Using a thermal time index to predict dormancy loss in Polygonum aviculare L. seeds.

BATLLA D. AND BENECH-ARNOLD R.L.

Brisbane, Australia

Congreso; VIII International Workshop on Seeds; 2005

International Society for Seed Science

A stratification thermal time index was developed to account for the effect of variable stratification temperature on Polygonum aviculare seeds dormancy loss. To develop the thermal time index changes in the thermal range permissive for germination of P. aviculare buried seeds were related to the accumulation of thermal time units under a threshold temperature for dormancy loss to occur. A set of experiments was designed to assess changes in the base water potential, the response to alternating temperatures and the sensitivity to light of P. aviculare seeds buried at different stratification temperatures. Changes in seed responses to the different environmental factors were also satisfactorily described by the developed thermal time index.. The data obtained with the whole experimental set was used to generate a model that might be able to predict seed responses to the most important environmental factors that usually triggers germination under natural conditions in relation to the temperature experienced by the buried seed-bank during winter. Moreover, model performance was evaluated against independent data showing acceptable prediction of timing and percentage of weed emergence under field and controlled conditions.