Contribution of leaves to the yield of sunflowers - Gurley
2015 - 2016
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To quantify the contribution of different sunflower leaves to yield and oil quality through applying 12 leaf defoliation treatments.
Sunflower yields were very low at this site in 2015–16, averaging 0.24 t/ha, and overall variability was very high.
The total removal of leaves at the budding stage had the largest impact on plant structures; plant height, head diameter and arc length.
Lead research organisation
Department of Primary Industries NSW
Host research organisation
Trial funding source
Trial funding source
DPI NSW DAN00197
Tactical agronomy for selected crops in the northern region (safflower, linseed, sunflower)
This experiment was part of the project Tactical agronomy for selected crops in the northern region (safflower, linseed, sunflower) (DAN00197), with joint investment by NSW DPI and GRDC. Thanks to Nuseed and Neil Weier for supplying experiment seed. Technical assistance provided by Delphi Ramsden, Angus Hombsch, Alice Bowler and Bronwyn Brennan (NSW DPI) is gratefully acknowledged. Thanks to Doug Clark, ‘Kyntyre’, Gurley for hosting the experiment.
Trial results Affect from defoliation treatments on sunflower plant structures
Head diameter (cm)
Plant height (cm)
Head arc length (cm)
Control - no leaves removed (0/3)
Budding - remove all leaves (3/3)
Budding - remove top 10 leaves (1/3)
Budding - remove top 20 leaves (2/3)
Budding - remove bottom 10 leaves (1/3)
Start of flowering - remove top 10 leaves (1/3)
Start of flowering - remove top 20 leaves (2/3)
Start of flowering - remove all leaves (3/3)
Start of flowering - remove bottom 10 leaves (1/3)
Flowering complete - remove top 10 leaves (1/3)
Flowering complete - remove top 20 leaves (2/3)
Flowering complete - remove all leaves (3/3)
Head arc length cm
Head diameter cm
Plant height cm
Site 3, Gurley NSW 2015
Observed climate information
Rainfall avg ann (mm)
Rainfall trial gsr (mm)
Derived climate information
Site 3, Gurley NSW
NOTE: Exact trial site locality unknown - Climate data may not be accurate
SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.
Loretta Serafin, Mark Hellyer and Peter Perfrement (NSW DPI)
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Trial last modified: 06-08-2019 07:54am AEST
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