Factors affecting seed germination and emergence of Aegilops tauschii

Information on seed germination and emergence ecology of Aegilops tauschii is scant, despite it being a widespread invasive weed in China. We conducted this study to determine the effects of various factors on seed germination and seedling emergence in three A. tauschii populations. Seeds germinated across a wide range of temperatures (5-35 degrees C), with germination of over 90% at 15-20 degrees C. Germination was completely inhibited when dry seeds were exposed to a temperature of 160 degrees C for 5 min; a similar response was observed for pre-soaked seeds at 100 degrees C. Light was neither required for nor inhibited germination. Germination was not significantly affected by pH. Aegilops tauschii was relatively tolerant to low osmotic potential and high salt stress: over 80% of seeds germinated at -0.3 MPa, and all three populations germinated in the presence of 400 mM salt (NaCl) although salt tolerance varied among the populations. Seeds buried at depths of 1-3 cm emerged well, but emergence was completely inhibited at depths greater than 8 cm. The addition of maize straw caused a linear reduction in seedling emergence, although the rate of reduction varied among the populations. The results of this study have contributed to understanding the requirements of A. tauschii germination and emergence and optimising an integrated management system for this weed in Huang-Huai-Hai Plain of China. In addition, our study provides data for development of models to predict the geographical distribution of this weed.