To elucidate the source of withering and injury of trunks of young peach trees in the Hida district in Gifu prefecture, several rootstock cultivars were tested. We investigated the differences in parasitic nematode density in rhizospheric soil among species, its effects on peach growth and development, and its relationship to the occurrence of withering and injury. Among plant parasitic nematodes isolated from the soil, there was no significant relationship of Pratylenchus penetrans (Cobb) to the occurrence of withering. Criconemella rustica (Micoletzky) exhibited important inter-specific differences. For ‘Ohatsumomo’, belonging to the group with higher density, tree rootlets fell off and decreased: the incidence rate of withering and injury was higher. In contrast, the incidence rate of ‘Hida kokuhubenishidare’, belonging to the group with lower density, was lower.
A new F1 hybrid bitter melon (Momordica charantia L.) named ‘Kumaken BP1’ has been bred using a gynoecious inbred line for the seed parent. ‘Kumaken BP1’ belongs to an Ao-chunaga (green semi-long) type of bitter melon. Seasonal adaptability of ‘Kumaken BP1’ in early-spring, spring and autumn was investigated. ‘Kumaken BP1’ showed characteristics of high female flower formation in those three seasons and especially its percentage of female flower nodes in late autumn cultivation was highly maintained while that of ‘Erabu’ decreased. Yields of ‘Kumaken BP1’ slightly increased in early-spring and spring, and increased by 50% in autumn as compared with ‘Erabu’. Therefore, in bitter melon breeding, F1 hybrids using gynoecious inbred lines for the seed parents are clearly advantageous. In the young stage, ‘Kumaken BP1’ needs a pollinizer to set fruits because the plant has few male flowers.
Common Japanese eggplant varieties are non-parthenocarpic and need 4-CPA treatment to bear fruit in forcing culture. Performing this treatment is quite time consuming, and culturing parthenocarpic eggplant require fewer working hours. Therefore, we examined the effects of seasons and air temperatures on fruit setting and the growth of parthenocarpic eggplant lines in forcing culture. We classified parthenocarpic eggplant lines by three stable parthenocarpic eggplant lines and two unstable lines in the preliminary test. The fruit setting percentages of all parthenocarpic eggplant lines in autumn and spring were lower than those in winter. The fruit growth percentages of all parthenocarpic eggplant lines in autumn, winter and spring were very high in greenhouse test. Although the fruit setting percentages of all parthenocarpic eggplant lines were equal in winter, the fruit setting percentages of the three stable parthenocarpic eggplant lines were higher than those of the two unstable lines in autumn and spring. These results suggest that it is important for breeding of parthenocarpic eggplant varieties to select stable parthenocarpic eggplant lines in autumn or spring.
An Asiatic hybrid lily ‘Akita petit white’ was selected from a cross between ‘Mont Blanc’ and ‘Apollo’. It is male-sterile with antherless stamens. In a field trial designed to extend the duration in order to allow year-round shipping, the antherless phenotype was stable when planted in December and May, allowing the harvesting cut flowers in April and July, respectively. However, these antherless stamens showed restoration of anthers under retarded flowering conditions in a green house in July. We demonstrated that the antherless stamens were restored to intact anthers in response to high temperature in summer. ‘Akita petit white’ showed a few spots in a perianth at 18/11°C in a growth cabinet. However, the number of these spots increased to 4.5 spots at 25/18°C and 6.3 spots at 32/25°C, respectively. It was suggested that the expression of the flower organ of lily was influenced by temperature. Moreover, this temperature-sensitive male-sterile cultivar would be useful as a breeding parent.
In order to produce a mass propagation method of highbush blueberries (Vaccinium corymbosum L.), short cut (2 to 3 cm) one-year-old dormant shoots were used. Sprouting of axillary buds on the dormant shoots was promoted at about 20°C in a dark chamber. Sprouting of axillary buds was inhibited especially in ‘Blueray’ as compared with ‘Dixi’ under the dark condition. The axillary buds of both cultivars sprouted rapidly under lighting for 16 h per day using fluorescent lamps. Application of 300 ppm and 600 ppm 6-benzyladenine did not promote the sprouting of axillary buds of short cut dormant shoots. When new shoots on the short cut dormant shoots grew to 1 cm under the 16-h lighting condition and the dark condition, after sprouting of axillary buds on the dormant shoots was promoted under 16-h lighting, the short cut dormant shoots were inserted into propagation beds (1 : 1 mixture of peat moss and Kanumasoil). The bases of new shoots were buried so they were not exposed. About 90% of cuttings rooted. Roots were formed almost at the basal parts of the current shoots. This propagation method could obtain a 3 times greater number of rooted cuttings than the customary method.
Effects of the structure of the cultivating bed, soil, watering and fertilization on carnation stunting and proliferation syndrome were evaluated by multi-regression analysis (quantification method 1) based on the results obtained from the relationship between the syndrome and items related to soil environment. The syndrome was promoted by poor drainage caused by the structure of the isolation bed with a flat concrete floor and wooden frame and also by the soil structure with a less solid phase and more liquid phase including rich organic amendment. The rapid change in soil moisture and fertilization concentration, for example watering at long intervals and application of dense liquid fertilizer, was also an important factor influencing the syndrome.
The effects of nitrogen (N), phosphates (P2O5), and potash (K2O) application on growth and flowering of Odontioda orchid were investigated for two years to demonstrate the optimal amounts of fertilizer for Odontioda potted in bark. N application caused an increase of dry matter production and leaf area of the current shoot (CS), and an increase in the number of florets; the effects were remarkable at the second year. The optimal amount of N application was 560 mg/pot/year using slow release fertilizer. When Odontioda were grown under the optimal N application, N concentration of the final leaf of CS before flowering was 1.86%. Chlorophyll concentration (SPAD) was positively correlated with N concentration (r = 0.854) in the final leaf, N concentration in the leaf could be estimated easily by measuring chlorophyll concentration (SPAD). The impact of P2O5 and K2O application on growth and flowering was limited, and the application of 240 mg P2O5/pot/year and 280 mg K2O/pot/year using slow release fertilizer was sufficient for the stable production of Odontioda.
Emergence of pulp hardening syndrome in the pickled ‘Nanko’ Japanese apricot is a serious problem of quality management. This study investigated the cause of this syndrome. The hardened pulp was estimated to include callose because the cell walls were stained with aniline blue. When the fresh fruit demonstrated a cavity adjacent the stone and the cell walls surrounding the cavity were stained with aniline blue, the fruit was found to develop pulp hardening when pickled. These findings suggest that wounding the pulp during removal of the stone causes the formation of pulp hardening by accumulation of callose in the cell walls. The pulp pulled away from the stone due to vigorous fruit thickening. In addition, decreased starch content in the bearing branch or drought stress during the early stage of fruit growth will decrease the cell numbers, which may also promote pulp removal.
It has been demonstrated that the coloring area rate of a picotee petal of Eustoma grandiflorum (Raf.) Shinn. is affected by temperature and the rate increases remarkably at constant 20°C temperature. In this study, we investigated the relationship between the amount of fertilizer applied, the coloring area rate in picotee petals and the cut flower characters of ‘Candy Marin’. Fertilizer application influenced the picotee coloring area rate under temperatures of 20°C and 22°C, but the effect was uncertain at 25°C. The coloring area rate increased on the temperature and fertilizer condition, which increased the amount of growth indicated by cut flower weight and the node number of the main stem. In addition, 12 cultivars with different picotee stabilities were grown under constant 20°C temperature. The coloring area rate increased with the amount of applied fertilizer. The cut flower weight and the numbers of nodes on the main stem also increased. The remarkable differences in the increase degree of the coloring area rate with fertilizer application between cultivars were observed. Therefore, the coloring area rate of a picotee petal of Eustoma was influenced by fertilizer application, but the degree of influence was differed depending on the picotee formation stability of each cultivar.
To examine effects of root zone heating during the daytime on the flowering characteristics, growth and yield of strawberry plants (Fragaria × ananassa Duchesne ‘Akihime’) grown in substrate culture, Experiment 1 (September 26, 2005 to May 24, 2006) and Experiment 2 (September 26, 2006 to May 24, 2007) were conducted in a heated plastic house. Treatments in Experiment 1 consisted of 4 heating periods (0, 0.5, 2 and 6 h) starting from 05:00 for all treatment conditions. The mean root zone temperature during the daytime throughout the experiments was 16.2°C, 16.8°C, 18.6°C and 21.0°C, respectively. Treatments in Experiment 2 consisted of 3 heating periods (0, 2 and 10 h) starting from 6:00. The mean root zone temperature was 17.4°C, 19.3°C and 22.0, respectively. As a result, the flowering date of the 1st flower of each flower cluster was enhanced after the 2nd axillary flower cluster at the heating treatments in both experiments 1 and 2, because flowering duration between the clusters was reduced at the 2nd to 4th axillary flower cluster. With increases in the substrate temperature, the flowering duration was reduced and the flowering date was enhanced significantly. Finally enhancement of the flowering date at the root zone heating treatments increased one flower cluster, especially at 6 and 10 h heating treatments in Experiments 1 and 2. This increment resulted in the number of fruit harvested and marketable yield. Days to maturation and soluble solid contents of fruit were not affected by the heating treatment.
The effect of temperature and use of ethephon on growth in late-July flowering type chrysanthemums (‘Kosame’, ‘Michinoku’ and ‘Yayoi’) was investigated. Anthesis time fluctuated according to the temperature in each year. A delay in anthesis was caused by low temperatures during flower differentiation or high temperatures during flower development, and it was shown that the latter had more influence than the former. ‘Kosame’ showed the largest delay in anthesis due to both high and low temperatures, with inhibition of flower development after flower budding. ‘Michinoku’ represented a small fluctuation in anthesis time with flower differentiation and flower development before flower budding was inhibited only by low temperatures. The ‘Yayoi’ cultivar showed a medium delay of anthesis, with flower development after flower budding inhibited by high temperatures. Anthesis was also delayed by spraying ethephon, and the degree of the effect was different among the three cultivars. Ethephon mainly inhibited flower differentiation and flower development before flower budding. However, for ‘Kosame’ and ‘Yayoi’, there was a large fluctuation of anthesis due to ethephon spraying, with inhibited flower development after flower budding depending on temperature. During the development of early-August harvest by spraying ethephon, ‘Michinoku’ turned out to be suitable for early-August harvest because of the small fluctuations of anthesis. To harvest chrysanthemums in earlier August, it will be necessary research spray timing and frequency and to select suitable cultivars.
In grapes, caps stuck to flower clusters can become a source of infection with gray mold disease. Thus, it is generally recommended that such caps are removed. We designed a new tool to remove the caps at the 1st gibberellin treatment to induce artificial seedless grape berries when its application time is near full bloom. A round brush was attached to the upper part of the cup used for gibberellin treatment. When a flower cluster soaked with gibberellin solution passed through the brush, the caps were efficiently removed from the flowers. ‘Kyoho’ and ‘Pione’ grapes cultivated in an open field were treated with gibberellin using this tool 3 days after full bloom. The cap removal rate immediately after treatment was 46–56% in the experimental group (the cup with a brush), whereas that in the control group (cup without a brush) was 4–8%. On the second day after gibberellin treatment, the cap removal rate increased to 70–76% in the experimental group because even more caps fell off the day after treatment, whereas the rate in the control group was 38–53%. A visual comparison of the young berries and the fruit at harvest showed that use of the tool did not cause scars on the surfaces of the berries. The tool did not have any undesirable effect on fruit quality. Therefore, this new tool is a useful labor-saving method for removing caps from flowers during the 1st gibberellin treatment in ‘Kyoho’ and ‘Pione’ grapes.
The yield in strawberry (Fragaria × ananassa Duch., ‘Nohime’) plants inoculated with arbuscular mycorrhizal fungi (Gigasporamargarita, Glomus mosseae, Gl. aggregatum) were investigated by elevated bench culture using fabric pots. Mycorrhizal plants accumulated more dry weight in the shoots and roots than non-mycorrhizal plants 10 weeks after inoculation; there were no differences by fungal species. The level of mycorrhizal colonization in roots differed with the fungal species; Glomusmosseae showed the highest level. As for fluctuations in yield, mycorrhizal plants produced more large fruit (3L, 2L) in apical and axillary fruit bunches than non-mycorrhizal plants. Total yield was greater in mycorrhizal plants than in non-mycorrhizal plants, regardless of the fungal species; this increase was mainly the result of large fruits from mycorrhizal plants. These findings suggest that mycorrhizal strawberry plants showed higher potential yield in elevated bench culture using fabric pots.
The state of inflorescence formation in turnip plants (Brassica rapa L.) cultiver ‘Taibyo-hikari’ was investigated to clarify the degree of vernalization by the “flower formation index”. First, germinated seeds were exposed to 0, 3, 6 and 9°C for 7–42 days under darkness. As a result, the index increased as the duration of low temperature lengthened in all plots. However, each plot at 3°C showed a highest index, which was 1.7–47.1% at 14–28 days of low temperature. The indices of 0 or 6°C plots were lower than that at 3°C. The lowest index was the percentage of 9°C which was 0–8.3%. Thus we thought that the most optimal temperature for vernalization was around 3°C. Second, the germinated seeds were exposed in the same way to 3°C for 14–35 days and then the seedlings were grown for 0–50 days under a short photoperiod (8 h at 20°C). As a result, the index decreased as the duration of the short photoperiod lengthened in all plots. However, each plot with a 50-day short photoperiod showed the lowest index. Thus, we thought that effort to promote vernalization was lost as the duration of short photoperiods lengthened, while suppression of vernalization was conversely maintained as the duration of low temperature lengthened.
A series of studies was conducted to improve the practical management of tankan (Citrus tankan Hayata) ‘Tarumizu 1 go’. Seasonal changes in fruit growth, peel color, and other important parameters of internal fruit quality such as sugar content and acidity of juice together with juice vesicle growth and respiration rate were monitored throughout the production cycle. The findings showed that mean fruit mass increased between July and December. Increased juice vesicle weight is considered to contribute to this increase in fruit mass. The rate of fruit growth decreased from December onward. The number of juice vesicles per section was determined by July and did not show any increase thereafter. The weight of juice vesicles increased dramatically between July and November and then increased gradually. The length of juice vesicles slowly increase between August and February. Juice vesicle respiration decreased rapidly between July and November, and remained constant thereafter. Coloring of the peel started from October, but delayed that of fruit pulp. Brix rose from October. This was attributed to the increase in sucrose, the principle sugar component. There was a slight increase in glucose and fructose content towards fruit maturity, though these sugar contents were lower. The titratable acidity fraction reached its peak in August and decreased drastically through September into December. A level around 1% was maintained thereafter. The change in the titratable acidity fraction coincided with that of citric acid fraction which comprised more than 90% of the total acid fractions. Though malic acid was also found, its concentration was consistently low.
Using shoot segments of Dendranthema grandiflora (Ramat.) Kitamura ‘Jinba’, hydration with hot water and water containing surfactants was studied in relation to the physical properties of vase water. Under nearly 100% relative humidities, fresh weight recovery was rapid with higher vase water temperatures. The fresh weight measured 6 h after the start of hydration (y) was negatively proportional to the kinematic viscosity of vase water (x) (y = −3.86x + 103.10, R2 = 0.92**), which decreased with an increase in vase water temperature, and water uptake during the initial 6 h (y) was inversely proportional to the kinematic viscosity [y = 10.36x/(−0.28 + x), R2 = 0.94**]. These results indicate that water uptake by cut stems can partly be explained by the Hargen-Poiseuille law and that the promotive effect of hot water on fresh weight recovery is attributed mainly to the decrease in kinematic viscosity by lowering the water conductance in the xylem vessels. The addition of surfactants such as polyoxyethylen (7) lauryl ether and "Shinguramin" to the vase water facilitated hydration even under a low temperature condition. These surfactants decrease surface tension by nearly half, which elevates the matric potential of water sucked into the xylem vessels, resulting in rapid hydration.
This study investigated attitudes, evaluation and the corresponding requirements for lectures of horticulture and agriculture by students enrolled in educational programs to become kindergarten and nursery school teachers. Twenty-one students were involved in horticultural and agricultural research, and the plant material, objectives and achievements of the research were investigated. The horticulture and agriculture programs were evaluated using a questionnaire by 21 students from the department of early childhood care and education in Fukushima College. The major theme of research by the students was the ‘Culture of vegetable crops for eating’, which was performed by 13 students. The major objectives of the research by the students were “the pleasure of growing” and “the pleasure of eating”. The eating programs were highly evaluated; cooking curry with saffron rice using cultured vegetables and sweet potatoes cultured by the students, which were roasted over fallen leaves fire, were the most highly evaluated. Rice culture was rated seventh, mostly by students who had not undertaken the lecture program. The results indicated that horticultural and agricultural programs should be included in the training of kindergarten and nursery school teachers because the students found them useful for early childhood care and education.