著者

Yuya Mochizuki Ryuta Ninohei Manato Ohishi Yukio Yonezu Tsuyoshi Okayama Eiichi Inoue

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-095, (Released:2023-10-18)

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Strawberries can be categorized into June-bearing and ever-bearing depending on the environmental conditions that determine flower bud initiation. In Japan, the harvest yield and distribution of strawberry fruits during summer and autumn are low because of high temperatures and heavy fruit load. Therefore, cultivation of ever-bearing strawberries is limited to areas with cool summers such as Hokkaido and Tohoku. In this study, we investigated whether air treatment before liquefied carbon dioxide (CO2) application within the strawberry plant canopy could improve CO2 absorption efficiency and increase dry matter production. Four treatments were investigated: application of air within the plant canopy, application of CO2, application of CO2 after air application, and a control. We investigated the CO2 concentration, dry matter production, yield characteristics, individual leaf photosynthesis characteristics, projected leaf area, cumulative light interception, light use efficiency, and fruit quality. The results showed that the local application of only CO2 or Air and, application of CO2 after air application (Air/CO2) treatment within the plant canopy considerably increased the dry matter production. Total fruit yield of Air/CO2 was the highest among all treatments. This is probably because the application of CO2 and air expanded the leaf area, increased cumulative light interception, and improved light use efficiency. In addition, the photosynthetic rate of Air, CO2 and Air/CO2 treatments was higher than that of the control because of higher stomatal conductance. This suggests that local application of liquefied CO2 after air application can effectively increase fruit yield, and that air treatment will improve plant vigor, further increasing strawberry production in summer and autumn.

著者

Kaori M. Nakajima Manato Ohishi Fumio Sato Megumu Takahashi

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-045, (Released:2023-05-31)

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In Japan, broccoli (Brassica oleracea L. var. Italica) is primarily harvested manually. Some Japanese broccoli cultivars have short stems, but these broccoli heads are more difficult to harvest, and complicate the introduction of mechanical harvesters. Therefore, research is focused on strategies to control stem length. The present study examined the effects of the plant hormone gibberellin (GA) on the morphological and agronomic traits of broccoli shoots. The broccoli cultivar ‘SK9-099’, widely distributed in Japan and characterized by a short stem, was studied. These experiments were conducted over three cropping seasons, i.e., spring (Exp. 1), summer (Exp. 2), and fall (Exp. 3), with four GA treatment plots at 0 ppm (Control), 20 ppm, 100 ppm, and 500 ppm. This study observed that, on average, GA elongated stem length from approximately 16.0 cm in the control plot to 24.7 cm in the 500 ppm plot for the three cropping seasons, without decreasing yield. In addition, GA treatment accelerated apical bud growth and shortened the overall growth period by 16 days in the 500 ppm plot compared to the control in the fall, equivalent to 20.5% of the growth period from transplantation to harvest in the latter.This study highlights several practical benefits of GA application for growers, minimizing manual harvesting labor, avoid the difficult of designing mechanical harvesters for short-stemmed cultivars, and increase field usage efficiency by shortening the growth period.

著者

Manato Ohishi Megumu Takahashi Machiko Fukuda Fumio Sato

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-022, (Released:2022-11-22)

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The demand for broccoli (Brassica oleracea L. var. italica) is increasing for use as fresh produce and for use in the processing industry. Therefore, growth prediction technology is required for its stable production. In this study, several cultivations of experiments were conducted to clarify the critical characteristics of the parameters needed to predict the growth of broccoli in a dry matter production model. The extinction coefficient was determined based on the leaf area index and intercepted solar radiation rate. Radiation-use efficiency was demonstrated using a linear function of the accumulated solar radiation intercepted amount and the total dry weight above-ground. The distribution of dry matter to the head and stem was indicated by the sigmoid function of the accumulated average temperature. The dry matter percentage of the leaf, dry matter percentage of the head and stem, and the ratio of leaf area to the fresh weight of the leaf were represented by a power function with dry weight above-ground. The fresh weight above-ground (R2 = 0.92) and the fresh weight of the head and stem (R2 = 0.98) were highly correlated with the estimated and observed values. Verification was performed using the developed growth model. As a result, the error between the harvest date and the predicted harvest date could be forecasted to within 4 days and the error in the fresh weight of the head could be predicted with an accuracy of −0.3 ~ +7.7 g·plant−1.

著者

Manato Ohishi-Yamazaki Miho Watanabe Ai Nakanishi Jingai Che Naomi Horiuchi Isao Ogiwara

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-136, (Released:2018-03-13)

被引用文献数

5

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We attempted to shorten the juvenile phase of southern highbush blueberries by using controlled rooms under artificial light. Seeds were extracted from fresh fruits and sowed in the Woody Plant Medium (WPM) immediately after harvest. When these seeds were irradiated with red LED, their germination rate was over 80% by the 35 days after sowing. The seedlings in the controlled room continued to grow without entering the dormant phase. Especially, maximum growth was observed under the long-day condition of 12-h light. Even under the short-day condition of 8-h light, increased growth was observed when grown at a high light intensity (400 μmol·m−2·s−1). For the seedlings that were moved from the long-day controlled room to the short-day controlled room after 10 months, the ‘Misty’ seedlings flowered within 327 days after sowing while the ‘Sharpblue’ seedlings flowered within 357 days after sowing. Furthermore, when cultivated under the short-day condition at 400 μmol·m−2·s−1 for the entire length of the experiment, the flowering of ‘Misty’ seedlings was observed within 300 days after sowing. The seedlings maintained under the short day condition of high light intensity flowered earlier than seedlings moved from the long-day controlled room to the short-day controlled room. Thus, southern highbush blueberries were successfully induced to flower in less than a year from seed planting, using a combination of techniques to promote germination and control the growth environment conditions in a controlled room.