甘藷簇葉病之硏究(Ⅰ)

Studies on Witchs' Broom of Sweet Potato in Taiwan

楊一郎(I-Lang Yang)

《中華農業研究》 18卷3期 (1969/09) Pp. 50-60

https://doi.org/10.29951/JARC.196909.0007

摘要

1．甘藷品系對簇葉病感病性嫁接試驗結果，第一批已罹病品系有臺農10號等73種。病徵分爲A,B,C,D四型，不同品系之病徵有顯著之差異，可知其感病性亦有差異，由於品系間耐病性之測定可以選擇抗病性品種。
2．11月至翌年2月間，由於冬季低溫環境之影響，各甘藷苗經嫁接接種感染後至病徵出現之潛伏期，長達4至5個月。
3．田間發病嚴重區，不同品種間發病程度亦有差異，其發病株率訓爲，金瓜接44%，菜頭接20%，離斤已尾5.8%。
4．甘藷挨葉病病株熱處理結果，病株之耐溫界限爲，溫水處理54℃ 5分鐘，50℃ 30分鐘，以下。在此耐溫界限下，熱處理之效果，未能殺減其病原。
5．本病經嫁接接種在Ipomoca Pes-caprae Sweet及Ipomoea Nil Roth, 之結果，顯示典型之花器葉化，枝葉短小，叢生，萎黃病徵，與新海昭(1964)報告之琉球甘藷天狗巢病相類似。

並列摘要

This paper reports the experimental results on varietal resistance. Eradication by thermotherapy and Host range of sweet potato witchs' broom in Taiwan were conducted at the Chiayi Agricultural Experiment Station from July, 1968 to June, 1969. The results are briefed as follows:
1. Seventy-three varieties of sweet potato growing in the Chiayi Agricultural Experiment Station were used in this graft transmission test. All of these showed infected symp tom, were susceptible ranging from the infection degree of A (Severe form) to D (Mild form). 27 of these showed typical symptom (A-B, Severe form). For the remaining varieties, 18 showed mild symptom (C-D). Scions taken from diseased plants were grafted to healthy stocks and were obtained with an incubation period ranged from 50 days in summer time and to 120 days in winter time.
2. Observation on the intensity of field varietal infection rate. total of 6,396 plants including three varieties of sweet potato were used. It is apparent that the difference of field infection rate to the disease among varieties are very significant. All of them were either susceptible or highly susceptible ranged from 5.9% to 44.2% in their infection rate. While the Ching-Kua-Chie variety was the highest one. However, it still needs further observations to confirm whether they ore real varietal resistance or the escaping to the disease due to the environmental condition.
3. Infected cuttings of sweet potato were treated by hot water at the temperature of 45-65℃, in attempts to eliminate sweet potato witchs' broom disease by heat treatment. Cuttins survived up to 5 minutes under 54℃ and 30 minutes under 50℃, all of them can not eliminate the pathogene or eradicate the disease by thermotherapy.
4. Plants confirmed as host plant by graft transmission of sweet potato witchs' broom disease were creeping herb (Ipomoea pes-Caprae Sweet) and morning glory (Ipomoea Nil Roth.). It's vines become shortened, leaves curled, elongated axillary buds and green flower petals presenting typical symptoms. While China aster (Callistephus Chinensis Nees.), zinnia (Zinnia elegans L.). Gromphrena globosa L. were not attacked by it.