Effects of Temperature on Germination in Populations of Dactylis glomerata from NW Spain and Central Italy

Abstract

A study of the germination requirements of local populations of Dactylis glomerata from NW Spain and central Italy showed that, with the exception of one ecotype from central Italy, there was a positive germination response to alternating temperatures. With five bred varieties from the Welsh Plant Breeding Station, Aberystwyth there was no such response and constant temperatures were as effective as alternating temperatures. A low temperature treatment (2 °C) before germination at constant temperatures, also increased germination of the Spanish and Italian populations with the exception of the ecotype from central Italy. Increasing air temperature from 15 °C to 25 °C during seed development increased subsequent germination at constant and alternating temperatures. The relationship between the mean July temperature and the germination of seven stocks of a diploid cocksfoot from NW Spain suggested that, under field conditions also, air temperature at the time of seed development is an important factor determining seed germination.