Project overview
As Australian cotton moves fully into varieties containing XtendFlex®, growers and agronomists need clear guidance on how these new varieties respond to Mepiquat Chloride (MC) which is an important tool for managing canopy growth, maturity, and yield. While MC is widely used across the industry, responses can vary greatly depending on variety, timing, crop stress, and seasonal conditions, creating uncertainty and inconsistent outcomes.
This Initiative was developed to generate robust, variety-specific data that helps growers apply MC with confidence. The project uses drone-applied MC treatments, aerial crop monitoring, and physical growth measurements to quantify how varieties respond at first flower (FF), mid-flower (MF), and across different rates. These trials build on existing variety evaluation sites, ensuring efficient, replicated comparisons under real-world conditions.
The project will deliver practical, field-tested recommendations to support canopy management in cotton crops, helping growers achieve more predictable growth, stronger boll retention, and improved yield outcomes under a range of seasonal scenarios.
Outcomes and achievements
- Designed a structured investigation with six MC treatments across key timings: FF Low/High, FF+14 days Low/High, and split-timing programs
- Validated drone-based MC application as a precise and cost-effective method for consistent PGR treatment delivery
- Integrated aerial monitoring using drones for daily NDVI and canopy growth tracking across a 30-day monitoring period
- Aligned all in-season measurements (height, NAWF, internodes, retention, growth habit) with best-practice protocols to enable comparable data across sites
- Combined CSD Farms + grower trial sites (Gwydir & Darling Downs) to maximise trial efficiency and variety representation
- Generated insights that will directly feed into future variety management guides and CSD decision-support tools (including CottonTracka).
Key contributors and partners
Our thanks to growers from the Gwydir and Darling Downs districts who participated in the Mepiquat Chloride responses in XtendFlex® varieties project.
Project status
- In progress
Contact
Stuart McFadgen
Extension and Development Agronomist – Gwydir
Cotton Seed Distributors
smcfadgen@csd.net.au
© Cotton Seed Distributors Ltd 2025. General guide only; not comprehensive or specific technical advice. Circumstances vary from farm to farm. To the fullest extent permitted by law, CSD expressly disclaims all liability for any loss or damage arising from reliance upon any information, statement or opinion in this document or from any errors or omissions in this document. ThryvOn™, XtendFlex®, Roundup Ready Flex®, Roundup Ready®, Bollgard II® and Bollgard® 3 are registered trademarks of Monsanto Technologies LLC, used under licence by Monsanto Australia Ltd. Insect control technology incorporated into these seeds is commercialised under a licence from Syngenta Crop Protection AG. Sicot, Sicala, Siokra and Sipima cotton varieties are a result of a joint venture research program, Cotton Breeding Australia, conducted by CSIRO and Cotton Seed Distributors Ltd (CSD). CSD is a partner in the CottonInfo joint venture, in partnership with Cotton Research Development Corporation and Cotton Australia.