In Sweetpea, the tendril-less trait is very important as a labor saving trait in forced cut flower production, because unnecessary tendrils and lateral buds markedly increase the amount of labor and production management cost. Two new tendril-less cut flower cultivars, ‘Musica rose’ and ‘Musica purple’, were bred and their labor saving effects were investigated. These cultivars were derived from crosses between tendril-less and normal tendril cultivars. Because the tendril-less trait is recessive, it was selected in the F2 generation and fixed in the F3 generation. ‘Musica rose’ is a spring-flowering-type cultivar, with strong purplish pink flowers of a large diameter, whereas ‘Musica purple’ is a winter-flowering-type cultivar, with vivid reddish purple flowers of a medium diameter. Although ‘Musica purple’ is a winter-flowering-type cultivar, it is possible to cultivate it as a spring-flowering-type cultivar on forced culture. Under routine training, the operation times for the two new tendril-less cultivars were less than half that for normal tendril cultivars. Furthermore, the results of motion analysis suggest that the required angles of movement of worker’s elbows and wrists were narrower and distances of movement of elbows were shorter for tendril-less cultivars than for normal tendril cultivars. These results suggest that tendril-less cultivars reduce the burden on workers.
The relationship between the flower color and flavonoid composition of petals was investigated in 16 cultivars of Catharanthus roseus. Eleven anthocyanins, including two new anthocyanins (hirsutidin 3-galactoside and rosinidin 3-galactoside) and 7-methylcyanidin 3-galactoside, which has never been reported in C. roseus, were identified from the flowers of Catharanthus roseus along with two known caffeoylquinic acids and ten known flavonol glycosides. Regarding the flower color from red to purple-violet, decreases in the hue values (b*/a*) of these cyanic petal colors excluding the eyes were suggested to be responsible for increasing the ratio of flavonol glycosides, decreasing total anthocyanins, and controlling hydroxyl and methoxyl patterns of the B-ring in anthocyanins.
To collect necessary data to promote understanding of the mechanism and develop methods to prevent blueberry fruit cracking, we investigated pathways of water absorption and influences of the fruit weight, picking time and maturity on fruit cracking. At the ripe stage, there were significant positive correlations among the fruit weight, fruit cracking rate, amount of water absorption after 24 hours of immersion and water absorption rate. A heavy fruit weight may increase the water absorption rate and total amount of water absorbed, making fruit crack easily. Most immature fruits did not crack, but ripe fruits did crack and the severity was dependent on the picking time and parts of fruit. Regarding water absorption, the amount of water absorption through fruit skin was small relative to that through the fruit-pedicel junction; therefore, the pathway of water causing fruit cracking was suggested to be through the fruit-pedicel junction.
In Madonna lily (Lilium candidum L.), the influence of the bulb size (circumference), temperature and length of cold treatment, and culture temperature on flowering was studied and the possibility of double harvesting was investigated. The minimum bulb size of Madonna lily for readiness to flower was about 5 cm in circumference. The bulb circumference yielding a high flowering rate and good flowering quality, with an about 80-cm plant height and around five flowers, was 10 cm or more for seasonal flowering and 20 cm or more for forced flowering at 4°C for 10 weeks. Furthermore, in the case of forcing, the possibility of producing a flowering bulb of a smaller size by carrying out two-stage cold treatment was recognized. Cold treatment of bulbs promoted shoot emergence and stem elongation, and 10-week cold treatment was sufficient for vernalization to flowering. The flowering rate with the 10°C, 10-week treatment was higher than that with the 2°C, 10-week treatment, but it was further improved by the addition of 2°C, 5-week treatment to 10°C, 5-week treatment. The marked requirement of chilling of a bulb for flowering at a 25°C cultivation temperature was suggested, and with cultivation at high temperatures, such as a constant 25°C or 35°C (day)/25°C (night), the abortion of flower buds and floral abnormalities occurred. Moreover, bulbs showing forced flowering within the year flowered again on receiving natural chilling and those flowering in January also did so with appropriate cold treatment. Therefore, on implementing forced culture at these flowering times, it was confirmed that flowers of Madonna lily could be double-harvested.
The photosynthetic rates of ‘Hiratanenashi’ trees (Diospyros kaki Thunb.) grafted on a dwarfing rootstock, ‘MKR1’, and vigorating rootstocks, D. kaki seedling and rootstock a, as well as own-rooted trees, which were established in an orchard in March 2003, were measured at several times on May 2, May 6, July 11, August 6, August 15, and September 26, 2013. The photosynthetic rates at each time on each measurement date were not significantly different among the trees, except for that at 14:00 on May 6. Hence, the photosynthetic rate was not considered to cause the trees grafted on ‘MKR1’ to show dwarfism. The daytime reduction of the photosynthetic rate occurred in all types of tree when the photosynthesis active radiation exceeded 2000 μmol・m−2・s−1, and this phenomenon was thought to be an effect of photoinhibition. The photosynthetic rate of the trees on ‘MKR1’ decreased markedly at 14:00 on May 6, being the greatest daytime reduction among all types of tree. A reason that the leaves of trees on ‘MKR1’ showed the photoinhibition more readily may be that the dwarfed trees had fewer, smaller leaves, and so they received stronger sunlight par unit area.
This study investigated the effects of the air temperature at different shoot developmental stages on the occurrence of abnormal inflorescence (OAI) in Gypsophila paniculata ‘Altair’. The proportion of OAI decreased in plants which had attained a shoot length of 20 cm when heated at 15°C for 2 weeks, similarly to those heated for 8 weeks. Short-term heating (15°C/2 weeks) resulted in heavier and longer cut flowers than long-term heating (15°C/8 weeks). Heating from vegetative growth to sepal differentiation on the terminal floret (shoot length = 1~20 cm) was the most effective way to prevent OAI. We investigated the effects of low temperature treatment (7°C) at different shoot developmental stages on OAI. Consistent with the effect of heating, the stage from vegetative growth to sepal differentiation at the terminal floret was the most sensitive to the low temperature, enhancing OAI. We conclude that by avoiding exposure of the terminal floret (shoot length = 1~20 cm) to a low temperature at the stage between vegetative growth and sepal differentiation, we could prevent OAI and improve the quality of cut flowers.
Cyclamen (Cyclamen persicum Mill.), whose growth and flowering are retarded by high temperatures during the summer season, was used in this experiment to investigate the effect of root-zone cooling on growth and flowering. Root-zone temperatures were preset at 20, 23, and 26°C during the summer season. The control was without root-cooling. Each root-zone temperature was maintained at ±1 to 2°C of the preset temperature. The averages of minimum and maximum temperatures of the control were about 25 and 28°C, respectively. Vegetative growth was promoted at 23°C compared with that of the control. Flowering at 20°C started in the middle of October, and the number of flowers per plant reached about 7 after 20 days. Flowering rates increased with a drop in the root-zone temperature: 20% at the control temperature, 44% at 26°C, 60% at 23°C, and 88% at 20°C. The number of flower buds per plant was maximal at 23°C, and was about 65, having 25 and 10 more than those at 20°C and the control temperature, respectively. In conclusion, root-zone cooling at 23°C significantly promoted both vegetative growth and flower bud formation of cyclamen, and that at 20°C accelerated the flowering rate. Thus, controlling the root-zone temperature between 23 and 20°C may be markedly advantageous for cyclamen cultivation during the hot summer season.
Garlic bulbs are stored at about −2°C for year-round shipping. When the bulbs are removed from storage, they start to develop roots and sprouts, which lowers their commercial value. Hot air treatment of garlic bulbs after removal from storage is often conducted to inhibit root and sprout growth. Here, we examined the response of garlic bulbs to different hot air temperatures to obtain basic data for the selection of an appropriate treatment temperature. Bulbs which had been harvested and cured in July and stored at −2°C for designated periods were treated with different temperatures between 37 and 50°C for 12 or 18 h, and then kept at 15°C for 4 weeks until growth investigation. In bulbs removed from storage in November or earlier, the inhibitory effect of the treatment on root growth reached a peak at about 43°C, decreased transiently at a higher temperature, and increased with a further rise in temperature. Bulbs removed from storage in February and May showed a similar temperature response, although the temperature promoting the peak inhibitory effect slightly decreased with a delay in removal from storage: 41–43 and 40–41°C in bulbs removed from storage in February and May, respectively. The temperature range with a marked inhibitory effect on root growth expanded with a delay in removal from storage. The effect of the treatment temperature on sprout growth was similar to that on root growth. The treatment temperature causing heat injury lowered with a delay in removal from storage. On the basis of these results and the heating cost, we discussed appropriate treatment temperatures for garlic bulbs removed from storage at different times.
The juices of whole, mature fruit of ‘Kara mandarin’ and immature and mature ‘Niihime’ were squeezed at various levels of pressure: 6, 8, 10, 12 and 14 Mpa, with a compressed juice machine. The squeezing ratio increased as the pressure rose regardless of the fruit’s maturity or cultivar. The flavonoid content of whole fruit juice was determined by the HPLC method. The juice of ‘Niihime’ contained significant amounts of sinensetin, tangeretin, eriocitrin, and nobiletin, and their concentrations increased as the squeezing pressure rose. The taste of whole fruit juice was evaluated with a taste sensor system. The whole fruit juice showed higher values for astringency and bitterness compared with that not including the peel Furthermore, the smell of the whole fruit juice was slightly fishy, and evaluation using a smell sensor revealed that it contained more amine components than the other juices.
The present study investigated the effects of polypropylene film bags allowing different rates of oxygen diffusion on fruit ripening in ‘Koshisayaka’ pears. Fruits harvested at commercial maturity were immediately packaged in polypropylene film bags allowing different oxygen transmission rates (2,500 to 100,000 mL・m−2・24 hr−1・atm−1). When the fruits were ripened in an incubator at 20°C, their normal ripening was inhibited. In another experiment, fruits treated with a low temperature of 0–1°C for 14 days after harvest at commercial maturity were packaged in polypropylene film bags with different oxygen transmission rates (20,000 to 200,000 mL・m−2・24 hr−1・atm−1). Those fruits softened during ripening at 20°C. The gas composition in the film bag with the high oxygen transmission rate (200,000 mL・m−2・24 hr−1・atm−1) was almost the same concentration as the surrounding atmosphere. Fruit moisture loss during ripening was controlled by film packaging, and so the external appearance was favorably maintained.
As green soybeans, immature seeds of Glycine max (L.) Merr., are usually harvested during summer, their quality rapidly deteriorates after harvest. We determined several quality attributes of postharvest green soybeans stored at various temperatures with short intervals and the effects of configuration (with or without leaves and stems) in ‘Hukura’ and ‘Yuagari-musume’. In both cultivars, green soybeans stored at 15°C or higher showed a 20% or greater decrease in total sugars and free amino acids only 3 h and 6 h after harvest respectively, compared with levels at harvest. Storage temperatures at 10°C or lower were effective in preserving the appearance of pods and resulted in an 80% or greater retention of the level at harvest of total sugars and free amino acids even after 10 h and 24 h storage, respectively. Storing green soybeans with leaves and stems at room temperature had a slightly beneficial effect on the retention of quality attributes; however, the effects of the storage temperature were much more marked than those of the configuration. These results indicate that cooling at 10°C or lower within 3 h after harvest is important for the quality control of green soybeans.
Onions contain polyphenolic flavonoid compounds, especially quercetin glycosides. Quercetin has been reported to exhibit antihypertensive effects on humans, and epidemiological studies reported that the polyphenolic flavonoid intake is inversely associated with cardiovascular disease. Onion is a major source of flavonoid intake. Increasing dietary onion intake would increase flavonoid intake, which may reduce the risk of disease. We developed an onion cultivar containing a high concentration of quercetin, ‘Quergold’, a new long-day onion cultivar. ‘Quergold’ was developed by the National Agriculture and Food Research Organization (NARO) and is a hybrid of ‘OSP-3’ and ‘OPP-5’. The male sterile line ‘OSP-3’ was bred from ‘W404A’ and the male fertile line ‘OPP-5’ was bred from an Australian open-pollinated variety (‘Spearwood late brown’) at NARO in 2002. The yield of ‘Quergold’ was lower than those of ‘Kitamomiji-2000’ and ‘Quer-rich’; however, ‘Quergold’ contained a higher concentration of quercetin (5.4 mg quercetin equivalent (Q)・g−1 DW), compared with ‘Kitamomiji-2000’ (3.2 mg Q・g−1 DW) and ‘Quer-rich’ (3.4 mg Q・g−1 DW). Consumers could increase their intake of quercetin through the addition of ‘Quergold’ onions to their daily diet. In addition, foods containing high concentrations of quercetin may be sold at an increased cost and be used to develop a new marketing strategy for selling agricultural products which aim to improve the quality of life through the diet.