to the fresh weight and height standards required by the processing plant; thus, monitoring spinach growth in fields is crucial. However, ground measurements require substantial labor. In recent years, unmanned aerial vehicles (UAVs) have been established as effective labor-saving tools for monitoring crop growth. This study aimed to clarify: 1) which model and image type are appropriate for mono-regression in the estimation of fresh weight and height of processing spinach, 2) whether a combination of images from RGB and multispectral cameras and the application of machine learning can improve the estimation accuracy in multivariate regression, and 3) which model shows the highest estimation accuracy over extrapolation data. In the mono-regression, the highest fresh weight estimation accuracy was achieved with the soil adjusted vegetation index (SAVI) using a multispectral camera at 50 m altitude (test root mean squared error (RMSE) = 0.795). The highest height estimation accuracy was achieved with the modified green red vegetation index (MGRVI) using an RGB camera at 50 m altitude (test RMSE = 5.01). Estimation accuracy was highly dependent on image type, suggesting that the effectiveness of appropriate selection for accurate estimation. In multivariate regression, machine learning models showed higher accuracy for fresh weight estimation compared to multiple linear regression. Although most support vector regression models exhibited higher accuracy than that of the multiple linear regression model, random forest regression models exhibited lower accuracy for height estimation. These findings suggest that the selection of an appropriate model type is critical. Although combining images from RGB and multispectral cameras improved accuracy in machine learning models, the effects were inconsistent because of other factors including target traits, model types, and UAV altitude. After comparing all models with the highest accuracy in each category, the fresh weight estimation model developed using support vector regression with images from an RGB camera at 30 m altitude, and the height estimation model based on support vector regression with images from both cameras at 30 m altitude showed the highest accuracies (test RMSE = 0.720 and 4.19, respectively). These machine learning-based models can thus facilitate precise monitoring of the fresh weight and height of spinach for processing use.

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  • Takumi Adachi, Haruna Okamoto, Yoko Shiroto, Mizuki Murakami, Chika Ta ...
    Article type: Original Articles
    Article ID: SZD-022
    Published: 2025
    Advance online publication: January 11, 2025
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Supplementary material

    Broccoli produces green florets under normal growth conditions, but produces darkish-colored florets after low-temperature exposure due to the accumulation of anthocyanin, which often reduces its commercial value. Selecting anthocyanin-free genotypes requires exposing the florets to low temperatures, which is laborious and time-consuming. We identified a genomic region on chromosome C09, which was associated with anthocyanin pigments in florets at low temperatures, through quantitative trait locus sequencing (QTL-seq) analysis using the phenotype data obtained from field evaluation of anthocyanin pigments of F2 plants over two years. Among nine differentially expressed genes in the QTL region, one gene encoding flavonoid 3′-hydroxylase (F3′H) was selected as a candidate. Sequence analysis of Brassica oleracea F3′H (BoF3′H) of parental lines revealed the presence of three alleles, with one derived from the anthocyanin-free parents, Bof3′h-2, exhibiting a 43-bp deletion in the second exon, causing a frame-shift mutation. Designing DNA markers capable of distinguishing this mutation, we demonstrated that, among 35 F1 cultivars released in Japan, eight homozygous for the Bof3′h-2 allele showed no anthocyanin pigments and lower anthocyanin contents in florets in the autumn- to over-winter harvesting. The expression level the BoF3′H gene was not necessarily related to the difference in anthocyanin contents. Furthermore, seedlings of the Arabidopsis f3′h mutants exhibited no pigments and a significantly reduced anthocyanin content under low-temperature treatment compared to that in the wild type. These results suggested that the 43-bp deletion in BoF3′H is responsible for the anthocyanin-free trait in broccoli genetic resources, and the developed marker was deemed useful for marker-assisted breeding.

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  • Atsushi Kono, Miho Tatsuki, Hideaki Yaegaki
    Article type: Original Articles
    Article ID: SZD-028
    Published: 2025
    Advance online publication: January 11, 2025
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Supplementary material

    The Freestone-Melting flesh (F-M) locus in peach controls two strongly linked traits that have significant effects on fruit quality: pit adhesion (freestone/clingstone) and flesh type (melting/non-melting). Recently DNA markers have been developed to identify major haplotypes of M0, M1, M2, M2b, and M3 at this locus. Japanese peach cultivars were historically developed using cultivars introduced from overseas; however, how the haplotypes have changed at the F-M locus during major cultivar improvement remains unknown. In this study, we aimed to clarify the transition of haplotypes at the F-M locus in major varieties of peach cultivars from the past to the present. First, we modified the F-M locus haplotype genotyping method by multiplexing the PCR to genotype many cultivars efficiently. Then, we genotyped the F-M locus of 63 cultivars, including major cultivars in 1934, 1980, and 2020 using this method. The results show that the number of cultivars harboring the M1 haplotype, which is a dominant freestone haplotype, decreased significantly, and cultivars homozygous for the M0 haplotype dominated. Haplotypes other than M0 and M1 were infrequent among major cultivars. Cultivars harboring M1 have not always been evaluated as freestone in the literature, while we found a strong relationship between the presence of the M1 haplotype and the freestone trait. All the genetically non-melting cultivars were evaluated as non-melting. There has been only one case in which a genetically melting cultivar was previously evaluated as semi-melting, although all other genetically melting cultivars were evaluated correctly. This result suggests that DNA markers could be effective for freestone breeding and there were no major problems in flesh texture prediction using this marker system. The haplotype transition at the F-M locus during Japanese peach breeding elucidated in this study could lead to new research on freestone/clingstone and flesh texture traits and their application in breeding.

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  • Yosuke Fujiwara, Soichiro Nishiyama, Noriyuki Onoue, Atsushi Kono, Aki ...
    Article type: Original Articles
    Article ID: SZD-004
    Published: 2025
    Advance online publication: December 14, 2024
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Supplementary material

    Persimmon fruit synthesizes and accumulates proanthocyanidins (PAs), resulting in its astringent taste. The pollination-constant and non-astringent (PCNA) trait is conferred by recessive alleles at the ASTRINGENCY (AST) locus, which has been exploited to control PA accumulation of persimmon fruit. However, some individuals with recessive homozygosity at the AST marker locus in breeding populations produce mature fruit with astringency, thereby reducing the marker-selection efficiency for the PCNA trait. In this study, we genetically and physiologically characterized the predicted ast-homozygous individuals exhibiting strong astringency in a cross population of ‘Taigetsu’ (non-PCNA) and ‘Kanshu’ (PCNA). The fruit PA content of these astringent individuals was higher than that of the other PCNA fruit, but lower than that of the non-PCNA fruit. These astringent individuals were similar to the other PCNA plants in terms of tannin cell size. Gene expression analysis revealed that PA synthesis-related genes (e.g., DkMYB4, DkMYC1, and DkANR) were expressed at a higher level in the astringent individuals than in the other PCNA fruit during the early fruit development stage. Furthermore, in the presumed ast-homozygous individuals with various PA contents, the expression of cellular function-related genes was highly correlated with PA accumulation. These genes may be important for tannin cell development and PA synthesis, potentially offering a novel approach to further modulate astringency in persimmons.

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  • Yukie Takeuchi, Sogo Nishio, Atsushi Imai, Takushi Yoshida, Norio Taka ...
    Article type: Original Articles
    Article ID: SZD-020
    Published: 2025
    Advance online publication: December 14, 2024
    JOURNAL OPEN ACCESS ADVANCE PUBLICATION
    Supplementary material

    Pear scab, a fungal disease caused by Venturia nashicola, is the most serious disease in Asian pear production, leading to decreases in yield and fruit quality. Five major scab resistance genes (Rvn1Rvn4 and Vnlf) and two QTLs (Rvn5 and Rvn6) identified from different cultivars have been used in pear breeding programs to produce resistant cultivars. Here, we validated the effectiveness of three simple sequence repeat (SSR) markers (LFA02a04, LFA02a09, and LFA02b20) linked to Vnlf (possibly allelic to Rvn2) by using 29 cultivars and four breeding populations. Since there was little discrepancy between the phenotype and genotype in any of the breeding populations, with the frequency of correct classification ranging from 89% to 100%, these markers will be useful for breeding programs. In a population segregating for Rvn1 and Vnlf, the ratio of resistant to susceptible individuals fitted a 3:1 model, confirming that both genes are dominant. Although symptoms with sporulation were observed on leaves of some individuals with only Rvn1 and on those with no resistance gene, no sporulation was observed on leaves of gene-pyramided individuals (Vnlf + Rvn1) or on those carrying only Vnlf. Moreover, we revealed that resistant Chinese pear (Pyrus bretschneideri Rehder) ‘Changxili’ is heterozygous for a previously unidentified host-resistance gene that behaves as a single dominant gene with the observed segregation ratios in four progeny populations. These segregation results in combination with marker data suggest that this newly discovered gene, designated Rvn7, is at a locus distinct from both Rvn1 (derived from ‘Kinchaku’) and Rvn4 (derived from ‘Hongli’). We expect these findings to contribute to pear breeding programs working to develop resistant cultivars with single and multiple resistance genes.

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  • Satoshi Ohta, Takaya Moriguchi
    Article type: Original Articles
    Article ID: SZD-008
    Published: 2025
    Advance online publication: December 03, 2024
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    Supplementary material

    In recent years, due to an aging workforce and labor shortages in the agricultural sector, coupled with difficulties in finding work in the welfare sector, agriculture-welfare collaboration has been promoted in Japan. However, owing to a lack of understanding in the agricultural sector about the abilities of individuals with disorders and how to deal with them, it has been assumed that individuals with disorders are unable to perform agricultural work. To address this lack of knowledge, in this study, 45 participants with intellectual disorders (Medical Rehabilitation Handbook A: 6 and B: 39) and 12 with mental disorders (Mental Disability Certificate Level 1: 1, Level 2: 8, and Level 3: 3) were asked to perform three tasks of varying difficulty levels in citrus orchards (bagging, harvesting, and fruit thinning). Their work abilities were evaluated based on measurements of work efficiency and observations of their work. The results showed that 96%, 50%, and 40% of the participants with disorders were able to comprehend the bagging (low difficulty), harvesting (medium difficulty), and fruit thinning (high difficulty) tasks, respectively. The average efficiencies of participants with disorders who comprehended the tasks were 55%, 71%, and 111% of those without disorders for bagging, harvesting, and fruit thinning, respectively. For fruit-thinning, six participants were more efficient than all participants without disorders. As described above, some aspects of the work efficiency of individuals with disorders at the start of the initiative were clarified. In the future, it will be necessary to clarify the negative effects of long work hours on physical strength and concentration, as well as on efficiency gains, through further experience and work process innovations.

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