Seedbank persistence and emergence pattern of Argemone mexicana, Rapistrum rugosum and Sonchus oleraceus in the eastern grain region of Australia

Abstract

A thorough understanding of the emergence pattern and persistence of weed seeds is a prerequisite in framing appropriate weed management options for noxious weeds. In a study conducted at the University of Queensland, Australia, the emergence and seed persistence behavior of three major weeds Sonchus oleraceous, Rapistrum rugosum, and Argemone mexicana were explored with seeds collected from Gatton and St George, Queensland, Australia, with an average annual rainfall of 760 and 470 mm, respectively. Seed persistence was evaluated by placing seeds at the surface layer (0 cm) or buried at 2 and 10 cm depths enclosed in nylon mesh bags and examined their viability for 42 months. In another study, the emergence pattern of four populations, each from these two locations, was evaluated under a rainfed environment in trays. In the mesh-bag study, rapid depletion of seed viability of S. oleraceous from the surface layer (within 18 months) and lack of seed persistence beyond two years from 2 and 10 cm depths were observed. In trays, S. oleraceous germinated 3 months after seeding in response to summer rains and there was progressive germination throughout the winter season reaching cumulative germination ranging from 22 to 29% for all the populations. In the mesh-bag study, it took about 30 months for the viability of seeds of R. rugosum to deplete at the surface layer and a proportion of seeds (5 to 13%) remained viable at 2 and 10 cm depths even at 42 months. Although fresh seeds of R. rugosum exhibit dormancy imposed due to the hard seed coat, a proportion of seeds germinated during the summer months in response to summer rains. Rapid loss of seed viability was observed for A. mexicana from the surface layer; however, more than 30% of the seeds were persistent at 2 and 10 cm depths at 42 months. Notably, poor emergence was observed for A. mexicana in trays and that was mostly confined to the winter season.

Interference of sterile oat (Avena ludoviciana) and Mexican pricklepoppy (Argemone mexicana) in chickpea

“…The seeds of A. mexicana could persist in the soil for a longer period if fresh seed production, reinfestation, and dispersal are not controlled. In Australia, it was observed that at 2 and 10-cm soil depths, >30% of seeds of A. mexicana were viable after 42 months of seed burial (Manalil and Chauhan 2021). In another study, it was observed that plants of A. mexicana were unable to produce seeds when infested in wheat crop due to high competition offered by the crop (Manalil and Chauhan 2019).…”

Biotechnological Road Map for Innovative Weed Management

“…Most weed species are known to be hardy and persistent in nature, producing thousands of seeds that can withstand various adverse environmental conditions, while staying dormant in the soil for long periods ( Manalil and Chauhan, 2021 ; Chauhan and Manalil, 2022 ). When optimal germination conditions are met, the seeds will germinate and compete with the crops sown on the same area of land.…”

Interference of Brassicaceae weeds (Brassica tournefortii, Rapistrum rugosum, and Sisymbrium thellungii) in chickpea

“…The germination of R. rugosum was found to be >85% at temperatures ranging from 15/5 to 25/15 C (day/night temperature), suggesting the ability of this weed to germinate in winter environments (Manalil et al 2018). With optimal germination temperatures coinciding with chickpea cultivation, long seed persistence (>3.5 yr) in the soil and the ability to emerge from near the soil surface may increase R. rugosum infestation in chickpea crops in Australia (Gill et al 2022; Manalil and Chauhan 2021).…”