Inbreeding is a great concern for strawberry plant breeders because of the repeated crossings among a limited number of breeding materials. Coefficients of inbreeding (CI) in recently developed cultivars of strawberry were calculated using a personal computer and a programming language, Prolog. The relation between CI and yield was also investigated in the strawberry. There was no correlation between the selection rate of F1 seedling plants and CI of those plants. In the strawberry breeding lines from Tochigi Branch, Tochigi Prefectural Agricultural Experiment Station, the correlation coefficient between CI and yield was −0.37, which was significant at the 1% level. The figure showed that strawberry plants with a CI less than 0.3 did not show any inbreeding depression. The CIs of several recently bred strawberry cultivars of the June-bearing type were approximately 0.2. CIs of ‘Tochiotome’, ‘Akihime’, ‘Sagahonoka’, ‘Amaou’, ‘Satumaotome’, ‘Hinosizuku’ and ‘Yayoihime’ were 0.261, 0.222, 0.257, 0.213, 0.257, 0.247 and 0.346, respectively. Those of CIs of ever-bearing type cultivars were approximately 0.1, except ‘Summer Princess’ and ‘Kiminohitomi’. Hypothetical diallel crossing among 15 representative June-bearing type cultivars resulted in CIs of their offsprings ranging from 0.067 to 0.440 with an average CI of 0.210.

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Pecans belonging to the same group as Japanese chestnut would be advantageous trees to extend the business cycle of tourism farming of chestnut trees in the autumn season. We investigated the flowering period of male and female flowers in twenty-five cultivars, and the harvest period and fruit quality in sixteen cultivars. It was observed that the female flower bloomed earlier than the male flower in most cultivars. However, there was an overlapping period of several days during the blooming of male and female flowers. Then we investigated the length of the male spike and flowering period of male flower. Blooming changed yearly and there was no correlation between the two. The harvest period lasted for two months, from early September to early November. Cultivars were classified into five groups; very early, early, middle, late and very late maturing. Fruit size was significantly larger in ‘CLS-61’ and ‘Dess’, very late maturing than the other cultivars. Two cultivars, ‘MISS-10’ and ‘CLS-61’ provided a fresh kernel weight of 7 g or more. There was no correlation between the harvesting time and kernel oil content.
In conclusion, cultivars with overlapping flowering periods of male and female flowers were identified. Harvest time of pecan trees in Wakayama Prefecture could be extended to two months by introducing cultivars from very early to very late maturing. ‘Pawnee’ and ‘MISS-10’ are promising cultivars for commercial production due to the large edible portion and high oil content.

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We investigated the flower characteristics of interspecific hybrids between Spiraea thunbergii Sieb. ex Blume. and S. japonica L. fil. via ovule culture. The flower bud differentiation of hybrid plants started in December and the flower cluster formation started in February, then flowered in the middle of April. The flowering period of hybrid plants was 2 months from April to May, which was the intermediate between S. thunbergii and S. japonica. In hybrid plants and S. japonica, the flower setting was observed in the terminal of a current shoot elongated in the present year. Although the inflorescence of S. thunbergii was the unbel type, that of hybrid plants and S. japonica showed the corymb type. In the hybrid plants, the size of style, the number of stamen and the number of flowers per one inflorescence showed intermediate values between S. thunbergii and S. japonica. The color of petals in S. japonica was deep pink or red, while the hybrid plants had pink petals. Total anthocyanin concentration in petals of the hybrid plant was lower than that of S. japonica. Six types of anthocyanin (Cy3Ga, Cy3G, Cy3Ara, Pg3G, Mv3G, unknown) were detected in the petals of S. japonica, and the hybrid plant had four cyanidin pigments (Cy3Ga, Cy3G, Cy3Ara, Unknown) among six anthocyanins contained in S. japonica petals. The amounts of Pg3G and Mv3G seem to cause changes in the petal hue of S. japonica and hybrid plants. Furthermore, the fading of petals in the hybrid plant through flower senescence was caused by the marked decrease of Cy3Ga, which was one of main anthocyanin in hybrid plant.

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The availability of marker-assisted selection (MAS) using DNA markers close to QTLs of resistance to bacterial wilt in carnations (Dianthus caryophyllus L.) was examined. The STS-WG44 marker tightly linked to the major resistant gene was detected in all backcross lines with resistance selected by the root-soaking method. Quantities of markers OQ12 and STS-WB66 close to QTLs with slight effects in resistant lines were lower in succeeding generations of backcrossing. These findings suggested that STS-WG44 is available for selecting resistant lines. In practical breeding populations, the difference of mean disease incidence between two groups categorized as having or lacking STS-WG44 was 62.6% and STS-WG44 was possessed in most lines showing resistance less than 20% in disease incidence. These findings suggest that STS-WG44 as a selective marker facilitated narrowing of populations to those that are highly resistant for practical breeding. Marker-assisted selection would be available for breeding improved resistance to bacterial wilt in carnations.

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Effects of applying soil amendments and the rate of nitrogen fertilizer application on tree and fine root growth and fruit quality were surveyed in ‘Shiranuhi’ 〔‘Kiyomi’ (Citrus unshiu Marc. × C. sinensis Osb.) × C. reticulata Bla.〕, which shows weak vigor. Soil amendments (bark manure, peat-moss, perlite) were applied to improve the physical condition of the soil and to increase the number of fine roots. Excess supply of nitrogen suppressed fine root development, and enhanced the peel ratio and concentration of soluble solid (Brix) in fruits. The effect of an excess supply of nitrogen was about twice as strong as those obtained from the application of soil amendments. Applications of soil amendments and the conventional amount of fertilizer were necessary to improve tree vigor and the number of fine roots.

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A ¹⁵N-tracer method was used to study the absorption of nitrogen applied in the spring to Satsuma mandarin trees and Rat’s-tail fescue, Vulpia myuros, in a mandarin orange orchard covered with Rat’s-tail fescue. The amount of nitrogen applied in the spring that was absorbed by mandarin orange trees in a plot covered with Rat’s-tail fescue was markedly smaller, about 47%, than that in a clean cultivated plot; the difference was particularly large in new leaves. The amount of nitrogen absorbed by Rat’s-tail fescue in a sod culture plot was about twice as large as that absorbed by the trees in the plot. Trees in the clean cultivated plot showed higher rates of ¹⁵N occupied by supplied nitrogen in all organs than trees in the sod culture plot did; the difference was particularly large in newly developed organs. However, Rat’s-tail fescue in the sod culture plot showed a markedly higher rate of ¹⁵N occupied by supplied nitrogen than the trees showed. A comparison of the utilization rates of nitrogen applied in the spring to trees in two different plots demonstrated that the rate was 16.7% in the sod culture plot and 35.3% in the clean cultivated plot; the rate was markedly higher in the clean cultivated plot. However, the utilization rate including an absorbed amount by Rat’s-tail fescue was 51.6% in the sod culture plot, which was about 1.5 times as high as that in the clean cultivated plot.

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Eight commercial cultivars of Lilium × formolongi hort. were raised in cell trays that were bottom-heated at 15°C or 25°C until transplanted on May 12, 2003. Flowering of six cultivars raised at 25°C showed retarded development by the middle of September, but many rosetted plants were found among most cultivars. Only ‘F₁ Augusta’ showed desirable characteristics for autumn production with a low rate of rosetted plants and high quality cut flowers. It is considered that ‘F₁ Augusta’ bolts after exposure to relatively limited chilling, and is less influenced by the high temperature in summer resulting in rosetting.

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A modified nutrient solution formula was evaluated for tomato production in a new closed hydroponics system aimed to reduce emission. The new system is a closed organic substrates (cryptomeria bark) culture using the capillary uptake method. The modified nutrient solution formula had a higher K level, lower Ca, Mg and SO₄ levels than the Ootsuka-A formula. EC, NO₃-N, Ca, Mg and SO₄ of the solution in the organic substrates were lower when the modified nutrient solution formula was applied. Using this newly developed system combined with the modified nutrient solution formula, the yield of 18.2 t • 10 a⁻¹ from twelve clusters per plant was obtained by tomatoes grown without emitting NO₃-N and exhaust solutions.

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In several satsuma mandarin (Citrus unshiu Marc.) cultivars, the parameters of productivity (flowering, fruiting, yield, etc.) of one year correlated negatively with those of the next year, while the fruit weight and concentration of soluble solids in fruit juice of one year correlated positively with the productivity parameters of the next year. Our multiple regression analyses demonstrate that the concentration of soluble solids is an effective second factor, whereas fruit load is the main factor associated with productivity of the next year. The relation was clearer in cultivars with more variable yields. In those cultivars, the flowering intensity of the next year tended to increase in parallel with increase in the concentration of soluble solids, and the number of set fruit and yield showed similar relations at least until a concentration of about 12% soluble solids. These findings indicate that the concentration of soluble solids is a useful parameter for estimating the productivity of the next year and appropriately high fruit quality might correlate with high productivity.

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Seasonal changes in the starch contents of leaves, shoots and roots, and the photosynthetic rate of the alternate-bearing ‘Aoshima Unshu’ Satsuma mandarin were investigated from fall to spring. Off-year trees showed higher starch levels in the leaves, shoots and roots from fall to spring than on-year trees. Accumulations of starch were observed earlier in roots than in other organs. The starch contents in the roots of off-year trees increased from November and the starch contents of on-year trees increased from January in Shizuoka. The organs showing the strongest concentrations of starch were the roots, and the months were November to February.
Photosynthetic activity of Satsuma mandarin was observed in winter, indicating that photosynthesis by the leaves plays a role in starch accumulation in the roots during winter.
Relationships of the negative correlation were found between the starch content of the roots in December and the numbers of flowers (number of leaves/number of flowers) the following spring. These results show that the numbers of flowers can be forecast from the content of roots that were collected in the winter of the same season.

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The influence of calcium formate on flower thinning of ‘Fuji’ apple (Malus domestica Borkh.) was investigated. Spraying 1% calcium formate on the pistil 1 hour before, 1 or 24 hours after pollination reduced fruit set. Spraying 1% calcium formate on the pistil 24, 48 or 72 hours after pollination, fruit set was clearly reduced by spraying 24 hours after pollination, whereas spraying 72 hours after pollination was ineffective. When spraying calcium formate at concentrations ranging from 0.2 to 1.0%, higher concentrations of calcium formate were more effective for flower thinning. Spraying calcium formate ranging from 1.0 to 3.3% on flower bud, did not have any significant effect on fruit set. Neither one-time nor two-times of 1% calcium formate application was effective. Therefore, directly exposing the pistil to calcium formate seemed to prevent fertilization and reduce fruit set.

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To obtain early and high yield from young trees of the Japanese pear ‘Gold Nijisseiki’, the effects of different training systems on the dry matter production and distribution of above ground organs was investigated. Permanent trees with 3 scaffolds and filler trees with 6 different tree forms having 3 to 12 scaffolds were compared. The dry matter production of the above ground organ was increased in training systems with larger numbers of scaffolds. The dry matter production of the above ground part was higher in the training systems with larger numbers of scaffolds. This tendency indicated that the assimilate partitioning rate for fruit was higher in training systems with a larger numbers of scaffolds. Higher partitioning rates were shown for training systems with a smaller number of scaffolds in both the shoots on 4 to 6-year-old trees and older wood on 6 to 8-year-old trees. There was no significant difference between plots in the dry matter production above the ground per dry weight of leaves. However, the dry weight of fruit per dry weight of leaves remained higher in the plot with large numbers of scaffolds. Filler trees with larger numbers of scaffolds showed higher rates of assimilate partitioning on dry weight of fruit and higher efficiency of fruit production.

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The effects of various light sources for night irradiation and light intensity on the flowering of stock [Matthiola incana (L.) R. Br.]were investigated. The flowering of stock was promoted by the irradiation of compact self-ballasted fluorescent lamps of far-red light. The effects of incandescent lamps were similar. This promotion was accelerated by increasing the irradiance of far-red light. Significant effects of these light sources were observed in summer-sown and autumn-cultivated plants. During these periods, day length was short, and temperature was cool during the flowering period. Compact self-ballasted fluorescent lamps of far-red light were superior to incandescent lamps in cost performance. Furthermore, these lamps were easily installed instead of incandescent lamps. These results indicated that these lamps have high potential for extention.

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We developed a sloped greenhouse and a hydroponics system suitable for use on sloping land. To use the greenhouse and the system effectively during the winter season, we investigated forcing culture of blueberry. We transplanted 15 cultivars of blueberry plants in containers filled with a peat-moss and supplied nutrient solution by the hydroponics system. Ten to 17 months after transplanting to the container, we investigated the death rate among plants of each cultivar. The death rate of plants was the highest in ‘Earliblue’. We considered that ‘Earliblue’ was unsuitable for the hydroponics system. In forcing culture, the plants experienced a term of cold temperature when placed outdoors in hilly and mountainous area (about 300 m above sea level) in Mikamo, Tokushima until 3 February, 2004. After 3 February, the plants were brought into a heated greenhouse near the field. Flowering of plants in forcing culture started at the end of February, which was 35–40 days earlier than flowering of plants under standard culture in Zentsuji, Kagawa. Harvesting from plants in forcing culture started at the end of April, which was about 35 days earlier than that from plants in standard culture. In forcing culture, at the beginning of harvesting term, fruit yields from ‘Patriot’ and ‘Weymouth’ were higher than those from other cultivar. However, for the experimental term, the yields from ‘Northland’ and ‘Sharpblue’ were higher than those from other cultivars. ‘Sunshineblue’ was unsuitable for forcing culture because of the late harvest period. The average price of shipped fruits from forcing culture was higher (¥3,389 kg⁻¹) than that during other seasons. We supposed that forcing culture of blueberry using the greenhouse and the hydroponics system was promising culture method in hilly and mountainous areas.

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To establish systematic year-round production of potted miniature rose, rose growth and environmental factors such as solar radiation and air temperature were investigated for one year and the relationships of growth to these factors were analyzed. The period from the start to end of cultivation was longer in order of summer, spring and autumn cultivation. Leaf area, fresh weight of leaf and plant, leaf number and plant height as response variables were analyzed to explain the relation to environmental factors as explanatory variables using multiple linear regression analysis. The cumulative daily mean solar radiation, cumulative daytime and nighttime temperature within explanatory variables were significant main explanatory variables. Rose growth factors; leaf area, fresh weight of leaf and plant, leaf number and plant height, showed close correlation with three environmental factors, respectively. Rose growth factors demonstrated significant multiple linear regressions using three environmental factors, and the parameters in multiple linear regression equations were also significant. Therefore, we demonstrated that the rose growth could be predicted using cumulative daily mean solar radiation, cumulative daytime and nighttime temperature and could be controlled by changing solar radiation and temperature.

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This study investigated the effects of irradiated light intensity on the amount of antioxidants and antioxidative capacity in broccoli, mustard, kale, and red cabbage sprouts. Antioxidant concentrations were estimated by quantitating total polyohenol, flavonol, and anthocyanin concentration. Antioxidative capacity was evaluated by measuring DPPH radical absorbing capacity and superoxide scavenging ability. Polyphenol and flavonol concentrations were significantly increased in accordance with the light intensity. Antioxidative activity was also increased with light intensity. However, the lengths of sprout hypocotyls were decreased by strong light. These results indicate that the contents of polyphenol including flavonol are increased by strong light and consequently the antioxidative ability becomes stronger. These findings suggest that strong light irradiation should be useful for producing sprouts with higher antioxidative capacity.

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Concentrations of functional components in the growing persimmon leaf were determined using 14-year-old Japanese persimmon ‘Saijo’ tree. The concentrations of functional components were extracted using hot water to estimate the utility of persimmon leaf tea. The results were as follows. The concentrations of T-AsA and polyphenol in persimmon leaf were at their highest levels from June to July (3,700 mg/100 gDW and 16,100 mg astragalin eq./100 gDW, respectively). The concentrations of isoquecitrin and astragalin in persimmon leaf were at their highest levels in May (480 and 520 mg/100 gDW, respectively). The latter two components demonstrated dramatic decreases in June during the time of rapid shoot growth.

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Chinese Yam is produced by vegetative reproduction and the tubers inherit the genetic shape-traits of the seed tubers. Shape is an important factor affecting commercial classification and price, and is thus the target of breeding and culture selection. Since market prices are vigorously dependent on shape, easy and accurate analyzing systems have been developed using 3-D image analyses and the image analysis soft ware, HALCON. A modified method of obtaining image data using the known cube model was carried out, and the accuracy of the values was calibrated. Consequently, simple and quantitative shape classification and evaluation methods using 4 different techniques were applied, and satisfactory results were obtained after comparison with the logistic regression analyses.

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‘Kawazu-zakura’ (Prunus lannesiana Wils.) is the representative early-flowering cherry in Izu peninsula. The time of flowering was recorded to examine the relationship between flowering time and air temperature in Minamiizu.
‘Kawazu-zakura’ trees in the Minamiizu region generally bloomed earlier at warmer places. The time of flowering ranged over about one month among various sites. The average flowering time in these regions showed a range of about two weeks. The appreciable flower life defined as the period from two tenths blooming to full bloom was comparatively long at eighteen days. The flowering time showed a high negative correlation to the temperature average for 51 to 70 days before flowering. Maintenance of continuous flowering over a prolonged period was noted at the Aono river embankment (Minamiizu-cho) and at Tanaka (Kawazu-cho).

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