Germination characteristics of Amaranthus quitensis as affected by seed production date and duration of burial

Abstract

Summary Thermal requirements for the germination of Amaranthus quitensis, a common annual weed in Argentina, were studied. In addition, temporal changes in dormancy from seeds produced at different times during the growing season were examined. For this second objective, thermal and light requirements for germination were tested in seeds buried at different depths, with or without crop residues. Base and optimum temperatures for germination rates were 12.8°C and 37°C respectively. At dispersal time, maximum percentage germination was 60–70% and this was generally recorded at 35°C/25°C in a 14‐h photoperiod. Seed germination tended to increase in later seed collection dates. Seeds of A. quitensis showed seasonal changes in germinability in the soil. In winter, germination of retrieved seeds increased to over 90% until summer, after which there was a decrease until the following winter when germination was close to 40%. There were no differences in germinability between burial depths and crop residue levels. Germination requirements for alternating temperatures and light tended to disappear after burial. Initial viability was 99% and declined slightly during burial. Soil temperature seems to play a crucial role not only by regulating seasonal changes in dormancy, but also by defining the percentage and the germination rate in non‐dormant seeds.

Germinative response of redroot pigweed (Amaranthus retroflexusL.) to environmental conditions: Is there a seasonal pattern?

“…Seeds set in the later season (October), though might be able to germinate in the Mediterranean area thanks to the rather mild temperatures, will not do so because they are characterised by a very prolonged after ripening dormancy (see also Chadoeuf-Hannel & Barralis 1983). Temporal changes in dormancy from seeds produced at different times during the growing season were also reported by Faccini and Vitta (2005) in A. quitensis Kunth.…”

Response of Amaranthus retroflexus L. seeds to gibberellic acid, ethylene and abscisic acid depending on duration of stratification and burial

“…A possible induction of secondary dormancy by high temperature has been shown in an experiment with A. caudatus seeds (Kępczyński and Bihun 2002). In addition, A. quitensis and A. palmeri seeds have shown a seasonal dormancy pattern (Faccini and Vitta 2005;Jha et al 2010), indicating that the behavior of seeds kept in soil is characteristic for the genus Amaranthus. Similarly, dormancy of other annual species has been released due to a low temperature during burial and reinduced by ahigh temperature (Karssen 1995 (Fig.…”

First Report of Amaranthus hybridus with Multiple Resistance to 2,4-D, Dicamba, and Glyphosate

“…hybridus (smooth pigweed) particularly cited as a major weed in summer crops [2]. This species is a widespread weed in agricultural systems in many countries.…”

“…of A. quitensis) is an annual erect herb that is up to 1 m tall and characterized by glabrous stems and petiolate leaves, ovate shape, pointed apices, terminal panicle form inflorescence, and hermaphrodite flowers [6]. Its presence as a weed is partially explained by the fecundity and longevity of its seeds [2].…”