2017

iHSD Mill Efficacy on the Seeds of Australian Cropping System Weeds

This research paper, “iHSD mill efficacy on the seeds of Australian cropping system weeds” by M Walsh, J Broster, S Powles, quantifies the efficacy of Harrington Seed Destructor (HSD) mills in destroying weed seed in the grain harvester chaff fraction.

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PAM: Decision Support for Long-Term Palmer Amaranth (Amaranthus palmeri) Control

pigweed

PAM is a bio-economic model focussed on simulations of Palmer amaranth control practices that can be used to control this devastating weed in US crop production farming systems. PAM was produced at the University of Arkansas (M Bagavathiannan now at Texas A & M), particularly involving the program led by Jason Norsworthy.

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A double EPSPS gene mutation endowing glyphosate resistance shows a remarkably high resistance cost

This study was done with an Eleusine indica population originating from Malaysia that evolved resistance to glyphosate. This population was studied by AHRI PhD research student Adam Jalaludin. He established that this population exhibits extremely high-level glyphosate resistance (Jalaludin et al, 2014, Weed Research).  Subsequent AHRI mechanistic studies found that this high-level glyphosate resistance is conferred by a double mutation within the EPSPS gene, known as TIPS, 102 Ile/106 Ser (Yu et al, 2015, Plant Physiology). Thus far, this is the only known case of this novel glyphosate resistance endowing double TIPS mutation evolving in weed plants under glyphosate selection.

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How do spatial heterogeneity and dispersal in weed population models affect predictions of herbicide resistance evolution?

Gayle Somerville, pre-em

Weed population simulations can be useful to predict the effects of alternative management practices on herbicide resistance (HR) evolution. Almost all previous simulations have ignored the possibility ofwithin-field spatial structure in a weed population, instead making the implicit assumption of perfectdispersal and spatial homogeneity in population density and genetics. The effects of this simplifying assumption have not been examined, despite the fact that dispersal limitations and spatial structure within the population are likely to occur and to affect the evolution of resistance. Therefore, we developed a new spatially-explicit model called SOMER. Click through for more.

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High Levels of Adoption Indicate That Harvest Weed Seed Control Is Now an Established Weed Control Practice in Australian Cropping

Not so long ago, harvest weed seed control (HWSC) was only used by a minority of early adopting grain growers. Now it has gone mainstream and pretty soon just about everyone will be doing it.

This is the result from a national Australian GRDC grower survey reported in a recent scientific publication by Michael Walsh from University of Sydney. Every few years GRDC fund a large grower practices telephone survey. The most recent survey was conducted by CSIRO in 2014, and they collaborated with Michael to design the HWSC questions.

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Harvest Weed Seed Control Systems are Similarly Effective on Rigid Ryegrass

harvest weed seed control

Our latest published paper is Harvest Weed Seed Control Systems are Similarly Effective on Rigid Ryegrass by Michael Walsh, Charlotte Aves & Stephen Powles. This field research led by Michael Walsh was in itself a major logistics task. AHRI purchased, with GRDC support, a John Deere combine grain harvester, which was transported across the nation from west to east at wheat harvest time.

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Inheritance of 2,4-D resistance traits in multiple herbicide-resistant Raphanus raphanistrum populations

Wild radish in flower

Arelatively low number of weed species have evolved resistance to auxinic herbicides despite their use for almost 70 years. This inheritance study with two Raphanus raphanistrum populations multiple-resistant 2,4-D and the ALS-inhibiting herbicide chlorsulfuron determined the number of genes and genetic dominance of 2,4-D resistance and investigated the association between traits conferring resistance to the two herbicide modes of action. Levels of 2,4-D phenotypic resistance and resistance segregation patterns were assessed in parental populations, F1 and F2 families.

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Characterisation of glufosinate resistance mechanisms in Eleusine indica

An Eleusine indica population has evolved resistance to glufosinate, a major post-emergence herbicide of global agriculture. This population was analysed for target-site (glutamine synthetase) and non-target-site (glufosinate uptake, translocation and metabolism) resistance mechanisms.

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Can herbicide safeners allow selective control of weedy rice infesting rice crops?

Rice is a major field crop of paramount importance for global food security. However, the increased adoption of more profitable and resource-efficient direct-seeded rice (DSR) systems has contributed to greater weed infestations, including weedy rice, which has become a severe problem in several Asian regions. In this study we have developed a conceptually novel method to protect rice plants at high doses of clomazone and triallate.

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