移植體系下雜草型紅米之危害、傳播與防治策略

Infestations and Control Strategies of Weedy Red Rice under transplanting model

吳東鴻(Dong-Hong Wu) ； 李長沛(Charng-Pei Li) ； 黃永芬(Yung-Fen Huang)

《中華民國雜草學會會刊》 39卷1期 (2018/06) Pp. 71-83

https://doi.org/10.6274/WSSROC.201806_39(1).0005

摘要

雜草型紅米具有明顯的休眠與落粒性等雜草化性狀，易被保存於土壤中形成田間自生苗，而成為基因流布與病蟲害等媒介。其生長勢旺盛造成與水稻間的養分競爭，又因具有紅色種皮與口感不佳等負面品質，大幅增加稻作生產成本、降低商品價值而限制全球產業發展，世界各國無不積極尋找因應對策。臺灣習於水稻移植栽培，此法強化生育初期的雜草控制，但近年全臺仍遭受雜草型紅米的入侵，雖混雜率約莫0.5-1.0%，入侵後隨跨區聯合收穫加速擴散風險，加上一期作水稻收穫後馬上進行翻耕種植二期作水稻或部分產區使用宿根栽培，導致田間自生苗蔓延，使產量及品質大幅滑落。防治策略在考量經濟效益、有效性與可行性下，建議收穫後先湛水使殘留稻種發芽再進行翻耕作業，移植後連續間隔7 天施用3 次選擇性除草劑，推延自生苗的發生期，打破其繁殖週期，最終再針對少數雜草型紅米進行田間移除。

關鍵字

雜草型紅米 ； 種子休眠性 ； 種子落粒性 ； 移植體系 ； 防治策略

並列摘要

Weedy red rice (WRR) possesses weediness traits, including higher seed dormancy and shattering, which facilitate the growth of volunteer plants in the paddy the next season. The off-type plants are not only the source of pollen-mediated gene flow, of pest or disease, but also a competitor of fertilizer due to its good growth vigour. In addition, WRR's red pericarp and poor eating quality increase production cost, reduce product value and consequently limit the development of global rice industry. Rice cultivation regions world-wide are looking for efficient WRR control. The rice production system in Taiwan is transplanting-based, which is a recommended system to improve weed control at the seedling stage. However, the occurrence of WRR in rice paddy is getting more and more serious in the past few years in Taiwan. Although the WRR occurrence rate is between 0.5 and 1% per contaminated paddy, WRR can be easily spread through shared combine across rice fields. Ratoon cropping or tillage immediately after harvest increase the instances of volunteers and result in yield loss. The efficient control strategies should meet the balance between economic benefit, efficiency, and feasibility. The recommended WRR control under transplanting system would start with irrigating the paddy field after harvest in order to induce the sprouting of shattered seed and then plow the WRR seedlings into the land. Herbicide would then be applied three times in succession every 7 days to delay the development of volunteer plants and to break the life cycle of WRR. The final step would be the manually removal of remaining off-type plants of WRR.

並列關鍵字

weedy red rice ； seed shattering ； seed dormancy ； transplanting system ； control strategy