著者

William Olubero Asiche Oscar Witere Mitalo Yuka Kasahara Yasuaki Tosa Eric Gituma Mworia Koichiro Ushijima Ryohei Nakano Yasutaka Kubo

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-028, (Released:2017-01-14)

被引用文献数

36

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The responses of three kiwifruit cultivars, Actinidia chinensis ‘Sanuki Gold’, A. chinensis ‘Rainbow Red’, and A. deliciosa ‘Hayward’ to various storage temperatures (0, 5, 10, 15 and 20°C) for 8 weeks were investigated. The rate of fruit which initiated ethylene production due to rot development increased with increases in storage temperature. Early-maturing cultivars, ‘Rainbow Red’ and ‘Sanuki Gold’ fruit stored at 5, 10, and 15°C showed drastic softening and a decrease in titratable acidity (TA) to an edible level within 4 weeks without detectable ethylene production, whereas fruit stored at 0 and 20°C maintained high firmness and TA even after 8 weeks unless they were infected with rot. A late-maturing cultivar, ‘Hayward’ fruit stored at 5 and 10°C softened more rapidly than when stored at 0, 15, or 20°C. Treatment with 1-Methylcyclopropene (1-MCP) did not suppress the low temperature modulated fruit ripening in any cultivars, indicating its independence from ethylene. These results suggest that ‘Sanuki Gold’ and ‘Rainbow Red’ are more sensitive to low temperatures compared to ‘Hayward’ and the sensitivity is involved in the determination of storage life and how early the fruit matures on the vine.

著者

Abdul H. Kazimi Oscar W. Mitalo Azimullah Azimi Kanae Masuda Chikara Yano Takashi Akagi Koichiro Ushijima Yasutaka Kubo

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-012, (Released:2022-11-25)

被引用文献数

2

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A major challenge in terms of commercializing 1-methylclopropene (1-MCP) to extend the storage life and control physiological disorders in European pears is that it irreversibly inhibits fruit ripening in some cultivars, particularly flesh softening that is necessary for optimal consumption quality. In this study, we examined the effect of 1-MCP pretreatments on fruit ripening and associated transcriptomic changes in ‘La France’ (Pyrus communis L.) pears during storage at 20°C and 5°C. Compared to non-treated controls, 1-MCP pretreatment suppressed fruit respiration and ethylene production rates, and markedly delayed flesh softening. Normal ripening (ethylene production and flesh softening to eating quality firmness) was observed in 1-MCP treated fruit after 42 d at 20°C, and 112 d at 5°C. Subsequent RNA-Seq analysis revealed that 6,427 genes, including those associated with ethylene biosynthesis (ACS1, ACS1b, ACO1, and ACO2), cell wall degrading enzymes (PG3, β-GAL, EG, and EXP1), and transcription factors (AGL18 and NAC29) were up- or down-regulated in non-treated fruit both at 20°C and 5°C. The expression patterns of these genes were disrupted by 1-MCP pretreatment, but up- or down-regulation was also observed when ethylene was detected in 1-MCP-treated fruit. Together, these findings demonstrate the potential for practical use of 1-MCP to extend storage life in ‘La France’ pears given that (i) a single application markedly extended storage life to 56 d at 20°C and 112 d at 5°C, and (ii) treated fruit could regain their softening capacity, thus eliminating previous irreversible ripening blockage concerns.

著者

Maria Suzuki Kanae Masuda Hideaki Asakuma Kouki Takeshita Kohei Baba Yasutaka Kubo Koichiro Ushijima Seiichi Uchida Takashi Akagi

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-323, (Released:2022-05-25)

被引用文献数

6

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In contrast to the progress in the research on physiological disorders relating to shelf life in fruit crops, it has been difficult to non-destructively predict their occurrence. Recent high-tech instruments have gradually enabled non-destructive predictions for various disorders in some crops, while there are still issues in terms of efficiency and costs. Here, we propose application of a deep neural network (or simply deep learning) to simple RGB images to predict a severe fruit disorder in persimmon, rapid over-softening. With 1,080 RGB images of ‘Soshu’ persimmon fruits, three convolutional neural networks (CNN) were examined to predict rapid over-softened fruits with a binary classification and the date to fruit softening. All of the examined CNN models worked successfully for binary classification of the rapid over-softened fruits and the controls with > 80% accuracy using multiple criteria. Furthermore, the prediction values (or confidence) in the binary classification were correlated to the date to fruit softening. Although the features for classification by deep learning have been thought to be in a black box by conventional standards, recent feature visualization methods (or “explainable” deep learning) has allowed identification of the relevant regions in the original images. We applied Grad-CAM, Guided backpropagation, and layer-wise relevance propagation (LRP), to find early symptoms for CNNs classification of rapid over-softened fruits. The focus on the relevant regions tended to be on color unevenness on the surface of the fruit, especially in the peripheral regions. These results suggest that deep learning frameworks could potentially provide new insights into early physiological symptoms of which researchers are unaware.

著者

Oscar Witere Mitalo William Olubero Asiche Yuka Kasahara Yasuaki Tosa Willis Omondi Owino Eric Gituma Mworia Koichiro Ushijima Ryohei Nakano Yasutaka Kubo

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-035, (Released:2018-04-19)

被引用文献数

11

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‘Rainbow Red’ kiwifruit have been reported to gradually ripen during low temperature storage and on the vine in the absence of detectable ethylene. This study was conducted to compare the expression of ripening-related genes during storage at different temperatures and on the vine. Fruit at 5°C and 10°C ripened faster to eating quality within four weeks accompanied with increased expression of ripening-related genes: AcACO3, AcXET2, AcEXP1, AcPG, AcPMEi, AcSUS, AcβAMY1, AcβAMY2, AcGA2ox2, AcNAC3, AcNAC4, and AcMADS2. Fruit at 15°C required a longer period of eight weeks to attain eating quality in concurrence with delayed accumulation of the ripening-related genes. Fruit at 22°C ripened at the slowest rate and did not attain eating quality even after eight weeks, with very minimal accumulation of ripening-related genes. On-vine ripening occurred slowly at the early stages when the average field temperature was ~20°C, but the rate increased as the temperature dropped to ≤15°C accompanied by increased expression of ripening-related genes. These results indicate that both ripening on-vine and during low temperature storage are modulated by low temperature independent of ethylene.

著者

Ryohei Nakano Hidemi Akimoto Fumio Fukuda Takashi Kawai Koichiro Ushijima Yosuke Fukamatsu Yasutaka Kubo Yuichiro Fujii Ken Hirano Kunihisa Morinaga Naoki Sakurai

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-094, (Released:2017-10-12)

被引用文献数

15

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Split-pit in peach fruit is a problematic disorder. Split-pit fruit cannot be detected based on external appearance, and contamination of fruit by split-pit reduces its reliability in the marketplace. Here, we demonstrate that split-pit fruit can be identified by a nondestructive acoustic vibration method and a unique approach based on the ratio of the third (f3) to the second (f2) resonant frequency. The response-resonant frequency spectra showed that the peaks of f2 frequencies in split-pit fruit were shifted to much lower values than those in normal fruit, whereas those of f3 frequencies showed only small shifts. The calculated f3/f2 ratios in most normal fruit were in the range of 1.35–1.4, whereas those in split-pit fruit were 1.45–2.0. Analysis of more than 300 fruit samples revealed that by setting the f3/f2 cut-off value at >1.45, 95% of split-pit fruit in the fruit samples were detected, whereas only 1.5% of normal fruit were missorted as split-pit fruit. A model for simulating the vibration properties of peach fruit was developed by using the finite element method. The simulated vibration patterns showed that f3/f2 values were increased by the insertion of split pit, indicating that, at least partially, the observed high f3/f2 values in split-pit fruit directly reflected split-pit occurrence. These results clearly demonstrate that the use of f3/f2 ratios obtained using an acoustic vibration method can effectively detect fruit with split-pit. The possibility of installing acoustic vibration devices in peach sorting lines and the application of portable devices to unpicked fruit on the tree are discussed.