Water restriction, salinity and depth influence the germination and emergence of sourgrass

Abstract

Background: Substantial losses to crops can occur due to the presence of sourgrass in agroecosystems, which is promoted by its seed dispersal ability. Environmental factors can affect sourgrass germination and emergence. Objective: The objective of this study was to determine the effects of water restriction, salinity, and depth of sowing on the sourgrass germination and emergence processes. Methods: Experiments using sourgrass seeds were conducted under controlled conditions simulating osmotic and saline stress and seeding depths. The data collected was submitted to analysis of variance and adjusted to models by regression analysis. Results: Smaller osmotic potentials reduced germination, normal seedlings, and increased quiescence, with no germination occurring from-0.80 MPa. Salinity caused a decrease in germination from 20 mM NaCl, influencing the percentage of normal and abnormal seedlings and quiescent seeds. Seed depth influenced the emergence of seedlings, with the maximum percentage of emergence (83%) in the seeds placed on the substrate surface. The maximum depth from which sourgrass seedlings emerged was 7.6 cm. Conclusions: The results lead to the conclusion that the sourgrass germination process tolerates low osmotic potentials and salinity levels. Despite being small sized seeds, they can emerge from high depths. These characteristics justify its occurrence in several regions and agroecosystems, especially in perennial and no-till crops lacking soil cover.

The population density of Digitaria insularis influences Phaseolus vulgaris agronomic traits

“…Due to huge losses caused to crops and its difficulty of control, sourgrass [Digitaria insularis (L.) Mez ex Ekman] has drawn attention from Brazilian farmers in the last years (Braz et al, 2021;Silveira et al, 2018). Its high persistence in the environment because of rhizome formation and easy dispersion due to its high number of seeds with high germination percentage (Zambão et al, 2020) is aggravated by the glyphosate resistant biotypes (Takano et al, 2018). However, despite its importance, there are few studies evaluating sourgrass influence in agronomic characteristics of major summer crops in Brazil, including in common bean.…”