This report illustrates interspecific crossings between 7 cultivars of sweet cherries (P. avium L.) and 1 cultivar of ornamental cherry (P. × yedoensis Matsum.). Our objective is to obtain hybrids that have edible fruits as well as attractive flowers. Almost all of crossings of P. × yedoensis as the seed parent with sweet cherries (P. avium) as the pollen parents were unable to set fruit. However, 6 of 7 reverse cross combinations (P. avium × P. × yedoensis) set fruits (0.2–26.7%). A total of 456 fruit were obtained from the above crossing experiment, however, only 192 fruit (42.1%) produced normal and vivid embryos. These could be transferred to an embryo culture. As a result of crossing in three combinations, a total of 42 F₁ seedlings were obtained. Some morphological traits of the F₁ plants such as pubescence and the color of the leaves or fruit were supposed to be dominant on the basis of their segregation ratio. This also certified that these hybrids were not derived from any pollination error. Further, RAPD analysis detected derivative bands from both parents in the hybrids, confirming the hybrid nature of the offspring.

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Wild chrysanthemums and chrysanthemum cultivars (Chrysanthemum morifolium Ramat.) form non-glandular trichomes on the leaves. By scanning electron microscope and light microscope, the density and length of non-glandular trichomes on the leaves were measured. Highly significant differences in the density on the abaxial leaf side were found among 10 wild chrysanthemums. More and longer non-glandular trichomes were formed on the abaxial leaf side than the adaxial side. Similar traits were observed among 20 chrysanthemum cultivars but the degree of differences in the variation was minor. C. weyrichii (Maxim.) Miyabe & T. Miyake line 8913 had longer and characteristic non-glandular trichomes compared with other wild chrysanthemums. The densities in C. weyrichii line 8913 and cv. ‘Pingguoxiang’ were less than 0.3 per mm² leaf area. The densities in cv. ‘Chrysanthemum Tsukuba No. 1’ and cv. ‘Oki-no-shiranami’ was higher than those other chrysanthemum cultivars. They are interspecific hybridizations between C. morifolium and C. pacificum that was extremely hairy. The density of non-glandular trichome may be inherited. Non-glandular trichomes were initiated by the enlargement of single epidermal cells followed by anticlinal devision on leaf primordia in cv. ‘Jimba’. The head of non-glandular trichome was spindle-shaped on developing leaves but became a flat ellipse on expanded leaves. The density decreased as the leaf expanded.

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Interspecific hybrid of Delphinium, in which sepals were not abscised without silver thiosulphate pre-treatment, was raised. Interspecific cross between D.elatum ‘Magic Fountains White’ and D.grandiflorum ‘Blue Mirror’ was carried out and 18 interspecific hybrid plants were obtained through ovule culture. Seventeen plants were similar to the plant form and flower shape of the belladonna-type, however, one plant (‘M8-16’) was a dwarf-type of ‘Blue Mirror’. The polyploidy of belladonna-like plants and ‘M8-16’ were estimated as triploid and tetraploid, respectively, by flow cytometry. Three plants were obtained by backcrossing ‘Blue Mirror’ to ‘M8-16’. One of them (‘B10’) had very long flowering periods without abscission of sepals. Even sepals of cut florets were not abscised and the vase life of ‘B10’ was significantly longer than ‘Bellamosum’.

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Flower type of single or double is one of the important characters in carnation (Dianthus caryophyllus L.). Therefore, we selected random amplified polymorphic DNA (RAPD) markers associated with the genes controlling flower type in a segregated population of 127 progeny plants derived from a cross between ‘Carnation Nou No. 1’ (double) and ‘Pretty Favvare’ (single), which were used for construction of our genetic linkage map in carnations. Four RAPD markers identified by bulked segregant analysis of 696 primers were linked to a recessive gene controlling a single flower type derived from a wild species, D. capitatus ssp. andrzejowskianus. In particular, three RAPD markers, OM19-800, AT90-1000, DT52-700 appeared in all 45 single plants individually, but not in any of the double plants, indicating these three markers were tightly linked to the gene controlling the single flower type. The RAPD marker AT90-1000 was successfully converted to a sequence-tagged site (STS) marker. Linkage analysis revealed that this single gene was located on group 16 in our genetic linkage map. However, the STS marker was not detected in the four single flowered carnation cultivars. This result indicates that this STS marker is highly specific for the single gene derived from D. capitatus ssp. andrzejowskianus.

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To establish of seed propagation methods in Acanthopanax sciadophylloides, GA₃ application (200 mg•L⁻¹), warm (20°C) stratification and cold (5°C) stratification procedures were conducted. Seeds in ripening fruits had immature embryos showing globular or heart shapes. GA₃ pretreatment accelerated embryo development among plants receiving four-months warm stratification treatment. The effect of cold stratification treatment on embryo development was observed in seeds with GA₃ + three-months warm stratification treatment. After four months of warm stratification treatment, however, many seeds decayed during cold stratification. These findings indicated that GA₃ treatment prior to warm stratification treatment and following cold stratification treatment promoted embryo development. The most effective method for seed ripening was GA₃ pre- and post-treatment plus three months of warm stratification plus four months of cold stratification treatment.

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In the raising of peach nursery stock, the effects of the materials comprising the pots and soil moisture on the growth of nursery stock and the yield after planting were examined. If the soil moisture management was the same the growth of nursery stock was superior in non-woven fabric pot (the walls had properties that obstruct the root while the base had properties that allowed root growth through) than plastic pot. It was possible to raise nursery stock in non-woven fabric pot without a watering system in an open field, while this technique was impossible in plastic pots. There was no difference in the growth of nursery stock between a non-woven fabric pot without a watering system and a plastic pot with an automatic watering system activated when the soil becomes dry at pF 2.6. The yield from peach trees raised in the non-woven fabric pot with a automatic watering system was about 5 kg per tree in the first year and about 9 kg per tree in the second year after the nursery stock was planted. The first year’s yield from the peach tree raised in a plastic pot was about 2 kg per tree.

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The effects of substrate materials mixed with sand on the physicochemical properties, fruit quality and yield of tomato plants were investigated to improve tomato production by sandponic cultivation system. Zeolite-mixed substrate lost moisture more easily and contained more Na than sand substrate. EC and NO₃-N content in this substrate remained low during the cultivation period. In the zeolite-mixed substrate, plant growth was restricted, resulting in a low yield and the production of fruits with high Brix values. Addition of activated carbon to sand restricted the early growth of plants and deteriorated fruit quality, while it increased fruit weight. The addition of soil to sand improved fruit quality without any detrimental effects on yield. The addition of coconut coir improved the physicochemical properties of substrates (e.g., gravity and water retentivity), stimulating early growth of plants and early yield. The results suggested that the potential usefulness of coconut coir as a conditioner of sand substrate should be further studied under different irrigation schedules.

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Spinach (Spinacia oleracea L.) is one of the major agricultural products in Iwate prefecture, Japan. To evaluate the effect of compost made from cattle waste and saw dust, the growth and nitrogen (N) uptake of spinach were examined between 1998 and 2001, compared to those with standard fertilization using a chemical fertilizer. The compost was applied annually at a rate of 45 g N•m⁻² before sowing, then spinach was cultivated 2–4 times per year without supplemental N application. In the standard fertilization using ammonium nitrate, super phosphate and potassium chloride, N, P₂O₅ and K₂O were applied to the soil at rates of 16–20 g•m⁻², 20–24 g•m⁻² and 16–20 g•m⁻², respectively. Morphological index, i.e. leaf length, leaf width and number of spinach leaves in plants receiving compost were comparable to those of plants treated with chemical fertilizer. Dry matter production and N uptake in spinach applied with the compost was higher than that applied with chemical fertilizer, while the concentration of inorganic N in soil treated with compost was much lower than that treated with chemical fertilizer after every cultivation. Furthermore, the proportion of nitrate to total N in spinach receiving compost was much lower than that in spinach treated with chemical fertilizer, a though N uptake was higher in spinach treated with compost than that treated with chemical fertilizer. These findings suggest that N uptake in spinach would not be fully explained by the concentration of inorganic N in soil. However, concentration of phosphate buffer extractable organic N, which is considered an easily decomposable organic N, increased in soil treated with compost compared to that in soil treated with chemical fertilizer.

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A method was developed to evaluate water contents of fruit trees using infra-red photography. The irrigation of potted Satsuma mandarin trees and grapevines was suppressed to induce water stress. During the drought treatment, the leaf edges of basal parts of the shoots of grapevines became necrotic and the area of necrosis extended as the duration of stress increased. Necrosis was clearly distinguished from the viable areas on infra-red images. In Satsuma mandarin, an abscission layer formed at the basal part of the petiole, then the leaves fell. Thus, detailed analysis was indispensable for detecting of the leaf water content. After obtaining infra-red images of Satsuma mandarin leaves with or without water stress, a background treatment (subtraction of the background image) was performed on the images, then the average brightness of the leaf was determined using image analyzing software (Image Pro-plus). Coefficient correlation between the water status index using the infra-red camera and water content determined from dry weight and fresh weight of leaves was significant (r = 0.917 for adaxial surface data and r = 0.880 for abaxial surface data). These data indicate that infra-red photography is useful for detecting the degree of plant water stress.

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Effects of the ionic composition of nutrient solutions on the dry weight and the chemical contents of Doritaenopsis plant potted by sphagnum moss were investigated. Dry weight of shoot, root, inflorescence and these dry weight ratios were relatively constant in different treatment. However, increase of K⁺ levels increased shoot dry weight, while that of Ca²⁺ levels had a reverse effect. Dry weight ratios showed large difference among different organs. The values were 6–7%, 9–10%, and 7–8% in shoot, root, and inflorescence, respectively. Mineral content increased corresponding the increase in mineral ions in the nutrient solution, but the absorption of the other ions were inhibited antagonistically in the same ion group, i.e. in cations or anions. In cationic treatments, significant differences of Ca and P concentrations in the shoot were observed. In anionic treatments, significant differences in P and Ca concentrations in the root and N and Ca concentrations in the inflorescence were observed. These differences indicated that absorption and translocation of each ion was affected by composition of the nutrient solution. K⁺ inhibited H₂PO₄⁻ absorption and the translocation and NO₃⁻ accelerated Ca²⁺ absorption but the mechanism was not clear.

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Cultivar ‘F₁ Candy Marine’ and ‘F₁ Neo Peach’ of Eustoma grandiflourum were grown in various seasons to investgate the correlation between the coloration rate of petal and temperature. The correlation between the product aristhmetic time below 20°C and petal coloration were examined. The main findings of this study were as follows; 1. The coloration of the petal in colored picotee cultivars is normal when harvested between May and November and the coloration area expanded from winter through spring. In January and February the coloration area reached 80% of the whole petals. 2. As for the coloration rate of petals, the coefficient of positive is high significantly with the product arithmetic time below 20°C. 3. The coloration rate of the petal increased markedly when the time below 20°C during the sixty days before harvest increased to more than 800 hours.

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Effects of the starting time of salinity treatment, planting density and lateral shoot leaves under the truss on yield and quality of double-truss tomato fruits grown in hydroponics were investigated. Salinity treatment starting 20 days after anthesis and continuing onto the end of experiment, increased total soluble solids of the fruit to about 9.0 Brix %, but suppressed the fruit weight about 30% compared to the control. Under high planting density (950 plants•a⁻¹), tomato fruit yield per unit area was increased 34% compared to that under low planting density (670 plants•a⁻¹), without negative effects on fruit quality. By leaving the lateral shoot leaves under each truss, soluble solid content of the fruit increased under salinity treatment. These findings suggest that salinity treatment, leaving lateral shoots having 4 to 6 leaves under the truss and high planting density can be an effective method of producing high quality tomato fruits in hydroponics.

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The effect of planting density (330–3178 trees/ha) on net production (t DW/ha/y) and partitioning was studied in 11 to 13-year-old ‘Starking Delicious’ apple trees on M.9, M.26, M.7 and MM.106 without pruning. On all rootstocks, individual annual dry matter production (⊿pn) and annual dry matter production per tree of fruit (fd), leaf (ld), branch (⊿pb), trunk (⊿pt) and root (⊿pr) decreased as planting density (ρ) increased. The density effects on ⊿pn, z (ld, ⊿pb, ⊿pt or ⊿pr) and fd could be represented by the following equations, respectively: 1/⊿pn = A₁ρ + B₁, 1/z = A₂ρ + B₂, and fd = K exp (−kρ). On all rootstocks, net production (⊿Pn) and net production of leaf (Ld), branch (⊿Pb), trunk (⊿Pt) and root (⊿Pr) increased as planting density (ρ) increased, but on three rootstocks excluding M.26, the net production of fruit (fruit production: Fd) was maximized at the optimum planting density (ρ_opt). The density effects on⊿Pn, Z (Ld,⊿Pb,⊿Pt or⊿Pr) and Fd could be represented by the following equations, respectively: 1/⊿Pn = A₃ + B₃/ρ, 1/Z = A₄ + B₄/ρ, and Fd = H´ρ/(A₁ρ + B₁)^h´. Partitioning ratio into leaf (Ld/⊿Pn), branch (⊿Pb/⊿Pn), trunk (⊿Pt/⊿Pn) and root (⊿Pr/⊿Pn) increased as planting density (ρ) increased, but that into fruit (Fd/⊿Pn) decreased. The density effects on Z/⊿Pn (Ld/⊿Pn, ⊿Pb/⊿Pn, ⊿Pt/⊿Pn or ⊿Pr/⊿Pn) and Fd/⊿Pn could be represented by the following equations, respectively: 1/(Z/⊿Pn) = A₅ + B₅/ρ and Fd/⊿Pn = K´ exp (−k´ρ). The relationship between fruit production (Fd) and net production (⊿Pn) could be represented by the following quadratic function: Fd = −a₁(⊿Pn)² + b₁(⊿Pn) + c₁. The relationship between fruit production (Fd) and partitioning ratio into fruit (Fd/⊿Pn) could be represented by the following quadratic function: Fd = −a₂(Fd/⊿Pn)² + b₂(Fd/⊿Pn) + c₂. The relative relation between the net production (⊿ Pn) and the partitioning ratio into fruit (Fd/⊿ Pn) was defined as ⊿ Pn/(Fd/⊿ Pn), and the relations between fruit production (Fd) and ⊿ Pn/(Fd/⊿ Pn) plotted on the log~log coordinates (Fig. 6) showed the same pattern as the log Fd~logρ curves (Fig. 2). From these results, it was suggested that the density effect on fruit production is a phenomenon that ⊿Pn/(Fd/⊿Pn) changes with planting density, and, as a result, fruit production changes.

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Replanting of asparagus (Asparagus officinalis L.) often results in lower yields and extensive damage of young plants. One of the causes is considered allelopathy. In this study, we examined the participation of allelopathy on injury by continuous cropping of asparagus in alluvial soil. The presence of strong allelochemical substances, which have the growth-inhibitory activity, was detected by bioassay of rhizosphere soil around asparagus. This growth-inhibitory activity was not attributed to salt accumulation, pH fluctuation, or inorganic nutrient imbalance in the rhizosphere soil. Asparagus foliage incorporated into the soil did not demonstrate a close relation to the growth inhibition or decreased yield of asparagus. However, strong growth-inhibitory activity was demonstrated in the storage roots of asparagus. It is assumed that an allelochemical is exuded from the storage roots and is one of the causes of unsuccessful continuous cropping of asparagus.

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The growth-inhibitory activities of allelopathy in asparagus (Asparagus officinalis L.) was studied using the ‘Plant Box Method’ of bioassay. By this methods we confirmed that asparagus produced allelochemical substances. Then we developed a modified plant box method to examine the relationship between the growth-inhibitory activity and the adsorption of materials to allelochemical substances from asparagus. As a result, a type of activated carbon has the ability to absorb the allelochemical substances and prevent the growth inhibition of lettuce, an assay plant. Furthermore, in a field replanted with asparagus, treatment with activated carbon increased the fresh weights of rhizomes and storage roots, as well as the number of storage roots, the growth amount, and the growth index (GI’), when compared to those of asparagus grown on non-treated plots.

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We developed a new method of examining the effects of allelochemical substances exuded from the roots of asparagus (Asparagus officinalis L.) to rhizosphere soil. This rhizosphere soil bioassay method provided results similar to those from the conventional bioassay method in which asparagus germinates in the soil. The new method was more effective than the conventional bioassay method because the soil samples could be tested using a smaller volume. This method could also evaluate flowable activated carbon as one of the materials to absorb allelochemical substances at a laboratory level. An appropriate orientation of cultivation is expected to become possible using the rhizosphere soil assay method developed in this study to examine obstructions to continuous cropping that may be related to allelopathy.

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Effects of freezing damage were investigated for several cultivar rootstocks and native selection of ornamental peach on withering and injury of trunks in ‘Hakuho’ and ‘Shouwahakuto’ peach trees. For ‘Ohatsumomo’ rootstock, injury occurred mainly in scions at 3 years old; plants died at 4 years old. In contrast, for ‘Peach tree rootstock Tsukuba-1’ ‘Harrow Blood’, and ‘Kokuhu HM-1’ rootstocks, injury occurred in scions and rootstocks at 3–4 years old in some trees, but the plants did not die. ‘Kokuhu HM-1’ was the most tolerant to cold injury in four rootstocks examined. It was inferred to be effective for avoiding injury. The period of bud break, flowering and leafing showed little difference. Vigor of trees did show a difference, but its relation to injury was not clear.

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Effects of cultivation temperature and high temperature treatment on seed-germination of rocket larkspur were investigated. The optimal temperature for seed-germination was 15~20°C, and high germination rates were also observed at alternating temperature 15/25°C (16 h/8 h) and 15/30°C (16 h/8 h). Treatment of alternating temperature 25/30°C (12 h/12 h) for 10 days before sowing was more effective than those of 25, 27.5, 30 and 25/35°C (12 h/12 h) for 5, 15 and 20 days to shorten the period of seed-germination. Using this method, seed-germination of rocket larkspur ‘Miyoshi White’ and ‘Sydney White’ became more uniform.

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For HPLC analysis of soluble carbohydrate concentration in petals, a simple and rapid extraction method using a centrifugal filter device was developed. Rose ‘Sonia’ petals were placed in a centrifugal filter device, frozen in liquid nitrogen and centrifuged. The resulting leached fluid was used as a soluble carbohydrate sample for HPLC analysis. The amount of leached fluid increased with the increasing duration of centrifugation, but reached a plateau after centrifugation for 30 min. When soluble carbohydrate composition of fluid obtained from this method was compared with that from a conventional extraction method using hot ethanol, there was no significant difference between the two methods. When leached fluid was held at room temperature, its sucrose concentration decreased with time, but this decrease was suppressed when the fluid was stored at 4°C. This suggests that soluble carbohydrate samples prepared by this method should be stored at a low temperature and analyzed as soon as possible. Soluble carbohydrate samples were extracted from rose ‘Madeleine’, ‘New Bridal’, ‘Rote Rose’, ‘Saturn’, carnations, Eustoma and Oxypetalum petals using this method and the compositions of these samples were compared with those obtained by the conventional method. There were no marked differences between the two methods. These results suggested that the extraction method using a centrifugal filter device is a simple and rapid method of determining soluble carbohydrate concentrations in the petals of various flowers.

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Effect of calcium and/or silverthiosufate (STS) treatment on the vase life of snapdragon (Antirrhinum majas L. cv. Athlete Red) was investigated. Cut flowers kept in water showed inflorescence bent, while those pretreated with 1% CaCl₂ for 16 h did not show such symptoms. STS pretreatment prevented floret wilting but calcium did not. Calcium pretreatment enhanced inflorescence elongation and open florets. When vase water contained 5% glucose and germicide the calcium and STS pretreated flowers produced inflorescence with larger florets, resulting in extended vase life.

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