annual ryegrass

Enhanced production of water-soluble cinmethylin metabolites by Lolium rigidum populations with reduced cinmethylin sensitivity

Dr Danica Goggin

Cinmethylin, a pre-emergence herbicide inhibiting fatty acid thioesterase activity, has recently been introduced to Australian cereal cropping for the control of Lolium rigidum Gaud. (annual ryegrass). To date, there have been no confirmed cases of cinmethylin resistance identified in this species, but some populations exhibit reduced sensitivity to this herbicide.

Transfer of resistance alleles from herbicide-resistant to susceptible grass weeds via pollen-mediated gene flow

This paper reviews the reproductive biology, herbicide-resistant biotypes, pollen-mediated gene flow (PMGF), and potential for transfer of alleles from herbicide-resistant to herbicide-susceptible grass weeds including barnyard grass, creeping bentgrass, Italian ryegrass, Johnson grass, rigid (annual) ryegrass, and wild oats.

A dinitroaniline herbicide resistance mutation can be nearly lethal to plants

Dr Yanhui Wang and Dr Heping Han

Lolium rigidum is the most important weed in Australian agriculture and the pre-emergence dinitroaniline herbicides (e.g. trifluralin) are widely and persistently used for Lolium control. Consequently, resistance evolution to dinitroaniline herbicides has been increasingly reported. Resistance-endowing target-site 𝛼-tubulin gene mutations are identified with varying frequencies. The present study investigated the putative fitness cost associated with the common resistance mutation Val-202-Phe, and the rare resistance mutation of Arg-243-Met causing helical plant growth.

Download PDF

Rapid On-Farm Testing of Resistance in Lolium rigidum to Key Pre- and Post-Emergence Herbicides

Lolium rigidum (annual ryegrass) is a species that is prone to evolve resistance to a wide range of herbicide modes of action. Rapid detection of herbicide-resistant weed populations in the field can aid farmers to optimise the use of effective herbicides for their control.

Download PDF

Pyroxasulfone-Resistant Annual Ryegrass (Lolium rigidum) Has Enhanced Capacity for Glutathione Transferase-Mediated Pyroxasulfone Conjugation

The herbicide pyroxasulfone was widely introduced in 2012, and cases of evolved resistance in weeds such as annual ryegrass (Lolium rigidum Gaud.) and tall waterhemp [Amaranthus tuberculatus (Moq.) Sauer] have started to emerge.

Download PDF

Loss of trifluralin metabolic resistance in Lolium rigidum plants exposed to prosulfocarb recurrent selection

This study provides evidence that trait(s) enabling efficient trifluralin metabolism in Lolium rigidum are purged from the population under prosulfocarb recurrent selection.

It is speculated that survival to prosulfocarb via a lack of metabolic herbicide activation, and survival to trifluralin conferred by enhanced herbicide metabolism, are mutually exclusive.

Download PDF

Metribuzin resistance via enhanced metabolism in a multiple herbicide resistant Lolium rigidum population

Most Australian crop farm populations of the grass weed Lolium rigidum are multiple herbicide-resistant. Most resistant populations exhibit target site mutations (e.g. ACCase, ALS), as well as metabolic resistance due to cytochrome P450, catalysed by enhanced rates of herbicide metabolism.

Download PDF

A Val-202-Phe alpha-tubulin mutation and enhanced metabolism confer dinitroaniline resistance in a single Lolium rigidum population

The research by AHRI PhD student Jinyi Chen (now Dr Jinyi Chen!) documents both target site and non-target site resistance to dinitroaniline herbicides in Lolium individuals. We are long accustomed to documenting multiple mechanisms of resistance existing within Lolium individuals/populations because of the high genetic diversity and obligate cross-pollination between Lolium which enables multiple resistance mechanisms to be a frequent occurrence.  In this particular Lolium population, resistance to dinitroaniline herbicides is due to a mutation in the alpha tubulin gene (Val-202-Phe) and non-target site enhanced rates of dinitroaniline herbicide trifluralin metabolism.   Unequivocal evidence for the target site Val-202-Phe mutation endowing resistance was obtained by expressing in transgenic rice, where it endowed resistance.

Download PDF

Genetic inheritance of dinitroaniline resistance in an annual ryegrass population

The increasing number of weedy species resistant to dinitroaniline herbicides warrants studies on the evolutionary factors contributing to resistance evolution, including genetic inheritance of resistance traits.

In this study, the researchers investigated the genetic control of trifluralin resistance in a well-characterised Lolium rigidum Gaud. (annual ryegrass) population from Western Australia. This population was purified to contain plants homozygous for the Val-202-Phe α-tubulin mutation, and used as the resistant (R) parents and crossed with susceptible (S) parents to produce eight reciprocal F1 families.

Download PDF

Influence of Crop Competition and Harvest Weed Seed Control on Rigid Ryegrass (Lolium rigidum) Seed Retention Height in Wheat Crop Canopies

The obvious evolutionary reality is that persistent use of harvest weed seed control (HWSC) is a selection pressure for any mechanisms enabling L. rigidum seed to avoid HWSC. For example, seed shatters before grain harvest or a greater percentage of retained seed at a height below that at which the crop is cut in the harvesting operation.

Download PDF

1 2

Get access to short and sharp insights into the world of more crop, fewer weeds with AHRI Insight.
Subscribe Now