Australia
May 17, 2017
There has been a lot of talk about time of sowing and when it comes to matching wheat variety with climatic conditions to maximise grain yield potential, planting time is a critical part of the farming equation.
NSW DPI crop physiologist Felicity Harris said growers need to consider how different wheat varieties develop and yield in different environments.
Long-term results from a Grains Research and Development Corporation (GRDC) and NSW Department of Primary Industries (DPI) investment in southern New South Wales has reinforced the importance of sowing time as a key tool for wheat growers in their quest to lift productivity.
NSW DPI crop physiologist Felicity Harris said results emphasised the need for growers to consider development characteristics of specific wheat varieties and the effect different environments have on yield to effectively time planting.
“The aim is to have crops flowering in the optimum window to maximise potential yield,” Dr Harris said.
“Wheat varieties suited to southern NSW vary in phenology from slow developing winter wheats to fast developing spring varieties.
“The optimum flowering window is determined by balancing water-use during canopy development, grain formation-filling stages and declining frost risk.
“Crops that flower too early are unable to produce enough biomass to support grain yield and have increased risk of frost damage, while crops that flower too late have increased risk of heat and moisture stress.”
She said wheat varieties differed in their ability to achieve high grain yields at different planting times from very early sowing (early April), to early (mid-April to early May) or main season (late April onwards).
Last year southern NSW experienced a warmer winter and cooler spring with above average rainfall during winter and early spring.
“The milder winter meant thermal time accumulated rapidly, so many varieties developed quickly, reaching stem elongation and flowering 10 to 14 days earlier than in 2015,” Dr Harris said.
“Despite this, the lack of frost events during winter and mild conditions during grain-fill meant varieties, which flowered earlier or later than optimum, did not suffer yield penalties.
“Above average rainfall resulted in some waterlogging, in other situations good soil moisture and milder spring temperatures produced late tillers, which delayed harvest particularly for early flowering crops.”
Dr Harris said 2016 trials in southern NSW, including Condobolin and Wagga Wagga, evaluated the varietal performance of commercial varieties and new lines planted at three different sowing times from mid-April to late May.
Despite warmer temperatures and limited frost events, the accelerated development of fast spring varieties, like Hatchet CL Plus
and Dart, meant early-sown crops were exposed to frost and suffered yield penalties.
Dr Harris said a cooler spring last year favoured late-maturing varieties to deliver reasonably stable yields across the three sowing dates, with the greatest grain yields in Condobolin achieved from early sowing.
Slower developing varieties, such as EGA Wedgetail, EGA Eaglehawk, Bolac, Cutlass and Longreach Lancer , achieved high yields from earlier sowing. Newly released winter wheat Longreach Kittyhawk yielded similarly to EGA Wedgetail, flowering three to four days earlier. Delayed sowing of fast maturing varieties, such as Hatchet CL Plus, Longreach Dart, Condo, Sunmate, Emu Rock, Corack and Longreach Reliant , had positive grain yield responses, with the highest yields delivered by the later May 20 sowing time.
Some varieties, such as BeckomA, CoolahA, ScepterA, LongReach TrojanA and LongReach LancerA , have shown flexibility in sowing date across 2015 and 2016, achieving above site mean grain yields consistently across sowing times.
“All seasons are unique, so it is important to consider the suitability of varieties based on matching phenology and sowing time for your growing environment,” Dr Harris said.
Long term yield comparisons of varieties across a range of environments are available online, http://www.nvtonline.com.au/
Species
