The cultivar ‘Yubeni’ was discovered as a mutant of Meiwa kumquat (Fortunella crassifolia Swingle) in Kushima city, Miyazaki. According to the results of flow cytometry analysis and morphological investigation of several tissues and organs, ‘Yubeni’ was supposed to be a ploidy periclinal chimera with diploid (2n = 2X = 18) in the outermost layer (histogenic layer L-I) and tetraploid (2n = 4X = 36) inner layer (histogenic layer L-II and L-III) in the shoot apical meristem. Compared with the diploid line, it showed similar morphology to the tetraploid line such as larger leaves, flowers and pollen grains. The weight and size of the fruit were both greater than those of the diploid line. Furthermore, this cultivar has desirable traits for kumquat such as smaller number of developed seed and thicker pericarp.

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‘Kyuri Chukanbohon Nou 5 Go’, a cucumber (Cucumis sativus L.) cultivar with resistance to powdery mildew (Podosphaera xanthii (Castaggne) U. Braun & N. Shishkoff) not only at higher temperatures (above 26°C), but also at relatively cool temperatures (20°C) was bred as potential breeding material. This cultivar is the progeney from crosses among CS-PMR1, ‘Sharp 1’ (Saitama Gensyu Ikuseikai Co. Japan) and ‘Rira’ (Enza Zaden BV, the Netherlands). The resistance to powdery mildew is thought to be controlled by 2 gene pairs, a major ressessive gene and an incompletely dominant gene that enhances the resistance at cooler temperature. Fruits are borne on the main stem and lateral branches. The fruit is relatively small (approximately 60 g) and similar to Beit Alfa type cucumber and has smooth surface without warts or spines. The color of the fruit skin is dark green. The skin is tougher and flesh is slightly softer without bitterness in fruit. Mature fruits are yellowish green with dense netting. This cultivar is a useful breeding material for powdery mildew-resistant cucumber.

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The natural populations of Rhododendron ripense Makino distributed in the San-in and Shikoku area, Japan, were investigated for the application in breeding materials. Genetic diversity was evaluated based on their morphological characters and chloroplast DNA polymorphism. Wild habitats of R. ripense in the San-in area have been considered to be disturbed by construction of dams and river improvements compared to vegetation of about 40 years ago. R. ripense in the San-in area have flower corolla of approximately 6 cm diameter and showed local morphological diversity in corolla broche and sepal length. They tended to have bigger corolla diameter, deeper broche color and wider leaves than flowers of the Shikoku area. On principal component analysis, the first and second principal component had a high contribution ratio in morphological characteristics of flower and leaf. In the scatter diagram of distribution, the main San-in river populations were distributed closely, whereas the west San-in and Shikoku river populations were distributed beyond these areas. The sequence mutation that indicates local genetic diversity was detected in intron of trnW-trnP on chloroplast DNA. The populations in the San-in river area have mainly TA sequence type, whereas those of the Shikoku river area showed both TA and AT sequence types.

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Flowering characteristics and effects of timing the cutting and pinching of flowers in Hydrangea serrata (Thunb.) Ser. were investigated in order to establish a pot plant cultivation system. Sixteen varieties most of which were the lateral branch-flowering types were used. In most of the cuttings, flower bud differentiation started in late-October and differentiated sepals developed in late-November. Sepals of ‘Hakusen’ and ‘Maiko Ajisai’ differentiated in late-December. Cuttings of ‘Shichihenge’ and ‘Shichidanka’ were planted in early-, middle- and late-June and the shoots were pinched 5 and 6 weeks after planting. The number of flower clusters of ‘Shichihenge’ gradually decreased with delay in the planting date of cuttings. Pinching promoted the emergence of lateral branches but decreased the number of flower clusters. These results indicate that a sufficient number of flower clusters develop in the lateral branch-flowering type of H. serrata when cuttings are planted in early-June and cultivated without pinching.

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To establish a method of raising one-year-old well-feathered apple trees, ‘Fuji’ and ‘Akitabeniakari’ were grafted on JM7, M.9 and M.26 rootstocks or interstems planted in 17 liter volume of non-woven fabric pots. Three different grafting times (February and March in a greenhouse, April in open field) were compared. Shoots were sprayed one to three times with 6-Benzyladenine (BA, 300 or 600 ppm) to induce feathering. Shoot growth, stem girth, total and average feather length of trees grafted in the early season (February and March) showed greater values than those grafted in the later season. Feathering from new shoots was favorable in all grafting time plots, regardless of the number of treatments or concentration of BA. Ten to fifteen feathers grew from the axillary buds of the shoot of ‘Fuji’, five to thirteen feathers grew from ‘Akitabeniakari’. It was shown that one-year-old well-feathered trees could be raised by grafting apple varieties on dwarfing rootstocks or interstems planted in non-woven fabric pots in the greenhouse in February or March with later application of BA to growing shoots.

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A study was carried out to determine the most effective nitrogen fertilizer application rate for optimal tree growth, fruit quality, and leaf mineral content of the young citrus ‘Shiranuhi’ [‘Kiyomi’ (Citrus unshiu Marcow × C. sinensis (L) Osbeck) × C. reticulata Blanco] trees. The study was conducted over a period of four years from April 1999 to March 2003. Fruit yield increased with increasing nitrogen fertilizer application rate up to twice the recommended application rate (448 kgN·ha⁻¹ for 7-year-old trees). Fruit quality was also influenced by nitrogen fertilizer application rate. Increasing the nitrogen in application rate increased the proportion of the peel in the fruit in 2001 and decreased the specific gravity in fruit in 2001 and 2003. The concentration of total soluble solids (Brix) increased with increasing nitrogen fertilizer application rate in 2003, whereas the citric acid level in the fruit decreased with increasing nitrogen fertilizer application rate in 2002. Total nitrogen concentration in the leaves increased with increasing nitrogen fertilizer application rate up to twice the standard application rate. However, no further increases in leaf total nitrogen concentration were observed in the N-application rate of three times the recommended rate. Lowering the nitrogen fertilizer application rate to half the recommended rate resulted in leaf total nitrogen concentration that was below the accepted content for optimal plant nutrition. From this study, the optimal annual nitrogen fertilizer application rate for 7-year-old ‘Shiranuhi’ trees appears to be between 224 kgN·ha⁻¹ and 448 kgN·ha⁻¹.

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This study investigated causes of increased susceptibility to excess moisture injury during the fruit developmental stage compared with vegetative stage in tomato plants. Dry matter, distribution patterns of photosynthates and bleeding rate in tomato plants under transient waterlogged condition were investigated. After whole shoots of tomato were exposed to ¹³CO₂ for 5 hours, the tomato plants were waterlogged for 43 hours. The waterlogged treatment did not affect the distribution of newly fixed carbon to the roots during either stage of the tomato plant. Only 2% of assimilates translocated to the roots during the fruit developmental stage under waterlogged condition. The bleeding rate was lower in both stages following waterlogged treatment. The bleeding rate per unit root dry mass was lower during the fruit developmental stage compared with that at the vegetative stage. Therefore, it is suggested that relatively low distribution rate of photosynthate to the root, which is natural during the fruit developmental stage, and the greater decline in root activity would be factors promoting increased susceptibility of tomato to excess moisture injury.

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We estimated Brix values of Japanese pear ‘Gold Nijisseiki’ fruit on the tree using a portable non-destructive near infrared spectrometer to compare net Brix value of the fruit during the 30-day period before harvest at different fruit load. Although the bias (mean of difference between actual Brix value and non-destructively derived value) differed on each measurement day, the correlation between estimated and measured values was high. Therefore, estimated Brix value of tree fruit could be used to adapt a bias correction for each measurement time. The increase in Brix value during 30 days before harvest for 5 seasons ranged from 1.4% to 2.3%. Thus, we could predict Brix value of mature fruit using an estimated Brix value of the tree fruit 30 days before harvest. Fruit load was regulated to 4, 6, 8, and 10 fruit per one meter length of lateral branch 30 days before harvest, and then the changes in fruit Brix value were estimated using the described method until harvest. The lower fruit load resulted in the higher increase in Brix value from 2 weeks after treatment. Defoliated branches showed a lower increase in Brix value than control branches, even if they had the same fruit load. Therefore, we concluded that the leaf-fruit ratio affects sugar accumulation during maturation in Japanese pear fruit and that an appropriate ratio to produce fruit having adequate Brix value (greater than 11) was 35/50.

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The effects of decapitation and defoliation just after pinching on the plant form were examined in order to develop methods of inducing branching in flowering cabbage (Brassica oleracea L. Acephala Group) with three lateral branches for bedding plants. When ‘Hatsuyume’ was sown in early July, hard pinching at potting after four weeks caused the plant form of flowering cabbage to become more compact. It was clear that removing the upper three leaves just after pinching effectively produced branches from axillary buds, especially in ‘Suruga no hatsuhi’, ‘Fuyubeni’, ‘Hatsubeni’ and ‘Hatsuyume’.

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Morphological changes in the shoot apex of Gloriosa superba L. ‘Rose Queen’ during floral initiation and development were observed using a scanning electron microscope. The sequence of events in floral initiation and development of G. superba was similar to that in Lilium longiflorum except for morphology of perianth primordium in which both inner and outer primordia had the same shape as Tulipa gesneriana. Effects of cultivating season on flower bud formation were investigated in three genotypes ‘Misato Red’, ‘Tropical Red’ and ‘Rose Queen’. Tubers of each genotype were forced to sprout under dry conditions at 30°C for 22-24 days, and then were planted on December 2 (winter culture), on April 3 (spring culture) and on July 3 (summer culture) in a glasshouse, respectively. Most leaves were formed before planting. Floral initiation occurred when about 30 leaves were formed in any season in ‘Misato Red’ and ‘Tropical Red’. In ‘Rose Queen’, however, floral initiation occurred when 47 leaves had formed in summer culture, and at about 35 leaves in winter and spring culture. The differences in floral initiation among these genotypes seem to be caused by differences in response to temperature, especially high soil temperature which may inhibit floral initiation depending on the genotype. Once floral initiation occurred the flower bud developed rapidly in all culture season.

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The effect of temperature on the occurrence of yellow-leaf-spot, a physiological disorder of cut chrysanthemum, was investigated in ‘Seikou-no-makoto’ chrysanthemum. After long day treatment, plants were grown under natural day length in a temperature gradient chamber (TGC), in which air temperature followed the fluctuation of outside ambient temperature. Slight yellow-leaf-spot occurred in plants grown at intermediate temperature in TGC. This temperature regime was similar to the temperature regime before transfer to TGC. However, yellow-leaf-spot occurred remarkably higher in low or high temperature regimes. To investigate the effect of fluctuation of temperature on the occurrence of yellow-leaf-spot, plants were grown in low, intermediate and high temperature regimes in TGC, and after 10 days, plants were transferred to other temperature regimes or grown under the same temperature. The occurrence of yellow-leaf-spot was slight in low or intermediate temperature regimes 10 days after the start of treatment, but severe in high temperature regime. The occurrence of yellow-leaf-spot remarkably increased in plants transferred from high temperature regime to low temperature regime. In conclusion, the occurrence of yellow-leaf-spot in ‘Seikou-no-makoto’ was promoted by high temperature, and further increased by a drop in temperature after exposure to a high temperature.

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To facilitate the production of white asparagus (Asparagus officinalis L.) spears in winter, we studied spear blanching in rootstock planting forcing culture. A strong correlation was observed between the fresh weight of one-year-old rootstocks and their yields. Light conditions during the harvesting time had little influence on the yield, but, they influenced anthocyanin pigmentation in the spear. When asparagus spears were harvested under darkness maintained by an opaque film covering, anthocyanin pigments in the spears disappeared. There were differences between cultivar yields; these were caused by the differences in the extent of chilling exposure, which is necessary for each cultivar to break the dormancy of its rootstock. These results suggested that white asparagus spears can be produced with no anthocyanin pigment in forcing culture by using one-year-old rootstocks of cultivars with a low level of dormancy (‘UC-157 F₁’, ‘GrandeF₁’), if spears are harvested under dark conditions maintained by opaque film covering.

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To clarify the flowering habit of Delphinium grandiflorum L. in the cool northern areas of Japan, the relationship between the developmental stage of flower bud and the expression of bolting was examined. Plants were sown in late May and began to form flower buds two weeks prior to bolting at the beginning of August. They flowered three weeks after the start of bolting. When plants were sown between July and September, the days to bolting increased markedly. However, in plants sown between the end of March and June, early bolting occurred and the days to bolting decreased. Among plants sown between July and August, two groups were observed with different numbers of days to bolting. Positive correlation was observed between the days to bolting and the days to flowering.

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Jasmonic acid (JA) is widely distributed in higher plants and its derivatives are considered novel plant hormones, while salicylic acid (SA) regulates various physiological responses including fruit ripening through the production of reactive oxygen species and ethylene in some plant species. To elucidate the involvement of JA and SA in the maturation of persimmon fruit (Diospyros kaki Thunb. cv. Fuyu), the effects of methyl jasmonate (MeJA), SA, ethrel and hydrogen peroxide (H₂O₂) on fruit maturation were evaluated in this study. H₂O₂ most strongly enhanced coloration as determined by “color chart”, followed in order by MeJA and SA, whereas ethrel did not show any effect on color promotion. H₂O₂, MeJA and SA also increased lycopene and decreased chlorophyll concentration in the skin at harvest. Severe fruit drop was caused by both H₂O₂ and ethrel treatments, but there was almost no effect of MeJA treatment at 500 ppm. MeJA at 500 ppm did not soften the fruit flesh at all, although H₂O₂ and ethrel softened the fruit significantly. Persimmon fruit treated with MeJA emitted about 10 times more ethylene than the control, and SA treatment hastened the ethylene emission peak about 6 days compared to the control. Thus, JA and SA appear to be involved in maturation of persimmon fruit, possibly through the production of endogenous ethylene and reactive oxygen species. MeJA is a promising chemical for enhancing coloration of persimmon fruit.

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Seven potted dormant tetraploid grapevine cultivars grown under forced conditions were treated immediately after pruning with the supernatants of a 20% suspension of CaCN₂, 2% H₂CN₂ and 5% diallyl disulfide in different chilling exposures: late November (73 hours), early January (620 hours) and late February (1,275 hours). The effectiveness of the chemicals in initiating budbreak was assessed by the number of days to initial and 60% budbreak after treatment, indicating the promotion and uniformity of budbreak, respectively. Although the chemicals were most effective when applied in November, there was large variation in the response of buds among cultivars and treatment times. For November treatment, H₂CN₂ was the most effective in accelerating budbreak initiation and enhancing uniformity for almost all cultivars, followed by CaCN₂, whereas in the January and February treatments, there were no differences in the promotion and uniformity of budbreak between the two chemicals. Response of buds to diallyl disulfide varied largely among the cultivars. Diallyl disulfide delayed budbreak initiation or reduced percentage budbreak for ‘Aki Queen’ and ‘Takatsuma’ in all the treatment times and for ‘Pione’ in November and January treatments. For ‘Fujiminori,’ there was no significant difference in the effectiveness of chemicals on budbreak regardless of treatment time. We conclude that H₂CN₂ is the most effective chemical for budbreak of tetraploid cultivars, followed by CaCN₂, and diallyl disulfide. However, the response of grapevine buds to chemicals varies with the depth of dormancy and cultivar.

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Effects of light irradiation, water-supply and storage temperature on quality and nitrate nitrogen concentration in Komatsuna (Brassica campestris L.) plants were evaluated during film packaging (FP) storage. Plants were stored in FP with low-temperature (7-14°C), lighting (PPFD 2.85-4.56 μmol·m⁻²·s⁻¹) and water-supply. The fresh weights of plants may be increased because transpiration was suppressed by FP and water was continually absorbed from roots. Leaf color did not fade because chloroplasts were synthesized by light irradiation. In addition, nitrate nitrogen concentration in plants was reduced by about 36%, when plants were stored for 4 days at 14°C. It seemed that the decrease is caused by an increase in nitrate metabolism in the results of photosynthesis, chloroplast, respiration, and so on. Thus the quality of Komatsuna plants could be maintained during storage in film packaging under low-temperature (14°C), with lighting and water-supply, and the nitrate nitrogen concentration could also be reduced.

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Effects of sucrose concentrations in solution on petal color pigmentation, concentrations of sugars and anthocyanins in the petals of bud cut carnations (Dianthus caryophyllus L., ‘Nora’) were investigated. Bud cut carnation flowers were treated with sucrose solutions of up to 15% at 23C. Sucrose in high concentrations (2–15%) improved petal color pigmentation. In the petals of fully opened carnations, the concentrations of fructose and glucose increased markedly after treatment with sucrose at increasing concentrations. The concentration of sucrose increased slightly, although that of pinitol and myo-inositol remained almost constant. Two types of anthocyanins, pelargonidin 3-(6"-malylglucoside) (Pg3-MG) and pelargonidin 3-glucoside (Pg3-G), were found as pigments in the petals, of which Pg3-MG was the major pigment. The concentrations of these pigments increased markedly with sucrose concentrations. The results indicated that the application of sucrose at high concentration resulted in high accumulation of soluble sugars in the petals, and this accelerated the synthesis of these two anthocyanins and improved the petal color pigmentation.

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The applicability of commercial carnation cultivars (Dianthus caryophyllus L.) to Bud Anthesis Acceleration (BAA) method was investigated. Six standard type cultivars and five spray type cultivars were placed in BAA solution containing 5% sucrose, and kept at temperature of 25°C (75%RH), light intensity of 1 klx and 12 h photoperiod. Harvesting at the small bud stage promoted calyx splitting and petal wilting in all cultivars. In the range of available bud diameter without causing damage on flower, the BAA treatment shortened the recommended days to shipping in all cultivars. Flower diameter was decreased by the treatment in ‘Pleasure’ and ‘Roland’. Petal color pigmentation was inhibited in ‘Opera’, ‘Riccard’ and ‘Lavender Tessino’. Vase life was shortened in ‘Pleasure’, ‘Saleya’, ‘Lavender Tessino’ and ‘Roland’. Although most of these problems were solved by harvesting at large bud stage, petal color pigmentation in ‘Lavender Tessino’ and flower diameter and vase life in ‘Roland’ could not be improved by modification of BAA treatment since these cultivars have a high sugar concentration in the petal. It was concluded that ‘Lavender Tessino’ and ‘Roland’ were unsuitable for BAA method.

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Varietal differences of fruit firmness, soluble solids concentration, titratable acidity, anthocyanin concentration and soluble sugar composition as influenced by storage temperature were evaluated in 4 strawberry cultivars including ‘Mae-hyang’, ‘Seol-hyang’, ‘Keum-hyang’ and ‘Akihime’. The major soluble sugar in ‘Keum-hyang’ and ‘Mae-hyang’ was sucrose whereas ‘Seol-hyang’ had a higher concentration of reducing sugars such as fructose and glucose as shown in the Japanese cultivar, ‘Akihime’. Moreover, changes in sugar composition at each storage temperature differed according to the major soluble sugar. The levels of fruit firmness were increased by low temperature storage in all cultivars, and ‘Mae-hyang’ showed a remarkable increase. ‘Mae-hyang’ showed limited change in the acid concentration and sugar/acid ratio during both 4°C and 20°C storage. Furthermore, the decrease in the total soluble sugar in ‘Mae-hyang’ during 20°C storage was less than those in the other 3 cultivars. Thus, the shelf life of ‘Mae-hyang’ strawberry is longer than those of the other cultivars examined. However, the changes in acid concentration and sugar/acid ratio of ‘Seol-hyang’ at 20°C storage occurred earlier than those in the other cultivars. ‘Keum-hyang’ showed a high concentration of anthocyanin at both 4°C and 20°C storage and the soluble sugar concentration decreased even at 4°C storage. These findings indicated that ‘Mae-hyang’ had a great potential for long term transport because a firm texture and stable quality were well maintained.

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Effect of the duration of ripening on quality of harvested fruit and processed Japanese apricot liqueur (ume liqueur) were investigated in ‘Nanko’ Japanese apricot (Prunus mume Sieb. et Zucc.). Rapid softening of harvested fruit was observed, followed by yellowing with the increase of ethylene production. β-carotene concentration in the flesh (with skin) sharply increased from 3–5 days after harvest. Antioxidant activity of the flesh changed becoming equal or below the level at harvest, except for that in immature fruit. When fruit picked before the commercial harvest time was processed to ume liqueur, sorbitol content and extracted volume from fruit in the ume liqueur decreased as the processed fruit was stored for longer periods. However, ume liqueur possessed the highest concentration of citric acid, total organic acid, phenolics and the highest browning strength in the stored period when fruit ripened for 4–6 days were processed. When fruit were picked after the commercial harvest and ripened for 4 days then processed into ume liqueur, it showed the highest browning strength. However, concentrations of malic acid, total organic acid, sorbitol and extracted volume from fruit in the ume liqueur were highest when the fruit was processed immediately after harvest. Therefore, it is suggested that mature fruit should be processed to ume liqueur immediately while immature fruit should be held for about 4 days before processing.

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Effects of pulse treatment with sucrose in combination with silver thiosulfate complex (STS) on the quality and vase life of cut Delphinium flowers were investigated. Cut flowers of Delphinium Belladonna ‘Ballkleid’ and ‘Sky waltz’ were treated with 0, 2, 4, 6 and 8% sucrose in combination with 0.2 mM STS. Treatment with sucrose in combination with STS significantly improved pigmentation of flower color, increased floret size and extended vase life compared to that with STS alone except for the vase life of ‘Sky waltz’. These positive effects by STS and 4% sucrose were remarkable when cut flowers were held at 10°C for 48 h to simulate long-distance transport. The combined treatment increased the fresh weight of cut flowers and prevented bending of upper flower stalks, and thus improved their plant forms.

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In tomato hydroponics, the construction of an efficient recycling system for liquid waste has been expected. In this study, we developed a nutrient sterilization device using silver-supported photocatalyst, and evaluated its ability to sterilize specific fungi, suppress infections and influence on plant growth, fruit quality and yield of tomato. The sterilization device is especially characterized by the silver-coated non-woven cloth filter and visible light source. Using this device, Ralstonia solanacearum and Pythium aphanidermatum in nutrient solution were almost completely eliminated 8 and 4 minutes after innoculation, respectively, and Fusarium oxysporum was also decreased to 3% of the primary number of pathogens after 16 minutes. Investigation of the effective flow speed of nutrient solution from 10 L·min⁻¹ to 20 L·min⁻¹ for sterilizing Fusarium oxysporum showed that the sterilization ability of the device improved as the flow quickened. A closed hydroponic system equipped with this sterilization device could remarkably suppress the infection of root rot to plants. Consequently, significant difference was not detected for plant growth, fruit quality, yield of tomato and concentration of inorganic elements in the nutrient solution between the system and the control. Furthermore, neither conspicuous elution of silver ion into nutrient solution nor accumulation of that into tomato fruits in the system was recognized compared with the control. Our results demonstrated that the sterilization device utilizing the silver-supported photocatalyst is highly useful for practical tomato hydroponics.

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Potted cyclamens, a popular indoor plant during the winter season, were used in this study. Differences in plant growth status depending on the individuals who cared for them and the responses of human emotion to the plant were examined. Forty-six women (mean age = 46.1) living in Tochigi prefecture were asked to care for potted cyclamens in their homes for three months. Growth and quality varied greatly with the subjects. The plants were classified into five groups depending on their status after three months. Self-evaluation (r = 0.7, p < 0.001), satisfaction (r = 0.61, p < 0.001) and pleasure (r = 0.38, p < 0.012) of the subjects correlated with the growth and quality of the plant in their care. On POMS, the scores for Tension-Anxiety (T-A), Depression-Dejection (D), Anger-Hostility (A-H), and Confusion (C) dropped significantly due to the intervention of the plant into the household, but these scores were slightly increased on the final test after three months. The categories of D and A-H were especially decreased in the group with the best plant quality. On the egograms in the group with the best quality plants, the scores for Nurturing Parent (NP), Adult (A) and Free Child (FC) were slightly increased, while that of Adapted Child (AC) was decreased. As for the semantic differential technique, factor analysis was performed based on twenty-six semantic differential (SD) scales on sensory evaluation. Among the three extracted factors, ‘comfortable’ and ‘gorgeous’ increased but ‘simple and clean’ decreased with the introduction of the potted cyclamen. The results indicated not only positive effects of potted plants on consumers’ emotions, shown by scores for as D, A-H and ‘comfortable’, but also a certain level of relationship between plant growth and the satisfaction and pleasure of the owner.

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“Azalea Research Notes 1917 & 1918” of Kanagawa Agricultural research station were discovered at Kanagawa Prefectural Ofuna Botanical Garden in 2006. The notes described not only detailed morphological characters of 338 evergreen azalea cultivars and 7 species, but also their breeding records. From our investigations, 170 of these cultivars are extant, and there is evidence of a breeding trend for greater variation in flower colors and shapes, mainly of Kurume azalea in the Taisho era. These results are valuable because of the sparse information available about morphological features of extinct cultivars and the lack of studies of genetic separation of flower colors and shapes of azalea hybridization in Japan and elsewhere including Europe.

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