Time of sowing trials in south west Victoria over four years have showed that sowing in the last week of April and first week of May gives the highest wheat yields.
CSIRO research team leader James Hunt said the key to sowing early is selecting the best variety to suit the time of sowing.
“Sowing within five days of the optimal sowing window will give the best results, so growers who want to sow a majority of their wheat program within its optimal window can do so by choosing a range of varieties including fast and slow spring wheats and winter wheats,” he said.
Trials were conducted across Victoria including Quambatook, Westmere, Inverleigh, Hamilton and by Baker Seed Co at Rutherglen.
Trials by BCG and FAR Australia at Quambatook compared crops sown on April 1 and May 6. Of all varieties sown on April 1, Wedgetail and Rosella were the best performers, with spring wheats Lancer and Scout severely damaged by several frost events.
“This shows the importance of lining up the sowing date with the variety. Spring wheats sown too early had headed early in the season so were hit hard by frost, whereas winter wheats were held back by their vernalisation (cold) requirement so were less susceptible to frost in July and August,” Dr Hunt said.
Wedgetail sown on April 1 out-yielded Scout sown on May 6 by 0.3t/ha, demonstrating that winter wheats can succeed in the Mallee. Slow-maturing spring wheat Lancer yielded the highest out of all varieties sown on May 6, a result likely due to its slower maturity meaning it escaped flowering frost in mid-September.
Time of sowing trials were conducted by SFS and FAR Australia at Westmere, Inverleigh and Hamilton with three to four sowing dates and six to eight varieties at each site.
Beaufort, a slow-maturing spring wheat, was the best performer of the feed wheats, with Trojan and Derrimut giving the highest yields of the milling wheats (Table 1).
Table 1: Western Districts best performers in time of sowing trials
||Ideal Sowing Date
||May 8 - May 21
A key barrier to sowing earlier in south-west Victoria is Septoria tritici blotch (Zymoseptoria tritici). Grazing or furrow applications of flutirafol were shown to have a significant effect on infection severity, equivalent to a foliar fungicides at Z31 (Figure 1).
Figure 1: Influence of early application of seed treatment, in-furrow flutriafol, grazing and GS31 fungicide on STB control in early sown wheat (11 April) with Revenue in Inverleigh, Victoria 2014. Source: James Hunt.
The highest yields in the trials conducted by Baker Seed Co in north-east Victoria came from sowing at April 29 with slow to mid-fast maturing spring wheats, with earlier sowing dates severely infected by Barley Yellow Dwarf Virus and lower yields for later sowing dates.
“The results of the Rutherglen trials demonstrates the importance of aphid control when sowing early, especially in years such as 2014 where warm May conditions resulted in later persistence of aphids. Wheat sown early need to be treated with an appropriate seed treatment and backed up with a foliar insecticide,” Dr Hunt said.
02 6246 5066
Read the GRDC update paper
Long season wheats pose stem rust risk
The risks of developing stem rust in longer season winter wheat crops are being highlighted as Victorian wheat growers begin to prepare for the 2015 growing season.
Plant pathologist at the South Australian Research and Development Institute (SARDI) Dr Hugh Wallwork, who is part of the Australian Cereal Rust Control Program with Department of Economic Development, Jobs, Transport and Resources Plant pathologist Dr Grant Hollaway said growers needed to be aware of the susceptibility ratings of the long-season wheats and to ensure they plan appropriately to manage any rust outbreaks.
“Some of the longer season winter wheats are attractive for their high yield but the problem is that some of them have susceptible or very susceptible ratings to stem rust and this is made worse by a greatly shortened break between crops over summer in the long season cropping areas,” he said.
“Rust needs a green living host, often called the green bridge, to survive between the seasons. Normally this is in the form of volunteer cereals growing as weeds, however, in the areas where these long season wheats are grown, the natural summer break between crops is greatly reduced. This therefore requires greater monitoring and rust management planning to prepare for any potential outbreaks.
“Stem rust is the most difficult of the three types of rust to control with fungicide as it is difficult for foliar fungicides to penetrate the canopy and protect the stem.”
Dr Wallwork advised that growers choosing a long-season wheat obtain information on that variety’s susceptibility rating from the breeding company or their local advisor before seeding and ensure they have an effective stem rust monitoring plan in place.
“There are other long-season wheat varieties available that have a higher stem rust resistance rating, including Bolac, Forrest, EGA-Wedgetail, Manning and SQP Revenue, and we recommend that growers should, if possible, look to growing these or others with stem rust resistance in the next season,” he said.
Cereal disease variety guides can be found at the RustBust website
03 5362 2111