Information about undesirable characteristics in eggplant cultivars was gathered by questionnaire. Responses indicated that the existence of spines and trichomes and the purple coloring of eggplant were the three unpleasant characteristics most frequently cited. In particular, the existence of spines was considered the most unpleasant character because it causes discomfort during handling and specks on the eggplant fruits. Through cross breeding the spineless Dutch cultivar ‘Freia’ with the Japanese cultivars ‘Senryo nigo’ and ‘Binan’, spineless lines with more favorable characters could be developed for the Japanese market. The spineless characteristic from ‘Freia’ is suggested to have no close relationship with the unfavorable characters. Development of spineless Japanese F1 cultivars is possible by introducing the spineless variety into their parental lines.
‘Chinese Cabbage Parental Line No.6’ is selected from a cross between Chinese cabbage and lage bolting turnip. Its bolting resistance is due to low sensitivity to low temperature. This line showed high marketability when other bolting-resistance cultivars could not be harvested because of early bolting. No.6 is to be abole to use for bolting-resistant Chinese cabbage breeding, because more than 10% of bolting resistant individuals were observed in the F2 segregated population. It may facilitate more stable cultivation of spring sown Chinese cabbage, saving both labor and energy.
Effect of pre-mixing bark amendment into water purification sludge before auto-composting on nitrogen and manganese content of the sludge and quality as material for potting media was investigated. Each of the sludge with and without pre-mixing bark amendment was piled to a volume of about 50 m3, 2.5 m height and was fermented at factory production scale. Pre-mixing the sludge with bark amendment accelerated the fermentation of the compost and decreased the amount of manganese ion(Mn2+) in the sludge. Inorganic nitrogen content of the pre-mixed composed was smaller than that of non-premixed compost. Each composted sludge was used as potting media for bottle guards. The plants with potting media of 70% pre-mixed sludge grew better than those with potting media of 70% non-premixed sludge. One of the main reasons for these results was considered the reduction in Mn2+ content of the sludge pre-mixing with bark amendment. However, this phenomenon was not seen when potting media consisted of 40 or 55% sludge.
In plug seedling production, lack of uniformity of soil moisture can occur among different cells in the same tray. This phenomenon is thought to be caused by differences in air humidity surrounding plants in the center of the tray compared to that surrounding those at the edge of the tray leading to differences in transpiration rates. We used NaCl subirrigation treatment to reduce individual differences in transpiration rate, and thus improved the uniformity of soil moisture in each tray.
This study evaluated the sorting method that could select high viability seeds in cabbage. Cabbage seeds were sorted by detection of fluorescent compound leakage from water-sorked seeds, then the percentage of emerged seedlings and percentage of abnormal seedlings on a plug tray were investigated. Before sorting, the percentage of emerged seedlings and percentage of abnormal seedlings was 95.2% and 3.0%, respectively. After discarding fluorescent-positive seeds, the percentage of emerged seedlings and percentage of abnormal seedlings were more than 98.5% (P<0.05) and less than 0.9% (P<0.05), respectively. These results indicated that the percentage of emerged seedlings and percentage of normal seedlings in a cabbage seedlot could be improved by this fluorescent screening method, which could be a useful method of upgrading seed quality.
The effects of temperature on induction and growth of somatic embryos in cyclamen were investigated. Both the induction of embryogenic callus from explants and formation of somatic embryos from the callus were examined at 20, 25 or 30°C. The calli induced at 20°C formed a markedly smaller number of somatic embryos after subculture on medium without plant growth regulators than calli induced at 25 or 30°C. In vitro germination and growth of somatic embryos were also examined at 15, 20 or 25°C. Obviously, the higher temperature of 25°C inhibited germination and growth. Although the temperature of 20°C was suited for germination, the lower temperature of 15°C was effective for growth of the germinated somatic embryos. These results suggest that the optimal temperature in plant regeneration through somatic embryogenesis in cyclamen differs by stage.
Heat hardiness of 16 geophytes was assessed for use in landscape planting in Japan. The bulbs were planted in pots and grown in growth chambers under three simulated temperatures i.e. ambient air temperature in Osaka, ambient +5°C and ambient −5°C from July 9 or July 16, 1999 to September 20, then all of the plants were transferred to the outdoors. All of the +5°C Dahlia and Lilium ‘White Angel’ plants died. The other geophytes did not die under any temperature conditioins. Under higher temperature conditions, delayed sprouting of Muscari armeniacum, and Narcissus tazetta var. chinensis, decreased unfolding of leaves of Agapanthus africanus, decreased plant height of Muscari armeniacum and Crocosmia x crocosmiiflora, decreased number of shoots of Gladiolus, and decreased flowering percentage of x Amacrinum howardii, Crocosmia x crocosmiiflora, Gladiolus and Hedychium were observed. There were no significant effects of high temperature on growth of Allium chinense, Bletilla striata, Liatris spicata, Lillium ‘Elite’, Lycoris albiflora and Zephyranthescandida. Canna grew better under higher temperature condition.
The effects of node order of fruit set on total leaf area and final fruit weight were examined in vertically trained watermelon [Citrullus lanatus (Thunb.) Matsum. et Nakai] plants. Two primary lateral vines were allowed to grow in each plant, and one fruit per plant was set at the 5-7th, 8-11th, 14-16th or 18-22nd node. Each vine was pinched at the 22nd node. As the nodal order of fruit set rose, fruit weight became larger, while the amount of soluble solids in the fruit decreased. Total leaf area per plant during the fruit development period increased as the node order of fruit set rose. Fruit weight at harvest was closely related to the total leaf area per plant 5 days, 20 days and 40 days (at harvest) after pollination. We concluded that decreased photosynthetic production due to small leaf area and competition between fruit and vegetative organs during the fruit development period would cause smaller fruit in plants with fruit at a lower node.
Relationship between sugar accumulation in juice during fruit development and physiological characteristics of ‘Imamura No.9’ satsuma mandarin (Citrus unshiu Marc.) tree grafted on ‘Hiryu’ (Flying Dragon) rootstock, trifoliate orange strain (Poncirus trifoliata Raf. var. monstrosa), was investigated. The trees grafted on common trifoliate orange (P. trifoliata) rootstock were used as a standard. Until around October, sucrose, glucose and fructose contents in fruit juice on ‘Hiryu’ were greater than those of the common trifoliate orange, while the difference in the proportions of sugar constituents between the two rootstocks was not significant. Thereafter, the sucrose content and percentage to toal sugar content of ‘Hiryu’ increased markedly during fruit ripening. The photosynthetic capacity of new leaves and respiration rate of fine roots were lower, and water stress was more severe during the daytime on ‘Hiryu’ than those on common trifoliate orange. It was suggested that continuous water stress during fruit development and ripening in the tree on ‘Hiryu’ accelerated sugar accumulation in juice. However, it is possible that the mechanism of sugar accumulation in the tree on ‘Hiryu’ is different from that in the tree under low soil moisture condition on common trifoliate orange, because the increase in monosaccharides in juice that was usually observed under water stress was not observed on ‘Hiryu’.
The effects of cultivating conditions during fruit enlargement on the browning of cucumber fruit were examined in fruit preserved at about 10°C during transportation. Conditions that increased the browning rate of the fruit were as follows: A higher rate occurred in spring and early summer than winter. A higher minimum temperature in the greenhouse also promoted the rate. Fine weather before the harvest caused a higher rate than either wet (snowy) or cloudy weather. Fruits harvested at 100 g demonstrated the highest rate, while that of fruits over 200 g was low. These results suggested that rapid enlargement of fruit is apt to promote browning when the fruit is preserved at 10°C after harvesting.
A new and simple boiling method for extracting chrysanthemum stunt viroid (CSVd) RnA is described. Fresh leaves of CSVd-infected chrysanthemum were homogenized in an equal volume of CTAB buffer then centrifuged. The supernatant was boiled for three min then centrifuged again. Transparent supernatant of boiled sample was collected. CSVd-RNA was then purified by the following procedures: the supernatant (300 μl) was added to 1/10 volume of 3M sodium acetate and an equal volume of isopropyl alcohol, transferred gently to a microcentrifuge tube containing 400 μl 2M LiCl, incubated at room temperature for 10 min and centrifuged. Northern blot hybridization analysis showed that the extracted CSVd-RNA survived although it was partially broken by boiling. This was confirmed by RT-PCR amplifying about 350 base pairs cDNA, showing the full length of CSVd. Dot blot hybridization analysis indicated that the boiling extraction method has a higher detection sensitivity than the guanidine thiocyanate/phenol extraction method. It is also concluded that boiling is a safe method that does not require toxic reagents such as phenol and chloroform.