著者

Akira Yamazaki Ao Takezawa Kazusa Nishimura Ko Motoki Kyoka Nagasaka Ryohei Nakano Tetsuya Nakazaki Munetaka Hosokawa

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-094, (Released:2023-10-17)

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Chili pepper is cultivated in the absence of fruit-promoting treatments or insect pollinators. The fertilization ability of both males and females, as well as natural self-pollination ability under high temperatures, are necessary for autonomous set fruit under high temperatures. The reproductive traits related to autonomous self-pollination ability and fertilization ability of both males and females after pollination under control (CK) and high temperature (HT) treatments were investigated in this study. ‘Takanotsume’ (TK) showed a significantly higher percentage of autonomous fruit set than ‘Peruvian Purple’ (PP) in both CK and HT treatments, suggesting that TK has a strong autonomous fruit set regardless of temperature. On the other hand, the percentage of autonomous fruit set of PP was 0% in the HT treatment, while autonomous fruit set was observed in the CK treatment. Therefore, TK had autonomous fruit set ability even at high temperatures when PP did not have any. TK had more pollen on the stigma than PP, suggesting that TK has a higher ability for autonomous self-pollination. Flower morphology was not considered a factor in the autonomous self-pollination of TK. In contrast, TK tended to release more pollen than PP. One factor that can support autonomous self-pollination is pollen dispersion. A significant difference was observed in the fruit set rate during artificial pollination between the treatments (CK and HT) of the pollen parent and the cultivars (TK and PP) of the seed parent. In fact, female fertility in TK was higher than that in PP, regardless of the temperature condition. Almost no fruit set of PP was observed via autonomous self-pollination in the HT treatment, but fruits were set by artificial pollination using both the pollen and pistil of PP in the HT treatment. This result is consistent with the finding that PP exhibits decreased autonomous self-pollination at high temperatures. The higher autonomous fruit-set ability of TK than PP under high temperatures may be attributed not only to superior female fertility, but also to its autonomous self-pollination ability under high temperatures. Therefore, pollen dispersal ability under high temperatures was considered a key factor for autonomous fruit-set.

著者

Ayumu Kono Ayumu Kawabata Akira Yamazaki Yuma Ohkubo Adriano Sofo Munetaka Hosokawa

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-037, (Released:2022-11-30)

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We investigated the effect of ultraviolet-B (UV-B) irradiation on the development of black spot disease caused by Diplocarpon rosae Wolf., which is a major problematic disease in rose (Rosa × hybrida) production. The growth of D. rosae colonies was suppressed on potato dextrose agar (PDA) medium under UV-B irradiation (peak wavelength: 310 nm; full width at half maximum: 30 nm) at an intensity of 15 μW·cm−2 with 1 h daily treatment. In addition, black spot conidia were inoculated to the rose ‘Danjiri Bayashi’ leaves and the effective growth suppression of black spot symptoms was observed on the leaves under UV-B irradiation. Next, various rose cultivars were planted in two greenhouses: one for supplemental UV-B irradiation treatment and one as a control without the treatment. In the UV-B irradiation greenhouse, the roses were irradiated at an intensity of 3–5 μW·cm−2 every day from 23:00–23:30 and 0:00–0:30 (total: 1 h). No chemical pesticides other than a starch agent for aphid control were used throughout the experiment. With the exception of the data for ‘Papa Meilland’ in 2019, UV-B irradiation significantly reduced the number of leaves infected with black spot disease. In September 2019, the non-UV-B irradiated ‘Danjiri Bayashi’ and ‘Papa Meilland’ had severe black spot symptoms on over 20 leaves. The number of plants with black spot symptoms increased in July 2020 compared to 2019. On the other hand, in UV-B irradiated plants, fewer black spot symptoms were observed than in non-UV-B irradiated plants. Although some visible damage was observed in the UV-B irradiated plants, the chlorophyll and carotenoid contents in the leaves decreased, indicating that UV-B irradiation had a certain negative effect on the photosynthetic apparatus. Over a five-month period, the cumulative number of flowers in the UV-B irradiation greenhouse did not decrease, and actually increased, depending on the cultivar, compared to the control treatments. Our results suggest that supplemental UV-B irradiation is effective at suppressing black spot disease in roses and can contribute to the production of pesticide-free edible rose production.

著者

Sho Ohno Wakako Hori Munetaka Hosokawa Fumi Tatsuzawa Motoaki Doi

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-099, (Released:2017-08-04)

被引用文献数

7

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Bicolor flowering dahlias are a group of cultivars that produce inflorescences with bicolored petals characterized by a colored basal part and a white tip. However, they frequently produce single-colored petals, even if they are vegetatively propagated. In a previous study, strong relationships between inflorescence color and leaf phenotype were observed in a red–white bicolor flowering dahlia ‘Yuino’; red petal-producing individuals accumulate flavonoids in leaves, whereas only bicolor petal-producing individuals tend not to accumulate them in leaves. Flavonoids in leaves are assumed to be chalcones. In this study, we investigated flavonoids in the leaves of ‘Yuino’ by nuclear magnetic resonance analysis and identified six caffeoyl esters, four flavonol derivatives, and three novel butein derivatives in the flavonoid-rich leaves of ‘Yuino’. The three novel compounds were butein 4',4-O-di-[2-O-(β-glucopyranosyl)-β-glucopyranoside], butein 4'-O-[2-O-(β-glucopyranosyl)-β-glucopyranoside]-4-O-β-glucopyranoside, and butein 4'-[6-O-(3-hydroxy-3-methylglutaryl)-β-glucopyranoside]-4-O-β-glucopyranoside. On the other hand, only caffeoyl esters were detected in flavonoid-poor leaves. These data demonstrated that flavonoid-rich leaves accumulated the flavonoids of butein and flavonol derivatives. The common enzyme for the biosynthesis of butein and flavonol derivatives is chalcone synthase; thus, the importance of chalcone synthase for phenotypic lability in ‘Yuino’ was confirmed.

著者

Nao Ota Tomoyuki Nabeshima Masahiro Osakabe Shinichi Aoki Tatsuya Awano Munetaka Hosokawa

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-021, (Released:2016-11-22)

被引用文献数

5

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Although ultraviolet-B (UV-B) light (280–315 nm) irradiation effectively controls spider mites in horticultural crop production, it also causes plant damage, leading to growth suppression, changes in morphology, and leaf scorching. However, sensitivity to UV-B varies among plant species. Here, we assessed the effect of UV-B on growing perilla (Perilla frutescens var. crispa) plants. Three experiments were conducted. In the first experiment, plants of the variety ‘Akachirimenshiso’ were grown in a plastic house with natural light conditions and subjected to three treatments: natural UV (control), −UV, and natural UV plus artificial UV-B treatment (50 mW·m−2) from 0:00 to 3:00. The length of leaf blades that received additional UV-B treatment was reduced by 16.5% and 32.3% in two trials compared with that of the respective controls. In this experiment, additional UV-B irradiation turned the leaf color greener. During UV-B treatment, the values of leaf a*, an indicator of leaf redness, were significantly lower than their respective controls in both trials: 21.5 vs. 31.6 in trial I and 20.2 vs. 30.7 in trial II. For most of the parameters measured in this experiment, no differences were observed between the control and −UV treatment groups. In the second experiment, plants were irradiated with UV-B for 3 weeks at nighttime (0:00–3:00) or daytime (12:00–15:00). In the cultivar ‘Houkouakashiso’, the length of leaf blades significantly decreased by 15.9% and 20.6% under nighttime UV-B irradiation at 80 and 120 mW·m−2, respectively, compared with that of the non-irradiated controls. Irradiation at 80 mW·m−2 also decreased the width of the leaf blades by 13.1% and that at 120 mW·m−2 further decreased it by 25.0%. These results showed that UV-B irradiation at night decreased the size of perilla leaves. In addition, the value of a* became lower under UV-B irradiation in the nighttime. Thus, UV-B irradiation appeared to turn purple perilla leaves green. When plants were irradiated with UV-B in the daytime, there was no significant difference between irradiated and non-irradiated plants in the length or width of leaf blades, a*, or fresh weight of aerial parts and number of nodes on the main stem. In the third experiment, visible rays (VIS) emitted by fluorescent lamps were applied at 0:00–3:00 and 6:00–22:00. Plants were irradiated with 120 mW·m−2 of UV-B at 0:00–3:00. UV-B + VIS treatment of ‘Akachirimenshiso’ with VIS from fluorescent lamps did not significantly affect the parameters measured in this experiment compared to −UV treatment. The results of this study suggest that UV-B damage to perilla leaves can be avoided by combined irradiation with visible light.

著者

Ayumi Deguchi Fumi Tatsuzawa Munetaka Hosokawa Motoaki Doi Sho Ohno

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.MI-121, (Released:2016-02-04)

被引用文献数

14

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The black flower color of dahlias (Dahlia variabilis) has been suggested to be attributed to a high accumulation of cyanidin (Cy)-based anthocyanins. A possible explanation for this effect is that Cy-based anthocyanins in dahlias contribute more to the black flower color than pelargonidin (Pg)-based anthocyanins by lowering petal lightness (L*) and chroma (C*), but no obvious evidence has been reported. In this study, four major anthocyanins accumulated in dahlia petals, 3,5-diglucoside (3,5diG) and 3-(6''-malonylglucoside)-5-glucoside (3MG5G) of Pg and Cy, were purified and their colors were evaluated in vitro at various pHs (3.0, 4.0, 4.5, 5.0, 5.5, 6.0, or 7.0) and various concentrations (0.25, 0.5, 1.0, 2.0, or 3.0 mg·mL−1 at pH 5.0 or pH 3.0). The color of solution of purified anthocyanins varied depending on pH. At pH 5.0, which is approximately the same as pH of dahlia petals, and at pH 3.0, at which anthocyanins are relatively stable, the L* and C* of Cy 3,5diG were similar to or higher than those of Pg 3,5diG, suggesting that Cy 3,5diG did not contribute more to the black flower coloring than Pg 3,5diG. On the other hand, the L* and C* of Cy 3MG5G were significantly lower than those of Pg 3MG5G, particularly above 2.0 mg·mL−1, suggesting that Cy 3MG5G contributed more than Pg 3MG5G. A similar tendency was observed in the color measurement of mixed anthocyanins in various proportion of Pg and Cy. The L* and C* of Pg 3MG5G were much higher than those of the other three anthocyanins; therefore, its color was considered to be the farthest from black among the four anthocyanins. The accumulated amount of 3MG5G-type anthocyanins was much higher than that of 3,5diG-type anthocyanins in all nine cultivars, although the proportion of Pg- and Cy-based anthocyanins varied among the cultivars. Considering these results, it was suggested that because 3MG5G-type anthocyanins predominantly accumulate in petals, and Cy 3MG5G has a significantly higher contribution to lowering L* and C* than Pg 3MG5G, the high accumulation of Cy-based anthocyanins is critical for the black flower coloring of dahlias. The contribution of each anthocyanin is considered to depend on the structure; therefore, identifying the anthocyanin with the highest contribution to lowering L* and C* may enable the production of black flowers in various species through the high accumulation of the anthocyanin in petals.

著者

Ko Motoki Yu Kinoshita Ryohei Nakano Munetaka Hosokawa Tetsuya Nakazaki

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-018, (Released:2022-12-15)

被引用文献数

1

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Floral induction by grafting without vernalization treatment (NV grafting method) has potential to shorten breeding times and to diversify the seed production of cabbage, an important leafy vegetable with a long and absolute low temperature exposure requirement for its floral induction. However, it is unknown whether the NV grafting method can be actually used for cabbage breeding and seed production. This is because the NV grafting method’s effect on the field performance of obtained progenies has not been investigated, as opposed to the conventional floral induction method by vernalization treatment. Therefore, in this study we compared the effects of two different floral induction methods on the agricultural traits of the obtained progenies. Two clonal lines of ‘Watanabe-seiko No.1’ cabbage were used for the experiment. In the two-year field experiment, we observed a consistent effect of clonal lines on vegetative growth; however, almost no effects of the floral induction methods on either vegetative or reproductive growth were observed. This was further supported by similar expression levels of FLOWERING LOCUS C homologs in the progenies at the young seedling stage. Pollen production and seed formation of the progenies were confirmed regardless of the floral induction method. In conclusion, cabbage seeds obtained by the NV grafting method are likely to show the same traits as those obtained by the conventional vernalization method. This indicates the direct applicability of this method to cabbage breeding and seed production.

著者

Sayumi Matsuda Mitsuru Sato Sho Ohno Soo-Jung Yang Motoaki Doi Munetaka Hosokawa

出版者

園芸学会

雑誌

Journal of the Japanese Society for Horticultural Science (ISSN:18823351)

巻号頁・発行日

pp.MI-009, (Released:2014-09-20)

被引用文献数

3 15

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For determination of the endogenous and exogenous causes of somaclonal variation in in vitro culture, a bioassay system was developed using the variegated Saintpaulia (African violet) ‘Thamires’ (Saintpaulia sp.), having pink petals with blue splotches caused by transposon VGs1 (Variation Generator of Saintpaulia 1) deletion in the promoter region of flavonoid 3',5'-hydroxylase. Not only true-to-type but also many solid blue and chimeric plants regenerate in vitro-cultured explants of this cultivar. Using multiplex PCR that enables the determination of these variations, we attempted to evaluate the effects of four candidate triggers of mutation: pre-existing mutated cells, shooting conditions in vitro or ex vitro, cutting treatment of explants, and addition of plant growth regulators (PGRs) to the medium. The percentages of somaclonal variations among total shoots regenerated from leaf segments and stamens were 46.6 and 56.5, which were higher than the percentages expected from pre-existing mutated cells (3.6 and 1.4, respectively). These results indicate that pre-existing mutated cells are not a main cause of somaclonal variations. The percentage of somaclonal variation was independent of culture conditions for mother plants; the mutation percentages of adventitious shoots regenerated from ex vitro- and in vitro-grown leaves were 9.2% and 8.5%, respectively. In addition, the percentage of somaclonal variations of adventitious shoots regenerated under in vitro conditions from the in vitro grown mother plants was also low, at 4.9%. This indicates that the in vitro condition itself is not a main cause of somaclonal variation. However, when adventitious shoots were regenerated from 10 × 5-mm cut-leaf laminas on a PGR-free medium, the percentage of somaclonal variation was 26.4%. In addition, the percentage of somaclonal variations dramatically increased when PGRs were added to the medium for both leaves and leaf segments (39.9 and 46.6, respectively). The bioassay system using Saintpaulia ‘Thamires’ will enable the screening of many environmental factors because of its rapidity and ease of use and will facilitate the development of a new tissue culture technology for avoiding mutation.

著者

Sota Koeda Kosuke Sato Kenichi Tomi Yoshiyuki Tanaka Rihito Takisawa Munetaka Hosokawa Motoaki Doi Tetsuya Nakazaki Akira Kitajima

出版者

園芸学会

雑誌

Journal of the Japanese Society for Horticultural Science (ISSN:18823351)

巻号頁・発行日

pp.CH-105, (Released:2014-05-10)

被引用文献数

3 19

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‘No.80’ (Capsicum chinense) from the Caribbean is a valuable genetic source from the aspect of its non-pungent and highly aromatic traits. In the present study, the non-pungency, volatile components, and phylogenetic origin of ‘No.80’ were analyzed with another C. chinense cultivar, ‘No.2’ from Brazil, which is also non-pungent but less aromatic. Expressions and deduced amino acid sequences of acyltransferase (Pun1) of ‘No.80’ and ‘No.2’ were normal compared with a pungent cultivar, ‘Habanero’. Insertions of 7-bp and 8-bp resulting in frameshift mutations were found in the coding regions of putative aminotransferase (p-AMT) of ‘No.80’ and ‘No.2’, respectively. Co-segregation of these insertions with the non-pungent phenotypes in F1 and F2 populations obtained from crossing ‘No.80’ or ‘No.2’ with ‘Habanero’ suggested that non-pungency in these cultivars arose from genetic mutations of p-AMT that occurred independently. Moreover, molecular phylogenetic analysis suggested that ‘No.80’, a close relative of ‘No.2’, originates from capsicums migrated from the South American mainland. In addition to pungency, we assessed the volatile components of the highly aromatic ‘No.80’, the less aromatic ‘No.2’, and their F1 hybrid using gas chromatography. ‘No.80’ contained higher levels of aroma-contributing volatiles than ‘No.2’, which correlated with the stronger and weaker aromas of two cultivars. Further, the fruit of F1 progenies emitted a number of volatile compounds between or higher than their corresponding parents. Based on these results, the approaches for breeding highly aromatic non-pungent cultivars are discussed.