Assessing the impact of harvest aid timing on fibre quality and textile performance Dr Robert L. Long CSIRO Textile and Fibre Technology, Geelong, Australia

CSIRO The effect of harvest aid timing on fibre quality and textile performance There are concerns relating to high micronaire, short fibre content and neps in Australian cotton Management practices that force open immature bolls to include in the harvest to increase yield or to reduce micronaire may detrimentally effect fibre quality Harvest aids are typically applied from 60% open bolls to maximise yield and fibre quality Objective: Take a close look at harvest aid practice for a standard high yielding irrigated Gossypium hirsutum variety Assess: Yield and traditional fibre quality parameters (HVI) Novel fibre quality parameters maturity and linear density Fibre neps, treatment x lint cleaner Yarn and textile performance Background and aims

CSIRO The effect of harvest aid timing on fibre quality and textile performance Experimental design Gossypium hirsutum (Bollgard II® Roundup Ready® (Monsanto) Sicot 71BR (CSIRO, Australia) Experiment was established and grown with full irrigation and thorough insect control Harvest aid -0.2 L ha-1 Dropp Liquid® (Bayer CropScience, active constituent 500g L-1Thidiazuron) -3 L ha-1 Prep 720® (Bayer CropScience, active constituent 720g L-1 Ethephon) -2 L ha-1 D-C Tron® (Caltex, active constituent 991ml L-1 Petroleum Oil) Applied every 5 days from 143 days after sowing (8 treats) RCBD - ANOVA 4 replicates Harvested with a spindle picker and ginned using a 20 saw gin (pre cleaning, no lint cleaning)

CSIRO The effect of harvest aid timing on fibre quality and textile performance Plant status and yield

CSIRO The effect of harvest aid timing on fibre quality and textile performance HVI length and strength

CSIRO The effect of harvest aid timing on fibre quality and textile performance Fibre maturity

CSIRO The effect of harvest aid timing on fibre quality and textile performance Lint cleaner Feed loading ratio 100 gm -2 Saw speed 855 rpm Combing ratio optimised to 23 Grid bar (x4) distance 0.5 mm Lint cleaning

CSIRO The effect of harvest aid timing on fibre quality and textile performance Lint cleaning

CSIRO The effect of harvest aid timing on fibre quality and textile performance Yarn performance 168g (4 x 42g) Card 1 st drawing = 4 ends (4.5-5 ktex) 2 nd drawing full-scale ‘Shirley’ card – Platt Bros (England) ‘Shirley’ draw frame Trutzschler HSR1000 Zinser 660 twisted roving frame Zinser 350 ring spinning frame

CSIRO The effect of harvest aid timing on fibre quality and textile performance 20 tex ring spun yarns, twist factor of αe 4.0 (798 turns per metre) Early harvest aid 29% open boll Late harvest aid 100% open boll Yarn performance

CSIRO The effect of harvest aid timing on fibre quality and textile performance Yarn performance 20 tex ring spun yarns, twist factor of αe 4.0 (798 turns per metre)

CSIRO The effect of harvest aid timing on fibre quality and textile performance Fabric dyeing Knitted single jersey fabric on 10 inch F.A.K. circular knitter Scoured, and dyed with cibacron blue LS3R (1%) Reflectance via Gretag-Macbeth Color-Eye 7000A spectrophotometer

CSIRO The effect of harvest aid timing on fibre quality and textile performance Conclusion Yield was significantly less for treatments applied up to 56% open bolls, yet remained constant for later harvest aid treatments. Micronaire and linear density were significantly less for treatments applied up to 42% open bolls. Lint cleaning significantly generated neps at 100 counts/ g per LC passage but there was no strong evidence that the changes in fibre quality measured in the early treatments exaggerated the effect of LC on the level of neps and short fibre. No significant impact on yarn performance Dye uptake in knitted fabric was significantly less for treatments applied up to 42% open bolls Current practice of applying harvest aids at or more than approximately 60% open bolls will insure maximum yield, fibre quality and textile performance for this commonly grown Australian G. hirsutum variety

CSIRO The effect of harvest aid timing on fibre quality and textile performance Mike Bange, Stuart Gordon, Rene van der Sluijs, Geoff Naylor, Greg Constable Jane Caton, Darin Hodgson, Rebecca Giles, Fred Horne, Mark Freijah, Susan Miller, Geni Kozdra, Susan Horne and Colin Brackley Thanks