Predicting dormancy changes in weed seed banks: a simulation model for Polygonum aviculare L

ROBERTO BENECH-ARNOLD Y DIEGO BATLLA

Durban, Sudáfrica

Conferencia; IV International Weed Science Congress.; 2004

International Weed Science Society

Dormancy is a common attribute of many weed seed populations, and this hampers the task of predicting emergence from weed seed banks under field conditions. Of the many environmental factors that regulate seed behaviour in the field, temperature has been identified as one of the main factors governing changes in dormancy status of seed populations. On this basis, 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 permissive thermal range for germination,  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 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.