School of Agriculture and Food Sciences (SAFS), The University of Queensland, Gatton, QLD, 4343, Australia.
Namtumbo District Council, Namtumbo, Ruvuma, Tanzania.
Sci Rep. 2022 Sep 9;12(1):15241. doi: 10.1038/s41598-022-19418-8.
Hood canarygrass (Phalaris paradoxa L.) is a problematic weed in winter crops of Australia. Experiments were conducted to determine the effects of environmental factors on seed germination of P. paradoxa and wheat (Triticum aestivum L.) and herbicide options for P. paradoxa control. Results revealed that P. paradoxa had higher germination (> 89%) at a temperature range from 15/5 ℃ to 25/15 ℃ [day/night (12 h/12 h] compared with 30/20 ℃ and 35/25 ℃. At a temperature regime of 30/20 ℃, P. paradoxa had 1% germination; however, wheat at this temperature range resulted in 79% germination. Exposure of seeds of P. paradoxa to > 150 ℃ pretreatment (radiant heat for 5 min) resulted in no germination. These results suggest that infestation of P. paradoxa could be reduced by residue burning or by planting wheat crops early in the season when the temperature is relatively high. At a water potential of -0.8 MPa, seed germination of P. paradoxa and wheat was 75 and 96%, respectively. Similarly, at the highest salt concentration (200 mM sodium chloride), seed germination of P. paradoxa and wheat was 73 and 79%, respectively. These observations suggest that like wheat, P. paradoxa is also highly tolerant to water and salt stress conditions, therefore, it could invade the agro-ecosystem under water and salt stress situations. Germination of P. paradoxa was found to be low (10%) on the soil surface, suggesting that no-till systems could inhibit the germination of P. paradoxa. Pre-emergent (PRE) herbicides, namely cinmethylin, pyroxasulfone, and trifluralin, provided 100% control of P. paradoxa; however, in the presence of 2 t ha of residue cover, pyroxasulfone provided better control of P. paradoxa compared with other herbicides. Post-emergent (POST) herbicides clethodim, haloxyfop, and paraquat provided excellent control of P. paradoxa, even if the plant size was large (10-leaf stage). Knowledge generated from this study will help in strengthening the integrated management of P. paradoxa.
黑麦草（Phalaris paradoxa L.）是澳大利亚冬季作物中的一种有害杂草。本研究旨在确定环境因素对黑麦草和小麦（Triticum aestivum L.）种子萌发的影响以及控制黑麦草的除草剂选择。结果表明，与 30/20℃和 35/25℃相比，黑麦草在 15/5℃至 25/15℃的温度范围内（昼/夜 12 小时/12 小时）的发芽率较高（＞89%）。在 30/20℃的温度条件下，黑麦草的发芽率为 1%；然而，在该温度范围内，小麦的发芽率为 79%。黑麦草种子在＞150℃的预处理（辐射加热 5 分钟）下暴露后，没有发芽。这些结果表明，通过残茬燃烧或在温度相对较高的季节早期种植小麦作物，可以减少黑麦草的侵染。在水势为-0.8 MPa 时，黑麦草和小麦的种子发芽率分别为 75%和 96%。同样，在最高盐浓度（200 mM 氯化钠）下，黑麦草和小麦的种子发芽率分别为 73%和 79%。这些观察结果表明，与小麦一样，黑麦草也对水和盐胁迫条件具有高度耐受性，因此，它可能会在水和盐胁迫情况下侵入农业生态系统。黑麦草在土壤表面的发芽率较低（10%），表明免耕系统可以抑制黑麦草的萌发。芽前（PRE）除草剂，即二甲戊灵、吡氟草酮和氟乐灵，对黑麦草的防治效果达到 100%；然而，在 2 t ha 残茬覆盖的情况下，吡氟草酮对黑麦草的防治效果优于其他除草剂。芽后（POST）除草剂氯氟草醚、精恶唑禾草灵和百草枯对黑麦草的防治效果极好，即使植株较大（10 叶期）也是如此。本研究获得的知识将有助于加强黑麦草的综合治理。
