Soil water potential and temperature sum during reproductive growth control seed dormancy in Alopecurus myosuroides Huds.

Abstract

The sustainable management of unwanted vegetation in agricultural fields through integrated weed control strategies requires detailed knowledge about the maternal formation of primary seed dormancy, to support the prediction of seedling emergence dynamics. This knowledge is decisive for the timing of crop sowing and nonchemical weed control measures. Studies in controlled environments have already demonstrated that thermal conditions and, to some extent, water availability during seed set and maturation has an impact on the level of dormancy. However, it is still unclear if this applies also under field conditions, where environmental stressors and their timing are more variable. We address this question for Alopecurus myosuroides in south‐western Sweden. We quantified the effects of cumulated temperature and precipitation as well as soil water potential during the reproductive growth phase of A myosuroides on primary seed dormancy under field conditions. Empirical models differing in focal time intervals and, in case of soil water potential, focal soil depths were compared regarding their predictive power. The highest predictive power for the level of primary dormancy of A. myosuroides seeds was found for a two‐factorial linear model containing air temperature sum between 0 and 7 days before peak seed shedding as well as the number of days with soil water potential below field capacity between 7 and 35 days before peak seed shedding. For soil water potential, it was found that only the top 10 cm soil layer is of relevance, which is in line with the shallow root architecture of A. myosuroides. We conclude that for this species the level of dormancy depends on the magnitude and timing of temperature and water availability during the reproductive growth phase. Water availability appears to be more important during maternal environmental perception and temperature during zygotic environmental perception.

Interaction of Preventive, Cultural, and Direct Methods for Integrated Weed Management in Winter Wheat

“…Considering that only 28% of the observed variation in A. myosuroides density and 36% of the observed variation in A. myosuroides reproduction could be explained by the experimental factors, a large proportion of the probability of weed control failure cannot be controlled by agronomic means (discrepancy between marginal and conditional R 2 , see Table 1). This is partly explained by the biology of A. myosuroides: The species is characterized by a low germination base temperature (0 • C) and short primary dormancy [29,30]. This gives a wide germination period, ranging from late summer into early winter, when the competitive ability of winter annual crops is low.…”

“…The efficacy of pre-and early post-sowing direct weed control measures is mainly driven by their timing relative to the germination and emergence pattern of the weed seeds in the soil seed bank. This pattern is driven by seed dormancy status and is hence a result of the environmental conditions during seed set and seed ripening [30], as well as the environmental conditions during autumn and early winter. This finding emphasizes that the management of the soil seed bank needs to become the centre of attention for improving the overall weed control efficacy.…”

Weed Seed Dormancy: The Ecophysiology and Survival Strategies

“…Studies in controlled environments have already demonstrated that thermal conditions and, to some extent, water availability during seed set and maturation have an impact on the level of dormancy [43]. The level of dormancy in Alopecurus myosuroides Huds.…”

“…seeds depends on the magnitude and timing of temperature and water availability during the reproductive growth phase. Water availability seems more important during maternal environmental perception and temperature during zygotic environmental perception [43]. Both temperature and soil moisture content are important factors in seed germination induction.…”

Growth Stage of Alopecurus myosuroides Huds. Determines the Efficacy of Pinoxaden

“…The predicted percentage control of A. myosuroides required to maintain a static population in the continuous winter cereals is >90% to achieve its long-term control [ 11 ]. The low base temperature (0–1 °C) for germination [ 1 , 12 ], combined with a short primary dormancy, gives this weed species a broad emergence spectrum, which further increases its competitiveness [ 13 ]. As a weed species whose life cycle reveals a wide range of adaptation to conventional cropping systems [ 14 ], A. myosuroides peak emergence occurs in early autumn, coinciding with the sowing time and early development stage of winter cereals.…”