Bidens pilosa is one of the major weeds in annual and perennial crops in midsouthern Brazil. High seed production is one of its most important survival strategies and the knowledge of the fundamental conditions for seedling germination and emergence is essential to establish prediction models of its population growth and to elaborate management models for control and prevention of herbicide resistant populations. This research aimed to understand the importance of B. pilosa seed depth in the soil profile to enhance its germination and seedling emergence potential. Thus, four assays were carried out under greenhouse conditions and the seeds were sown at 0, 1, 2, 3, 4, and 5 cm from the soil surface. The emergence of B. pilosa seedlings was reduced as sowing depth was increased, with drastic reduction from two centimeters. This reproductive biology feature presented by B. pilosa is very important for the formation of dense seed banks in soils submitted to conventional tillage system.
common blackjack; germination; reproductive biology
