Base Temperatures for Germination of Selected Weed Species in Iran

Weed emergence models require the estimation of base temperature for germination (Tb) that was estimated for Abutilon theophrasti, Echinochloa crus-galli, Amaranthus retroflexus, Sorghum halepense, Amaranthus albus, and Amaranthus hybridus in Iran, to calibrate an existing model called AlertInf. Two statistical procedures were adopted: Model 1 - linear regression of germination rate and Model 2 - probit analysis. Model 1 provided lower Tb values. Abutilon theophrasti and A. hybridus presented lower Tb values (about 4 and 8°C), while the remaining species had values above 10°C. Since the estimated values of Tb were in agreement with those adopted for the Alertinf model in Italy, the first step was achieved to adapt AlertInf to Iranian conditions.