Farmers are shifting from swathing to direct harvesting of canola. This allows them to speed up their operations. It is unclear if all cultivars chosen by growers are suitable for direct harvesting. Whilst cultivars are marketed as suitable for direct harvesting, there appears to be no systematic testing of cultivars to determine if these claims stack up. In particular it is unknown if some cultivars shed more seed prior to harvest than others. If farmers move to direct harvesting this could become an issue.
Bayer have just released a variety (IH51 RR) into the Australian market which has their podguard trait. This is a non GM trait which is reputed to virtually eliminate shedding of seed out of the pods of canola. This trial includes another Bayer Podguard line and this experiment will provide a source of independent testing of the trait in Western Australia.
To determine if canola cultivars vary in their rates of shedding.
|Property||Esperance Downs Research Station – Gibson, paddock W14|
|Agzone 6 growing season rainfall (GSR, April - October)||352mm, GSR + stored water (estimate) = 387mm|
|Soil type||Fleming sand/duplex (1.46% organic carbon)|
|Paddock rotation||2015 - canola, 2014 - wheat, 2013 - pasture, 2012 - pasture/oats sown for grazing, 2011 - pasture, 2010 - barley, 2009 - canola|
|Sowing date||28 April with Impact in-furrow 400mL/ha|
|Fertiliser||400kg/ha of gypsum (17% Ca, 14% S) and 120kg/ha of Muriate of Potash topdressed over whole site before seeding, 110kg/ha of Agras No.1 at seeding (16%N, 9.1%P, 14.3%S, 0.06% Zn), 100L/ha of UAN (32%N) 9 June|
|Sprays||28 April – 2L/ha Treflan + 2L/ha SpraySeed, 6 May – 80mL/ha Talstar, 24 June - 100g/ha Lontrel Granule, 330mL/ha Select Xtra, plus Hasten 1%; 18 August – 450mL/ha Prosaro|
|12 treatments|| |
Four cultivars - AN14R9012, IH30 RR, Hyola 404RR and ATR Stingray
Three harvest times - on time, three weeks later and six weeks later
|Split plot design|| |
Main plots – times of harvest, sub plots – varieties
At the first harvest on 4 November, the podguard variety AN14R9012 had the lowest losses both before and during harvest. ATR Stingray had less shedding prior to harvest than Hyola 404RR and IH30RR – which had highest losses during harvest and highest losses overall.
In between the first harvest on 4 November and the second harvest on 25 November we experienced extreme weather events. Fire and harvest bans were in place so we were unable to conduct our second harvest as planned, two weeks after the first harvest. On 17 November wind gusts of 87km/hr combined with 40°C temperatures caused widespread catastrophic fires in the Esperance region. Therefore we delayed the second harvest to three weeks after the first harvest and decided to change the third harvest to six weeks after the first to allow for an even period between harvests.
Under these extreme weather events all varieties dropped pods and shed seeds between the first and second harvests. The podguard line AN14R9012 losses were mostly due to pod drop as we were able to count and weigh unopened pods in the trays below AN14R9012 whilst Hyola 404RR had very low numbers of un-opened pods. It would have been interesting to have had swathed treatments to investigate if AN14R9012 would have held onto its pods better within a swath compared to a standing crop.
Between the second and third harvests the crops were exposed to wet weather and associated strong frontal winds gusting at 67-72km/hr on 6-7 December. This led to a further loss in yield.
Bayer podguard variety AN14R9012 produced highest yield, equal highest oil and highest oil yield and had the lowest overall loss in yield with delayed harvest of 735kg/ha, equivalent to a 27% yield loss worth $385/ha. Hyola 404RR and IH30RR had the highest yield losses of ~1.4t/ha, equivalent to a 60-64% yield loss worth ~$750/ha, and ATR Stingray had losses of ~1.2t/ha, equivalent to a 49% yield loss worth $580/ha.
This trial (15ED07) is one of a series conducted throughout WA as part of the GRDC/DAFWA co-funded project Tactical Break Crop Agronomy in Western Australia. Thanks to the Chris Matthews for excellent trial management. Pam Burgess (DPIRD Esperance) provided technical assistance to ensure all measurements occurred in a timely and accurate fashion.