The growth and fruit quality of sixty-four blueberry cultivars were evaluated in a three-year trial in Tokyo, Japan where three species of blueberries can be grown. Cultivars belonging to 3 species were classified into a RB group that inclueded only rabbiteye blueberry cultivars and a HB group that included both northern highbush blueberry (NHB) and southern highbush blueberry (SHB) cultivars but excluded ‘Pearl River’, a pentaploid SHB cultivar, based on principal component analysis of their traits. SHB distributed the bottom part of HB group in the scatter diagram of eighteen characteristics of fruits with small fruits, low percentage of citric acid content, high sugar-acid ratio and high malic acid percentage. The correlations between individual parameters of characteristic showed that the harvest day of cultivars was influenced by the earliness of flowering day and the day that coloration started. In the NHB group, positive correlations between the harvest day and the fruit weight, between the harvest day and organic acid content, between the harvest day and citric acid content were observed. Negative correlations between harvest day and sugar-acid ratio were also observed in the NHB group. Cultivars with useful characteristics for blueberry breeding were evaluated from this study.

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There are 286 Edo-kirishima azalea specimens, estimated to be over 100 years old, in private gardens in the northern part of the Noto district, in Ishikawa Prefecture. These azaleas are called “Noto-kirishimatsutsuji” in Noto and used to attract tourism as a source of revitalization for the area. Such a large number of old Edo-kirishima plants distributed over a wide area is unknown in other parts of Japan. According to the literature of the Edo era, a representative cultivar of the Edo-kirishima azalea group, ‘Hon-kirishima’, existed in Noto before 1738 and was introduced from the Edo and Kansai districts. Based on our morphological studies, Edo-kirishima azaleas in Noto consisted of 7 cultivars of ‘Hon-kirishima’, ‘Mino-kirishima’, ‘Nijun-kirishima’, ‘Yae-kirishima’, ‘Shikizaki-kirishima’, ‘Beni-kirishima’, and ‘Murasaki-kirishima’ as well as 3 unidentified strains of single, semi-hose in hose, and hose-in-hose flowers of “Kera-sho”. The results of RAPD analyses of ‘Hon-kirishima’ demonstrated that they have the same band patterns among Noto but the clones differ from those found in Noto and Tsutsujigaoka Park in Tatebayashi, Gunma Prefecture.

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Specific and varietal differences of ascorbic acid (AsA) concentration and DPPH radical scavenging activity of citrus juice citrus were investigated. In 2006-2007, 41 species and/or cultivars (accessions) were used as materials. Their AsA concentrations ranged from 8.2 mg·100 mL⁻¹ (Shiikuu) to 50.0 mg·100 mL⁻¹ (‘Amakusa’); the average was 26.6 mg·100 mL⁻¹. Their DPPH radical scavenging activity ranged from 0.64 nmol-Trolox equivalent·μL⁻¹ (Shiikuu) to 3.49 nmol (‘Amakusa’); the average was 1.96 nmol. There was a high positive correlation between AsA concentration and DPPH radical scavenging activity (r = 0.859 (significance at the 1% level)). Correlation coefficient between AsA concentration and DPPH radical scavenging activity of 2006–2007 and those of 2007–2008 were r = 0.843 (significance at the 1% level) and r = 0.951 (significance at the 1% level), respectively in juice of 13 accessions. Seasonal change in the AsA concentration in juice and DPPH radical scavenging activity using ten accessions was investigated in 2007–2008. AsA concentration of six accessions increased during fruit maturation, but that of three accessions was decreased. In particular, a remarkable increase of Keraji and decrease of Sakurajima komikan and ‘Nova’ was observed in their AsA concentration. DPPH radical scavenging activity was increased in general during fruit maturation, and the activity in January was higher than that in October in eight accessions. Increase of this activity was very rapid in Keraji and ‘Shiranui’.

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We studied field performance of meristem culture-derived plants of a cultivar ‘Futagoimo’ of Colocasia esculenta originated from Kitakami, Iwate of northern Japan. Four groups of planting materials were used for evaluation in the filed: plantlets directly regenerated from tissue culture (P), corms developed on plants one year after regeneration (C1), corms developed on C1 plants 2 years after regeneration (C2), corms used in local farmers practice (C). P plants tended to carry more above-ground lateral buds in September compared to those of other groups. This large number of lateral buds decreased thereafter. P plants also exhibited rapid growth of corms that tended to have a more oval shape than other groups. C1 plants tended to keep a large number of above-ground lateral buds during September-October and also maintained tall stature. Although the yield of C1 plants was high, the quality of corms was medium with oblong shape and late maturation. C2 plants showed a growth tendency and yield similar to those of C plants. These findings suggest that differences in growth habits among P, C1, C2 and C plants were not due to genetic changes that may occur during tissue culture but reflected the physiological conditions of the materials used for planting.

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The carnation ‘Nora’ was continuously cropped under the same soil management and fertilization over 25 years in an isolated bed in order to investigate the effects on the physical and chemical properties of the soil as well as the yield and quality of carnations. There were positive correlations between the years of continuous cropping and the phosphate buffer extractable nitrogen and Troug-phosphate in soil nutrients. There was a negative correlation between years of continuous cropping and the exchangeable magnesium in the soil nutrients. There was a positive correlation between the years of continuous cropping and pore space (the water and air ratio). There was a negative correlation between the years of continuous cropping and the solid ratio. There was no correlation between the years of continuous cropping and the plant nutrients. During 25 years of continuous cropping, the cut-flower total yield of the first year was less than the yields after 11 and 17 years of continuous cropping. However, there was no significant difference in cut-flower yields between 6 and 25 years of continuous cropping. Moreover, 6 to 25 years of continuous cropping did not affect the quality of cut flowers. Thus, it has been indicated that long-term continuous cropping in carnation cultivation is possible if the physical and chemical properties of the soil can be maintained at a suitable level in soil sterilized by steam in an isolated bed.

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The annual fluctuation and difference among fields or among trees during on-tree fruit softening (OTFS) of the Japanese persimmon ‘Saijo’ were investigated. The mineral concentrations, especially the Mn concentration, were compared between OTFS trees and healthy trees in order to obtain basic information about OTFS. The annual fluctuation and difference among fields of OTFS were found over a four-year period (1995 to 1998). Comparing the concentrations of the main minerals in the flesh, the Mn concentration in fruit from the OTFS tree was about 1/3 of that from healthy trees, except in 1998 when the OTFS rate was markedly higher and there were significant differences at a 5% level in 1996 and 1997 as well. Negative correlation between Mn concentration in each organ; fruit, calyx and leaf, of tree and the OTFS rate was found at a 1% significance level. There was a tendency for the OTFS rate to increase as the Mn concentration in each organ decreased. The Mn concentrations in the flesh, calyx and leaf of trees with a high OTFS rate were less than 20, 180 and 300 ppm, respectively.

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This experiment was intended to examine the effects of a black liquid-coating mulch on the growth and yield of Komatsuna greens. Four treatments (1, 0.5, 0.25 L·m⁻²) of spray amount were tested in combination with seeding date (Sep. 21^st, Oct. 5^th, Oct. 20^th in an open field and the Jan. 22^nd in a plastic film house). As a result, we found this liquid-coating mulch increased yields of Komatsuna greens, unrelated to the spray amount. Generally, the daily highest soil temperature (−5 cm) under the mulching exceeded the control in every treatment however the daily lowest temperature were less than control except in the case of seeding at Sep. 21^st. These phenomena were remarkable in the early stage of growing and the differences in temperature between the control and mulch treatments were reduced during the growth. There was no significant difference in the hourly-integrated temperature during the first 10 days between the 4 treatments on same seeding date. These findings suggest that the expansion of the daily soil temperature range contributed the increased yields of Komatsuna greens.

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Long-day treatment by pre-dawn lighting (6 h) was applied to Eustoma grandiflorum cultivars to investigate flowering responses and cut flower qualities for early-autumn shipment. Seedlings were irradiated by using bulb-type red-light fluorescent lamps, that R : FR ratio was 8.8, with photon flux density (PFD) of red-light (660±30 nm) of 0.1, 0.2 or 0.5 μmol·m⁻²·s⁻¹. Control plants were grown under ambient day conditions of 14–15 h without long-day treatment. The times from planting to flower budding under long-day treatments were significantly longer than that of the controls. However, there was no significant difference among the times from planting to flower budding in each treatment. Long-day treatment with the highest red-light intensity showed the greatest increase in the number of nodes on the main stem at anthesis of the first floret. The stem lengths of plants grown under long-day treatment with red-light intensities above 0.2 μmol·m⁻²·s⁻¹ were significantly longer than that of the control. Long-day treatment using bulb-type red-light fluorescent lamps was applied to 11 Eustoma cultivars. Compared with those of control plants, the times from planting to flower budding under long-day treatment were longer in 9 cultivars and the number of nodes on the main stem at anthesis of the first floret was increased to a maximum of 2.4 in 10 cultivars. Moreover, cut flower length under the long-day treatment was 11.3 cm longer at maximum and cut flower weights were increased in 9 cultivars at harvest (at anthesis of the third floret) compared with those of the controls. The increase in the number of nodes on the main stem under long-day treatment was significantly correlated with the days to flowering in the controls.

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The effect of daytime root zone heating at different stages on the flowering, growth and yield of strawberry (Fragaria × ananassa Duchesne ‘Akihime’) was studied by growing the plants under substrate culture in a heated plastic house. Two experiments were conducted. Experiment 1 was performed from September 28, 2007 to April 30, 2008 and Experiment 2 was conducted from December 6, 2007 to April 30, 2008. Both experiments consisted of one control (non-heated) and three treatments. In Treatment 1 (T1), the substrate was heated for the whole growing period (from the flower bud initiation stage to the end of the experiment). In Treatment 2 (T2), heating was initiated at the flowering stage (from flowering time to the end of the experiment). In Treatment 3 (T3), heating was initiated during the flower bud development stages (from flower bud initiation stage to flowering stage). Results showed that root zone heating treatments during daytime at the terminal flower cluster hardly affected the flowering date of the terminal flower of each cluster and fruit yield. There was no significant difference in the development of flower buds by any heating treatments. However, root zone heating treatments during the daytime at the flowering stage of the second lateral flower cluster tended to enhance the date of flowering at the terminal flower of the 2^nd lateral flower cluster at T1 and T3, and that of the 3^rd lateral flower cluster at all heating treatments. Fruit yield in February and March, and during the whole period increased at T1 and T3. The development stages of flower bud 5 weeks after initiation of the heating was advanced and the size of flower buds after heating treatments was significantly greater than that of the control. In conclusion, the present experiment showed that daytime root zone heating in the development stages of flower bud cluster during low temperature seasons (after December) enhanced the development of flower buds and then flowering, and finally increased the yield.

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Differences of the late wood discoloration were investigated for apple trees (Malus domestica Borkh.) grafted onto dwarfing rootstocks. In dissection of adult trees of ‘Fuji’ and ‘Jonagold’ grafted onto JM1 and JM7, the late wood discolorations differed with the rootstocks. One year old trees of ‘Mishima-Fuji’ grafted onto three rootstock cultivars, JM7, M.9, and M.26, were frozen to observe browning in the cambium and its surroundings and to measure the rate of damaged cells in the bark. The browning degree increased as the treatment temperature decreased. The rate of damaged cells decreased in that order M.9, JM7, M.26, especially in the rootstock part. These results indicated that there were differences among rootstock cultivars for the late wood discoloration and the rate of damaged cells, which affected the degree of freezing injury under the field condition.

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Acceleration of flowering of Eustoma grandiflorum in early winter by day-extension treatments with far-red rich bulb-type fluorescent lamps was investigated after culturing short-day treatment was performed from transplant to the end of August, followed by under long-day treatment after the middle of September, which is appropriated for cool area in Japan. Far-red rich bulb-type fluorescent lamps were made for trial purposes and in addition to incandescent lamps and red rich bulb-type fluorescent lamps on the market were used as light sources. As a result, far-red rich bulb-type fluorescent lamps, as well as incandescent lamps, accelerated the flowering and development of flower buds compared to red rich bulb-type fluorescent lamps or intact natural daylength. When the intensity of far-red light exceeded 0.7 μmol·m⁻²·s⁻¹, lateral flowers of the second order and higher increased, thus, cut flowers volume were enhanced. Furthermore, this promotion was further accelerated by continuous lighting compared to that under 16 h and 12 h photoperiods. These findings indicated that day-extension treatments from the middle term of growth until flowering time with more than 0.7 μmol·m⁻²·s⁻¹ of far-red light promoted a high production of marketable cut flowers of the Eustoma grandiflorum and the effect was greatest with continuous lighting in early winter during the cool area.

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The effect of brief irradiation with far-red (FR) light at the end of the day (EOD-FR) on stem elongation of spray type chrysanthemums in winter was investigated with two cultivars, ‘Sei Prince’ and ‘Remidas’ in order to reduce the growing period in cut flower production. EOD-FR exposure enhanced shoot extension. Plants were grown under night break or short day conditions, with or without EOD-FR. The effect of EOD-FR under short day condition was more efficient than that under night break conditions. Under short day conditions, plants were exposed to FR light for one hour after dusk, in the middle of night, or before dawn. Exposure to FR light after dusk or in the middle of night effectively promoted stem elongation, whereas FR light exposure before dawn had little or no effect. There was no delay in flowering under any of the FR light treatments. In ‘Sei Prince’, the number of inflorescence was reduced by exposure to FR light in the middle of the night. Based on these results, it is considered that EOD-FR treatment under a short day condition is applicable to reduce the growing period efficiently by promoting stem elongation in spray type chrysanthemums.

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Root pruning, uniconazole treatments, and early sowing were performed in peach seedlings of the current year in order to hasten flower bud induction. Early sowing after stratification increased the growing period and node number, and resulted in inducing more flower buds. In ‘Yaguchi’, root pruning in early to middle July increased the number of plants with flower buds and the numbers of the flower buds, although its effects varied by year. In ‘Hokimomo’, root pruning in early July slightly increased the numbers of plants with flower buds. In ‘Yaguchi’, treatments with uniconazole significantly increased plants with flower buds and numbers of flower buds. Moreover, uniconazole significantly lowered the lowest node with flower buds, mean node number with flower buds and maximum node number. Although root pruning induced flower buds only on nodes formed after the treatment, uniconazole induced flower buds on nodes that had been formed before treatment. Root pruning induced flower buds that ranged from the node at treatment to the upper 60th node, while uniconazole formed flower buds from the lower 16th node to the upper 23th node. Combined treatment with root pruning and uniconazole tended to increase the number of flower buds, which were distributed in intermediate parts of the two single treatments. These findings suggest that it is possible to promote phase transition of nodes from the juvenile phase to the transition or reproductive phase by early sowing and to suppress vegetative growth and accelerate flower bud differentiation by root pruning and uniconazole treatments in nodes at the transition phase on seedlings of the current year. Since uniconazole treatments induced flower buds at about the 70th node, ‘Yaguchi’ seedlings of the current year could attain the transition phase around the 70th node at 6–7 months after sowing.

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Development of a mucilage cavity and ultrastructure of mucilage-producing cells in taro corm (Colocasia esculenta cv. Ohno) were observed by electron microscope. Mucilage cavities were formed lysigenously from mucilage-producing cells and located within a certain distance around the vascular bundles. Degradation and melting of starch granules were found in the cells adjacent to the mucilage cavity. In the mucilage-producing cells adjacent to the cavity, fibrous materials were present in a space comprised of loose cell wall fibers on the cavity side. Although the ultrastructure of secretion through the plasmalemma and cell wall were not demonstrated, mucilage is thought to be secreted to the mucilage cavity after accumulation in a space of loose cell wall fibers.

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Cut flowers of Delphinium × belladonna ‘Sky Waltz’ and D. grandiflorum ‘Highland Blue’ were treated with STS solution at 0.1–0.4 mM for different periods. The vase life of ‘Sky Waltz’ flowers was longest when the Ag content in florets was more than 3 μmol·100 g⁻¹ FW. Similarly, the vase life of ‘Highland Blue’ flowers was longest when the Ag content in florets was more than 2 μmol·100 g⁻¹ FW. The vase life of cut flowers was not influenced by STS concentration or duration of treatment as long as the Ag content in florets was more than the level described above. To achieve this Ag levels, treatment with STS at a concentration of 0.2 mM or higher was necessary for both varieties.

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To clarify factor contributing to cultivar variations in the vase life of unpollinated flowers, the vase life, ethylene production and sensitivity to ethylene were investigated using flowers from six cultivars of Eustoma. There was cultivar variation in flower vase life ranging from 9.8 to 18.5 days. In all cultivars, ethylene production by flowers increased during senescence. There was no significant correlation between the maximum amount of ethylene production until the petals wilted and the days of flower vase life. We tried to estimate the sensitivity to ethylene by the degree of flower diameter reduction after ethylene treatment. In six cultivars, relative flower diameter was either temporarily or continuously reduced by ethylene treatment. The flower diameter tended to be reduced more in short-lived cultivars than in long-lived cultivars following exposure to ethylene. These findings suggest that sensitivity to ethylene, which is indicated by a reduction of flower diameter, appears to be a factor involved in cultivar variation in the vase life of cut unpollinated Eustoma flowers.

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The reaction of iodine in the nutrient solution was investigated. Iodine reacted only with Fe-EDTA very slowly, iodine in a Fe-EDTA solution decreased from 10 ppm to 1 ppm one day later. Iodine stability in nutrient solution under different pH condition was measured. Under weakly acidic condition around pH 6, iodine tended to remain stable. An iodine disinfection system for soilless culture system consisting of an iodine release resin and iodine recovery resin was assembled. The effect of the disinfection system on the growth of spinach was evaluated in NFT with two disinfection methods using Fusarium oxysporum (f. sp. spinaciae) infected nutrient solution. The first method (Two steps system); 2 ppm of iodine could be stably eluted to the nutrient solution and circulated the whole cultivation system for disinfection and then recovered iodine from the solution. In this method, wilt disease was completely controlled. The second method (Series system); iodine eluting, disinfection and iodine recovery were concluded in a closed system. Although the solution introduced to the system was complete, but the whole cultivation system was not disinfected. It is necessary to reconsider the treatment condition. As both treatments can be combined during culture, the series system can be used usually and the two-step system should be used if symptoms of disease are found in the plants.

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The taste of broad bean is associated with the seed components including sugars and free amino acids, but details changes in these components and their association with taste remain unknown. This study investigated changes in sugar and free animo acid concentrations during the development of broad bean seeds and the effects of these changes on the taste of these beans. The two cultivars (‘Amaekubo’ and ‘Uchikoshi Issun’) were grown by the conventional cultural method, and seeds were sampled at 5-day intervals from 35 days after flowering (DAF) for chemical analysis. Concentrations of fructose, glucose, sucrose and maltose peaked during 35–45 DAF with a yearly variation, while those of raffinose peaked at 50 DAF irrespective of year. Concentrations of stachyose and verbascose tended to increase until 55 DAF. The concentration of sucrose exceeded the level that would be expected to affect the taste of the seeds, whereas that of other sugars was far below that level, suggesting that sucrose is the most critical sugar affecting taste. Most of the free amino acids analyzed showed their peak concentrations around 45–50 DAF, and only glutamic acid and alanine showed concentrations that would be expected to affect the taste. Sensory tests demonstrated that seeds harvested around 45 DAF had the best taste. These findings indicate that the appropriate time for harvesting broad beans as a vegetable is around 45 DAF.

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