碩士 / 國立臺灣大學 / 園藝暨景觀學系 / 106 / Abstract
Cultivars of pear are gradually diversified, at least five cultivar of oriental pear are currently available in top-grafting pear industry. This study was divided into three parts. The first part was to verify the currently-main-import pear cultivars, and pears which was produced at high altitudes area. The second part was to study the effects of growing-season-pruning on shoots growth and flower differentiation of ‘Shinko’ pear in lowland area. In the third part, the factors affecting the percentage of flower buds were analyzed by forward stepwise analysis. In the first part, 4 kinds of pear cultivars were collected from foreign contries and domestic varieties.2 kinds of cultivars were collected from high altitude area in Taiwan which had more potential in Top-grafting pear industry. Bud characteristics such as bud angle, lenticels and shape of bud were used to distinguish the 6 cultivars and establish identify key of pear cultivars. Result of flower bud differentiation status observation showed that the percentage of flower buds was not significant different between cultivars. It may cause from that the pear scions had been previously selected. The second part was conducted in Xinpu township for summer pruning to investigate the effects of growing-season-pruning on shoots growth, flower bud development, dormancy of lateral bud, and the impact of pruning on the endodormancy of buds after harvesting. The results showed that, shoots pruned in April had best shoot length, shoot diameter, and the length of internode. After May, the growing of shoots was significantly limited. All shoots had growth cessation in July. The frequency of pruning has no significant effect to shoots growth. It is presumed that the reason may be the shoot matures early then stops, so it cannot be expressed. After pruning, percentage of lateral bud burst decreased along with delay of pruning. It speculated that the growth of shoots were not only affected by the high temperature in environment, but also restricted by the inhibitory substances of the shoots itselves. Flower bud formation could be observed visually in July, and the percentage of bud necrosis was the most serious due to a longer growth period in relative high temperature. Growing-season-pruning would reduce the necrosis of buds and also improved the proportion of flower buds in shoots. The flower bud drop rate of each pruning treatment was reduced. Pruned in April had best flower bud formation, and decreased the most percentage of bud drop. Pruning after May, the percentage of flower bud formation was low, which might be due to short growing time. Thus, to improve the flower bud formation, harvest time should be adjusted. Macronutrient of shoots showed that there were no significant difference among the pruning treatments except for potassium content in shoots. After the pear scions were harvested, the effect of storage treatment on the percentage of bud break in each pruning treatment was investigated by single-bud-cutting. The results showed that, bud break were inconsistent between one-week storage treatment and two-week storage treatment, which might be due to chilling requirement insufficient. In three-week storage treatment, bud break was observed in all of the pruning treatment. And the best storage treatment was performed in storage treatment for 4 weeks. Among them, the percentage of bud break for shoots pruned in May and pruned in April+May was the most, and all above 50%. The percentage of bud break was affected by the storage time. The longer storage time the higher percentage of bud break. In the future, storage time can be adjust to improve the percentage of bud break. In the third part, forward stepwise analysis was used to explore the contribution of each factor to the percentage of flower buds, and the relevant prediction equation was established for the reference of future research on the relationship between shoot nutrient elements and flower bud differentiation. C/N ratio and carbohydrate were the main factors in the two prediction equations, but the C/N ratio is the calculated value, so the equation which without the factor of C/N ratio is recommended. The content of potassium is closely related to the proportion of flower buds, but the causality needs to further elucidation. In order to solve the problem of pear scions, it is necessary for Taiwan to produce pear scions. Growing-season-pruning can shorten the high temperature period of the growing season, and reduced the necrosis of buds, so that the production of pear scions can be carried out in low altitude areas. This study can be used as the basis for the production of pear scions in low altitude areas in the future.
| Identifer | oai:union.ndltd.org:TW/106NTU05378011 |
| Date | January 2018 |
| Creators | Chun-Leng Ooi, 黃俊陵 |
| Contributors | Iou-Zen Chen, 陳右人 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 68 |
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