Effects of stratification, temperature, and oxygen on woolly cupgrass (Eriochloa villosa) seed dormancy

Laboratory and field experiments were conducted to determine the effects of temperature, oxygen, and seed burial depth on woolly cupgrass seed dormancy. Woolly cupgrass seeds at physiological maturity are innately dormant. Stratifying these seeds at 5 C for 8 wk increased germination to greater than 90%, regardless of the germination temperature. Alternating the germination temperature hastened germination by 2 wk, while seedcoat removal hastened germination by another 4 wk. Low oxygen concentration was more detrimental to seed germination when seeds were subjected to constant temperatures in comparison to alternating temperatures. Oxygen concentration did not affect seed germination when seeds were placed in an alternating 15/25 C regime. Seed germination was approximately 15% less when seeds were stratified for 2 wk and subjected to oxygen concentrations below the ambient oxygen concentration, whereas this decrease was present only at the 8% oxygen concentration when seeds were stratified 4 wk. In the field, the stratification requirement was satisfied by early December for the study year. Seeds remaining on the soil surface overcame dormancy sooner than seeds buried 2 or 4 cm.