Differences in emergence of Echinochloa crus-galli populations
Echinochloa crus-galli (Poaceae) has a very wide global distribution and the species is considered to be native to tropical Asia. It is invasive in Africa, Asia, North and South America. Australia and New Zealand. E. crus-galli is widespread in the EPPO region and recorded as invasive in Denmark, Italy and Portugal (Azores and Madeira). E. crus-galli can grow in a wide range of environmental conditions including varying temperatures and rainfall. Throughout the range of Echinochloa crus-galli, there is the potential that populations have adapted to different climates and farming systems and in-particular emergence patterns may vary between populations. This could have an impact on management programmes which may therefore need to be adapted to different regions and land use. Seed was collected from two populations (Italy and Norway) and with this seed field experiments were set up in 10 countries (Denmark, Iran, Italy, Latvia, Norway, Poland, Portugal, Spain, Sweden and Turkey) where seed were buried 5 cm deep in pots (with soil from the original location) in the autumn (2015). In spring 2016, the soil in the pots was disturbed and emergence parameters (total emergence, time of emergence) were recorded at each location. The Italian population showed a higher emergence than the Norwegian population in Southern locations. In almost all locations, Norwegian populations emerged earlier but the periods from 25% to 75% emergence were similar for both populations. Total emergence, and the times of onset and end of emergence seemed to be mainly under genotypic control, suggesting there were different temperature thresholds for seedling emergence in each population. Conversely, the duration of emergence seemed to be mainly under environmental control.
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Royo-Esnal A, Onofri A, Loddo D, Necajeva J, Jensen PK, Economou G, Taab A, Synowiec A, Calha IM, Anderson L, Uludag A, Uremis I, Murdoch AJ, Tørresen KS (2021) Comparing the emergence of Echinochloa crus-galli populations in different locations. Part I: Variations in emergence timing and behaviour of two populations. Weed Research. https://doi.org/10.1111/wre.12525