Four cool-season grass dry seeds of annual perennial(variety: Champion),Lolioum perenne(variety:Venus),Poa pratensis(variety:Glade),Festuca arundinacea(variety:Amigo) were treated with different doses of r-ray radiation processing.The treatments are 15000rad(named treatment Ⅰ),25000rad(treatmentⅡ),35000rad(treatmentⅢ).The doses used have little influence on the differentiation of seedlings of cool-season process,while treatment Ⅲ has a comparati...