In order to establish a method for evaluating everbearing strength in everbearing strawberry cultivars, the relationship between the nodal position of the first inflorescence in first-year runner plants and the everbearing strength was investigated. The nodal position of the first inflorescence was affected by the potting date and varied among cultivars. Potting on 24 June and 16 July led to a higher nodal position of the first inflorescence compared to potting on 14 May. A significant negative correlation was shown between the nodal position of the first inflorescence and the total number of inflorescences per plant. The 19 everbearing cultivars could be classified based on the average nodal position of the first inflorescence on 24 June and 16 July. It was found that cultivars with a lower nodal position of the first inflorescence were stronger in everbearing strength. Consequently, it was concluded that the nodal position of the first inflorescence in first-year runner plants is a suitable evaluation criterion for everbearing strength, and the potting of runner plants for evaluating is appropriate from late June to middle July.

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Rosa multiflora ‘Matsushima No. 3’ is tolerant to rose root rot disease caused by Pythium helicoides Drechsler, and the tolerance has been revealed through restraining germ tube elongation on penetration into root tissue. Phenolic substances are linked to preventing the germ tube from penetrating tissue; the retardants of germ tube elongation may be hydrolyzates of phenolic substances induced by penetration of a diseased germ tube. In this study, phenolic substances were extracted from the roots of tolerant rose ‘Matsushima No. 3’ and susceptible rose R. ‘Nakashima 91’, and we examined the retardant activity. The substances which restrained germ tube elongation of P. helicoides were detected in the root of ‘Matsushima No. 3’, and these exist as bound phenolic substances (glycosides) in the root. These substances show high retardant activity when hydrolyzed and change to free phenolic substances. The difference between the tolerant and susceptible rose appears to be due to the quantitative difference in the retardants contained in the roots. From the results of HPLC analysis of bound phenolic substances, the peak of the substance eluted before or after 10 minutes in ‘Matsushima No. 3’ was about three fold higher than that of ‘Nakashima 91’. An HPLC fraction containing this peak was tested for retardant activity. This fraction showed significantly higher retardant activity, and we infer that the substance contained in this fraction is related to the expression of tolerance of ‘Matsushima No. 3’.

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We investigated whether Eustoma grandiflorum (Raf.) Shinn bloomed in vitro using various culture conditions, and whether medium components, photosynthetic photon flux density (PPFD), sucrose concentration, and ventilation start time affected growth and blooming. When modified Hyponex (MH) medium was used, the blooming percentage was highest and plant height was shortest. In addition, when PPFD of over 80 μmol·m⁻²·s⁻¹ or sucrose concentration of 40 g·L⁻¹ or 60 g·L⁻¹ was used, the height of a blooming plant was observed to be approximately 8 cm. Furthermore, the blooming percentage was highest and plant height was shortest when ventilation was started 4 weeks after seeding. Concurrent with the above observations, we concluded that Eustoma grandiflorum blooms in vitro and the plant height reaches approximately 8 cm when a PPFD of 80 μmol·m⁻²·s⁻¹ is maintained from seeding to blooming; ventilation start time is 4 weeks after seeding; Murashige-Skoog medium with a sucrose concentration of 30 g·L⁻¹ is used during the 4 weeks, from seeding to first transplantation, and 8 weeks later, from first transplantation to second transplantation, and MH medium with a sucrose concentration of 40 g·L⁻¹ is used from second transplantation to blooming.

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‘Kyuri Chukanbohon Nou 6 Go’, a new type of cucumber (Cucumis sativus L.) which bears glossy fruits and has a glabrous trait, was bred from the glabrous accession NCG90 by four times of successive backcrossing with ‘Suisei Fushinari’ as a recurrent parent. ‘Kyuri Chukanbohon Nou 6 Go’ has a bloomless trait which makes fruits glossy. The fruit has a smooth surface without warts and spines. The taste is relatively favorable with no bitterness. Fruits are borne on the main stem and lateral branches. They are relatively thicker in shape than those of common Japanese cultivars. The color of the fruit skin is uniformly green and turns greenish-yellow on maturation. There are no hairs on leaves and stems. The glossy (bloomless) and glabrous traits seem to be due to pleiotropy, and are thought to be controlled by a single recessive gene. This cultivar is a useful material for glossy fruit appearance (bloomless) cucumber breeding. Moreover, due to its wartless and spineless traits, it also has a potential for hygienic cucumber breeding.

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In order to establish an in vitro culture model for male self-compatiblity and -incompatibility in Citrus, we assessed the culture environmental condition and optimal constitution of the liquid culture medium using mature pollen of Hyuganatsu (Citrus tamurana hort. ex Tanaka). A basal medium (Hirano·Hoshino, 2009) was used for examination of the optimum constitution. Mature pollen was cultured in a modified medium containing 0.04% (w/v) CaCl₂, 0.01% (w/v) H₃BO₃, 0.0007% (w/v) KH₂PO₄, 0.02% (w/v) yeast extract and 10% (w/v) sucrose with the pH adjusted to 7.0, at a density of 1 × 10⁵ pollen grains·mL⁻¹. These were kept at 25°C under dark conditions. In particular, the addition of CaCl₂, yeast extract and sucrose to the culture medium was essential for an efficient liquid culture system of mature pollen. In this culture, the nomal germination of pollen grains occurred after 4 hours, and the pollen tubes extended approximately 20 μm per hour. The nomal germination rate of mature pollen was highest (73.6%) after 6 hours of culture. Good growth of pollen tubes was maintained, and they reached 200 μm in length after 8 hours of culture.

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We investigated the budbreak rate in Taiwanese pear Yokoyama and Japanese pear strain TH3 (S₁ of ‘Osa-Nijisseiki’ and homozygous for the S₄^sm gene) and their F₁ for 3 years. All F₁ plants were identified as the offspring from a cross of TH3 × Yokoyama by S-allele genotypes and SSR marker analysis. The rate of budbreak in Yokoyama was higher than 60% on all observational days. Thus, Yokoyama did not show endodormancy from late November to early January for the 3 years. The rate of budbreak in TH3 was lower than in Yokoyama on all observational days, and it gradually increased from early December to early January. The rate of budbreak in F₁ plants was widely distributed between that of Yokoyama and TH3 on all observational days. On 8 of all a observational days, the average rate of budbreak in F₁ plants was nearer to that of TH3 rather than Yokoyama. We formulated the hypothesis that TH3 is homozygous for a dominant gene involved in the depth of endodormancy, but the hypothesis was rejected based on a chi-square test. From these results, it was suggested that pear plants had quantitative trait loci determining chilling requirements as a genetic factor. The defoliation period in many F₁ plants was closer to that in Yokoyama rather than TH3. Most F₁ plants foliated in April 9th when the day of foliation between that of Yokoyama and TH3.

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The induction of tetraploidy in Spathiphyllum wallisii Regel ‘Merry’ was successfully achieved using whole tuber colchicine treatment along with apical meristem culture to produce new cultivars or polyploidy breeding materials. The whole tubers, from which expanded and unexpanded leaves were removed, were treated with 0, 0.1, 1.0 and 10.0 mM colchicine in 1% (v/v) DMSO solution for 12, 24 or 48 h, respectively. Three chimeric plantlets, that were both diploid and tetraploid, checked with a flow cytometric procedure, were obtained with the 10.0 mM colchicine treatment. To obtain a complete tetraploid plantlet, shoot apical meristems of three chimeras were cut and cultured in vitro. The regenerated plantlets obtained through multiple buds were successfully acclimatized. Confirmation of the ploidy level in the developed plantlets by flow cytometry indicated that a complete tetraploid plantlet was obtained. In comparison with diploid plantlets, the tetraploid plantlet showed some morphological differences: enlargement of guard cells, thickening of floral stem, spadix and spathe, ovateness in spathe and leaf and increment of leaf width/leaf length ratio.

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In Japanese apricot (Prunus mume Siebold & Zucc.), most cultivars have a red-brown calyx, while, in some, the calyx remains green. The red-brown calyx results from anthocyanin pigmentation (AP); trees with a green calyx lack anthocyanin pigmentation (LA) in all parts, giving rise to their distinctive appearance with ornamental value. Inheritance patterns of LA were analyzed in various cultivars and selections. Crossings of LA parents produced LA progeny only. In contrast, the offspring from pairings of LA and AP parents were either all AP or mixed. LA plants may have originated from the hybridization of AP parents. We concluded that the green calyx is controlled by a simple recessive gene (a), and determined the genotypes of 25 cultivars and six selections.

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It has been reported that the self-sterility of the chestnut is incomplete because it exhibits weak self-fertility. However, the self-fertility rate has not been clarified among genotypes in the chestnut. In this report, we evaluated the self-fertility among chestnut varieties by means of shading treatment of the flower, and inspected self-fertility of the self-pollinated seedlings by genetic analysis of SSR loci. In 24 out of 51 genotypes, approximately 47%, various types of self-fertility were observed. Thirteen self-pollinated seedlings and their maternal parents were inspected by SSR analysis, and eight individuals derived from ‘Ibuki’, ‘Oomine’, and ‘Toyotamawase’ were confirmed to have the self-pollinated genotype. Surprisingly, ‘Toyotamawase’, one of the varieties, showed the highest rate of bur set (62.5%) and seed set (33.3%), and all their individuals were confirmed to have the self-pollinated genotype. The other five individuals derived from three varieties were also confirmed to have the cross-pollinated genotype. These results suggested that the chestnut has complete self-sterility, but some genotypes have weak self-fertility. Then, ‘Toyotamawase’ has the strongest self-fertility among the genotypes in this experiment.

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To establish an efficient polyploid induction method, we carried out in vitro chromosome doubling of multiple shoots in some Vaccinium species. Multiple shoots were aseptically treated with two antimitotic agents, oryzalin and colchicine, at different concentrations and times. After these treatments, the shoots were successively cultured on MW medium containing 5 mg·L⁻¹ zeatin. The ploidy levels of growth shoots were evaluated by both flow cytometry and chromosome counting. The frequency of chromosome-doubled plant production depended on the kinds of antimitotic agent, treatment concentrations and times, and species. Among the treatment conditions tested, oryzalin induced more chromosome doubling than colchicine. Four species of chromosome-doubled plants were obtained with 0.005% 24-hour oryzalin treatment at the following frequencies: V. corymbosum ‘Berkeley’: 23.3%, V. smallii: 5.6%, V. vitis-idaea: 40.0%, V. uliginosum: 57.8%. These results suggest that oryzalin is very effective for polyploid induction of multiple shoots in Vaccinium.

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To reconstitute the habitat of threatened Habenaria radiata (Thunb.) K. Spreng, orchid mycorrhizal fungi were isolated from the habitat with the aim of growing H. radiata seedlings, and the potential of seedling growth in the habitat was examined. First, sterilized tubers of H. radiata obtained with sterilized sowing were planted in the habitat in early spring, collected when the roots began to be infected with orchid mycorrhizal fungi, and fungal isolates of orchid mycorrhizal fungi were isolated from the root cells. Next, fungal isolates that extended the most mycelia under low temperature conditions and promoted the growth development of H. radiata protocorms were found. This fungal isolate was inoculated into gel covering protocorms obtained from the habitat, and was placed in the habitat. The survival rate of protocorms rose greatly to 76.7% and growth development was excellent; therefore suggesting strongly that the habitat can be reconstituted by this method.

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We investigated the effects of non-woven fabric sheet mulch and irrigation on the growth and fruit quality of fig (Ficus carica L. ‘Masui Dauphine’) with different tree vigor. Mulching treatment generally improved coloration and total soluble solid contents in fig fruit; however, when mulching was applied to weak trees due to soil sickness and/or less irrigation supply, mulching further weakened tree vigor with the production of smaller and distorted fruit characteristics. In contrast, mulching controlled excess tree vigor and improved fruit quality with an earlier harvesting date caused by high density cultivation under water conditions of pF≤2.5.

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The ‘packed bag-fertilization (PF)’ method of controlled-release fertilizer was applied to tomato sand culture using a root-proof capillary wick watering system for ease of media reuse. Plant growth, marketable fruit yield, and elution percentage of fertilizer were compared in four treatments, which were combined with growing media (mixed soil and sand) and the nutrient supply method (mixed fertilizer (MF) and PF method). Plants of medium-fruited tomato were grown for 132 days from September 2009 to February 2010, up to the 7th fruit truss. There were no differences in the plant growth and marketable fruit yield in soil and sand media, and in MF and PF. In sand media, the incidence of ‘green back’, a fruit-colouring disorder, increased at the later trusses compared with soil media. Also, fruit acidity of sand media at all trusses was lower than that of soil media. This reduction in fruit quality was probably caused by K₂O deficiency in sand media. At the end of the experiment, the fertilizer bag was removed from the media and analyzed. The elution percentages of total-N (T-N) and K₂O were more than 80%, which were slightly lower in sand than in soil media. There was little difference in the elution percentages between MF and PF of sand media. Apparent K₂O absorption per plant in the sand decreased by 4 g compared to that in the soil media. This difference was caused by the nutrient contents of the media before planting. As a result, fruit quality in the sand media was lower than that in the soil media. In conclusion, the PF in sand can sustain plant growth and yield at similar levels as soil or MF and with a similar elution percentage of fertilizer. However, sand media should be designed to show an improved fertilizer effect of K₂O from the first to end of the growth stages greater than for soil media to decrease the incidence of ‘green back’ fruit and improve fruit quality.

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The influences of the fruiting position in the canopy on the maturity and content of functional components in ‘Nanko’ Japanese apricot (Prunus mume Sieb. et Zucc.) fruit were investigated for 4 years. In fruit located on the inner side of the canopy, the time that the trichome fell out over 30% of their surface, an indicator of harvest, was later, and the beginning of harvest was 4-10 days later than on the outer side of the canopy every year. Fruit weight and b* value and L* value of skin color tended to increase, and firmness tended to decrease with fruit development, and there were no differences between fruit on the inner and outer sides of the canopy when they were compared at the same stage, the beginning of harvest. Contents of citric acid, sorbitol and β-caroten tended to increase with fruit development, and there were also no differences between the flesh of the fruit on the inner and outer sides of the canopy when they were compared at the same stage, the beginning of harvest. However, phenolic content and antioxidant activity tended to decrease with fruit development, and in the flesh of the fruit on the inner side of the canopy they tended to be lower than in fruit on the outer side of the canopy when they were compared at the same stage, the beginning of harvest. These results indicate that delaying the harvest time of fruit on the inner side of the canopy makes their fruit weight and some functional components equal to the fruit on the outer side of canopy, but causes poorer phenolic content and antioxidant activity than on the outer side of the canopy.

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To reduce the energy consumption involved in greenhouse heating, we investigated the effect of short-term rising temperature treatment performed around the end of the day (referred to hereafter as “EOD-heating treatment”) on the growth, flowering, and cut-flower quality of spray-type chrysanthemums. We used EOD-heating treatments for the 2 chrysanthemum cultivars ‘Sei-prince’ and ‘Remidas’ at 3 growth stages: vegetative growth, flower bud differentiation, and flower bud development. The EOD-heating treatments performed in the vegetative growth stage did not negatively affect the cut-flower quality, but the shoot extension growth was slightly suppressed during the lowest-temperature regime (17°C for 3 hours after dusk and maintained at 9°C thereafter). The following EOD-heating treatments were found to be practical to implement in the flower bud differentiation and flower bud development stages: (1) 20°C for 7 hours after dusk and maintained at 13°C thereafter; and (2) 17°C for 3 hours after dusk and maintained at 11°C thereafter. On comparing the treated with the control plants, it was found that these treatments did not negatively affect the days to flowering and cut-flower quality. The effect of EOD-heating treatment on flowering and cut-flower quality was investigated for all growth stages in the case of 21 cultivars. For 8 cultivars, the days to flowering were the same as those for the control. For 11 cultivars, the flowering was slightly delayed, and the days to flowering were 3 days longer than those for the control. For 18 cultivars, the cut-flower quality was equal to or better than that for the control. On the basis of these results, it is considered that EOD-heating can help reduce the energy consumption involved in greenhouse heating for spray-type chrysanthemum production during winter.

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We examined photographic methods and conditions for estimating the leaf area index (LAI) of the ‘Delaware’ grape using a digital camera with a fisheye lens. We separeted leaves from other parts in the pictures by binarizing the digital images and calculating the estimated LAI based on optical assumptions from the number of pixels. It was found that the optimum conditions for shooting hemispherical images were cloudy days. Furthermore, as the gap fraction changes significantly on clear days, it was found that the optimum conditions on these days were sunrise or sunset. Due to the nature of ‘Delaware’ grapes, which are trained to trellis heights of approximately 150 cm, it was determined that the estimated LAI more closely approached the measured LAI if images were taken from a distance of 100 cm to 150 cm from the trellis; however, the estimated LAI showed a trend toward overestimation. According to an examination into the cause of overestimation, the effect of the existence or non-existence of fruit was less than the effect of the shooting time. Because we could not discount the effect of the construction materials of the trellises, greenhouse, branches, and others, we added the effect to the gap fraction and recalculated the corrected estimated LAI. Using this correction, it was found that it is possible to estimate LAI faster and simpler than existing methods.

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To clarify the juvenility of bunching onion (Allium fistulosum L.), showing a green plant vernalization, we investigated the effects of the size and age of seedlings on flower-bud initiation. The relationship between flower-bud initiation and the plant size or cumulative leaf number was determined sequentially using young seedlings of ‘Kincho’, ‘Asagi-kujo’, ‘Cho-etsu’, and ‘Kinryo’ sown in a open field on October 1 and October 22. The leaf growth and cumulative leaf number in all cultivars increased over time, but had a suspended inflection period during the winter growing season, which nearly corresponded to the time of flower-bud initiation. In that period, for example, the cumulative leaf number was approximately 5 in ‘Kincho’ irrespective of the sowing time. It is suggested that the cumulative leaf number is a suitable index of the growth stage of the juvenile phase in flower initiation of bunching onion.

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For the effective control of mango anthracnose, we investigated the effect of short hot water treatment (SHWT), of which the operation time was shorter than that of hot water treatment (HWT), on effectiveness and fruit quality. In an in-vitro test, spores of the anthracnose fungus (Colletrichum gloeosporioides: Cg) were inhibited by dipping in hot water at 60°C for 5 s. Anthracnose in fruits inoculated with Cg spores was controlled by SHWT at 60°C for 30-60 s. SHWT for 40 s was the most efficient and controlled anthracnose development at the same level as HWT (52°C for 20 min followed by hydrocooling for 10 min). Because the temperature of the fruit core raised by SHWT was lower than by HWT, cooling after SHWT appears to be unnecessary. In sensory evaluation, the peel aroma and gloss of the fruits in SHWT were lower than those in non-treatment, but there were no significant differences in the aroma and taste of the fruit pulp between SHWT and non-treatment.

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Effects of harvest time and storing conditions after harvest on the aroma and bitter components of processed Japanese apricot liqueur (ume liqueur) were investigated with Japanese apricot (Prunus mume Sieb. et Zucc.) ‘Nanko’. Some of the aroma components in ume liqueur were identified as γ-decalactone, d-decalactone, ethyl butyrate and butyl acetate by the sniffing test. Content of these aroma components in ume liqueur was higher in fruit harvested later, and was high when the harvested fruit were stored for four days at 20°C or three days at 30°C. Ume liqueur made from fruit stored within five days at 20°C or within three days at 30 or 35°C showed equal or lower content of ethyl benzoate, exhibiting immature flavors, than that made from fruit immediately after harvest. Content of prunasin and oxalic acid that exhibited bitterness in ume liqueur decreased when the fruit was stored for four days at 20°C or three days at 30°C. These results suggest that aroma and bitter components in ume liqueur are influenced by the harvest time and storing conditions, and mature fruit should be harvested and the fruit stored for four days at 20°C or three days at 30°C before processing in order to increase aroma components and decrease bitter components.

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The effects of the frequency and timing of lateral branch girdling and crop load on the fruit quality of kiwifruit cv. ‘Rainbow Red’ (Actinidia chinensis) were studied. In addition, the effects of the position and consecutive application for 3 years of girdling on callus development and tree growth were also examined. As a result, lateral branch girdling showed a tendency to increase the fruit size and promote ripening. On the other hand, fruit color development appeared to be reduced by application. Girdling once within 30 days after full bloom, setting the number of fruit at 1 to 2 per bearing branch, was shown to be the most appropriate approach. In 3 years of consecutive application, the fruit size increased stably in all years, and the negative effects on the growth and number of flowers were not observed in girdled branches. Girdling of secondary scaffold limbs did not heal and the fruit size was smaller with this treatment than that with lateral branch treatment. These results suggest that lateral branch girdling is effective to increase the fruit size of ‘Rainbow Red’.

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