应用EPG技术分析不同品种苜蓿对苜蓿斑蚜的抗性

【目的】明确苜蓿斑蚜Therioaphis trifolii对不同品种苜蓿Medicago sativa的取食行为，探明抗蚜因子和抗虫位点，筛选抗蚜苜蓿品种。【方法】利用刺吸电位技术(electrical penetration graph, EPG)记录苜蓿斑蚜成蚜在10个苜蓿品种上的取食行为，并基于聚类分析方法筛选合适的EPG参数进行抗蚜性评价。【结果】苜蓿斑蚜成蚜在取食苜蓿过程中呈现np波、pd波、A波、B波、C波、E波、F波和G波8种波形，其中E波、F波和G波的总时间在不同品种间表现出显著差异。在5 h测试期间，E波持续时间在敖汉上最长，金皇后和中苜3号上次之，草原2号和阿尔冈金上最短；F波总时间以准格尔、阿尔冈金和金皇后上最长，敖汉、德宝和草原2号上最短，说明前者具有较强的机械抗性而后者机械抗性较弱。以第1次刺探持续时间、总刺探时间、F波总时间、C波总时间、E波总时间作为聚类分析的指标，10个苜蓿品种被聚成3类：阿尔冈金、草原2号、WL168HQ、德宝、中苜2号和新牧2号为第Ⅰ类，金皇后、中苜3号和准格尔为第Ⅱ类，敖汉为第Ⅲ类。【结论】苜蓿斑蚜成蚜在不同苜蓿品种上的取食行为存在差异，草原2号、阿尔冈金和WL168HQ在叶表皮、叶肉和韧皮部层次对苜蓿斑蚜成蚜存在抗性，金皇后在叶表皮和叶肉部位表现出抗性；苜蓿斑蚜成蚜在敖汉上能够长时间刺吸取食，因此敖汉抗性最弱。本研究为深入探讨苜蓿抗虫机理和蚜虫综合治理提供了理论参考。

Resistance of different alfalfa cultivars to Therioaphis trifolii (Hemiptera: Drepanosiphidae) analyzed by EPG technology

【Aim】 To clarify the feeding behaviors of Therioaphis trifolii on different cultivars of alfalfa (Medicago sativa), to ascertain the anti-aphid factors and insect resistance sites, and to screen out the M. sativa cultivars resistant to aphids. 【Methods】 The feeding behaviors of T. trifolii adults on 10 alfalfa cultivars were recorded using electrical penetration graph (EPG) technology, appropriate EPG parameters were selected based on clustering analysis and aphid resistance was evaluated with these EPG parameters. 【Results】 T. trifolii adults fed on different alfalfa cultivars showed eight waveforms including np waveform, pd waveform, A waveform, B waveform, C waveform, E waveform, F waveform and G waveform, and the total duration of E waveform, F waveform and G waveform of T. trifolii adults on different alfalfa cultivars showed significant differences. During the 5 h test period, the duration of E waveform on Aohan was the longest, followed by that on Golden Empress and Zhongmu No.3, and that on Caoyuan No.2 and Algonquin was the shortest. The total duration of F waveform on Zhungeer, Algonquin and Golden Empress was the longest, and that on Aohan, Derby and Caoyuan No. 2 was the shortest, suggesting that the formers have strong mechanical resistance and the latters have weak mechanical resistance. Using the duration of the first probe, total duration of probe wave, total duration of F waveform, total duration of C waveform, and total duration of E waveform as indices for cluster analysis, 10 alfalfa cultivars were clustered into 3 categories: Algonquin, Caoyuan No. 2, WL168HQ, Derby, Zhongmu No. 2 and Xinmu No. 2 in category I, Golden Empress, Zhongmu No. 3 and Zhungeer in category II, and Aohan in category III. 【Conclusion】 The feeding behaviors of T. trifolii adults on different alfalfa cultivars are different. The alfalfa cultivars Caoyuan No. 2, Algonquin and WL168HQ show resistance to T. trifolii adults at the levels of leaf epidermis, mesophyll and phloem, and Golden Empress shows resistance to T. trifolii adults when leaf epidermis and mesophyll are pierced. T. trifolii adults can pierce and suck for a long time on Aohan, so Aohan shows the lowest resistance to T. trifolii adults. This study provides a theoretical basis for further exploring the mechanisms of alfalfa resistance to insects and the integrated control of aphids.