To develop tomato strains (Lycopersicon esculentum Mill.) with Tomato yellow leaf curl virus (TYLCV) resistance and suitable characteristics for eating raw in Japan, the resistant variety ‘Athyla’ introduced from Holland and ‘Momotaro Fight’ were crossed, and progeny strains were selected and fixed. TYLCV resistant strains which were infected with the virus, but show characteristics of resistance such as suppression of viral growth in the plant and prevention of disease symptoms, were obtained by seedling test using the loop-mediated isothermal amplification (LAMP) method. Those strains show the same fruit characteristics as the typical Japanese cultivar such as big fruit size, clear fruit skin color, high fruit concentration of soluble solids and so on. It is considered that the seedling test using the LAMP method is suitable for breeding TYLCV resistant tomato, because high correlation was shown between resistance by this method and field test resistance in the TYLCV epidemic district.

View full abstract

In vitro chromosome doubling of Chinese lantern (Physalis alkekengi L. var. franchetii Makino) was studied and characteristics of the obtained tetraploids were clarified. The tetraploids could be obtained most efficiently by culturing the apical buds on MS medium containing 0.01 mg · L⁻¹ NAA after aseptic treatment of the apical buds in liquid MS medium (sucrose 3%) with colchicine at 0.05% for 48 h. The tetraploids showed lower height, thicker stems, more rounded leaves, lower pollen fertility and larger stomata, flowers, and pollen grains in comparison with the original diploids. The tetraploid fruits had round calyces and smaller numbers of developed seeds in comparison with fruits from the diploids. The present tetraploids might be available as a dwarf cultivar since the tetraploids showed smaller height and stronger stems in comparison with the original diploids under the same cultivation condition.

View full abstract

This study investigated the possibility of performing cross breeding between diploid (2x) and triploid (3x) apple cultivars. Well-grown king flowers of 2x were hand-pollinated with an abundance of pollen grains from the 3x; thinning for open-pollinated fruitlets on the experimental trees was carried out twice for the 2x × 3x, 3x × 2x and 2x × 2x crosses. Thereafter, the three types of crosses were compared for fruit set, seed formation, seedling growth at the early growth stage, and the number of well-grown seedlings established from 100 flowers crossed. Fruit set 60 days after pollination was 71.1 to 81.6% and 92.9 to 98.0% for 3x × 2x and 2x × 2x, respectively. For 2x × 3x, however, fruit set ranged from only 16.5 to 36.5%. Rate of normal seed formation was 76.5 to 77.5% for 2x × 2x, but only 16.5 to 42.6% for 2x × 3x and 9.4 to 33.6% for 3x × 2x. Rate of well-grown seedlings 1 year after sowing ranged from 47.3 to 54.0% and 2.4 to 7.2% for 2x × 3x and 3x × 2x, respectively, and 72.4 to 94.1% for 2x × 2x. Number of well-grown seedlings established from 100 flowers crossed was 456 to 772 for 2x × 2x, 24 to 93 for 2x × 3x and 1 to 13 for 3x × 2x; it was found that more well-grown seedlings can be obtained for 2x × 3x than for 3x × 2x, using the techniques of pollinating and fruit thinning described above. These findings show that cross breeding for a new apple cultivar will be successful for 2x × 3x, though the cross is less efficient for breeding than the 2x × 2x. Breeding from a 3x × 2x cross will have little success.

View full abstract

Effects of the excision of mother tuber on flowering and growth of daughter tubers of Sandersonia aurantiaca plants were investigated. By large excision of the mother tuber, the numbers of leaves and stem elongation were retarded and the numbers of flowers were decreased. The number of days to flower budding and the number of days to flowering were increased by large excision of the mother tuber. The length of normal fingerlike or fork shaped daughter tubers was not affected by excision of the mother tuber. The maximum diameter of daughter tubers was larger when excision of the mother tuber was smaller. The fresh weight of daughter tubers was larger when excision of the mother tuber was smaller, and was the greatest without removal (control), intermediate at removal of the enlarged stem base, leaving 1/2 remaining, and the smallest when only 1/4 was left remaining. The fresh weight of daughter tubers at 1/4 remaining treatment was about 50% of the control. It was concluded that flowering of Sandersonia is adversely affected by slight excision of the mother tuber at planting, while slight excision of the mother tuber hardly affect enlargement of the daughter tubers.

View full abstract

‘Shinano-sweet’ apple nursery trees (Malus domestica Borkh.), that were grafted on Pajam 1 rootstocks in February 2004, were hand-defoliated on 15 October, 14 November, or 3 December 2004, to investigate the effects of defoliation on freezing tolerance, starch content and growth after replanting. The nursery trees were dug on 3 December 2004, and stored in a cold room at 2°C with humidification. Freezing tolerance was tested in March 2005. It was clear that freezing tolerance decreased as the date of hand-defoliation advanced. The rootstocks of the nursery trees were kept at −17°C for 16 h.; subsequently the degree of freezing injury was evaluated on an index from 0: without injury to 1: complete injury. The rootstock of trees that had been defoliated on 15 October had an index of 1.00, while that of the nursery trees that were defoliated on 3 December was 0.41. The earliest defoliation (15 October) resulted in 40% tree mortality after replanting, and lower shoot growth in the remaining trees. In addition, early defoliation reduced the starch content; the earliest defoliation produced an 84% reduction in the starch content of the roots. In conclusion, it is desirable to delay hand-defoliation of nursery trees until as late in the season as possible in order to preserve cold tolerance, starch reserves, and tree vigor after replanting.

View full abstract

The relative value of the y coordinate of the center of gravity of the leaf area on video image (wilting index) has been proposed as useful for the image diagnosis of the water status of greenhouse vegetables. In order to evaluate the usefulness of this method, cucumber (cv. ‘Tokiwa Hikari 3A’) plants were grown in solution culture in a growth chamber and were subjected to osmotic stress, anoxic stress, and hypoxic stress and the responses of the transpiration rate, stem width and wilting index were compared. Stem width, which seems to reflect continuous changes in the turgor pressure of cells, seemed to be suited to the detection of relatively light water stress. However, for the detection of severe water stress that causes wilting, the wilting index, which seems to be able to detect a threshold value of turgor pressure, was superior. Thus, the use of stem width and the wilting index together was suggested to be useful for the detection of water stress.

View full abstract

This study investigated the real-time diagnosis of potassium concentration in ‘Muscat of Alexandria’ grapes grown in a soilless culture system using perlite medium. Potassium concentration in the squeezed sap of the petiole was investigated at different growth stages. Its relations to the severity of leaf injury attributable to potassium deficiency at stage III of fruit growth and fruit quality were assessed. Potassium concentration lower than 500 mg · L⁻¹ in sap at veraison engenders a higher correlation between the potassium level and leaf scald severity. These signs are more severe in plants with lower potassium concentrations. There were no such signs when potassium concentrations in the sap greater than 500 mg · L⁻¹. At 1000 mg · L⁻¹ or lower potassium concentration in the sap at veraison, a positive relationship was also observed between the potassium level and berry size. Berry size was smaller when the potassium level in the sap was less than 1000 mg · L⁻¹. Even when the potassium concentration was 4000 mg · L⁻¹, an extremely low sugar content, implying a lower commercial value, was not observed. Relationships between potassium concentrations in the sap at the berry set stage and leaf scald or fruit quality were not clearer than those at the veraison stage.

View full abstract

Effects of mixed application of liquid fertilizer on the sandy soil chemical properties of a satsuma mandarin (Citrus unshiu Marc.) orchard were investigated. One-year-old trees of ‘Miyagawa Wase’/trifoliate orange rootstocks planted in a 50 L pot were used for the plots. Six plots were settled. One was a non-fertilized plot, the others were solid fertilizer (control) and four liquid fertilizer application plots. Liquid fertilizer was prepared by dissolving solid mixed fertilizer containing 15% nitrogen, 15% phosphorus and 10% potassium in water at 150- and 300-fold dilution. Each dilutions of liquid fertilizer were applied six times or eighteen times starting from the end of May during the one-year experimental period. Mixed Liquid fertilizer application lowered soil pH compared with solid fertilizer application and the tendency was greater at 150-fold than at 300-fold dilution. In relation to this, 150-dilution application of mixed fertilizer lowered exchangeable calcium and magnesium concentration in the soil. The more frequent the applications of liquid fertilizer, the more rapid the increases in the nitrogen content in the soil. Phosphorus and potassium concentrations in the upper soil layer increased in response to liquid fertilizer application. The downward movement of phosphorus and potassium from the upper to lower soil layers showed a pattern similar to that after solid fertilizer application. These findings indicate that the mixed liquid fertilizer application is effective in the immediate supply of inorganic nutrients but that lime application is necessary for soil pH amendment.

View full abstract

Tomatoes were grown in a greenhouse using a hydroponic system with an improved nutrient solution (NO₃−N : NH₄−N : P : K : Ca : Mg : SO₄ = 7.0 : 0.2 : 2.1 : 5.6 : 2.9 : 1.0 : 1.1 me · L⁻¹), which has higher K and lower NH₄-N, Ca, Mg and SO₄ levels than the Ootsuka-A formula (control). The study investigated the effects of the concentration of the solution within the medium and the volume and concentration of the exhaust solution, on the growth and yield of the tomatoes. Stem diameter at the seventh cluster and above were significantly larger and the yield and ratio of marketable fruits were higher in the improved nutrient solution plot. Fluctuations of NO₃-N, Ca, Mg and SO₄ levels in the solutions within the medium and in the exhaust was smaller with the improved nutrient solution than with the control. EC also was lower with the improved nutrient solution. There was no difference in P uptake, whereas uptake of K was higher with the improved nutrient solution during the entire season, and from the begining of harvest to pinching for NO₃-N, Ca, Mg and SO₄. Changes in the ratio of nutrient absorption per water consumption (n/w) were limited and the ratio of n/w to nutrient concentration was 1.0 to 1.2. It was shown that the formation and concentration of the improved nutrient solution matched the uptake ratio of the tomato plant within the conditions of the experiment.

View full abstract

Control of the concentration of nutrient solution for a long-term forcing culture (LTFC) of tomatoes was studied in a non-circulating closed hydroponic system that was developed in order to decrease the load on the environment. An improved nutrient solution (NO₃−N : NH₄−N : P : K : Ca : Mg : S = 7.0 : 0.2 : 2.1 : 5.6 : 2.9 : 1.0 : 1.1 me · L⁻¹) was applied in both LTFC and normal-term forcing culture (NTFC). Nutrient solution and nitrogen supplied in LTFC increased immediately after planting and reached a maximum in mid-October, then decreased until mid-December. Thereafter, the trends of nutrient solution and nitrogen supplied were similar in both LTFC and NTFC, i.e. nutrient solution and nitrogen supplied tended to increase until late March and early February, respectively. Concentration of solution within the substrate toward greater fluctuation in LTFC, but there was no ingredient that markedly exceeded the concentration of the nutrient solution applied. It was suggested that adequate levels of EC in the supplying nutrient solution would be 1.2 dS · m⁻¹ from planting until early December, increased to 1.4 dS · m⁻¹ then lowered in February to 1.0 dS · m⁻¹.

View full abstract

This study investigated the cause of radial fruit cracking in tomato cultivation under rain shelter in the cool uplands in Gifu Prefecture. The effect of total integrated radiation using two types of training methods was determined over a three-year periodo. The percentage of refused radial fruit cracking associated with increased total integrated solar radiation from the young fruit stage to the mature green stage. Fruit cracking occurred in the training method which foliage and fruits recived a large amount of light-interception. Also, as for fruits that undergo vigorous enlargement, the frequency of the radial fruit cracking increased.

View full abstract

We investigated the effects of spraying ethephone on the flowering and cut flower quality of non-branching type chrysanthemum (Chrysanthemum morifolium Ramat.) cultivars with different flowering characteristics. In almost all June-August flowering cultivars tested, spraying with ethephone delayed flowering and increased cut flower length and the number of leaves. The longer the period between pinching and ethephone treatment, the more prominent these ethephone effects became. Eight of 10 September–October flowering cultivars that were treated with ethephone two weeks after pinching flowered late without an increase jn the lateral bud number, although the delay in flowering was limited comparing with June-August flowering cultivars.

View full abstract

Effects of cultivating season on growth and dormancy of Groliosa superba L. tubers were investigated using three genotypes ‘Misato Red’, ‘Tropical Red’ and ‘Rose Queen’. Twenty tubers of each genotype were planted on December 2nd (winter culture) in a plastic house kept above 10°C, on April 3rd (spring culture) in a glasshouse kept above 10°C, and on July 3rd (summer culture) in a glasshouse with ambient temperature, respectively. The fastest growth of tubers was observed in summer culture, and the slowest in winter culture. Secondary tuber formation occurred in spring and summer culture, especially for ‘Tropical Red’ and ‘Rose Queen’. In winter culture, the period required to sprout new tubers, i.e. index of dormancy, increased with development and peaked at the time of flowering, and then became shorter. In spring and summer culture, tuber dormancy was the same as that in winter culture, but it was rather inconsistent among genotypes in the late stage of tuber development.

View full abstract

During the harvest period, Japanese pear ‘Niitaka’ with a calyx lobe has sometimes been observed in production areas in Okayama prefecture. In 2001 and 2003, the effects of excising the calyx lobe in young fruits on the shape of ‘Niitaka’ were examined. When excised up to a depth of 2–3 mm within 30 days after full bloom, most of the traces of excision had disappeared, and the shape and quality of the matured fruits were observed to be almost ideal. Furthermore, the incidence of fruit cracking decreased. Weather conditions at excision did not influence the quality of the matured fruits undergoing excision of the calyx lobe. These results show that this treatment is effective in improving the shape of young fruits possessing a calyx lobe; hence, it is suitable for stable production of the pear.

View full abstract

The effects of temperature and amount of fertilizer applied after transplanting on the development of axillary buds on primary crowns were studied in three leading strawberry cultivars used for forcing, i.e., ‘Tochiotome’, ‘Nyoho’ and ‘Toyonoka’. The nodes were numbered basipetally; the nodes just below the primary inflorescence were designated as node 1. Plants were grown with different amounts of fertilizer (210 and 420 mg N/pot) under two temperature conditions (32/27 and 22/17°C). The axillary buds remained dormant, or developed into secondary crowns or runners. The developmental pattern of axillary buds at nodes 1 to 4 was checked 52 days after planting, for 15 plants per treatment. All axillary buds at node 1 developed into secondary crowns regardless of cultivars and treatments. In these cultivars, most axillary buds at nodes 3 and 4 remained dormant under 22/17°C, while they developed into runners under 32/27°C. In ‘Tochiotome’ and ‘Nyoho’, an increase in the amount of applied fertilizer decreased the number of plants with dormant buds at nodes 3 and 4, but there was little effect of fertilizer application rate on the fate of axillary buds in ‘Toyonoka’. There were few plants with dormant buds at node 2 in these three cultivars under 22/17°C, but the number of plants that formed runners at node 2 increased as temperature increased from 22/17°C to 32/27°C. An increase in the fertilizer application rate increased the number of plants that formed secondary crowns at node 2 in ‘Tochiotome’, but not in ‘Nyoho’ and ‘Toyonoka’. These findings suggest that temperature and the amount of applied fertilizer should be adapted to the cultivar to control the number of secondary crowns at node 2 according to the preference.

View full abstract

The pollination efficiencies of Melipona quadrifasciata anthidioides (Neotropical stingless bee) and Bombus terrestris (bumblebee) were evaluated in tomatoes ‘Hausumomotaro’ cultivated in a greenhouse in 2005. The house was divided into two sections. Colonies of M. quadrifasciata and B. terrestris were respectively introduced into each section. High pollination efficiency by both species was proven, but there was no significant difference in total fruit mass/inflorescence or in the ratio of normal fruits/plant between the two sections. Fruit set ratio was higher in M. quadrifasciata, in comparison with B. terrestris. This may be caused by differences in the foraging behavior between M. quadrifasciata and B. terrestris. In the later species, foragers visited the same flower repeatedly, when available numbers of flowers was reduced, and injured the style with its mandible during the buzz pollinating behavior while in M. quadrifasciata, there was no such over-visiting behavior.

View full abstract

To clarify the relation between coloration of grape berry skins and temperature in Hiroshima, skin coloration, temperatures as well as berry characteristics and cultutivation methods were measured among 7 vineyards of ‘Aki Queen’ grape (Vitis labrusca L.×V. vinifera L.), in 2001. Moreover, the effects of girdling and cluster thinning on skin color were examined in 3 vineyards where coloration was restricted, in 2005. Coloration markedly different among vineyards, with color index values (0-5 grade) between 0.2 and 4.5. Despite differences in culturing methods and vine age, there were positive relationships among total soluble solids (TSS), the duration of plant exposure to temperatures between 20 and 25°C from 8 to 21 days after the onset of coloring and the coloration. Girdling and cluster thinning increased the coloration and TSS in the vineyards where temperatures from 8 to 21 days after the onset of coloring were high. However, the effects of girdling and cluster thinning were low when shoot growth was vigorous. These findings indicate that factors other than temperatures and TSS are involved in the coloration of berry skins.

View full abstract

Effects of high and low temperature conditions in greenhouse on the fruit setting and growth of the parthenocarpic tomato ‘Renaissance’ were examined. Under high temperatures with a mean peak daytime temperature of 39.2°C, the fruit setting rate of ‘Renaissance’ was 100%, and there were no undergrown fruit due to the steady expression of parthenocarpy. At the same condition, the non-parthenocarpic tomato cultivar ‘Momotaro york’ was not able to fertilize, and the fruits did not develop normally without treatment using 4-chlorophenoxy acetic acid (4CPA). Furthermore, under low temperatures with a mean daytime low of 5.9°C, the fruit setting rate of ‘Renaissance’ was 100%, and there were no undergrown fruit due to the steady expression of parthenocarpy. Under the same condition, ‘Momotaro york’ fertilized imperfectlly, the incidence of undergrown fruit was 61%, and treatment with 4CPA was necessary to achieve normal fruit development. It was suggested that the productivity of ‘Renaissance’ was higher than that of the non-parthenocarpic tomato cultivar because the fruits of ‘Renaissance’ developed normally without pollination and the synthetic auxin treatment under high and low temperatures as in this experiment.

View full abstract

A new labor-saving method for preparing pollen suspension was developed for spray pollination of kiwifruit. Fresh anthers were dried on paper for anthesis. The dried anthers were directly suspended in the liquid extender (0.1% agar, 5% sucrose) and filtered through a 0.12 mm mesh. Sufficient pollen density in the suspension was obtained using more than 8% anthers (w/v) on a fresh weight basis. The pollen density of the preparation was determined by measuring the suspension at 400 nm using a spectrophotometer. There were no significant differences in fruit set, fruit weight, number of seeds or fruit quality in ‘Hayward’ when efficacy was compared between the newly developed preparation and the suspension prepared from pollen grains (0.5% [w/v]) that we formerly developed. The new preparation will eliminate the step previously performed to collect pollen grains from dried anthers and is thus a more labor-saving method for the artificial pollination of kiwifruit.

View full abstract

Effect of soil warming by electrically heated wire (about 20°C) on bolting and growth in Welsh onion (Allium fistulosum L.) was investigated. Soil warming promoted the rate of leaf emergence to twice the control value. Soil warming increased dry weight of both above and under-ground parts, but did not influence the plant height or leaf length. Reduced bolting rate due to soil warming was observed. It was shown that soil warming using a heated wire was an effective treatment to suppress bolting and promote growth in Welsh onions harvested in early summer.

View full abstract

Seeding time and short-day treatment in an early period of flowering of ‘Tanbaguro’, a late bearing soybean cultivar, were evaluated for summer harvesting. When the plant was seeded between March 1 and 15, 1998, it could be harvested in early July. The total yield was higher as the seeding time was earlier. However, when it was seeded on or after March 25, it could not be harvested in July. In 2001, the harvest time was mid-August even when the plant was seeded in early March, probably because the temperature before the flowering period was lower in 2001 than in 1998. However, when short-day treatment was performed for 5 days in the early flowering period, the pods enlarged steadily, and the plant could be harvested in early July. As the short-day treatment period was prolonged, harvesting could be started earlier, but the yield decreased.

View full abstract

In the higher plants, S-adenosylmethionine (SAM) synthesized from methionine serves as a common substrate for the biosynthesis of ethylene and polyamine. To clarify the relationship of ethylene and polyamine metabolism during the anthesis and senescence of Hibiscus syriacus L. flowers, ethylene production and changes in the concentration of 1-aminocyclopropane-1-carboxylic acid (ACC), ACC-conjugate, and polyamines in the petal were examined. A very low level of ACC was detected in the petal, and a very low ethylene evolution was observed, even before flower opening. Ethylene production greatly increased just around the beginning of petal in-rolling and paralleled an increase of ACC-conjugate in the petal. With regard to polyamine concentration, spermine decreased with petal senescence in contrast to the sharp rise in ethylene production. Aminoethoxyvinylglycine, which is a potent inhibitor of ACC synthesis from SAM and thereby represses ethylene formation, extended the flower longevity and maintained a high spermine concentration in the petal. In contrast, methylglyoxal-bis (guanylhydrazone), which is a potent inhibitor of SAM decarboxylation and also inhibits spermine biosynthesis, promoted ethylene production and shortened the flower longevity. These findings suggest that a competition for SAM between ethylene and polyamine biosynthesis may play a key role in determining flower longevity in H. syriacus L.

View full abstract

Fluctuations of flowering time and cut flower quality due to meteorological changes in temperature in the Tohoku region were investigated in summer-to-autumn flowering-type ‘Iwa-no-hakusen’ and autumn flowering-type ‘Jinba’ chrysanthemum. After long day treatment, plants were grown under natural day length and high and low temperature conditions in a temperature gradient chamber (TGC), in which the air temperature followed the natural outside temperature fluctuation. The experiments were carried out twice in different seasons; the dates of transfer to TGC were 8 July and 10 August for ‘Iwa-no-hakusen’, and 22 September and 13 October for ‘Jinba’. In ‘Iwa-no-hakusen’, the temperature greatly varied during transfer on 8 July, and the anthesis was delayed by the high temperature after flower budding. The days to anthesis in transfer on 10 August was decreased by the shorter photoperiod than that at transfer on 8 July. In ‘Jinba’, anthesis was delayed by low temperature in both experiments. The days to anthesis following transfer on 13 October were increased by the lower temperature before flower budding than that of transfer on 22 September. The percentages of disk florets in ‘Iwa-no-hakusen’ were increased by low temperature and short photoperiod, and the number of florets in ‘Jinba’ were decreased by low temperature. In conclusion, the fluctuation of August flowering time of ‘Iwa-no-hakusen’ is induced by fluctuation of temperature, and the low temperature induces the delay in autumn flowering-type ‘Jinba’ in the Tohoku region.

View full abstract

The effect of benzalkonium chloride (surfactant) on hydration of cut stocks (Matthiola incana (L.) R. Br.) was examined. Freshly harvested stock flowers were held in tap water (control) or 20, 100, 200 or 1000 ppm benzalkonium chloride solution. Treatment with benzalkonium chloride at a concentration of 200 ppm or higher increased the fresh weights of cut stocks, compared to the control. When cut stocks were placed in tap water with a depth of 1, 2 and 4 cm, increase in fresh weights was suppressed with decreasing water depth. However, benzalkonium chloride treatments increased fresh weights regardless of the depth of solution. Cut stocks were treated with benzalkonium chloride for 4 h, were packed in a corrugated cardboard box, then left for 18 h (transportation simulation). Thereafter the cut stocks were put in a vase. In the control (tap water), fresh weights of cut stocks did not increase without cutting their basal parts, but benzalkonium chloride treatments increased their fresh weights without cutting. These findings show that pulse treatment with benzalkonium chloride improves the hydration of cut stocks.

View full abstract

In this study, we investigated the psychological and physiological effects of horticultural activity, mainly involving herbs, among outpatients of a Kampo clinic using a general health questionnaire (GHQ), profile of mood state (POMS), salivary cortisol concentration and flicker test. Horticultural activity helped the outpatients lighten their symptoms of neurosis, and negative emotions, such as tension, anxiety, depression, fatigue and confusion. The salivary cortisol concentration after the activity were significantly decreased compared to that before the activity. This finding showed that the horticultural activity relieved stress in these outpatients. On comparison of open field activity (e.g. sowing seed, transplanting) with interior activity (e.g. making herb soap and scent bags), the open field activity in refreshing the outpatients' nervous fatigue was more effective than the interior activity. In conclusion, therapeutic effects of horticultural activity can be evaluated physiologically by the salivary cortisol concentration and the value of flicker test. Verification of the therapeutic effects of horticultural activity by the combination of psychological and physiological values can contribute to planning and prevalence of more effective activity programs.

View full abstract