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Spring 2007
To make a comment or subscribe to News & Views alert, click here WAHRI NEWSPollen mediated gene flow of herbicide resistance can occur over long distances for annual ryegrass (Lolium rigidum) During the 2005 growing season, researcher Roberto Busi set up an experiment to study the distance that ryegrass pollen can travel using herbicide resistance as an indicator. The study was done in Salmons Gums on the fringe of the WA wheatbelt. Several 'sink' populations were placed in isolated locations in the bush adjacent to farming paddocks (source). When the plants had reached maturity, seeds were collected and screened to herbicide the following year. more Mutations endowing resistance to glyphosate and clethodim in Lolium rigidum and metsulfuron in barley grass WAHRI researcher Qin Yu has been working on mutation in annual ryegrass that endow resistance to glyphosate and clethodim. Her work. more Frequency of herbicide resistance in wild oat (Avena fatua) across the Western Australian wheat belt In October 2005 a random seed collection survey of wild oat was conducted across the Western Australian wheat belt. In 2006 this seed was used in an extensive resistance screening study. The results show that levels of resistance to Group A' 'fops' (Diclofop) and low levels of resistance to the 'dims' (sethoxydim and tralkoxydim). For preliminary results and more information, click here New discovery grant for seed dormancy An ARC discovery grant has been awarded to Powles and Steadman along with International collaborators R Benech-Arnold (Argentina), H Hilhorst (The Netherlands), and P Toorop (UK) to examine the role for phytochrome in regulating annual ryegrass seed dormancy release. more Efficacy of florasulam on chlorsulfuron resistant and susceptible wild radish populations in Western Australia Does liming to increase soil pH limit the growth and development of Wild Radish (Raphanus raphanistrum)? In 2006, fouth year student Matt Willis investigated the impact of liming to increase soil pH on the growth and development of wild radish plants. Matt also examined if increased soil pH resulted in a reduction in competitive ability of wild radish in cropping system.The results from this study, indicate that wild radish is at a competitive disadvantage when the soil pH is increased by liming in the presence of a wheat crop more Control of phenoxy resistant wild radish through the combined effects of wheat competition and phenoxy herbicides Natalie Maguire investigated the combined impact of wheat crop competition and the application of 2,4-D amine on the growth and survival of two 2,4-D amine resistant wild radish populations (WARR 12 and WARR 20) for her fourth year project. The study has shown that some resistant populations are still affected when treated with phenoxy herbicides. It has been demonstrated that effective control of resistant populations through a combination of wheat competition and phenoxy herbicide application has the potential to be used as a control option on at least some phenoxy resistant wild radish populations. However, the continued use these herbicides may lead to the evolution of populations such as WARR 20, which contain more robust levels of resistance to phenoxy herbicides. more Burn narrow windrows in the wind Researchers Peter Newmand and Michael Walsh have found that narrow windrows burn hotter for longer than conventional windrows or standing stubble which results in improved destruction of weed seeds. Burning narrow windrows in light wind helps to fuel the fire with oxygen and improves the reliability of destroying weed seeds at the soil surface. more Glyphosate resistance confirmed at new sites Glyphosate resistant ryegrass has been confirmed at 10 new locations in Australia with one new case have been confirmed in WA. The new populations are now listed on the Australian Glyphosate Resistance Register, bringing the total number of populations to 58, with 24 of the cases in broadacre cropping. All are in annual ryegrass. more RIM in national workshops for advisors and growers The computer model Resistance Integrated Management program (RIM) has been used extensively throughout Victoria as part of the DPI State Focus project. Over 250 growers and advisors used RIM as part of the program. RIM sessions are also part of a national IWM training program being conducted for advisors this year through the CRC Weeds and ICAN. For more information on organising a workshop using RIM for your group contact Robert Barrett Lennard New appointments at WAHRI Dr. Linh Nguyen and Dr. Qin Yu appointed to ARC grant to unravel the mysteries of resistance in ryegrass. Mid 2007 will see the commencement of an Australian Research Council grant funded to work on the molecular genetic basis of herbicide resistance in Lolium. This is a collaborative grant between WAHRI and the Victorian Agri-Bioscience Centre (VABC) and will bring together the expertise and technology platforms for Lolium biotechnology at VABC with the understanding of herbicide resistance within WAHRI. In May 2007 Dr Linh Nguyen will commence at VABC and Dr. Qin Yu will commence the WAHRI-based postdoc. There are high hopes that this collaboration will make major advances in our molecular level understanding as to how Lolium can resist so many herbicides. Visiting European PhD students return home WAHRI has had the pleasure of hosting lengthy and productive research visits for two European PhD students who each spent six months working on research within WAHRI. Joel Torra is near the end of his PhD at the University of Lleida in Spain in which he studied the biology and management of poppies, the most severe weed of Spanish cereal cropping. At WAHRI, he used his data and made modifications to the RIM model to make great progress towards his goal of developing a model for the management of poppies in Spanish cropping. Alberto Collavo, a PhD student from Italy brought with him from Italy various Group A resistant Lolium populations. Working closely with Dr Qin Yu in WAHRI he was able to determine several mutations of the ACCase gene responsible for resistance to Group A herbicides. Both Alberto and Joel were excellent contributors within WAHRI. Agronomy jobs for just-graduated WAHRI-trained UWA undergraduates. Each year, a number of final year agricultural science students undertake their major research project in WAHRI. Many of these former students are now working as agronomists/ crop consultants in the WA wheatbelt and elsewhere in the country. In 2006 there were three students based in WAHRI who were aiming to secure employment as agronomists in 2007, however, even before they had completed their final year these students had all secured employment in their chosen profession. Jared Nelson conducted his research on barley grass from Mukinbudin resistant to Group B herbicides and shortly after graduation Jared joined the Elders agronomy team and he is now based at Carnamah. Likewise, Natalie Maguire investigated the reduced competitive ability of phenoxy herbicide resistant wild radish populations and is now employed with Elders based at Merredin. Matt Willis studied the interaction of liming effects on wild radish growth and development and has a position based with Farmworks in Moora as the Synergy team consultant. WAHRI is extremely encouraged by how rapidly these students were able to secure jobs as agronomists/consultants and believe that the training we provide is a significant factor. 4th Year projects In 2007 there are two fourth year students, Meagan Pearce and Kent Stone, undertaking their final year research projects with WAHRI. Both students will be exploring herbicide resistance issues in wild radish populations. Meagan is investigating the mechanisms responsible for diflufenican resistance in wild radish populations while Kent is exploring the possibility that there is a non-target site mechanism that is responsible for resistance atrazine resistance in wild radish populations. Together these studies will further our understanding of herbicide resistance issues in wild radish populations.
2007 Llewellyn, R.S, Lindner, R.K., Pannell, D.J., Powles, S.B (2007) Herbicide resistance and the adoption of integrated weed management by Western Australian grain growers. Agricultural Economics, 36, 121-128. Llewellyn. R.S., Lindner, R.K., Pannell, D.J. Powles, S.B. (2007) The influence of extension on learning and doing. Agricultural Systems. (accepted) Michael PJ, Steadman KJ and Plummer JA (2007). Seed development in Malva parviflora: onset of germinability, dormancy and desiccation tolerance. Australian Journal of Experimental Agriculture 47 (6) (in press) Owen, M.J., Walsh, M.J, Llewellyn, R.S. and Powles, S.B. (2007) Widespread occurrence of multiple herbicide resistance in Western Australian annual ryegrass (Lolium rigidum) populations. Australian Journal of Agricultural Research, 58 (7) Pederson BP, Neve PB, Andreason C & Powles SB (2007). Ecological fitness of a glyphosate resistant Lolium rigidum biotype: Growth, competitiveness and seed production along a competition gradient. Basic and Applied Ecology, (In press) available on-line Reboud, X., Majerus, N., Gasquez, J., Powles, S.B. (2007) Chlamydomonas reinhardtii as a model system for pro-active herbicide resistance evolution research. Biological Journal of the Linnean Society. (In press) Yu, Q., Cairns, A., Powles, S.B. (2007) Glyphosate, paraquat and ACCase multiple herbicide resistance in a Lolium rigidum biotype. Planta, 225 (2), 449-513 Walsh, M.J., Powles, S.B. (2007) Management strategies for herbicide-resistant weed populations in Australian dryland crop-production systems. Weed Technology, (in press) For a list of the other recent WAHRI journal articles, click here News & Views is edited by Mechelle Owen & David Minkey |
