Weeds Research Laboratory, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
Herbicide Bioscience, Syngenta, Jealott's Hill International Research Centre, Bracknell, UK.
Pest Manag Sci. 2022 Jun;78(6):2121-2128. doi: 10.1002/ps.6837. Epub 2022 Mar 4.
Beckmannia syzigachne (Steud.) Fernald has evolved herbicide resistance due to the long-term sole use of herbicides and has become a dominant weed in wheat fields in the middle and lower reaches of the Yangtze River in China. In addition to the selection pressure imposed by herbicides, pollen-mediated gene flow (PMGF) has been reported to cause the spread of herbicide resistance between populations within a certain range in some farmland weeds. It is not clear whether the same is true for the self-pollinated grass weed B. syzigachne.
In this study, we confirmed and quantified the level of PMGF in B. syzigachne through concentric circle planting and herbicide resistance tests. Results show that when the B. syzigachne pollen donor was close to the recipient (0.5 m), the average gene flow was 0.66%. Gene flow was detected as far as 10 m (the farthest distance studied) and decreased exponentially with increasing distance, which could be described by a double exponential decay model. Temperature also affected gene flow, whilst the average level of gene flow in all directions of wind was similar and wind speed caused insignificant difference in gene flow.
The results of this study confirmed that PMGF can occur between B. syzigachne populations in adjacent fields. Although the level of resistance spreading by pollen was low, especially across long distance, the results were relevant for smallholding farms, which is the dominant form of agricultural operation in China. It is therefore important to take proactive measures and integrate chemical and ecological weed control methods to prevent the spread of resistant B. syzigachne via both seeds and pollens. © 2022 Society of Chemical Industry.
由于长期单独使用除草剂，冰草（Beckmannia syzigachne（Steud.）Fernald）已经产生了抗药性，成为中国长江中下游麦田的主要杂草。除了除草剂的选择压力外，花粉介导的基因流（PMGF）已被报道在某些农田杂草种群内一定范围内导致除草剂抗性的传播。自花授粉的草本杂草冰草是否也是如此尚不清楚。
在这项研究中，我们通过同心圈种植和除草剂抗性试验证实并量化了冰草中的 PMGF 水平。结果表明，当冰草花粉供体接近受体（0.5 m）时，平均基因流为 0.66%。基因流可检测到 10 m 远（研究的最远距离），并随距离的增加呈指数衰减，可以用双指数衰减模型来描述。温度也影响基因流，而各个风向的平均基因流水平相似，风速对基因流没有显著影响。
本研究结果证实，PMGF 可在相邻田间的冰草种群之间发生。尽管花粉传播抗性的水平较低，特别是在长距离传播时，但对于中国以小农户为主的农业经营形式来说，这一结果很重要。因此，必须采取积极措施，整合化学和生态杂草控制方法，防止具有抗性的冰草通过种子和花粉传播。© 2022 英国化学学会。
