Ground Cover Supplement : GC Supplement - National variety trials
ground cover national variety trials 14 Resistance versus fungicides for disease control Resistance breakdown has increased the need to evaluate the place of fungicides in profitable foliar disease control in new varieties DiseAse MANAGeMeNt NeeDs to be an integrated package of measures and many believe that foliar fungicides represent the last line of defence when other measures have failed. to allow variety entries in NVt to clearly demonstrate their genetics for disease resistance, trials are run without the use of fungicides, unless extreme disease pressures exist and disease control of the entire site is requested by the grower who is the co-operator of the trial. yet the recent run of new rust incursions and breakdown of resistance has increased the reliance of growers on foliar fungicides to maintain the performance of key cereal varieties. this has been especially true in Western Australia (Figure 1). in response to growers’ requests, a foliar fungicide trial on wheat has been funded by the GrDc and is being run in parallel with NVt in WA. “the fungicide trial has been established to help illustrate the economic impact of relying on inherent variety resistance versus a package of variety resistance and strategic use of fungicides,” explains Peter Burgess, from Kalyx Agriculture, who is running the trial. the field trials were established in 2008 in locations designed to achieve a high level of infection for the diseases yellow spot, Septoria nodorum and stripe rust. these diseases have been targeted for evaluation as they are the three most yield-limiting diseases affecting WA wheat crops. this project will investigate the benefits to growers – in terms of yield, quality and financial benefit – of foliar fungicides applied as per commercial practice for the control of yellow spot, Septoria nodorum and stripe rust over a range of current and soon-to-be-released varieties, which are being evaluated in the NVt program. By providing an economic analysis for each variety, the plus and minus disease-control treatments will help growers to benchmark new varieties against their current varieties and to make more informed decisions on variety retention and selection for their farming enterprise. “Growers need to ensure that variety performance and farm profitability is not compromised, and breeders need the fungicide option – not to develop rust sucker varieties, but to have a buffer should unforeseen variety breakdown occur, especially as new varieties can take some time to be developed and reach the marketplace,” Mr Burgess says. □ more information: Peter burgess, managing director, Kalyx Agriculture, 08 6278 1777, email@example.com nvt resources TABlE 1 WA ExPERIENCE Of ThE SUSCEPTIBIlITy Of ThE MOST POPUlAR WhEAT VARIETIES TO fUNGAl DISEASE AND ThEIR POTENTIAl REPlACEMENTS variety Percentage of Wa plantings susceptibility to rust replacements Wyalkatchem A 30% in years of high stripe rust disease pressure will lose up to 1t/ha of yield potential soon-to-be-released replacements from all major breeding programs calingiri 16% stripe rust in 2004 october 2008 should see a variety released that has similar environmental adaptability, season length, yield and improved quality carnamah A 9% Plantings are reducing Possible replacement varieties soon to be released arrino 8% leaf rust in 2000 followed by stripe rust in 2004 binnu A and possibly yandanooka may be suitable replacements in 2009, although agronomically different ega bonnie rock A 7% very low stripe rust resistance replacement types in the pipeline Westonia 5% low leaf rust and stripe rust resistance replacement types in the pipeline from two major breeding institutions www.nvtonline.com.au ‘RESOURCES’ ‡ Cereal Rust Reports WhEATS IN WESTERN AUSTRAlIA In 2007 six WA-bred wheat varieties made up 75 per cent of all WA wheat plantings (Table 1). All are susceptible to at least one of the three rust types (leaf, stripe and stem). These varieties have returned millions of dollars to WA growers since their adoption, but fungal disease incursions can severely restrict yield potential if left unchecked by fungicide control. For example, in the NVT trial at Munglinup, WA, in 2006, with no fungicide application, Wyalkatchem A yielded 1.2 tonnes a hectare less than the highest-yielding variety in the trial, Carnamah A 1.4t/ha less, and Calingiri a massive 2.2t/ha less. There are now indications that there may be replacement varieties in the pipeline that perform equally well and have improved disease resistance.
GC Supplement - Feedgrains
GC Supplement - Grain hygiene