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

DIEGO BATLLA; ROBERTO LUIS BENECH-ARNOLD

Brisbane, Queensland, Australia

Workshop; VIII internacional Workshop on Seeds; 2005

International Seed Science Society

USING A THERMAL TIME INDEX TO PREDICT DORMANCY LOSS IN POLYGONUM AVICULARE L. SEEDS D. Batlla & R. Benech-Arnold Department of Plant Production, Faculty of Agronomy, University of Buenos Aires, Av. San Martín 4453, C1417DSE-Buenos Aires, Argentina; batlla@agro.uba.ar 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. Type of presentation preferred: Oral; Topic: Seed germination and dormancy