Enhanced crop competition could aid in the management of annual sowthistle (Sonchus oleraceus L.), a dominant weed of Australian cropping systems. A two-year pot study was conducted to evaluate the effect of wheat (Triticum aestivum L.) planting densities (0, 82, and 164 wheat plants/m) on growth and seed production of glyphosate-resistant (GR) and glyphosate-susceptible (GS) biotypes of annual sowthistle. Without competition, both biotypes produced a similar number of leaves and biomass, but the GS biotype produced 80% more seeds (46,050 per plant) than the GR biotype. In competition with 164 wheat plants/m, the number of leaves in the GR and GS biotypes was reduced by 62 and 61%, respectively, in comparison with the no-competition treatment, and similarly, weed biomass was reduced by 78 and 77%, respectively. Compared to no-competition treatment, the seed production of GR and GS biotypes was reduced by 33 and 69%, respectively, when grown with 82 wheat plants/m, but increasing wheat density from 82 to 164 plants/m reduced the number of seeds only in the GS biotype (81%). Both biotypes produced greater than 6,000 seeds per plant when grown in competition with 164 plants/m, suggesting that increased crop density should be integrated with other weed management strategies for efficient control of annual sowthistle.

中文翻译：

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增强的杂草作物竞争对抗除草剂和对除草剂敏感的一年生芥菜 (Sonchus oleraceus) 生长和种子产量的影响

加强作物竞争有助于管理一年生芥菜 (Sonchus oleraceus L.)，这是澳大利亚种植系统的主要杂草。进行了一项为期两年的盆栽研究，以评估小麦 (Triticum aestivum L.) 种植密度（0、82 和 164 株/平方米）对抗草甘膦 (GR) 和易感草甘膦的生长和种子产量的影响(GS) 一年生芥菜的生物型。在没有竞争的情况下，两种生物型产生相似数量的叶子和生物量，但 GS 生物型比 GR 生物型多产生 80% 的种子（每株植物 46,050）。在与 164 株小麦植物/m 的竞争中，与非竞争处理相比，GR 和 GS 生物型的叶子数量分别减少了 62% 和 61%，同样，杂草生物量减少了 78% 和 77% ， 分别。与非竞赛待遇相比，当以 82 株/平方米的小麦种植时，GR 和 GS 生物型的种子产量分别减少了 33% 和 69%，但将小麦密度从 82 株/平方米增加到 164 株/平方米仅减少了 GS 生物型的种子数量（81 %）。两种生物型在以 164 株/平方米的竞争生长时每株植物产生超过 6,000 粒种子，这表明增加的作物密度应与其他杂草管理策略相结合，以有效控制一年生蓟。