Seed germination ecology of Conyza stricta Willd. and implications for management

PLoS One. 2020 Dec 29;15(12):e0244059. doi: 10.1371/journal.pone.0244059. eCollection 2020.

Abstract

Numerous cropping systems of the world are experiencing the emergence of new weed species in response to conservation agriculture. Conyza stricta Willd. is being a newly emerging weed of barley-based cropping systems in response to conservational tillage practices. Seed germination ecology of four populations (irrigated, rainfed, abandoned and ruderal habitats) was studied in laboratory and greenhouse experiments. The presence/absence of seed dormancy was inferred first, which indicated seeds were non-dormant. Seed germination was then recorded under various photoperiods, constant and alternating day/night temperatures, and pH, salinity and osmotic potential levels. Seedling emergence was observed from various seed burial depths. Seeds of all populations proved photoblastic and required 12-hour light/dark period for germination. Seeds of all populations germinated under 5-30°C constant temperature; however, peak germination was recorded under 17.22-18.11°C. Nonetheless, the highest germination was noted under 20/15°C alternating day/night temperature. Ruderal and irrigated populations better tolerated salinity and germinated under 0-500 mM salinity. Similarly, rainfed population proved more tolerant to osmotic potential than other populations. Seeds of all populations required neutral pH for the highest germination, whereas decline was noted in germination under basic and alkaline pH. Seedling emergence was retarded for seeds buried >2 cm depth and no emergence was recorded from >4 cm depth. These results add valuable information towards our understanding of seed germination ecology of C. stricta. Seed germination ability of different populations under diverse environmental conditions suspects that the species can present severe challenges in future if not managed. Deep seed burial along with effective management of the emerging seedlings seems a pragmatic option to manage the species in cultivated fields. However, immediate management strategies are needed for rest of the habitats.

Publication types

  • Research Support, Non-U.S. Gov't
  • Retracted Publication

MeSH terms

  • Agricultural Irrigation
  • Biomass
  • Conyza / growth & development*
  • Germination*
  • Salinity
  • Soil / chemistry
  • Temperature
  • Weed Control / methods

Substances

  • Soil

Grants and funding

The current study was partially supported by Directorate of Land Reclamation, Lahore, Pakistan. The study also was also supported by the Researchers Supporting Project (RSP-2020/173), King Saud University, Riyadh, Saudi Arabia. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.