摘要:甘薯茎线虫（Ditylenchus destructor）是国际检疫植物寄生线虫，甘薯茎线虫病是危害我国甘薯生产的严重病害之一。本文通过不同种植方式下甘薯根际土壤线虫群落结构的变化，探索轮作对甘薯茎线虫病防治的作用，明确变性梯度凝胶电泳（DGGE）在土壤线虫群落研究上应用的可行性。试验在河北省卢龙县多年连作的甘薯地上进行，种植方式分别为：A1，休闲→甘薯；A2，玉米-冬闲→甘薯；A3，玉米-黑麦→甘薯；A4，大豆-冬闲→甘薯；A5，大豆-黑麦→甘薯；CK，甘薯连作。提取3个时期甘薯根际土壤线虫，扩增线虫ITS区序列，采用DGGE技术分析土壤线虫群落。结果表明，与连作相比，轮作方式显著提高甘薯根际土壤线虫群落多样性，降低根际土壤甘薯茎线虫数量（P < 0.05），冬季轮作黑麦（A3，A5）使甘薯根际土壤线虫群落结构更加稳定，随时间变化幅度小。甘薯根际土壤中检测到的线虫优势属有：茎线虫属、矛线虫属、滑刃线虫属、头叶线虫属、短体线虫属、小环线虫属、刺线虫属、真滑刃线虫属、双胃线虫属。轮作方式提高甘薯产量42.08%~55.83%，降低病情指数22.72%~30.79%，不同轮作方式之间对甘薯产量和病情的影响差异不显著，收获期的甘薯茎线虫数量与甘薯产量和病情指数显著相关（P < 0.05）。因此，轮作方式能够显著提高甘薯根际土壤线虫群落多样性和甘薯产量，DGGE可有效检测土壤线虫群落；大豆-黑麦→甘薯是经济效益和生态效益较好的轮作措施。
Abstract:Sweet potato rot nematode (Ditylenchus destructor) is a severe disease that can cause significant loss of sweet potato yield and that can destroy biotic community diversity in rhizosphere soils. In this study, nematode community structure in rhizosphere soils under sweet potato were investigated to verify the impact of rotation cropping patterns on rot nematode disease and the feasibility of denatured gradient gel electrophoresis (DGGE) in soil nematode research. The experiment was conducted on a long-term continuous sweet potato field in Lulong County, Hebei Province in 2014 to (→) 2015, where sweet potato rot nematode disease was seriously epidemic. The cropping patterns were included A1 (fallow→sweet potato), A2 (maize-fallow→sweet potato) A3 (maize-rye→sweet potato), A4 (bean-fallow→sweet potato), A5 (bean-rye→sweet potato) and CK (continuous sweet potato cropping). The nematodes were separately extracted from sweet potato rhizosphere soil in May, July and September in 2015, and the ITS genes analyzed using PCR-DGGE. The results showed that compared with continuous cropping, crop rotation significantly increased the diversity of nematode community, and decreased the population of sweet potato rot nematode in rhizosphere soil (P < 0.05). Community structure of nematodes in rhizosphere soil under sweet potato was stabilized by winter rotation with rye (A3 and A5). Based on PCR-DGGE, 9 genera of nematodes were detected in the rhizosphere soil of sweet potato-Ditylenchus, Dorylaimus, Aphelenchoides, Cephalobus, Pratylenchus, Criconemella, Belonolaimus, Aphelenchus, and Diplogasterida. While Ditylenchus was the dominant genus in all the cropping patterns, Dorylaimus, Aphelenchoides and Cephalobus were the main genera. Crop rotation increased sweet potato yield by 42.08%-55.83% and decreased disease index by 22.72%-30.79%. However, different crop rotations had no significant difference on sweet potato yield and disease index. The population of Ditylenchus destructor was significantly related with sweet potato yield and disease index at harvest time (P < 0.05). Therefore, crop rotation significantly increased the diversity of nematode communities in sweet potato rhizosphere soils and sweet potato yield. And DGGE was proved to be a useful tool to detect soil nematode community. For the economic and ecological effects, bean-rye→sweet potato was the best rotation pattern for the study area.
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