To facilitate efficient breeding of triploid loquats (Eriobotrya japonica Lindle.) by crossing diploid loquats with tetraploid loquats, we investigated differences of morphological and fruit bearing characteristics among diploid ‘Tanaka’, a tetraploid produced from the diploid ‘Tanaka’ and a triploid produced by crossing between the diploid ‘Tanaka’ and the tetraploid. In addition, we investigated the ratio of triploid seedlings produced by reciprocal crossing between diploid loquats and tetraploid loquats. Leaf width and thickness, stomata length, maximal diameter of calyx, petal length and width, and pollen grain diameter in the di-, tri- and tetraploid plants significantly increased with increasing polyploidy level in loquats. The ratios of shoots bearing flower clusters were about 70% in all di-, tri- and tetraploid plants. The pollen germination ratios were high at 95% in both the diploid ‘Tanaka’ and the tetraploid. However, it was markedly low at 8% in the triploid, and the fructification was also extremely low at 0.1%. The ratios of triploid seedlings produced by reciprocal crossing between tetraploids and diploids ranged from 92% to 100%. There were no great differences among the reciprocal crosses.
In this research, we quantitatively evaluated the shape of petal tips in lotus (Nelumbo nucifera Gaertn), using P-type Fourier descriptors. We developed a new program based on P-type Fourier descriptors to analyze the curves of petal tips from 7 varieties of lotus, which were extracted and described by Freeman chain codes. We then used principal component analysis to evaluate useful information to classify lotus cultivars in the coefficients of the P-type Fourier descriptors. 78% of the lotus cultivars could be identified from several principal components in Quadratic Discriminant Analysis (QDA) or Support Vector Machine (SVM) procedures programmed in R-language. The applications of the P-type Fourier descriptor can be extended to both open and closed curves.
We examined a few gynoecious plants obtained from balsam pear (Momordica charantia L.) ‘Aochu-naga’ in order to maintain the inbred gynoecious strain for future breeding. Foliar application of silver nitrate solution to the lateral shoot induced some bisexual flowers. The ovary and petal of these flowers were bigger than those in female flowers. However, the pollen function of the bisexual flowers was normal. About 10 bisexual flowers were obtained by foliar application of 250 mg · L-1 silver nitrate solution to 5 leaves or 400 mg · L-1 solution to 3 leaves at the top of the lateral shoot. There was no difference in the bloom number of bisexual flowers between the gynoecious balsam pear raised at 35°C (25°C at night) during the daytime and those raised at 25°C (15°C at night) during the daytime after foliar application.
By sowing protocorms of Habenaria radiata after they were gel covered and inoculated with orchid mycorrhizal fungi for some period, some enhancements were observed in the survival rate of protocorms and the rate of tuber formation by plants potted in non-sterilized soil. The suitable period for culturing protocorms from inoculation to sowing could be considered to have increased from 14 days to 42 days. The gel covered and fungi-inoculated protocorms were sown in habitat 28 days after the inoculation. As a result, 98 days after sowing, growth of the inoculated protocorms was recognized, but there was no apparent growth of non-inoculated protocorms. The survival rate of the protocorms sown was 46.1%, and the rate of tuber formation was 53.0%. From these results, the present method could be expected to be effective in the propagation of H. radiata in habitat. However, the tubers formed were very small. Further investigations are required to confirm the growth of plants sprouted from these small tubers in the next year.
The seed emergence of balsam pear (Momordica charantia L.) immediately after harvest tends to be delayed. The effect of ethephon treatment on seed emergence was compared with that of methods involving dipping in water and gibberellin solutions, seed coat-division treatments and seeds stored for 7 months. ‘Aochu-naga’ seeds 2 weeks after harvest were used in this experiment. Seeds in the control (non-dipping in water) began to emerge 8 days after seeding; 80% of those seeds had emerged by 17 days after seeding. However, seeds dipped in 200 or 1000 ppm ethephon solution for 12 hours began to emerge 5 days after seeding; 80% of those seeds had emerged by 8 days after seeding. The ethephon treatment promoted seed emergence more quickly than dipping in water and gibberellin solutions or seed coat-division treatments. The days for seed emergence did not differ between the seeds dipped in 1000 ppm ethephon solution and the seeds stored for 7 months and, furthermore, growth of the plants also was normal. We suggested that the effect of ethephon on breaking of dormancy in a fresh seed of balsam pear is not cultivar specific because the effect of ethephon on seed emergence was similar among the 5 cultivars.
Relations between seasonal growth and nitrogen uptake of potted miniature rose ‘Nakashima91’ cultivated in a recirculating Ebb & Flow system were investigated. The potted roses were cultivated in autumn; 2001/9/21-2002/1/15, spring; 2002/2/5-2002/5/13, and summer; 2002/6/17-2002/8/19. The cumulative temperatures from the start to end of cultivation were 1700-1900°C, irrespective of cultivation seasons. There was a significant correlation between the dry plant weight and the cumulative temperatures. A linear relation was found between increased dry weight and nitrogen uptake. This result indicates that the miniature roses absorbed nitrogen in proportion to the increase in dry weight. At the end of cultivation, the total nitrogen concentration in plants per pot was 80-95 mg, regardless of the cultivation season. However, the amounts of nitrogen supplied to a pot during summer, autumn and spring cultivation terms were 130, 180 and 240 mg respectively. The nitrogen absorption efficiency during summer cultivation was higher than other that during terms, and those in summer, autumn and spring were 68%, 41% and 34% respectively. The nitrogen concentration in soil solution in summer and autumn cultivation was fixed at 8 and 4-5 mg per pot respectively. However, that in spring cultivation was already higher than that in summer and autumn at the start of cultivation and was 12 mg per pot. Then the nitrogen concentration in soil solution rose beyond 15 mg per pot at the end of cultivation. This increase in nitrogen concentration in spring soil solution indicates that nitrogen had accumulated in the soil.
Effect of liquid fertilizer during flower-bud differentiation on nitrogen concentration, bolting, and yield were investigated to optimize management of the fertilizing schedule to avoid bolting in welsh onions harvested in early summer. Flower-bud differentiations started in the middle of February in this culture. Nitrogen concentration increased as the fertilizer concentration increased. The nitrogen concentration affected the bolting rate and yield, and it was indicated that there was a threshold in nitrogen concentration which suppressed flower-bud differentiation. In conclusion, fertilizing management during the flower-bud differentiation is important to control bolting and promote a higher yield in this culture.
The length and position distribution of 1-year-old bearing wood were compared among 3 varieties and between pruned and unpruned apple trees. In pruned trees, the proportion of long (10 cm<) and short (5 cm ≥, spur) bearing wood in all fruiting laterals with different orientations, were 25.3 and 66.3, 26.0 and 71.0, 13.0 and 81.1% in ‘Fuji’, ‘Jonagold’, and ‘Starking Delicious (SD)’. The percentage of spurs in ‘SD’ was higher than those of ‘Fuji’ and ‘Jonagold’, being about 90% in unpruned trees. Pruned trees had a lower spur ratio than unpruned trees in ‘Fuji’ and ‘SD’. The proportions of terminal and lateral long wood in pruned trees were 13.0 and 12.4, 13.2 and 12.8, 9.8 and 3.7% in ‘Fuji’, ‘Jonagold’ and ‘SD’. ‘SD’ had lower proportion of terminal and lateral long wood than the other varieties. The proportions of terminal and lateral spurs in pruned trees were 18.3 and 48.1, 21.9 and 49.3, 46.1 and 35.1% in ‘Fuji’, ‘Jonagold’, ‘SD’, respectively. Pruning increased the lateral spur ratio and decreased the terminal spur ratio in horizontal and pendant laterals of ‘Fuji’ and ‘Jonagold’ and in pendant laterals of ‘SD’.
Floral evocation and differentiation in Zanthoxylum piperitum (L.) DC. f. inerme Makino (Budousanshou) Japanese pepper were investigated to obtain basic data for developing cultural techniques that will increase the number of fruit set. Panicle formation occurring at the tip of a new shoot after grafting was investigated to evaluate floral evocation, and microscopic observation of apical and lateral buds on spring shoots was done to determine floral differentiation from June through March. Floral evocation was completed from late June through early July at Shimizu-Cho in Wakayama Prefecture in 2004. Floral differentiation was observed in July and August on the same tree. The number of small flowers in a panicle remained constant from August to February but increased rapidly in March before bud sprouting occurred.
This study characterized the “watercore-like” disorder in which the flesh of mature fruit in peach (Prunus persica Batsch) exhibits a water-soaked brown discoloration. There were varietal differences in the incidence of the disorder with ‘Kawanakajima Hakuto,’ ‘Beni Shimizu’ and ‘Hana Shimizu’ exhibiting higher rates. The incidence of disorder in ‘Hana Shimizu’ fruit ranged from 23 to 54% over the three years. In all cultivars, the disorder was highest on the side opposite to the fruit suture, then both cheeks and the suture, in that order. Fruit with the disorder showed higher weight, and total sugar, sucrose, sorbitol, water soluble pectic substances and total phenolic contents but lower flesh firmness, total amino acid concentrations and hydrochloric acid soluble pectic substances compared to normal fruit. The highest concentration of total soluble solids was observed at the portion of both cheeks of the fruit, followed by the opposite side of the suture and the suture. Symptoms of the disorder were prominent in mature fruit. We propose that “water-soaked brown flesh” be considered a common term for this disorder based on the fact that the symptoms of “watercore-like” disorder as it is commonly known in Okayama were similar to those of “watercore” or “internal browning” disorder, which is the popular term used in other peach producing areas in Japan.
The relationship between the inflorescence structure and setting of decorative flowers was investigated in lacecap cultivars of Hydrangea macrophylla and H. serrata in order to elucidate the mechanism of the setting of decorative flowers in lacecaps. Two types of structural change of the inflorescence that affect the numbers of decorative flowers were identified. In the first type of structural change, inflorescences bore numerous flowers, and the internodes of the inflorescence axes were long. In these inflorescences, the decorative flowers set in the secondary inflorescences on the third and fourth nodes of the axes of the primary inflorescences as well as in those on the first and second nodes. In the second type of structural change, there were changes in the setting pattern of lateral inflorescences on the tertiary inflorescences, which were located in the secondary inflorescences on the first and second nodes of the axes of the primary inflorescences. In these inflorescences, the numbers of decorative flowers varied.
The effects of ethylene action inhibitor (1-methylcyclopropene, 1-MCP) on the storage of three apple cultivars, ‘Sansa’, early-mature type, ‘Jonagold’, middle-mature type, and ‘Fuji’, late-mature type were investigated. As a result, 1-MCP significantly inhibited endogenous ethylene production in the fruit of three cultivars, but effects on quality during storage were different. Treatment of ‘Sansa’ fruits with 1-MCP delayed the decline of titratable acidity, but could not maintain the firmness, so the period of freshness was maintained for about one month after treatment. Furthermore, the effects of 1-MCP were shown only in fruit within three days after harvest. However, both the firmness and the titratable acidity in ‘Jonagold’ fruits were maintained two months after treatment performed up to seven days after harvest. Especially, volatile formation was significantly inhibited. Treatment with 1-MCP maintained the fruit qualities during two-month storage in ‘Fuji’ fruits which are similar to ‘Jonagold’, and the watercore was better preserved than that in the control throughout the entire treatment period. These results indicate that it is possible to maintain the freshness of fully ripe fruit which is impossible to store by CA storage, as well as contributing to the development of storage technology in the future.