Factors affecting seedbank dynamics of 'Lolium rigidum' Gaudin and other cropping weeds of northern NSW

Abstract

Annual ryegrass ('Lolium rigidum' Gaudin) is one of the most important weeds of the grain cropping regions of southern Australia. The over reliance on herbicides with similar modes of action has resulted in the evolution of herbicide resistance in many 'L. rigidum' populations. Recently, glyphosate-resistant 'L. rigidum' was discovered on the Liverpool Plains near Tamworth in northern NSW. Little published work exists on the current status of the size and composition of glyphosate resistant 'L. rigidum' seedbanks and other weeds identified as at risk of developing resistance on the Liverpool Plains. Also, there is little information available about the factors affecting dormancy and viability of 'L. rigidum' seeds or the effects of modified management (alternative tillage and burning) options on glyphosate resistant 'L. rigidum' seedbank dynamics, particularly in the northern grain region.