Ryegrass (Lolium multiflorum Lam.) is one of the most difficult annual weeds to control in cultivation systems worldwide, especially in temperate regions. The widespread use of herbicides in the past two decades has selected resistant biotypes of ryegrass in crops in Southern Brazil. Ryegrass seeds are dormant when disseminated and germination can be staggered over time (crop‐growing season). Knowledge of the germination behavior of seeds from herbicide‐resistant plants has been little studied, but it would be very useful in integrated weed management. Thus, this study aimed to characterize the dynamics of the soil seed bank of two biotypes of L. multiflorum, one glyphosate‐resistant and the other glyphosate‐susceptible, under a no‐tillage system. The treatments were arranged in a bifactorial scheme, using seeds from biotypes (glyphosate‐resistant and glyphosate‐susceptible) with monthly periods of removal from field (one to 12 months). Seeds of each biotype were placed on the soil surface and covered with soil and straw to simulate no‐till conditions. The percentage of germinated, dormant, and dead seeds was evaluated every 30 days. The ryegrass seed bank of glyphosate‐susceptible and glyphosate‐resistant biotypes was reduced to 11 and 15% of dormant seeds, respectively, at the end of 12 months. However, there was no variation in germination, dormancy, and seed mortality between susceptible and glyphosate‐resistant ryegrass. Seeds of glyphosate‐resistant biotype and susceptible showed germination behavior with similar dynamics in the soil over a period of 12 months.

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抗草甘膦和易感的意大利黑麦草（黑麦草）的种子发芽行为

黑麦草（Lolium multiflorum Lam。）是全世界耕作系统中最难控制的一年生杂草之一，特别是在温带地区。在过去的二十年中，除草剂的广泛使用已在巴西南部的农作物中选择了具有抗性的黑麦草生物型。黑麦草种子传播时处于休眠状态，发芽可能会随着时间（作物生长季节）而错开。关于抗除草剂植物种子发芽行为的知识鲜有研究，但在杂草综合治理中将非常有用。因此，本研究旨在表征两种生物型L. multiflorum的土壤种子库的动态。在免耕体系下，一种抗草甘膦，另一种对草甘膦敏感。处理采用双因素方案安排，使用生物型（抗草甘膦和草甘膦敏感性）的种子，每月从田间摘除一次（1至12个月）。将每种生物类型的种子放在土壤表面，并用土壤和稻草覆盖以模拟免耕条件。每30天评估发芽，休眠和死亡种子的百分比。在12个月末，草甘膦易感和草甘膦抗性生物型的黑麦草种子库分别减少到休眠种子的11％和15％。但是，易感草甘膦和耐草甘膦黑麦草的发芽，休眠和种子死亡率没有变化。